Merge branch 'master' into makefile_ruby_version_fixes

340 files changed, 8194 insertions, 4999 deletions

diff --git a/src/google_benchmark/gen_build_yaml.py b/src/benchmark/gen_build_yaml.py
index 302e08737a..09b76115a8 100755
--- a/src/google_benchmark/gen_build_yaml.py
+++ b/src/benchmark/gen_build_yaml.py
@@ -39,15 +39,15 @@ os.chdir(os.path.dirname(sys.argv[0])+'/../..')
 out = {}
 
 out['libs'] = [{
-    'name': 'google_benchmark',
+    'name': 'benchmark',
     'build': 'private',
     'language': 'c++',
     'secure': 'no',
-    'defaults': 'google_benchmark',
-    'src': sorted(glob.glob('third_party/google_benchmark/src/*.cc')),
+    'defaults': 'benchmark',
+    'src': sorted(glob.glob('third_party/benchmark/src/*.cc')),
     'headers': sorted(
-        glob.glob('third_party/google_benchmark/src/*.h') +
-        glob.glob('third_party/google_benchmark/include/benchmark/*.h')),
+        glob.glob('third_party/benchmark/src/*.h') +
+        glob.glob('third_party/benchmark/include/benchmark/*.h')),
 }]
 
 print yaml.dump(out)
diff --git a/src/compiler/csharp_generator.cc b/src/compiler/csharp_generator.cc
index a3af258d9c..cc7a7a96ae 100644
--- a/src/compiler/csharp_generator.cc
+++ b/src/compiler/csharp_generator.cc
@@ -68,13 +68,13 @@ namespace {
 // Currently, we cannot easily reuse the functionality as
 // google/protobuf/compiler/csharp/csharp_doc_comment.h is not a public header.
 // TODO(jtattermusch): reuse the functionality from google/protobuf.
-void GenerateDocCommentBodyImpl(grpc::protobuf::io::Printer *printer,
+bool GenerateDocCommentBodyImpl(grpc::protobuf::io::Printer *printer,
                                 grpc::protobuf::SourceLocation location) {
   grpc::string comments = location.leading_comments.empty()
                               ? location.trailing_comments
                               : location.leading_comments;
   if (comments.empty()) {
-    return;
+    return false;
   }
   // XML escaping... no need for apostrophes etc as the whole text is going to
   // be a child
@@ -107,18 +107,84 @@ void GenerateDocCommentBodyImpl(grpc::protobuf::io::Printer *printer,
         printer->Print("///\n");
       }
       last_was_empty = false;
-      printer->Print("/// $line$\n", "line", *it);
+      printer->Print("///$line$\n", "line", *it);
     }
   }
   printer->Print("/// </summary>\n");
+  return true;
 }
 
 template <typename DescriptorType>
-void GenerateDocCommentBody(grpc::protobuf::io::Printer *printer,
+bool GenerateDocCommentBody(grpc::protobuf::io::Printer *printer,
                             const DescriptorType *descriptor) {
   grpc::protobuf::SourceLocation location;
-  if (descriptor->GetSourceLocation(&location)) {
-    GenerateDocCommentBodyImpl(printer, location);
+  if (!descriptor->GetSourceLocation(&location)) {
+    return false;
+  }
+  return GenerateDocCommentBodyImpl(printer, location);
+}
+
+void GenerateDocCommentServerMethod(grpc::protobuf::io::Printer *printer,
+                                    const MethodDescriptor *method) {
+  if (GenerateDocCommentBody(printer, method)) {
+    if (method->client_streaming()) {
+      printer->Print(
+          "/// <param name=\"requestStream\">Used for reading requests from "
+          "the client.</param>\n");
+    } else {
+      printer->Print(
+          "/// <param name=\"request\">The request received from the "
+          "client.</param>\n");
+    }
+    if (method->server_streaming()) {
+      printer->Print(
+          "/// <param name=\"responseStream\">Used for sending responses back "
+          "to the client.</param>\n");
+    }
+    printer->Print(
+        "/// <param name=\"context\">The context of the server-side call "
+        "handler being invoked.</param>\n");
+    if (method->server_streaming()) {
+      printer->Print(
+          "/// <returns>A task indicating completion of the "
+          "handler.</returns>\n");
+    } else {
+      printer->Print(
+          "/// <returns>The response to send back to the client (wrapped by a "
+          "task).</returns>\n");
+    }
+  }
+}
+
+void GenerateDocCommentClientMethod(grpc::protobuf::io::Printer *printer,
+                                    const MethodDescriptor *method,
+                                    bool is_sync, bool use_call_options) {
+  if (GenerateDocCommentBody(printer, method)) {
+    if (!method->client_streaming()) {
+      printer->Print(
+          "/// <param name=\"request\">The request to send to the "
+          "server.</param>\n");
+    }
+    if (!use_call_options) {
+      printer->Print(
+          "/// <param name=\"headers\">The initial metadata to send with the "
+          "call. This parameter is optional.</param>\n");
+      printer->Print(
+          "/// <param name=\"deadline\">An optional deadline for the call. The "
+          "call will be cancelled if deadline is hit.</param>\n");
+      printer->Print(
+          "/// <param name=\"cancellationToken\">An optional token for "
+          "canceling the call.</param>\n");
+    } else {
+      printer->Print(
+          "/// <param name=\"options\">The options for the call.</param>\n");
+    }
+    if (is_sync) {
+      printer->Print(
+          "/// <returns>The response received from the server.</returns>\n");
+    } else {
+      printer->Print("/// <returns>The call object.</returns>\n");
+    }
   }
 }
 
@@ -319,7 +385,7 @@ void GenerateServerClass(Printer *out, const ServiceDescriptor *service) {
   out->Indent();
   for (int i = 0; i < service->method_count(); i++) {
     const MethodDescriptor *method = service->method(i);
-    GenerateDocCommentBody(out, method);
+    GenerateDocCommentServerMethod(out, method);
     out->Print(
         "public virtual $returntype$ "
         "$methodname$($request$$response_stream_maybe$, "
@@ -393,7 +459,7 @@ void GenerateClientStub(Printer *out, const ServiceDescriptor *service) {
 
     if (method_type == METHODTYPE_NO_STREAMING) {
       // unary calls have an extra synchronous stub method
-      GenerateDocCommentBody(out, method);
+      GenerateDocCommentClientMethod(out, method, true, false);
       out->Print(
           "public virtual $response$ $methodname$($request$ request, Metadata "
           "headers = null, DateTime? deadline = null, CancellationToken "
@@ -411,7 +477,7 @@ void GenerateClientStub(Printer *out, const ServiceDescriptor *service) {
       out->Print("}\n");
 
       // overload taking CallOptions as a param
-      GenerateDocCommentBody(out, method);
+      GenerateDocCommentClientMethod(out, method, true, true);
       out->Print(
           "public virtual $response$ $methodname$($request$ request, "
           "CallOptions options)\n",
@@ -432,7 +498,7 @@ void GenerateClientStub(Printer *out, const ServiceDescriptor *service) {
     if (method_type == METHODTYPE_NO_STREAMING) {
       method_name += "Async";  // prevent name clash with synchronous method.
     }
-    GenerateDocCommentBody(out, method);
+    GenerateDocCommentClientMethod(out, method, false, false);
     out->Print(
         "public virtual $returntype$ $methodname$($request_maybe$Metadata "
         "headers = null, DateTime? deadline = null, CancellationToken "
@@ -452,7 +518,7 @@ void GenerateClientStub(Printer *out, const ServiceDescriptor *service) {
     out->Print("}\n");
 
     // overload taking CallOptions as a param
-    GenerateDocCommentBody(out, method);
+    GenerateDocCommentClientMethod(out, method, false, true);
     out->Print(
         "public virtual $returntype$ $methodname$($request_maybe$CallOptions "
         "options)\n",
@@ -518,6 +584,9 @@ void GenerateBindServiceMethod(Printer *out, const ServiceDescriptor *service) {
       "/// <summary>Creates service definition that can be registered with a "
       "server</summary>\n");
   out->Print(
+      "/// <param name=\"serviceImpl\">An object implementing the server-side"
+      " handling logic.</param>\n");
+  out->Print(
       "public static ServerServiceDefinition BindService($implclass$ "
       "serviceImpl)\n",
       "implclass", GetServerClassName(service));
diff --git a/src/compiler/python_generator.cc b/src/compiler/python_generator.cc
index febaf135b6..4841da8da8 100644
--- a/src/compiler/python_generator.cc
+++ b/src/compiler/python_generator.cc
@@ -40,6 +40,7 @@
 #include <map>
 #include <memory>
 #include <ostream>
+#include <set>
 #include <sstream>
 #include <tuple>
 #include <vector>
@@ -64,7 +65,9 @@ using std::make_pair;
 using std::map;
 using std::pair;
 using std::replace;
+using std::tuple;
 using std::vector;
+using std::set;
 
 namespace grpc_python_generator {
 
@@ -73,6 +76,8 @@ namespace {
 typedef vector<const Descriptor*> DescriptorVector;
 typedef map<grpc::string, grpc::string> StringMap;
 typedef vector<grpc::string> StringVector;
+typedef tuple<grpc::string, grpc::string> StringPair;
+typedef set<StringPair> StringPairSet;
 
 // Provides RAII indentation handling. Use as:
 // {
@@ -651,6 +656,7 @@ bool PrivateGenerator::PrintPreamble() {
       "face_utilities\n");
   if (generate_in_pb2_grpc) {
     out->Print("\n");
+    StringPairSet imports_set;
     for (int i = 0; i < file->service_count(); ++i) {
       const ServiceDescriptor* service = file->service(i);
       for (int j = 0; j < service->method_count(); ++j) {
@@ -662,11 +668,15 @@ bool PrivateGenerator::PrintPreamble() {
           grpc::string type_file_name = type->file()->name();
           grpc::string module_name = ModuleName(type_file_name);
           grpc::string module_alias = ModuleAlias(type_file_name);
-          out->Print("import $ModuleName$ as $ModuleAlias$\n", "ModuleName",
-                     module_name, "ModuleAlias", module_alias);
+          imports_set.insert(std::make_tuple(module_name, module_alias));
         }
       }
     }
+    for (StringPairSet::iterator it = imports_set.begin();
+         it != imports_set.end(); ++it) {
+      out->Print("import $ModuleName$ as $ModuleAlias$\n", "ModuleName",
+                 std::get<0>(*it), "ModuleAlias", std::get<1>(*it));
+    }
   }
   return true;
 }
@@ -714,6 +724,9 @@ pair<bool, grpc::string> PrivateGenerator::GetGrpcServices() {
     out = &out_printer;
 
     if (generate_in_pb2_grpc) {
+      out->Print(
+          "# Generated by the gRPC Python protocol compiler plugin. "
+          "DO NOT EDIT!\n");
       if (!PrintPreamble()) {
         return make_pair(false, "");
       }
@@ -760,6 +773,32 @@ PythonGrpcGenerator::PythonGrpcGenerator(const GeneratorConfiguration& config)
 
 PythonGrpcGenerator::~PythonGrpcGenerator() {}
 
+static bool GenerateGrpc(GeneratorContext* context, PrivateGenerator& generator,
+                         grpc::string file_name, bool generate_in_pb2_grpc) {
+  bool success;
+  std::unique_ptr<ZeroCopyOutputStream> output;
+  std::unique_ptr<CodedOutputStream> coded_output;
+  grpc::string grpc_code;
+
+  if (generate_in_pb2_grpc) {
+    output.reset(context->Open(file_name));
+    generator.generate_in_pb2_grpc = true;
+  } else {
+    output.reset(context->OpenForInsert(file_name, "module_scope"));
+    generator.generate_in_pb2_grpc = false;
+  }
+
+  coded_output.reset(new CodedOutputStream(output.get()));
+  tie(success, grpc_code) = generator.GetGrpcServices();
+
+  if (success) {
+    coded_output->WriteRaw(grpc_code.data(), grpc_code.size());
+    return true;
+  } else {
+    return false;
+  }
+}
+
 bool PythonGrpcGenerator::Generate(const FileDescriptor* file,
                                    const grpc::string& parameter,
                                    GeneratorContext* context,
@@ -780,28 +819,15 @@ bool PythonGrpcGenerator::Generate(const FileDescriptor* file,
   }
 
   PrivateGenerator generator(config_, file);
-
-  std::unique_ptr<ZeroCopyOutputStream> pb2_output(
-      context->OpenForAppend(pb2_file_name));
-  std::unique_ptr<ZeroCopyOutputStream> grpc_output(
-      context->Open(pb2_grpc_file_name));
-  CodedOutputStream pb2_coded_out(pb2_output.get());
-  CodedOutputStream grpc_coded_out(grpc_output.get());
-  bool success = false;
-  grpc::string pb2_code;
-  grpc::string grpc_code;
-  generator.generate_in_pb2_grpc = false;
-  tie(success, pb2_code) = generator.GetGrpcServices();
-  if (success) {
-    generator.generate_in_pb2_grpc = true;
-    tie(success, grpc_code) = generator.GetGrpcServices();
-    if (success) {
-      pb2_coded_out.WriteRaw(pb2_code.data(), pb2_code.size());
-      grpc_coded_out.WriteRaw(grpc_code.data(), grpc_code.size());
-      return true;
-    }
+  if (parameter == "grpc_2_0") {
+    return GenerateGrpc(context, generator, pb2_grpc_file_name, true);
+  } else if (parameter == "") {
+    return GenerateGrpc(context, generator, pb2_grpc_file_name, true) &&
+           GenerateGrpc(context, generator, pb2_file_name, false);
+  } else {
+    *error = "Invalid parameter '" + parameter + "'.";
+    return false;
   }
-  return false;
 }
 
 }  // namespace grpc_python_generator
diff --git a/src/core/ext/README.md b/src/core/ext/README.md
new file mode 100644
index 0000000000..0812b20823
--- /dev/null
+++ b/src/core/ext/README.md
@@ -0,0 +1,5 @@
+Optional plugins for gRPC Core: Modules in this directory extend gRPC Core in
+useful ways. All optional code belongs here.
+
+NOTE: The movement of code between lib and ext is an ongoing effort, so this
+directory currently contains too much of the core library.
diff --git a/src/core/ext/census/grpc_filter.c b/src/core/ext/census/grpc_filter.c
index 397dbc40a8..8e4d4732b8 100644
--- a/src/core/ext/census/grpc_filter.c
+++ b/src/core/ext/census/grpc_filter.c
@@ -154,7 +154,8 @@ static grpc_error *server_init_call_elem(grpc_exec_ctx *exec_ctx,
   memset(d, 0, sizeof(*d));
   d->start_ts = args->start_time;
   /* TODO(hongyu): call census_tracing_start_op here. */
-  grpc_closure_init(&d->finish_recv, server_on_done_recv, elem);
+  grpc_closure_init(&d->finish_recv, server_on_done_recv, elem,
+                    grpc_schedule_on_exec_ctx);
   return GRPC_ERROR_NONE;
 }
 
@@ -167,11 +168,12 @@ static void server_destroy_call_elem(grpc_exec_ctx *exec_ctx,
   /* TODO(hongyu): record rpc server stats and census_tracing_end_op here */
 }
 
-static void init_channel_elem(grpc_exec_ctx *exec_ctx,
-                              grpc_channel_element *elem,
-                              grpc_channel_element_args *args) {
+static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
+                                     grpc_channel_element *elem,
+                                     grpc_channel_element_args *args) {
   channel_data *chand = elem->channel_data;
   GPR_ASSERT(chand != NULL);
+  return GRPC_ERROR_NONE;
 }
 
 static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
diff --git a/src/core/ext/census/grpc_plugin.c b/src/core/ext/census/grpc_plugin.c
index e43ceafd0c..c9fe453af8 100644
--- a/src/core/ext/census/grpc_plugin.c
+++ b/src/core/ext/census/grpc_plugin.c
@@ -51,7 +51,8 @@ static bool is_census_enabled(const grpc_channel_args *a) {
   return census_enabled();
 }
 
-static bool maybe_add_census_filter(grpc_channel_stack_builder *builder,
+static bool maybe_add_census_filter(grpc_exec_ctx *exec_ctx,
+                                    grpc_channel_stack_builder *builder,
                                     void *arg) {
   const grpc_channel_args *args =
       grpc_channel_stack_builder_get_channel_arguments(builder);
diff --git a/src/core/ext/census/tracing.c b/src/core/ext/census/tracing.c
index 51508b00ef..afb70441d2 100644
--- a/src/core/ext/census/tracing.c
+++ b/src/core/ext/census/tracing.c
@@ -34,7 +34,6 @@
 //#include "src/core/ext/census/tracing.h"
 
 #include <stdlib.h>
-
 #include <grpc/census.h>
 
 /* TODO(aveitch): These are all placeholder implementations. */
@@ -50,5 +49,3 @@ void census_trace_print(census_context *context, uint32_t type,
                         const char *buffer, size_t n) {
   abort();
 }
-
-// void SetTracerParams(const Params& params);
diff --git a/src/core/ext/client_channel/channel_connectivity.c b/src/core/ext/client_channel/channel_connectivity.c
index 9797e66564..dd70bc2c6c 100644
--- a/src/core/ext/client_channel/channel_connectivity.c
+++ b/src/core/ext/client_channel/channel_connectivity.c
@@ -76,6 +76,7 @@ typedef struct {
   gpr_mu mu;
   callback_phase phase;
   grpc_closure on_complete;
+  grpc_closure on_timeout;
   grpc_timer alarm;
   grpc_connectivity_state state;
   grpc_completion_queue *cq;
@@ -198,7 +199,10 @@ void grpc_channel_watch_connectivity_state(
   grpc_cq_begin_op(cq, tag);
 
   gpr_mu_init(&w->mu);
-  grpc_closure_init(&w->on_complete, watch_complete, w);
+  grpc_closure_init(&w->on_complete, watch_complete, w,
+                    grpc_schedule_on_exec_ctx);
+  grpc_closure_init(&w->on_timeout, timeout_complete, w,
+                    grpc_schedule_on_exec_ctx);
   w->phase = WAITING;
   w->state = last_observed_state;
   w->cq = cq;
@@ -207,7 +211,7 @@ void grpc_channel_watch_connectivity_state(
 
   grpc_timer_init(&exec_ctx, &w->alarm,
                   gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC),
-                  timeout_complete, w, gpr_now(GPR_CLOCK_MONOTONIC));
+                  &w->on_timeout, gpr_now(GPR_CLOCK_MONOTONIC));
 
   if (client_channel_elem->filter == &grpc_client_channel_filter) {
     GRPC_CHANNEL_INTERNAL_REF(channel, "watch_channel_connectivity");
diff --git a/src/core/ext/client_channel/client_channel.c b/src/core/ext/client_channel/client_channel.c
index 1fcff4388a..2f25fef9a7 100644
--- a/src/core/ext/client_channel/client_channel.c
+++ b/src/core/ext/client_channel/client_channel.c
@@ -44,6 +44,7 @@
 #include <grpc/support/useful.h>
 
 #include "src/core/ext/client_channel/lb_policy_registry.h"
+#include "src/core/ext/client_channel/resolver_registry.h"
 #include "src/core/ext/client_channel/subchannel.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/connected_channel.h"
@@ -82,8 +83,12 @@ static void *method_parameters_copy(void *value) {
   return new_value;
 }
 
+static void method_parameters_free(grpc_exec_ctx *exec_ctx, void *p) {
+  gpr_free(p);
+}
+
 static const grpc_mdstr_hash_table_vtable method_parameters_vtable = {
-    gpr_free, method_parameters_copy};
+    method_parameters_free, method_parameters_copy};
 
 static void *method_parameters_create_from_json(const grpc_json *json) {
   wait_for_ready_value wait_for_ready = WAIT_FOR_READY_UNSET;
@@ -248,7 +253,8 @@ static void watch_lb_policy(grpc_exec_ctx *exec_ctx, channel_data *chand,
   GRPC_CHANNEL_STACK_REF(chand->owning_stack, "watch_lb_policy");
 
   w->chand = chand;
-  grpc_closure_init(&w->on_changed, on_lb_policy_state_changed, w);
+  grpc_closure_init(&w->on_changed, on_lb_policy_state_changed, w,
+                    grpc_schedule_on_exec_ctx);
   w->state = current_state;
   w->lb_policy = lb_policy;
   grpc_lb_policy_notify_on_state_change(exec_ctx, lb_policy, &w->state,
@@ -326,7 +332,7 @@ static void on_resolver_result_changed(grpc_exec_ctx *exec_ctx, void *arg,
           grpc_service_config_create(service_config_json);
       if (service_config != NULL) {
         method_params_table = grpc_service_config_create_method_config_table(
-            service_config, method_parameters_create_from_json,
+            exec_ctx, service_config, method_parameters_create_from_json,
             &method_parameters_vtable);
         grpc_service_config_destroy(service_config);
       }
@@ -335,7 +341,7 @@ static void on_resolver_result_changed(grpc_exec_ctx *exec_ctx, void *arg,
     // be pointing to data inside chand->resolver_result.
     // The copy will be saved in chand->lb_policy_name below.
     lb_policy_name = gpr_strdup(lb_policy_name);
-    grpc_channel_args_destroy(chand->resolver_result);
+    grpc_channel_args_destroy(exec_ctx, chand->resolver_result);
     chand->resolver_result = NULL;
   }
 
@@ -356,18 +362,16 @@ static void on_resolver_result_changed(grpc_exec_ctx *exec_ctx, void *arg,
     chand->service_config_json = service_config_json;
   }
   if (chand->method_params_table != NULL) {
-    grpc_mdstr_hash_table_unref(chand->method_params_table);
+    grpc_mdstr_hash_table_unref(exec_ctx, chand->method_params_table);
   }
   chand->method_params_table = method_params_table;
   if (lb_policy != NULL) {
-    grpc_exec_ctx_enqueue_list(exec_ctx, &chand->waiting_for_config_closures,
-                               NULL);
+    grpc_closure_list_sched(exec_ctx, &chand->waiting_for_config_closures);
   } else if (chand->resolver == NULL /* disconnected */) {
     grpc_closure_list_fail_all(
         &chand->waiting_for_config_closures,
         GRPC_ERROR_CREATE_REFERENCING("Channel disconnected", &error, 1));
-    grpc_exec_ctx_enqueue_list(exec_ctx, &chand->waiting_for_config_closures,
-                               NULL);
+    grpc_closure_list_sched(exec_ctx, &chand->waiting_for_config_closures);
   }
   if (lb_policy != NULL && chand->exit_idle_when_lb_policy_arrives) {
     GRPC_LB_POLICY_REF(lb_policy, "exit_idle");
@@ -424,7 +428,7 @@ static void cc_start_transport_op(grpc_exec_ctx *exec_ctx,
                                   grpc_transport_op *op) {
   channel_data *chand = elem->channel_data;
 
-  grpc_exec_ctx_sched(exec_ctx, op->on_consumed, GRPC_ERROR_NONE, NULL);
+  grpc_closure_sched(exec_ctx, op->on_consumed, GRPC_ERROR_NONE);
 
   GPR_ASSERT(op->set_accept_stream == false);
   if (op->bind_pollset != NULL) {
@@ -443,9 +447,8 @@ static void cc_start_transport_op(grpc_exec_ctx *exec_ctx,
 
   if (op->send_ping != NULL) {
     if (chand->lb_policy == NULL) {
-      grpc_exec_ctx_sched(exec_ctx, op->send_ping,
-                          GRPC_ERROR_CREATE("Ping with no load balancing"),
-                          NULL);
+      grpc_closure_sched(exec_ctx, op->send_ping,
+                         GRPC_ERROR_CREATE("Ping with no load balancing"));
     } else {
       grpc_lb_policy_ping_one(exec_ctx, chand->lb_policy, op->send_ping);
       op->bind_pollset = NULL;
@@ -464,8 +467,7 @@ static void cc_start_transport_op(grpc_exec_ctx *exec_ctx,
       if (!chand->started_resolving) {
         grpc_closure_list_fail_all(&chand->waiting_for_config_closures,
                                    GRPC_ERROR_REF(op->disconnect_with_error));
-        grpc_exec_ctx_enqueue_list(exec_ctx,
-                                   &chand->waiting_for_config_closures, NULL);
+        grpc_closure_list_sched(exec_ctx, &chand->waiting_for_config_closures);
       }
       if (chand->lb_policy != NULL) {
         grpc_pollset_set_del_pollset_set(exec_ctx,
@@ -499,24 +501,40 @@ static void cc_get_channel_info(grpc_exec_ctx *exec_ctx,
 }
 
 /* Constructor for channel_data */
-static void cc_init_channel_elem(grpc_exec_ctx *exec_ctx,
-                                 grpc_channel_element *elem,
-                                 grpc_channel_element_args *args) {
+static grpc_error *cc_init_channel_elem(grpc_exec_ctx *exec_ctx,
+                                        grpc_channel_element *elem,
+                                        grpc_channel_element_args *args) {
   channel_data *chand = elem->channel_data;
-
   memset(chand, 0, sizeof(*chand));
-
   GPR_ASSERT(args->is_last);
   GPR_ASSERT(elem->filter == &grpc_client_channel_filter);
-
+  // Initialize data members.
   gpr_mu_init(&chand->mu);
-  grpc_closure_init(&chand->on_resolver_result_changed,
-                    on_resolver_result_changed, chand);
   chand->owning_stack = args->channel_stack;
-
+  grpc_closure_init(&chand->on_resolver_result_changed,
+                    on_resolver_result_changed, chand,
+                    grpc_schedule_on_exec_ctx);
+  chand->interested_parties = grpc_pollset_set_create();
   grpc_connectivity_state_init(&chand->state_tracker, GRPC_CHANNEL_IDLE,
                                "client_channel");
-  chand->interested_parties = grpc_pollset_set_create();
+  // Record client channel factory.
+  const grpc_arg *arg = grpc_channel_args_find(args->channel_args,
+                                               GRPC_ARG_CLIENT_CHANNEL_FACTORY);
+  GPR_ASSERT(arg != NULL);
+  GPR_ASSERT(arg->type == GRPC_ARG_POINTER);
+  grpc_client_channel_factory_ref(arg->value.pointer.p);
+  chand->client_channel_factory = arg->value.pointer.p;
+  // Instantiate resolver.
+  arg = grpc_channel_args_find(args->channel_args, GRPC_ARG_SERVER_URI);
+  GPR_ASSERT(arg != NULL);
+  GPR_ASSERT(arg->type == GRPC_ARG_STRING);
+  chand->resolver =
+      grpc_resolver_create(exec_ctx, arg->value.string, args->channel_args,
+                           chand->interested_parties);
+  if (chand->resolver == NULL) {
+    return GRPC_ERROR_CREATE("resolver creation failed");
+  }
+  return GRPC_ERROR_NONE;
 }
 
 /* Destructor for channel_data */
@@ -540,7 +558,7 @@ static void cc_destroy_channel_elem(grpc_exec_ctx *exec_ctx,
   gpr_free(chand->lb_policy_name);
   gpr_free(chand->service_config_json);
   if (chand->method_params_table != NULL) {
-    grpc_mdstr_hash_table_unref(chand->method_params_table);
+    grpc_mdstr_hash_table_unref(exec_ctx, chand->method_params_table);
   }
   grpc_connectivity_state_destroy(exec_ctx, &chand->state_tracker);
   grpc_pollset_set_destroy(chand->interested_parties);
@@ -662,8 +680,9 @@ static void retry_waiting_locked(grpc_exec_ctx *exec_ctx, call_data *calld) {
   calld->waiting_ops_count = 0;
   calld->waiting_ops_capacity = 0;
   GRPC_SUBCHANNEL_CALL_REF(a->call, "retry_ops");
-  grpc_exec_ctx_sched(exec_ctx, grpc_closure_create(retry_ops, a),
-                      GRPC_ERROR_NONE, NULL);
+  grpc_closure_sched(
+      exec_ctx, grpc_closure_create(retry_ops, a, grpc_schedule_on_exec_ctx),
+      GRPC_ERROR_NONE);
 }
 
 static void subchannel_ready(grpc_exec_ctx *exec_ctx, void *arg,
@@ -683,9 +702,15 @@ static void subchannel_ready(grpc_exec_ctx *exec_ctx, void *arg,
                                      "Failed to create subchannel", &error, 1));
   } else if (GET_CALL(calld) == CANCELLED_CALL) {
     /* already cancelled before subchannel became ready */
-    fail_locked(exec_ctx, calld,
-                GRPC_ERROR_CREATE_REFERENCING(
-                    "Cancelled before creating subchannel", &error, 1));
+    grpc_error *cancellation_error = GRPC_ERROR_CREATE_REFERENCING(
+        "Cancelled before creating subchannel", &error, 1);
+    /* if due to deadline, attach the deadline exceeded status to the error */
+    if (gpr_time_cmp(calld->deadline, gpr_now(GPR_CLOCK_MONOTONIC)) < 0) {
+      cancellation_error =
+          grpc_error_set_int(cancellation_error, GRPC_ERROR_INT_GRPC_STATUS,
+                             GRPC_STATUS_DEADLINE_EXCEEDED);
+    }
+    fail_locked(exec_ctx, calld, cancellation_error);
   } else {
     /* Create call on subchannel. */
     grpc_subchannel_call *subchannel_call = NULL;
@@ -739,14 +764,14 @@ static void continue_picking(grpc_exec_ctx *exec_ctx, void *arg,
   if (cpa->connected_subchannel == NULL) {
     /* cancelled, do nothing */
   } else if (error != GRPC_ERROR_NONE) {
-    grpc_exec_ctx_sched(exec_ctx, cpa->on_ready, GRPC_ERROR_REF(error), NULL);
+    grpc_closure_sched(exec_ctx, cpa->on_ready, GRPC_ERROR_REF(error));
   } else {
     call_data *calld = cpa->elem->call_data;
     gpr_mu_lock(&calld->mu);
     if (pick_subchannel(exec_ctx, cpa->elem, cpa->initial_metadata,
                         cpa->initial_metadata_flags, cpa->connected_subchannel,
                         cpa->on_ready, GRPC_ERROR_NONE)) {
-      grpc_exec_ctx_sched(exec_ctx, cpa->on_ready, GRPC_ERROR_NONE, NULL);
+      grpc_closure_sched(exec_ctx, cpa->on_ready, GRPC_ERROR_NONE);
     }
     gpr_mu_unlock(&calld->mu);
   }
@@ -778,9 +803,9 @@ static bool pick_subchannel(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
       cpa = closure->cb_arg;
       if (cpa->connected_subchannel == connected_subchannel) {
         cpa->connected_subchannel = NULL;
-        grpc_exec_ctx_sched(
+        grpc_closure_sched(
             exec_ctx, cpa->on_ready,
-            GRPC_ERROR_CREATE_REFERENCING("Pick cancelled", &error, 1), NULL);
+            GRPC_ERROR_CREATE_REFERENCING("Pick cancelled", &error, 1));
       }
     }
     gpr_mu_unlock(&chand->mu);
@@ -809,7 +834,6 @@ static bool pick_subchannel(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
         initial_metadata_flags &= ~GRPC_INITIAL_METADATA_WAIT_FOR_READY;
       }
     }
-    // TODO(dgq): make this deadline configurable somehow.
     const grpc_lb_policy_pick_args inputs = {
         initial_metadata, initial_metadata_flags, &calld->lb_token_mdelem,
         gpr_inf_future(GPR_CLOCK_MONOTONIC)};
@@ -832,12 +856,12 @@ static bool pick_subchannel(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
     cpa->connected_subchannel = connected_subchannel;
     cpa->on_ready = on_ready;
     cpa->elem = elem;
-    grpc_closure_init(&cpa->closure, continue_picking, cpa);
+    grpc_closure_init(&cpa->closure, continue_picking, cpa,
+                      grpc_schedule_on_exec_ctx);
     grpc_closure_list_append(&chand->waiting_for_config_closures, &cpa->closure,
                              GRPC_ERROR_NONE);
   } else {
-    grpc_exec_ctx_sched(exec_ctx, on_ready, GRPC_ERROR_CREATE("Disconnected"),
-                        NULL);
+    grpc_closure_sched(exec_ctx, on_ready, GRPC_ERROR_CREATE("Disconnected"));
   }
   gpr_mu_unlock(&chand->mu);
 
@@ -922,7 +946,8 @@ retry:
       calld->connected_subchannel == NULL &&
       op->send_initial_metadata != NULL) {
     calld->creation_phase = GRPC_SUBCHANNEL_CALL_HOLDER_PICKING_SUBCHANNEL;
-    grpc_closure_init(&calld->next_step, subchannel_ready, elem);
+    grpc_closure_init(&calld->next_step, subchannel_ready, elem,
+                      grpc_schedule_on_exec_ctx);
     GRPC_CALL_STACK_REF(calld->owning_call, "pick_subchannel");
     /* If a subchannel is not available immediately, the polling entity from
        call_data should be provided to channel_data's interested_parties, so
@@ -980,8 +1005,8 @@ static void read_service_config(grpc_exec_ctx *exec_ctx, void *arg,
     gpr_mu_unlock(&chand->mu);
     // If the method config table was present, use it.
     if (method_params_table != NULL) {
-      const method_parameters *method_params =
-          grpc_method_config_table_get(method_params_table, calld->path);
+      const method_parameters *method_params = grpc_method_config_table_get(
+          exec_ctx, method_params_table, calld->path);
       if (method_params != NULL) {
         const bool have_method_timeout =
             gpr_time_cmp(method_params->timeout, gpr_time_0(GPR_TIMESPAN)) != 0;
@@ -1004,7 +1029,7 @@ static void read_service_config(grpc_exec_ctx *exec_ctx, void *arg,
           gpr_mu_unlock(&calld->mu);
         }
       }
-      grpc_mdstr_hash_table_unref(method_params_table);
+      grpc_mdstr_hash_table_unref(exec_ctx, method_params_table);
     }
   }
   GRPC_CALL_STACK_UNREF(exec_ctx, calld->owning_call, "read_service_config");
@@ -1045,8 +1070,8 @@ static grpc_error *cc_init_call_elem(grpc_exec_ctx *exec_ctx,
       grpc_mdstr_hash_table *method_params_table =
           grpc_mdstr_hash_table_ref(chand->method_params_table);
       gpr_mu_unlock(&chand->mu);
-      method_parameters *method_params =
-          grpc_method_config_table_get(method_params_table, args->path);
+      method_parameters *method_params = grpc_method_config_table_get(
+          exec_ctx, method_params_table, args->path);
       if (method_params != NULL) {
         if (gpr_time_cmp(method_params->timeout,
                          gpr_time_0(GPR_CLOCK_MONOTONIC)) != 0) {
@@ -1059,7 +1084,7 @@ static grpc_error *cc_init_call_elem(grpc_exec_ctx *exec_ctx,
               method_params->wait_for_ready;
         }
       }
-      grpc_mdstr_hash_table_unref(method_params_table);
+      grpc_mdstr_hash_table_unref(exec_ctx, method_params_table);
     } else {
       gpr_mu_unlock(&chand->mu);
     }
@@ -1068,7 +1093,8 @@ static grpc_error *cc_init_call_elem(grpc_exec_ctx *exec_ctx,
     // get the service config data once the resolver returns.
     // Take a reference to the call stack to be owned by the callback.
     GRPC_CALL_STACK_REF(calld->owning_call, "read_service_config");
-    grpc_closure_init(&calld->read_service_config, read_service_config, elem);
+    grpc_closure_init(&calld->read_service_config, read_service_config, elem,
+                      grpc_schedule_on_exec_ctx);
     grpc_closure_list_append(&chand->waiting_for_config_closures,
                              &calld->read_service_config, GRPC_ERROR_NONE);
     gpr_mu_unlock(&chand->mu);
@@ -1087,7 +1113,7 @@ static void cc_destroy_call_elem(grpc_exec_ctx *exec_ctx,
                                  void *and_free_memory) {
   call_data *calld = elem->call_data;
   grpc_deadline_state_destroy(exec_ctx, elem);
-  GRPC_MDSTR_UNREF(calld->path);
+  GRPC_MDSTR_UNREF(exec_ctx, calld->path);
   GRPC_ERROR_UNREF(calld->cancel_error);
   grpc_subchannel_call *call = GET_CALL(calld);
   if (call != NULL && call != CANCELLED_CALL) {
@@ -1130,30 +1156,6 @@ const grpc_channel_filter grpc_client_channel_filter = {
     "client-channel",
 };
 
-void grpc_client_channel_finish_initialization(
-    grpc_exec_ctx *exec_ctx, grpc_channel_stack *channel_stack,
-    grpc_resolver *resolver,
-    grpc_client_channel_factory *client_channel_factory) {
-  /* post construction initialization: set the transport setup pointer */
-  GPR_ASSERT(client_channel_factory != NULL);
-  grpc_channel_element *elem = grpc_channel_stack_last_element(channel_stack);
-  channel_data *chand = elem->channel_data;
-  gpr_mu_lock(&chand->mu);
-  GPR_ASSERT(!chand->resolver);
-  chand->resolver = resolver;
-  GRPC_RESOLVER_REF(resolver, "channel");
-  if (!grpc_closure_list_empty(chand->waiting_for_config_closures) ||
-      chand->exit_idle_when_lb_policy_arrives) {
-    chand->started_resolving = true;
-    GRPC_CHANNEL_STACK_REF(chand->owning_stack, "resolver");
-    grpc_resolver_next(exec_ctx, resolver, &chand->resolver_result,
-                       &chand->on_resolver_result_changed);
-  }
-  chand->client_channel_factory = client_channel_factory;
-  grpc_client_channel_factory_ref(client_channel_factory);
-  gpr_mu_unlock(&chand->mu);
-}
-
 grpc_connectivity_state grpc_client_channel_check_connectivity_state(
     grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, int try_to_connect) {
   channel_data *chand = elem->channel_data;
@@ -1205,7 +1207,8 @@ void grpc_client_channel_watch_connectivity_state(
   w->pollset = pollset;
   w->on_complete = on_complete;
   grpc_pollset_set_add_pollset(exec_ctx, chand->interested_parties, pollset);
-  grpc_closure_init(&w->my_closure, on_external_watch_complete, w);
+  grpc_closure_init(&w->my_closure, on_external_watch_complete, w,
+                    grpc_schedule_on_exec_ctx);
   GRPC_CHANNEL_STACK_REF(w->chand->owning_stack,
                          "external_connectivity_watcher");
   gpr_mu_lock(&chand->mu);
diff --git a/src/core/ext/client_channel/client_channel.h b/src/core/ext/client_channel/client_channel.h
index ab5a84fdfb..f02587d0c1 100644
--- a/src/core/ext/client_channel/client_channel.h
+++ b/src/core/ext/client_channel/client_channel.h
@@ -38,6 +38,9 @@
 #include "src/core/ext/client_channel/resolver.h"
 #include "src/core/lib/channel/channel_stack.h"
 
+// Channel arg key for server URI string.
+#define GRPC_ARG_SERVER_URI "grpc.server_uri"
+
 /* A client channel is a channel that begins disconnected, and can connect
    to some endpoint on demand. If that endpoint disconnects, it will be
    connected to again later.
@@ -47,13 +50,6 @@
 
 extern const grpc_channel_filter grpc_client_channel_filter;
 
-/* Post-construction initializer to give the client channel its resolver
-   and factory. */
-void grpc_client_channel_finish_initialization(
-    grpc_exec_ctx *exec_ctx, grpc_channel_stack *channel_stack,
-    grpc_resolver *resolver,
-    grpc_client_channel_factory *client_channel_factory);
-
 grpc_connectivity_state grpc_client_channel_check_connectivity_state(
     grpc_exec_ctx *exec_ctx, grpc_channel_element *elem, int try_to_connect);
 
diff --git a/src/core/ext/client_channel/client_channel_factory.c b/src/core/ext/client_channel/client_channel_factory.c
index 4900832d57..d2707a1556 100644
--- a/src/core/ext/client_channel/client_channel_factory.c
+++ b/src/core/ext/client_channel/client_channel_factory.c
@@ -55,3 +55,33 @@ grpc_channel* grpc_client_channel_factory_create_channel(
   return factory->vtable->create_client_channel(exec_ctx, factory, target, type,
                                                 args);
 }
+
+static void* factory_arg_copy(void* factory) {
+  grpc_client_channel_factory_ref(factory);
+  return factory;
+}
+
+static void factory_arg_destroy(grpc_exec_ctx* exec_ctx, void* factory) {
+  // TODO(roth): Remove local exec_ctx when
+  // https://github.com/grpc/grpc/pull/8705 is merged.
+  grpc_client_channel_factory_unref(exec_ctx, factory);
+}
+
+static int factory_arg_cmp(void* factory1, void* factory2) {
+  if (factory1 < factory2) return -1;
+  if (factory1 > factory2) return 1;
+  return 0;
+}
+
+static const grpc_arg_pointer_vtable factory_arg_vtable = {
+    factory_arg_copy, factory_arg_destroy, factory_arg_cmp};
+
+grpc_arg grpc_client_channel_factory_create_channel_arg(
+    grpc_client_channel_factory* factory) {
+  grpc_arg arg;
+  arg.type = GRPC_ARG_POINTER;
+  arg.key = GRPC_ARG_CLIENT_CHANNEL_FACTORY;
+  arg.value.pointer.p = factory;
+  arg.value.pointer.vtable = &factory_arg_vtable;
+  return arg;
+}
diff --git a/src/core/ext/client_channel/client_channel_factory.h b/src/core/ext/client_channel/client_channel_factory.h
index 2b8fc577b3..bf2764b537 100644
--- a/src/core/ext/client_channel/client_channel_factory.h
+++ b/src/core/ext/client_channel/client_channel_factory.h
@@ -39,6 +39,9 @@
 #include "src/core/ext/client_channel/subchannel.h"
 #include "src/core/lib/channel/channel_stack.h"
 
+// Channel arg key for client channel factory.
+#define GRPC_ARG_CLIENT_CHANNEL_FACTORY "grpc.client_channel_factory"
+
 typedef struct grpc_client_channel_factory grpc_client_channel_factory;
 typedef struct grpc_client_channel_factory_vtable
     grpc_client_channel_factory_vtable;
@@ -83,4 +86,7 @@ grpc_channel *grpc_client_channel_factory_create_channel(
     const char *target, grpc_client_channel_type type,
     const grpc_channel_args *args);
 
+grpc_arg grpc_client_channel_factory_create_channel_arg(
+    grpc_client_channel_factory *factory);
+
 #endif /* GRPC_CORE_EXT_CLIENT_CHANNEL_CLIENT_CHANNEL_FACTORY_H */
diff --git a/src/core/ext/client_channel/client_channel_plugin.c b/src/core/ext/client_channel/client_channel_plugin.c
index a3e5079843..d50bba60f6 100644
--- a/src/core/ext/client_channel/client_channel_plugin.c
+++ b/src/core/ext/client_channel/client_channel_plugin.c
@@ -38,17 +38,20 @@
 #include <grpc/support/alloc.h>
 
 #include "src/core/ext/client_channel/client_channel.h"
+#include "src/core/ext/client_channel/http_connect_handshaker.h"
 #include "src/core/ext/client_channel/lb_policy_registry.h"
 #include "src/core/ext/client_channel/resolver_registry.h"
 #include "src/core/ext/client_channel/subchannel_index.h"
 #include "src/core/lib/surface/channel_init.h"
 
-static bool append_filter(grpc_channel_stack_builder *builder, void *arg) {
+static bool append_filter(grpc_exec_ctx *exec_ctx,
+                          grpc_channel_stack_builder *builder, void *arg) {
   return grpc_channel_stack_builder_append_filter(
       builder, (const grpc_channel_filter *)arg, NULL, NULL);
 }
 
-static bool set_default_host_if_unset(grpc_channel_stack_builder *builder,
+static bool set_default_host_if_unset(grpc_exec_ctx *exec_ctx,
+                                      grpc_channel_stack_builder *builder,
                                       void *unused) {
   const grpc_channel_args *args =
       grpc_channel_stack_builder_get_channel_arguments(builder);
@@ -66,9 +69,10 @@ static bool set_default_host_if_unset(grpc_channel_stack_builder *builder,
     arg.key = GRPC_ARG_DEFAULT_AUTHORITY;
     arg.value.string = default_authority;
     grpc_channel_args *new_args = grpc_channel_args_copy_and_add(args, &arg, 1);
-    grpc_channel_stack_builder_set_channel_arguments(builder, new_args);
+    grpc_channel_stack_builder_set_channel_arguments(exec_ctx, builder,
+                                                     new_args);
     gpr_free(default_authority);
-    grpc_channel_args_destroy(new_args);
+    grpc_channel_args_destroy(exec_ctx, new_args);
   }
   return true;
 }
@@ -81,6 +85,7 @@ void grpc_client_channel_init(void) {
                                    set_default_host_if_unset, NULL);
   grpc_channel_init_register_stage(GRPC_CLIENT_CHANNEL, INT_MAX, append_filter,
                                    (void *)&grpc_client_channel_filter);
+  grpc_http_connect_register_handshaker_factory();
 }
 
 void grpc_client_channel_shutdown(void) {
diff --git a/src/core/ext/client_channel/http_connect_handshaker.c b/src/core/ext/client_channel/http_connect_handshaker.c
index 82042897b2..fba32561ac 100644
--- a/src/core/ext/client_channel/http_connect_handshaker.c
+++ b/src/core/ext/client_channel/http_connect_handshaker.c
@@ -40,10 +40,14 @@
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 
+#include "src/core/ext/client_channel/client_channel.h"
+#include "src/core/ext/client_channel/resolver_registry.h"
 #include "src/core/ext/client_channel/uri_parser.h"
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/channel/handshaker_registry.h"
 #include "src/core/lib/http/format_request.h"
 #include "src/core/lib/http/parser.h"
-#include "src/core/lib/iomgr/timer.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/support/env.h"
 
 typedef struct http_connect_handshaker {
@@ -51,60 +55,113 @@ typedef struct http_connect_handshaker {
   grpc_handshaker base;
 
   char* proxy_server;
-  char* server_name;
+  grpc_http_header* headers;
+  size_t num_headers;
+
+  gpr_refcount refcount;
+  gpr_mu mu;
+
+  bool shutdown;
+  // Endpoint and read buffer to destroy after a shutdown.
+  grpc_endpoint* endpoint_to_destroy;
+  grpc_slice_buffer* read_buffer_to_destroy;
 
   // State saved while performing the handshake.
-  grpc_endpoint* endpoint;
-  grpc_channel_args* args;
-  grpc_handshaker_done_cb cb;
-  void* user_data;
+  grpc_handshaker_args* args;
+  grpc_closure* on_handshake_done;
 
   // Objects for processing the HTTP CONNECT request and response.
   grpc_slice_buffer write_buffer;
-  grpc_slice_buffer* read_buffer;  // Ownership passes through this object.
   grpc_closure request_done_closure;
   grpc_closure response_read_closure;
   grpc_http_parser http_parser;
   grpc_http_response http_response;
-  grpc_timer timeout_timer;
-
-  gpr_refcount refcount;
 } http_connect_handshaker;
 
 // Unref and clean up handshaker.
-static void http_connect_handshaker_unref(http_connect_handshaker* handshaker) {
+static void http_connect_handshaker_unref(grpc_exec_ctx* exec_ctx,
+                                          http_connect_handshaker* handshaker) {
   if (gpr_unref(&handshaker->refcount)) {
+    gpr_mu_destroy(&handshaker->mu);
+    if (handshaker->endpoint_to_destroy != NULL) {
+      grpc_endpoint_destroy(exec_ctx, handshaker->endpoint_to_destroy);
+    }
+    if (handshaker->read_buffer_to_destroy != NULL) {
+      grpc_slice_buffer_destroy_internal(exec_ctx,
+                                         handshaker->read_buffer_to_destroy);
+      gpr_free(handshaker->read_buffer_to_destroy);
+    }
     gpr_free(handshaker->proxy_server);
-    gpr_free(handshaker->server_name);
-    grpc_slice_buffer_destroy(&handshaker->write_buffer);
+    for (size_t i = 0; i < handshaker->num_headers; ++i) {
+      gpr_free(handshaker->headers[i].key);
+      gpr_free(handshaker->headers[i].value);
+    }
+    gpr_free(handshaker->headers);
+    grpc_slice_buffer_destroy_internal(exec_ctx, &handshaker->write_buffer);
     grpc_http_parser_destroy(&handshaker->http_parser);
     grpc_http_response_destroy(&handshaker->http_response);
     gpr_free(handshaker);
   }
 }
 
-// Callback invoked when deadline is exceeded.
-static void on_timeout(grpc_exec_ctx* exec_ctx, void* arg, grpc_error* error) {
-  http_connect_handshaker* handshaker = arg;
-  if (error == GRPC_ERROR_NONE) {  // Timer fired, rather than being cancelled.
-    grpc_endpoint_shutdown(exec_ctx, handshaker->endpoint);
+// Set args fields to NULL, saving the endpoint and read buffer for
+// later destruction.
+static void cleanup_args_for_failure_locked(
+    grpc_exec_ctx* exec_ctx, http_connect_handshaker* handshaker) {
+  handshaker->endpoint_to_destroy = handshaker->args->endpoint;
+  handshaker->args->endpoint = NULL;
+  handshaker->read_buffer_to_destroy = handshaker->args->read_buffer;
+  handshaker->args->read_buffer = NULL;
+  grpc_channel_args_destroy(exec_ctx, handshaker->args->args);
+  handshaker->args->args = NULL;
+}
+
+// If the handshake failed or we're shutting down, clean up and invoke the
+// callback with the error.
+static void handshake_failed_locked(grpc_exec_ctx* exec_ctx,
+                                    http_connect_handshaker* handshaker,
+                                    grpc_error* error) {
+  if (error == GRPC_ERROR_NONE) {
+    // If we were shut down after an endpoint operation succeeded but
+    // before the endpoint callback was invoked, we need to generate our
+    // own error.
+    error = GRPC_ERROR_CREATE("Handshaker shutdown");
+  }
+  if (!handshaker->shutdown) {
+    // TODO(ctiller): It is currently necessary to shutdown endpoints
+    // before destroying them, even if we know that there are no
+    // pending read/write callbacks.  This should be fixed, at which
+    // point this can be removed.
+    grpc_endpoint_shutdown(exec_ctx, handshaker->args->endpoint);
+    // Not shutting down, so the handshake failed.  Clean up before
+    // invoking the callback.
+    cleanup_args_for_failure_locked(exec_ctx, handshaker);
+    // Set shutdown to true so that subsequent calls to
+    // http_connect_handshaker_shutdown() do nothing.
+    handshaker->shutdown = true;
   }
-  http_connect_handshaker_unref(handshaker);
+  // Invoke callback.
+  grpc_closure_sched(exec_ctx, handshaker->on_handshake_done, error);
 }
 
 // Callback invoked when finished writing HTTP CONNECT request.
 static void on_write_done(grpc_exec_ctx* exec_ctx, void* arg,
                           grpc_error* error) {
   http_connect_handshaker* handshaker = arg;
-  if (error != GRPC_ERROR_NONE) {
-    // If the write failed, invoke the callback immediately with the error.
-    handshaker->cb(exec_ctx, handshaker->endpoint, handshaker->args,
-                   handshaker->read_buffer, handshaker->user_data,
-                   GRPC_ERROR_REF(error));
+  gpr_mu_lock(&handshaker->mu);
+  if (error != GRPC_ERROR_NONE || handshaker->shutdown) {
+    // If the write failed or we're shutting down, clean up and invoke the
+    // callback with the error.
+    handshake_failed_locked(exec_ctx, handshaker, GRPC_ERROR_REF(error));
+    gpr_mu_unlock(&handshaker->mu);
+    http_connect_handshaker_unref(exec_ctx, handshaker);
   } else {
     // Otherwise, read the response.
-    grpc_endpoint_read(exec_ctx, handshaker->endpoint, handshaker->read_buffer,
+    // The read callback inherits our ref to the handshaker.
+    grpc_endpoint_read(exec_ctx, handshaker->args->endpoint,
+                       handshaker->args->read_buffer,
                        &handshaker->response_read_closure);
+    gpr_mu_unlock(&handshaker->mu);
   }
 }
 
@@ -112,37 +169,41 @@ static void on_write_done(grpc_exec_ctx* exec_ctx, void* arg,
 static void on_read_done(grpc_exec_ctx* exec_ctx, void* arg,
                          grpc_error* error) {
   http_connect_handshaker* handshaker = arg;
-  if (error != GRPC_ERROR_NONE) {
-    GRPC_ERROR_REF(error);  // Take ref to pass to the handshake-done callback.
+  gpr_mu_lock(&handshaker->mu);
+  if (error != GRPC_ERROR_NONE || handshaker->shutdown) {
+    // If the read failed or we're shutting down, clean up and invoke the
+    // callback with the error.
+    handshake_failed_locked(exec_ctx, handshaker, GRPC_ERROR_REF(error));
     goto done;
   }
   // Add buffer to parser.
-  for (size_t i = 0; i < handshaker->read_buffer->count; ++i) {
-    if (GRPC_SLICE_LENGTH(handshaker->read_buffer->slices[i]) > 0) {
+  for (size_t i = 0; i < handshaker->args->read_buffer->count; ++i) {
+    if (GRPC_SLICE_LENGTH(handshaker->args->read_buffer->slices[i]) > 0) {
       size_t body_start_offset = 0;
       error = grpc_http_parser_parse(&handshaker->http_parser,
-                                     handshaker->read_buffer->slices[i],
+                                     handshaker->args->read_buffer->slices[i],
                                      &body_start_offset);
-      if (error != GRPC_ERROR_NONE) goto done;
+      if (error != GRPC_ERROR_NONE) {
+        handshake_failed_locked(exec_ctx, handshaker, error);
+        goto done;
+      }
       if (handshaker->http_parser.state == GRPC_HTTP_BODY) {
-        // We've gotten back a successul response, so stop the timeout timer.
-        grpc_timer_cancel(exec_ctx, &handshaker->timeout_timer);
         // Remove the data we've already read from the read buffer,
         // leaving only the leftover bytes (if any).
         grpc_slice_buffer tmp_buffer;
         grpc_slice_buffer_init(&tmp_buffer);
         if (body_start_offset <
-            GRPC_SLICE_LENGTH(handshaker->read_buffer->slices[i])) {
+            GRPC_SLICE_LENGTH(handshaker->args->read_buffer->slices[i])) {
           grpc_slice_buffer_add(
               &tmp_buffer,
-              grpc_slice_split_tail(&handshaker->read_buffer->slices[i],
+              grpc_slice_split_tail(&handshaker->args->read_buffer->slices[i],
                                     body_start_offset));
         }
         grpc_slice_buffer_addn(&tmp_buffer,
-                               &handshaker->read_buffer->slices[i + 1],
-                               handshaker->read_buffer->count - i - 1);
-        grpc_slice_buffer_swap(handshaker->read_buffer, &tmp_buffer);
-        grpc_slice_buffer_destroy(&tmp_buffer);
+                               &handshaker->args->read_buffer->slices[i + 1],
+                               handshaker->args->read_buffer->count - i - 1);
+        grpc_slice_buffer_swap(handshaker->args->read_buffer, &tmp_buffer);
+        grpc_slice_buffer_destroy_internal(exec_ctx, &tmp_buffer);
         break;
       }
     }
@@ -159,9 +220,12 @@ static void on_read_done(grpc_exec_ctx* exec_ctx, void* arg,
   // complete (e.g., handling chunked transfer encoding or looking
   // at the Content-Length: header).
   if (handshaker->http_parser.state != GRPC_HTTP_BODY) {
-    grpc_slice_buffer_reset_and_unref(handshaker->read_buffer);
-    grpc_endpoint_read(exec_ctx, handshaker->endpoint, handshaker->read_buffer,
+    grpc_slice_buffer_reset_and_unref_internal(exec_ctx,
+                                               handshaker->args->read_buffer);
+    grpc_endpoint_read(exec_ctx, handshaker->args->endpoint,
+                       handshaker->args->read_buffer,
                        &handshaker->response_read_closure);
+    gpr_mu_unlock(&handshaker->mu);
     return;
   }
   // Make sure we got a 2xx response.
@@ -172,11 +236,17 @@ static void on_read_done(grpc_exec_ctx* exec_ctx, void* arg,
                  handshaker->http_response.status);
     error = GRPC_ERROR_CREATE(msg);
     gpr_free(msg);
+    handshake_failed_locked(exec_ctx, handshaker, error);
+    goto done;
   }
+  // Success.  Invoke handshake-done callback.
+  grpc_closure_sched(exec_ctx, handshaker->on_handshake_done, error);
 done:
-  // Invoke handshake-done callback.
-  handshaker->cb(exec_ctx, handshaker->endpoint, handshaker->args,
-                 handshaker->read_buffer, handshaker->user_data, error);
+  // Set shutdown to true so that subsequent calls to
+  // http_connect_handshaker_shutdown() do nothing.
+  handshaker->shutdown = true;
+  gpr_mu_unlock(&handshaker->mu);
+  http_connect_handshaker_unref(exec_ctx, handshaker);
 }
 
 //
@@ -186,67 +256,91 @@ done:
 static void http_connect_handshaker_destroy(grpc_exec_ctx* exec_ctx,
                                             grpc_handshaker* handshaker_in) {
   http_connect_handshaker* handshaker = (http_connect_handshaker*)handshaker_in;
-  http_connect_handshaker_unref(handshaker);
+  http_connect_handshaker_unref(exec_ctx, handshaker);
 }
 
 static void http_connect_handshaker_shutdown(grpc_exec_ctx* exec_ctx,
-                                             grpc_handshaker* handshaker) {}
+                                             grpc_handshaker* handshaker_in) {
+  http_connect_handshaker* handshaker = (http_connect_handshaker*)handshaker_in;
+  gpr_mu_lock(&handshaker->mu);
+  if (!handshaker->shutdown) {
+    handshaker->shutdown = true;
+    grpc_endpoint_shutdown(exec_ctx, handshaker->args->endpoint);
+    cleanup_args_for_failure_locked(exec_ctx, handshaker);
+  }
+  gpr_mu_unlock(&handshaker->mu);
+}
 
 static void http_connect_handshaker_do_handshake(
     grpc_exec_ctx* exec_ctx, grpc_handshaker* handshaker_in,
-    grpc_endpoint* endpoint, grpc_channel_args* args,
-    grpc_slice_buffer* read_buffer, gpr_timespec deadline,
-    grpc_tcp_server_acceptor* acceptor, grpc_handshaker_done_cb cb,
-    void* user_data) {
+    grpc_tcp_server_acceptor* acceptor, grpc_closure* on_handshake_done,
+    grpc_handshaker_args* args) {
   http_connect_handshaker* handshaker = (http_connect_handshaker*)handshaker_in;
+  // Get server name from channel args.
+  const grpc_arg* arg = grpc_channel_args_find(args->args, GRPC_ARG_SERVER_URI);
+  GPR_ASSERT(arg != NULL);
+  GPR_ASSERT(arg->type == GRPC_ARG_STRING);
+  char* canonical_uri =
+      grpc_resolver_factory_add_default_prefix_if_needed(arg->value.string);
+  grpc_uri* uri = grpc_uri_parse(canonical_uri, 1);
+  char* server_name = uri->path;
+  if (server_name[0] == '/') ++server_name;
   // Save state in the handshaker object.
-  handshaker->endpoint = endpoint;
+  gpr_mu_lock(&handshaker->mu);
   handshaker->args = args;
-  handshaker->cb = cb;
-  handshaker->user_data = user_data;
-  handshaker->read_buffer = read_buffer;
+  handshaker->on_handshake_done = on_handshake_done;
   // Send HTTP CONNECT request.
-  gpr_log(GPR_INFO, "Connecting to server %s via HTTP proxy %s",
-          handshaker->server_name, handshaker->proxy_server);
+  gpr_log(GPR_INFO, "Connecting to server %s via HTTP proxy %s", server_name,
+          handshaker->proxy_server);
   grpc_httpcli_request request;
   memset(&request, 0, sizeof(request));
-  request.host = handshaker->proxy_server;
+  request.host = server_name;
   request.http.method = "CONNECT";
-  request.http.path = handshaker->server_name;
+  request.http.path = server_name;
+  request.http.hdrs = handshaker->headers;
+  request.http.hdr_count = handshaker->num_headers;
   request.handshaker = &grpc_httpcli_plaintext;
   grpc_slice request_slice = grpc_httpcli_format_connect_request(&request);
   grpc_slice_buffer_add(&handshaker->write_buffer, request_slice);
-  grpc_endpoint_write(exec_ctx, endpoint, &handshaker->write_buffer,
-                      &handshaker->request_done_closure);
-  // Set timeout timer.  The timer gets a reference to the handshaker.
+  // Take a new ref to be held by the write callback.
   gpr_ref(&handshaker->refcount);
-  grpc_timer_init(exec_ctx, &handshaker->timeout_timer,
-                  gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC),
-                  on_timeout, handshaker, gpr_now(GPR_CLOCK_MONOTONIC));
+  grpc_endpoint_write(exec_ctx, args->endpoint, &handshaker->write_buffer,
+                      &handshaker->request_done_closure);
+  gpr_mu_unlock(&handshaker->mu);
+  // Clean up.
+  gpr_free(canonical_uri);
+  grpc_uri_destroy(uri);
 }
 
-static const struct grpc_handshaker_vtable http_connect_handshaker_vtable = {
+static const grpc_handshaker_vtable http_connect_handshaker_vtable = {
     http_connect_handshaker_destroy, http_connect_handshaker_shutdown,
     http_connect_handshaker_do_handshake};
 
 grpc_handshaker* grpc_http_connect_handshaker_create(const char* proxy_server,
-                                                     const char* server_name) {
+                                                     grpc_http_header* headers,
+                                                     size_t num_headers) {
   GPR_ASSERT(proxy_server != NULL);
-  GPR_ASSERT(server_name != NULL);
-  http_connect_handshaker* handshaker =
-      gpr_malloc(sizeof(http_connect_handshaker));
+  http_connect_handshaker* handshaker = gpr_malloc(sizeof(*handshaker));
   memset(handshaker, 0, sizeof(*handshaker));
   grpc_handshaker_init(&http_connect_handshaker_vtable, &handshaker->base);
+  gpr_mu_init(&handshaker->mu);
+  gpr_ref_init(&handshaker->refcount, 1);
   handshaker->proxy_server = gpr_strdup(proxy_server);
-  handshaker->server_name = gpr_strdup(server_name);
+  if (num_headers > 0) {
+    handshaker->headers = gpr_malloc(sizeof(grpc_http_header) * num_headers);
+    for (size_t i = 0; i < num_headers; ++i) {
+      handshaker->headers[i].key = gpr_strdup(headers[i].key);
+      handshaker->headers[i].value = gpr_strdup(headers[i].value);
+    }
+    handshaker->num_headers = num_headers;
+  }
   grpc_slice_buffer_init(&handshaker->write_buffer);
   grpc_closure_init(&handshaker->request_done_closure, on_write_done,
-                    handshaker);
+                    handshaker, grpc_schedule_on_exec_ctx);
   grpc_closure_init(&handshaker->response_read_closure, on_read_done,
-                    handshaker);
+                    handshaker, grpc_schedule_on_exec_ctx);
   grpc_http_parser_init(&handshaker->http_parser, GRPC_HTTP_RESPONSE,
                         &handshaker->http_response);
-  gpr_ref_init(&handshaker->refcount, 1);
   return &handshaker->base;
 }
 
@@ -273,3 +367,33 @@ done:
   grpc_uri_destroy(uri);
   return proxy_name;
 }
+
+//
+// handshaker factory
+//
+
+static void handshaker_factory_add_handshakers(
+    grpc_exec_ctx* exec_ctx, grpc_handshaker_factory* factory,
+    const grpc_channel_args* args, grpc_handshake_manager* handshake_mgr) {
+  char* proxy_name = grpc_get_http_proxy_server();
+  if (proxy_name != NULL) {
+    grpc_handshake_manager_add(
+        handshake_mgr,
+        grpc_http_connect_handshaker_create(proxy_name, NULL, 0));
+    gpr_free(proxy_name);
+  }
+}
+
+static void handshaker_factory_destroy(grpc_exec_ctx* exec_ctx,
+                                       grpc_handshaker_factory* factory) {}
+
+static const grpc_handshaker_factory_vtable handshaker_factory_vtable = {
+    handshaker_factory_add_handshakers, handshaker_factory_destroy};
+
+static grpc_handshaker_factory handshaker_factory = {
+    &handshaker_factory_vtable};
+
+void grpc_http_connect_register_handshaker_factory() {
+  grpc_handshaker_factory_register(true /* at_start */, HANDSHAKER_CLIENT,
+                                   &handshaker_factory);
+}
diff --git a/src/core/ext/client_channel/http_connect_handshaker.h b/src/core/ext/client_channel/http_connect_handshaker.h
index c689df2b2b..c2e68de716 100644
--- a/src/core/ext/client_channel/http_connect_handshaker.h
+++ b/src/core/ext/client_channel/http_connect_handshaker.h
@@ -35,13 +35,18 @@
 #define GRPC_CORE_EXT_CLIENT_CHANNEL_HTTP_CONNECT_HANDSHAKER_H
 
 #include "src/core/lib/channel/handshaker.h"
+#include "src/core/lib/http/parser.h"
 
-/// Does NOT take ownership of \a proxy_server or \a server_name.
+/// Creates a new HTTP CONNECT handshaker.
 grpc_handshaker* grpc_http_connect_handshaker_create(const char* proxy_server,
-                                                     const char* server_name);
+                                                     grpc_http_header* headers,
+                                                     size_t num_headers);
 
 /// Returns the name of the proxy to use, or NULL if no proxy is configured.
 /// Caller takes ownership of result.
 char* grpc_get_http_proxy_server();
 
+/// Registers handshaker factory.
+void grpc_http_connect_register_handshaker_factory();
+
 #endif /* GRPC_CORE_EXT_CLIENT_CHANNEL_HTTP_CONNECT_HANDSHAKER_H */
diff --git a/src/core/ext/client_channel/lb_policy_factory.c b/src/core/ext/client_channel/lb_policy_factory.c
index 8a474c8818..7af9bb0411 100644
--- a/src/core/ext/client_channel/lb_policy_factory.c
+++ b/src/core/ext/client_channel/lb_policy_factory.c
@@ -112,11 +112,13 @@ int grpc_lb_addresses_cmp(const grpc_lb_addresses* addresses1,
   return 0;
 }
 
-void grpc_lb_addresses_destroy(grpc_lb_addresses* addresses) {
+void grpc_lb_addresses_destroy(grpc_exec_ctx* exec_ctx,
+                               grpc_lb_addresses* addresses) {
   for (size_t i = 0; i < addresses->num_addresses; ++i) {
     gpr_free(addresses->addresses[i].balancer_name);
     if (addresses->addresses[i].user_data != NULL) {
-      addresses->user_data_vtable->destroy(addresses->addresses[i].user_data);
+      addresses->user_data_vtable->destroy(exec_ctx,
+                                           addresses->addresses[i].user_data);
     }
   }
   gpr_free(addresses->addresses);
@@ -126,8 +128,8 @@ void grpc_lb_addresses_destroy(grpc_lb_addresses* addresses) {
 static void* lb_addresses_copy(void* addresses) {
   return grpc_lb_addresses_copy(addresses);
 }
-static void lb_addresses_destroy(void* addresses) {
-  grpc_lb_addresses_destroy(addresses);
+static void lb_addresses_destroy(grpc_exec_ctx* exec_ctx, void* addresses) {
+  grpc_lb_addresses_destroy(exec_ctx, addresses);
 }
 static int lb_addresses_cmp(void* addresses1, void* addresses2) {
   return grpc_lb_addresses_cmp(addresses1, addresses2);
diff --git a/src/core/ext/client_channel/lb_policy_factory.h b/src/core/ext/client_channel/lb_policy_factory.h
index e2b8080a32..9b8b03f982 100644
--- a/src/core/ext/client_channel/lb_policy_factory.h
+++ b/src/core/ext/client_channel/lb_policy_factory.h
@@ -40,6 +40,9 @@
 #include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/iomgr/resolve_address.h"
 
+// Channel arg key for grpc_lb_addresses.
+#define GRPC_ARG_LB_ADDRESSES "grpc.lb_addresses"
+
 typedef struct grpc_lb_policy_factory grpc_lb_policy_factory;
 typedef struct grpc_lb_policy_factory_vtable grpc_lb_policy_factory_vtable;
 
@@ -61,7 +64,7 @@ typedef struct grpc_lb_address {
 
 typedef struct grpc_lb_user_data_vtable {
   void *(*copy)(void *);
-  void (*destroy)(void *);
+  void (*destroy)(grpc_exec_ctx *exec_ctx, void *);
   int (*cmp)(void *, void *);
 } grpc_lb_user_data_vtable;
 
@@ -93,7 +96,8 @@ int grpc_lb_addresses_cmp(const grpc_lb_addresses *addresses1,
                           const grpc_lb_addresses *addresses2);
 
 /** Destroys \a addresses. */
-void grpc_lb_addresses_destroy(grpc_lb_addresses *addresses);
+void grpc_lb_addresses_destroy(grpc_exec_ctx *exec_ctx,
+                               grpc_lb_addresses *addresses);
 
 /** Returns a channel arg containing \a addresses. */
 grpc_arg grpc_lb_addresses_create_channel_arg(
diff --git a/src/core/ext/client_channel/resolver_factory.c b/src/core/ext/client_channel/resolver_factory.c
index 7c3d644257..00bbb92dd0 100644
--- a/src/core/ext/client_channel/resolver_factory.c
+++ b/src/core/ext/client_channel/resolver_factory.c
@@ -43,9 +43,10 @@ void grpc_resolver_factory_unref(grpc_resolver_factory* factory) {
 
 /** Create a resolver instance for a name */
 grpc_resolver* grpc_resolver_factory_create_resolver(
-    grpc_resolver_factory* factory, grpc_resolver_args* args) {
+    grpc_exec_ctx* exec_ctx, grpc_resolver_factory* factory,
+    grpc_resolver_args* args) {
   if (factory == NULL) return NULL;
-  return factory->vtable->create_resolver(factory, args);
+  return factory->vtable->create_resolver(exec_ctx, factory, args);
 }
 
 char* grpc_resolver_factory_get_default_authority(
diff --git a/src/core/ext/client_channel/resolver_factory.h b/src/core/ext/client_channel/resolver_factory.h
index 4da42e84d2..3792ddca18 100644
--- a/src/core/ext/client_channel/resolver_factory.h
+++ b/src/core/ext/client_channel/resolver_factory.h
@@ -37,6 +37,7 @@
 #include "src/core/ext/client_channel/client_channel_factory.h"
 #include "src/core/ext/client_channel/resolver.h"
 #include "src/core/ext/client_channel/uri_parser.h"
+#include "src/core/lib/iomgr/pollset_set.h"
 
 typedef struct grpc_resolver_factory grpc_resolver_factory;
 typedef struct grpc_resolver_factory_vtable grpc_resolver_factory_vtable;
@@ -48,6 +49,7 @@ struct grpc_resolver_factory {
 typedef struct grpc_resolver_args {
   grpc_uri *uri;
   const grpc_channel_args *args;
+  grpc_pollset_set *pollset_set;
 } grpc_resolver_args;
 
 struct grpc_resolver_factory_vtable {
@@ -55,7 +57,8 @@ struct grpc_resolver_factory_vtable {
   void (*unref)(grpc_resolver_factory *factory);
 
   /** Implementation of grpc_resolver_factory_create_resolver */
-  grpc_resolver *(*create_resolver)(grpc_resolver_factory *factory,
+  grpc_resolver *(*create_resolver)(grpc_exec_ctx *exec_ctx,
+                                    grpc_resolver_factory *factory,
                                     grpc_resolver_args *args);
 
   /** Implementation of grpc_resolver_factory_get_default_authority */
@@ -70,7 +73,8 @@ void grpc_resolver_factory_unref(grpc_resolver_factory *resolver);
 
 /** Create a resolver instance for a name */
 grpc_resolver *grpc_resolver_factory_create_resolver(
-    grpc_resolver_factory *factory, grpc_resolver_args *args);
+    grpc_exec_ctx *exec_ctx, grpc_resolver_factory *factory,
+    grpc_resolver_args *args);
 
 /** Return a (freshly allocated with gpr_malloc) string representing
     the default authority to use for this scheme. */
diff --git a/src/core/ext/client_channel/resolver_registry.c b/src/core/ext/client_channel/resolver_registry.c
index d0f0fc3f33..5110a7cad9 100644
--- a/src/core/ext/client_channel/resolver_registry.c
+++ b/src/core/ext/client_channel/resolver_registry.c
@@ -109,8 +109,8 @@ static grpc_resolver_factory *lookup_factory_by_uri(grpc_uri *uri) {
 }
 
 static grpc_resolver_factory *resolve_factory(const char *target,
-                                              grpc_uri **uri) {
-  char *tmp;
+                                              grpc_uri **uri,
+                                              char **canonical_target) {
   grpc_resolver_factory *factory = NULL;
 
   GPR_ASSERT(uri != NULL);
@@ -118,37 +118,54 @@ static grpc_resolver_factory *resolve_factory(const char *target,
   factory = lookup_factory_by_uri(*uri);
   if (factory == NULL) {
     grpc_uri_destroy(*uri);
-    gpr_asprintf(&tmp, "%s%s", g_default_resolver_prefix, target);
-    *uri = grpc_uri_parse(tmp, 1);
+    gpr_asprintf(canonical_target, "%s%s", g_default_resolver_prefix, target);
+    *uri = grpc_uri_parse(*canonical_target, 1);
     factory = lookup_factory_by_uri(*uri);
     if (factory == NULL) {
       grpc_uri_destroy(grpc_uri_parse(target, 0));
-      grpc_uri_destroy(grpc_uri_parse(tmp, 0));
-      gpr_log(GPR_ERROR, "don't know how to resolve '%s' or '%s'", target, tmp);
+      grpc_uri_destroy(grpc_uri_parse(*canonical_target, 0));
+      gpr_log(GPR_ERROR, "don't know how to resolve '%s' or '%s'", target,
+              *canonical_target);
     }
-    gpr_free(tmp);
   }
   return factory;
 }
 
-grpc_resolver *grpc_resolver_create(const char *target,
-                                    const grpc_channel_args *args) {
+grpc_resolver *grpc_resolver_create(grpc_exec_ctx *exec_ctx, const char *target,
+                                    const grpc_channel_args *args,
+                                    grpc_pollset_set *pollset_set) {
   grpc_uri *uri = NULL;
-  grpc_resolver_factory *factory = resolve_factory(target, &uri);
+  char *canonical_target = NULL;
+  grpc_resolver_factory *factory =
+      resolve_factory(target, &uri, &canonical_target);
   grpc_resolver *resolver;
   grpc_resolver_args resolver_args;
   memset(&resolver_args, 0, sizeof(resolver_args));
   resolver_args.uri = uri;
   resolver_args.args = args;
-  resolver = grpc_resolver_factory_create_resolver(factory, &resolver_args);
+  resolver_args.pollset_set = pollset_set;
+  resolver =
+      grpc_resolver_factory_create_resolver(exec_ctx, factory, &resolver_args);
   grpc_uri_destroy(uri);
+  gpr_free(canonical_target);
   return resolver;
 }
 
 char *grpc_get_default_authority(const char *target) {
   grpc_uri *uri = NULL;
-  grpc_resolver_factory *factory = resolve_factory(target, &uri);
+  char *canonical_target = NULL;
+  grpc_resolver_factory *factory =
+      resolve_factory(target, &uri, &canonical_target);
   char *authority = grpc_resolver_factory_get_default_authority(factory, uri);
   grpc_uri_destroy(uri);
+  gpr_free(canonical_target);
   return authority;
 }
+
+char *grpc_resolver_factory_add_default_prefix_if_needed(const char *target) {
+  grpc_uri *uri = NULL;
+  char *canonical_target = NULL;
+  resolve_factory(target, &uri, &canonical_target);
+  grpc_uri_destroy(uri);
+  return canonical_target == NULL ? gpr_strdup(target) : canonical_target;
+}
diff --git a/src/core/ext/client_channel/resolver_registry.h b/src/core/ext/client_channel/resolver_registry.h
index 2a95a669f0..4fb16131db 100644
--- a/src/core/ext/client_channel/resolver_registry.h
+++ b/src/core/ext/client_channel/resolver_registry.h
@@ -35,6 +35,7 @@
 #define GRPC_CORE_EXT_CLIENT_CHANNEL_RESOLVER_REGISTRY_H
 
 #include "src/core/ext/client_channel/resolver_factory.h"
+#include "src/core/lib/iomgr/pollset_set.h"
 
 void grpc_resolver_registry_init();
 void grpc_resolver_registry_shutdown(void);
@@ -60,8 +61,9 @@ void grpc_register_resolver_type(grpc_resolver_factory *factory);
     If a resolver factory was not found, return NULL.
     \a args is a set of channel arguments to be included in the result
     (typically the set of arguments passed in from the client API). */
-grpc_resolver *grpc_resolver_create(const char *target,
-                                    const grpc_channel_args *args);
+grpc_resolver *grpc_resolver_create(grpc_exec_ctx *exec_ctx, const char *target,
+                                    const grpc_channel_args *args,
+                                    grpc_pollset_set *pollset_set);
 
 /** Find a resolver factory given a name and return an (owned-by-the-caller)
  *  reference to it */
@@ -71,4 +73,8 @@ grpc_resolver_factory *grpc_resolver_factory_lookup(const char *name);
     representing the default authority to pass from a client. */
 char *grpc_get_default_authority(const char *target);
 
+/** Returns a newly allocated string containing \a target, adding the
+    default prefix if needed. */
+char *grpc_resolver_factory_add_default_prefix_if_needed(const char *target);
+
 #endif /* GRPC_CORE_EXT_CLIENT_CHANNEL_RESOLVER_REGISTRY_H */
diff --git a/src/core/ext/client_channel/subchannel.c b/src/core/ext/client_channel/subchannel.c
index b83c6882dc..1bac82b451 100644
--- a/src/core/ext/client_channel/subchannel.c
+++ b/src/core/ext/client_channel/subchannel.c
@@ -46,6 +46,7 @@
 #include "src/core/lib/channel/connected_channel.h"
 #include "src/core/lib/iomgr/timer.h"
 #include "src/core/lib/profiling/timers.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/support/backoff.h"
 #include "src/core/lib/surface/channel.h"
 #include "src/core/lib/surface/channel_init.h"
@@ -108,6 +109,9 @@ struct grpc_subchannel {
   /** callback for connection finishing */
   grpc_closure connected;
 
+  /** callback for our alarm */
+  grpc_closure on_alarm;
+
   /** pollset_set tracking who's interested in a connection
       being setup */
   grpc_pollset_set *pollset_set;
@@ -206,9 +210,9 @@ static void subchannel_destroy(grpc_exec_ctx *exec_ctx, void *arg,
                                grpc_error *error) {
   grpc_subchannel *c = arg;
   gpr_free((void *)c->filters);
-  grpc_channel_args_destroy(c->args);
+  grpc_channel_args_destroy(exec_ctx, c->args);
   gpr_free(c->addr);
-  grpc_slice_unref(c->initial_connect_string);
+  grpc_slice_unref_internal(exec_ctx, c->initial_connect_string);
   grpc_connectivity_state_destroy(exec_ctx, &c->state_tracker);
   grpc_connector_unref(exec_ctx, c->connector);
   grpc_pollset_set_destroy(c->pollset_set);
@@ -293,8 +297,9 @@ void grpc_subchannel_weak_unref(grpc_exec_ctx *exec_ctx,
   gpr_atm old_refs;
   old_refs = ref_mutate(c, -(gpr_atm)1, 1 REF_MUTATE_PURPOSE("WEAK_UNREF"));
   if (old_refs == 1) {
-    grpc_exec_ctx_sched(exec_ctx, grpc_closure_create(subchannel_destroy, c),
-                        GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, grpc_closure_create(subchannel_destroy, c,
+                                                     grpc_schedule_on_exec_ctx),
+                       GRPC_ERROR_NONE);
   }
 }
 
@@ -330,22 +335,25 @@ grpc_subchannel *grpc_subchannel_create(grpc_exec_ctx *exec_ctx,
   c->args = grpc_channel_args_copy(args->args);
   c->root_external_state_watcher.next = c->root_external_state_watcher.prev =
       &c->root_external_state_watcher;
-  grpc_closure_init(&c->connected, subchannel_connected, c);
+  grpc_closure_init(&c->connected, subchannel_connected, c,
+                    grpc_schedule_on_exec_ctx);
   grpc_connectivity_state_init(&c->state_tracker, GRPC_CHANNEL_IDLE,
                                "subchannel");
   int initial_backoff_ms =
       GRPC_SUBCHANNEL_INITIAL_CONNECT_BACKOFF_SECONDS * 1000;
   int max_backoff_ms = GRPC_SUBCHANNEL_RECONNECT_MAX_BACKOFF_SECONDS * 1000;
+  int min_backoff_ms = GRPC_SUBCHANNEL_MIN_CONNECT_TIMEOUT_SECONDS * 1000;
   bool fixed_reconnect_backoff = false;
   if (c->args) {
     for (size_t i = 0; i < c->args->num_args; i++) {
       if (0 == strcmp(c->args->args[i].key,
-                      "grpc.testing.fixed_reconnect_backoff")) {
+                      "grpc.testing.fixed_reconnect_backoff_ms")) {
         GPR_ASSERT(c->args->args[i].type == GRPC_ARG_INTEGER);
         fixed_reconnect_backoff = true;
-        initial_backoff_ms = max_backoff_ms = grpc_channel_arg_get_integer(
-            &c->args->args[i],
-            (grpc_integer_options){initial_backoff_ms, 100, INT_MAX});
+        initial_backoff_ms = min_backoff_ms = max_backoff_ms =
+            grpc_channel_arg_get_integer(
+                &c->args->args[i],
+                (grpc_integer_options){initial_backoff_ms, 100, INT_MAX});
       } else if (0 == strcmp(c->args->args[i].key,
                              GRPC_ARG_MAX_RECONNECT_BACKOFF_MS)) {
         fixed_reconnect_backoff = false;
@@ -362,11 +370,11 @@ grpc_subchannel *grpc_subchannel_create(grpc_exec_ctx *exec_ctx,
     }
   }
   gpr_backoff_init(
-      &c->backoff_state,
+      &c->backoff_state, initial_backoff_ms,
       fixed_reconnect_backoff ? 1.0
                               : GRPC_SUBCHANNEL_RECONNECT_BACKOFF_MULTIPLIER,
       fixed_reconnect_backoff ? 0.0 : GRPC_SUBCHANNEL_RECONNECT_JITTER,
-      initial_backoff_ms, max_backoff_ms);
+      min_backoff_ms, max_backoff_ms);
   gpr_mu_init(&c->mu);
 
   return grpc_subchannel_index_register(exec_ctx, key, c);
@@ -478,7 +486,8 @@ static void maybe_start_connecting_locked(grpc_exec_ctx *exec_ctx,
       gpr_log(GPR_INFO, "Retry in %" PRId64 ".%09d seconds",
               time_til_next.tv_sec, time_til_next.tv_nsec);
     }
-    grpc_timer_init(exec_ctx, &c->alarm, c->next_attempt, on_alarm, c, now);
+    grpc_closure_init(&c->on_alarm, on_alarm, c, grpc_schedule_on_exec_ctx);
+    grpc_timer_init(exec_ctx, &c->alarm, c->next_attempt, &c->on_alarm, now);
   }
 }
 
@@ -503,7 +512,8 @@ void grpc_subchannel_notify_on_state_change(
     w->subchannel = c;
     w->pollset_set = interested_parties;
     w->notify = notify;
-    grpc_closure_init(&w->closure, on_external_state_watcher_done, w);
+    grpc_closure_init(&w->closure, on_external_state_watcher_done, w,
+                      grpc_schedule_on_exec_ctx);
     if (interested_parties != NULL) {
       grpc_pollset_set_add_pollset_set(exec_ctx, c->pollset_set,
                                        interested_parties);
@@ -598,18 +608,24 @@ static void publish_transport_locked(grpc_exec_ctx *exec_ctx,
   /* construct channel stack */
   grpc_channel_stack_builder *builder = grpc_channel_stack_builder_create();
   grpc_channel_stack_builder_set_channel_arguments(
-      builder, c->connecting_result.channel_args);
+      exec_ctx, builder, c->connecting_result.channel_args);
   grpc_channel_stack_builder_set_transport(builder,
                                            c->connecting_result.transport);
 
-  if (grpc_channel_init_create_stack(exec_ctx, builder,
-                                     GRPC_CLIENT_SUBCHANNEL)) {
-    con = grpc_channel_stack_builder_finish(exec_ctx, builder, 0, 1,
-                                            connection_destroy, NULL);
-  } else {
-    grpc_channel_stack_builder_destroy(builder);
+  if (!grpc_channel_init_create_stack(exec_ctx, builder,
+                                      GRPC_CLIENT_SUBCHANNEL)) {
+    grpc_channel_stack_builder_destroy(exec_ctx, builder);
     abort(); /* TODO(ctiller): what to do here (previously we just crashed) */
   }
+  grpc_error *error = grpc_channel_stack_builder_finish(
+      exec_ctx, builder, 0, 1, connection_destroy, NULL, (void **)&con);
+  if (error != GRPC_ERROR_NONE) {
+    const char *msg = grpc_error_string(error);
+    gpr_log(GPR_ERROR, "error initializing subchannel stack: %s", msg);
+    grpc_error_free_string(msg);
+    GRPC_ERROR_UNREF(error);
+    abort(); /* TODO(ctiller): what to do here? */
+  }
   stk = CHANNEL_STACK_FROM_CONNECTION(con);
   memset(&c->connecting_result, 0, sizeof(c->connecting_result));
 
@@ -618,7 +634,7 @@ static void publish_transport_locked(grpc_exec_ctx *exec_ctx,
   sw_subchannel->subchannel = c;
   sw_subchannel->connectivity_state = GRPC_CHANNEL_READY;
   grpc_closure_init(&sw_subchannel->closure, subchannel_on_child_state_changed,
-                    sw_subchannel);
+                    sw_subchannel, grpc_schedule_on_exec_ctx);
 
   if (c->disconnected) {
     gpr_free(sw_subchannel);
@@ -637,9 +653,7 @@ static void publish_transport_locked(grpc_exec_ctx *exec_ctx,
   GPR_ASSERT(gpr_atm_rel_cas(&c->connected_subchannel, 0, (gpr_atm)con));
 
   /* setup subchannel watching connected subchannel for changes; subchannel
-     ref
-     for connecting is donated
-     to the state watcher */
+     ref for connecting is donated to the state watcher */
   GRPC_SUBCHANNEL_WEAK_REF(c, "state_watcher");
   GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connecting");
   grpc_connected_subchannel_notify_on_state_change(
@@ -680,7 +694,7 @@ static void subchannel_connected(grpc_exec_ctx *exec_ctx, void *arg,
   }
   gpr_mu_unlock(&c->mu);
   GRPC_SUBCHANNEL_WEAK_UNREF(exec_ctx, c, "connected");
-  grpc_channel_args_destroy(delete_channel_args);
+  grpc_channel_args_destroy(exec_ctx, delete_channel_args);
 }
 
 /*
diff --git a/src/core/ext/client_channel/subchannel.h b/src/core/ext/client_channel/subchannel.h
index 10bae620df..24aa9f73dc 100644
--- a/src/core/ext/client_channel/subchannel.h
+++ b/src/core/ext/client_channel/subchannel.h
@@ -164,8 +164,6 @@ struct grpc_subchannel_args {
   size_t filter_count;
   /** Channel arguments to be supplied to the newly created channel */
   const grpc_channel_args *args;
-  /** Server name */
-  const char *server_name;
   /** Address to connect to */
   grpc_resolved_address *addr;
 };
diff --git a/src/core/ext/client_channel/subchannel_index.c b/src/core/ext/client_channel/subchannel_index.c
index 227013a7d7..1ebe03ef11 100644
--- a/src/core/ext/client_channel/subchannel_index.c
+++ b/src/core/ext/client_channel/subchannel_index.c
@@ -86,7 +86,6 @@ static grpc_subchannel_key *create_key(
   } else {
     k->args.filters = NULL;
   }
-  k->args.server_name = gpr_strdup(args->server_name);
   k->args.addr = gpr_malloc(sizeof(grpc_resolved_address));
   k->args.addr->len = args->addr->len;
   if (k->args.addr->len > 0) {
@@ -113,8 +112,6 @@ static int subchannel_key_compare(grpc_subchannel_key *a,
   if (c != 0) return c;
   c = GPR_ICMP(a->args.filter_count, b->args.filter_count);
   if (c != 0) return c;
-  c = strcmp(a->args.server_name, b->args.server_name);
-  if (c != 0) return c;
   if (a->args.addr->len) {
     c = memcmp(a->args.addr->addr, b->args.addr->addr, a->args.addr->len);
     if (c != 0) return c;
@@ -131,8 +128,7 @@ void grpc_subchannel_key_destroy(grpc_exec_ctx *exec_ctx,
                                  grpc_subchannel_key *k) {
   grpc_connector_unref(exec_ctx, k->connector);
   gpr_free((grpc_channel_args *)k->args.filters);
-  grpc_channel_args_destroy((grpc_channel_args *)k->args.args);
-  gpr_free((void *)k->args.server_name);
+  grpc_channel_args_destroy(exec_ctx, (grpc_channel_args *)k->args.args);
   gpr_free(k->args.addr);
   gpr_free(k);
 }
diff --git a/src/core/ext/client_channel/uri_parser.c b/src/core/ext/client_channel/uri_parser.c
index 0fbc542ef8..f8c946b275 100644
--- a/src/core/ext/client_channel/uri_parser.c
+++ b/src/core/ext/client_channel/uri_parser.c
@@ -42,7 +42,6 @@
 #include <grpc/support/port_platform.h>
 #include <grpc/support/string_util.h>
 
-#include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/string.h"
 
 /** a size_t default value... maps to all 1's */
@@ -138,7 +137,6 @@ static int parse_fragment_or_query(const char *uri_text, size_t *i) {
   return 1;
 }
 
-static void do_nothing(void *ignored) {}
 static void parse_query_parts(grpc_uri *uri) {
   static const char *QUERY_PARTS_SEPARATOR = "&";
   static const char *QUERY_PARTS_VALUE_SEPARATOR = "=";
@@ -149,38 +147,32 @@ static void parse_query_parts(grpc_uri *uri) {
     uri->num_query_parts = 0;
     return;
   }
-  grpc_slice query_slice =
-      grpc_slice_new(uri->query, strlen(uri->query), do_nothing);
-  grpc_slice_buffer query_parts; /* the &-separated elements of the query */
-  grpc_slice_buffer query_param_parts; /* the =-separated subelements */
 
-  grpc_slice_buffer_init(&query_parts);
-  grpc_slice_buffer_init(&query_param_parts);
-
-  grpc_slice_split(query_slice, QUERY_PARTS_SEPARATOR, &query_parts);
-  uri->query_parts = gpr_malloc(query_parts.count * sizeof(char *));
-  uri->query_parts_values = gpr_malloc(query_parts.count * sizeof(char *));
-  uri->num_query_parts = query_parts.count;
-  for (size_t i = 0; i < query_parts.count; i++) {
-    grpc_slice_split(query_parts.slices[i], QUERY_PARTS_VALUE_SEPARATOR,
-                     &query_param_parts);
-    GPR_ASSERT(query_param_parts.count > 0);
-    uri->query_parts[i] =
-        grpc_dump_slice(query_param_parts.slices[0], GPR_DUMP_ASCII);
-    if (query_param_parts.count > 1) {
+  gpr_string_split(uri->query, QUERY_PARTS_SEPARATOR, &uri->query_parts,
+                   &uri->num_query_parts);
+  uri->query_parts_values = gpr_malloc(uri->num_query_parts * sizeof(char **));
+  for (size_t i = 0; i < uri->num_query_parts; i++) {
+    char **query_param_parts;
+    size_t num_query_param_parts;
+    char *full = uri->query_parts[i];
+    gpr_string_split(full, QUERY_PARTS_VALUE_SEPARATOR, &query_param_parts,
+                     &num_query_param_parts);
+    GPR_ASSERT(num_query_param_parts > 0);
+    uri->query_parts[i] = query_param_parts[0];
+    if (num_query_param_parts > 1) {
       /* TODO(dgq): only the first value after the separator is considered.
        * Perhaps all chars after the first separator for the query part should
        * be included, even if they include the separator. */
-      uri->query_parts_values[i] =
-          grpc_dump_slice(query_param_parts.slices[1], GPR_DUMP_ASCII);
+      uri->query_parts_values[i] = query_param_parts[1];
     } else {
       uri->query_parts_values[i] = NULL;
     }
-    grpc_slice_buffer_reset_and_unref(&query_param_parts);
+    for (size_t j = 2; j < num_query_param_parts; j++) {
+      gpr_free(query_param_parts[j]);
+    }
+    gpr_free(query_param_parts);
+    gpr_free(full);
   }
-  grpc_slice_buffer_destroy(&query_parts);
-  grpc_slice_buffer_destroy(&query_param_parts);
-  grpc_slice_unref(query_slice);
 }
 
 grpc_uri *grpc_uri_parse(const char *uri_text, int suppress_errors) {
diff --git a/src/core/ext/lb_policy/grpclb/grpclb.c b/src/core/ext/lb_policy/grpclb/grpclb.c
index 4262d2b9a4..97f98df03a 100644
--- a/src/core/ext/lb_policy/grpclb/grpclb.c
+++ b/src/core/ext/lb_policy/grpclb/grpclb.c
@@ -106,6 +106,7 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/time.h>
 
+#include "src/core/ext/client_channel/client_channel.h"
 #include "src/core/ext/client_channel/client_channel_factory.h"
 #include "src/core/ext/client_channel/lb_policy_factory.h"
 #include "src/core/ext/client_channel/lb_policy_registry.h"
@@ -116,6 +117,7 @@
 #include "src/core/lib/iomgr/sockaddr.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
 #include "src/core/lib/iomgr/timer.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/backoff.h"
 #include "src/core/lib/support/string.h"
@@ -123,10 +125,11 @@
 #include "src/core/lib/surface/channel.h"
 #include "src/core/lib/transport/static_metadata.h"
 
-#define BACKOFF_MULTIPLIER 1.6
-#define BACKOFF_JITTER 0.2
-#define BACKOFF_MIN_SECONDS 10
-#define BACKOFF_MAX_SECONDS 60
+#define GRPC_GRPCLB_MIN_CONNECT_TIMEOUT_SECONDS 20
+#define GRPC_GRPCLB_INITIAL_CONNECT_BACKOFF_SECONDS 1
+#define GRPC_GRPCLB_RECONNECT_BACKOFF_MULTIPLIER 1.6
+#define GRPC_GRPCLB_RECONNECT_MAX_BACKOFF_SECONDS 120
+#define GRPC_GRPCLB_RECONNECT_JITTER 0.2
 
 int grpc_lb_glb_trace = 0;
 
@@ -178,8 +181,7 @@ static void wrapped_rr_closure(grpc_exec_ctx *exec_ctx, void *arg,
   wrapped_rr_closure_arg *wc_arg = arg;
 
   GPR_ASSERT(wc_arg->wrapped_closure != NULL);
-  grpc_exec_ctx_sched(exec_ctx, wc_arg->wrapped_closure, GRPC_ERROR_REF(error),
-                      NULL);
+  grpc_closure_sched(exec_ctx, wc_arg->wrapped_closure, GRPC_ERROR_REF(error));
 
   if (wc_arg->rr_policy != NULL) {
     /* if *target is NULL, no pick has been made by the RR policy (eg, all
@@ -246,7 +248,8 @@ static void add_pending_pick(pending_pick **root,
       pick_args->lb_token_mdelem_storage;
   pp->wrapped_on_complete_arg.free_when_done = pp;
   grpc_closure_init(&pp->wrapped_on_complete_arg.wrapper_closure,
-                    wrapped_rr_closure, &pp->wrapped_on_complete_arg);
+                    wrapped_rr_closure, &pp->wrapped_on_complete_arg,
+                    grpc_schedule_on_exec_ctx);
   *root = pp;
 }
 
@@ -266,7 +269,8 @@ static void add_pending_ping(pending_ping **root, grpc_closure *notify) {
   pping->wrapped_notify_arg.free_when_done = pping;
   pping->next = *root;
   grpc_closure_init(&pping->wrapped_notify_arg.wrapper_closure,
-                    wrapped_rr_closure, &pping->wrapped_notify_arg);
+                    wrapped_rr_closure, &pping->wrapped_notify_arg,
+                    grpc_schedule_on_exec_ctx);
   *root = pping;
 }
 
@@ -323,6 +327,9 @@ typedef struct glb_lb_policy {
   /* A response from the LB server has been received. Process it */
   grpc_closure lb_on_response_received;
 
+  /* LB call retry timer callback. */
+  grpc_closure lb_on_call_retry;
+
   grpc_call *lb_call; /* streaming call to the LB server, */
 
   grpc_metadata_array lb_initial_metadata_recv; /* initial MD from LB server */
@@ -383,8 +390,8 @@ static bool is_server_valid(const grpc_grpclb_server *server, size_t idx,
 static void *lb_token_copy(void *token) {
   return token == NULL ? NULL : GRPC_MDELEM_REF(token);
 }
-static void lb_token_destroy(void *token) {
-  if (token != NULL) GRPC_MDELEM_UNREF(token);
+static void lb_token_destroy(grpc_exec_ctx *exec_ctx, void *token) {
+  if (token != NULL) GRPC_MDELEM_UNREF(exec_ctx, token);
 }
 static int lb_token_cmp(void *token1, void *token2) {
   if (token1 > token2) return 1;
@@ -418,7 +425,7 @@ static void parse_server(const grpc_grpclb_server *server,
 
 /* Returns addresses extracted from \a serverlist. */
 static grpc_lb_addresses *process_serverlist_locked(
-    const grpc_grpclb_serverlist *serverlist) {
+    grpc_exec_ctx *exec_ctx, const grpc_grpclb_serverlist *serverlist) {
   size_t num_valid = 0;
   /* first pass: count how many are valid in order to allocate the necessary
    * memory in a single block */
@@ -454,8 +461,8 @@ static grpc_lb_addresses *process_serverlist_locked(
           strnlen(server->load_balance_token, lb_token_max_length);
       grpc_mdstr *lb_token_mdstr = grpc_mdstr_from_buffer(
           (uint8_t *)server->load_balance_token, lb_token_length);
-      user_data = grpc_mdelem_from_metadata_strings(GRPC_MDSTR_LB_TOKEN,
-                                                    lb_token_mdstr);
+      user_data = grpc_mdelem_from_metadata_strings(
+          exec_ctx, GRPC_MDSTR_LB_TOKEN, lb_token_mdstr);
     } else {
       char *uri = grpc_sockaddr_to_uri(&addr);
       gpr_log(GPR_INFO,
@@ -578,7 +585,8 @@ static grpc_lb_policy *create_rr_locked(
   grpc_lb_policy_args args;
   memset(&args, 0, sizeof(args));
   args.client_channel_factory = glb_policy->cc_factory;
-  grpc_lb_addresses *addresses = process_serverlist_locked(serverlist);
+  grpc_lb_addresses *addresses =
+      process_serverlist_locked(exec_ctx, serverlist);
 
   // Replace the LB addresses in the channel args that we pass down to
   // the subchannel.
@@ -590,8 +598,8 @@ static grpc_lb_policy *create_rr_locked(
 
   grpc_lb_policy *rr = grpc_lb_policy_create(exec_ctx, "round_robin", &args);
   GPR_ASSERT(rr != NULL);
-  grpc_lb_addresses_destroy(addresses);
-  grpc_channel_args_destroy(args.args);
+  grpc_lb_addresses_destroy(exec_ctx, addresses);
+  grpc_channel_args_destroy(exec_ctx, args.args);
   return rr;
 }
 
@@ -665,7 +673,7 @@ static void rr_handover_locked(grpc_exec_ctx *exec_ctx,
       gpr_malloc(sizeof(rr_connectivity_data));
   memset(rr_connectivity, 0, sizeof(rr_connectivity_data));
   grpc_closure_init(&rr_connectivity->on_change, glb_rr_connectivity_changed,
-                    rr_connectivity);
+                    rr_connectivity, grpc_schedule_on_exec_ctx);
   rr_connectivity->glb_policy = glb_policy;
   rr_connectivity->state = new_rr_state;
 
@@ -742,12 +750,6 @@ static void glb_rr_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg,
 static grpc_lb_policy *glb_create(grpc_exec_ctx *exec_ctx,
                                   grpc_lb_policy_factory *factory,
                                   grpc_lb_policy_args *args) {
-  /* Get server name. */
-  const grpc_arg *arg =
-      grpc_channel_args_find(args->args, GRPC_ARG_SERVER_NAME);
-  const char *server_name =
-      arg != NULL && arg->type == GRPC_ARG_STRING ? arg->value.string : NULL;
-
   /* Count the number of gRPC-LB addresses. There must be at least one.
    * TODO(roth): For now, we ignore non-balancer addresses, but in the
    * future, we may change the behavior such that we fall back to using
@@ -755,7 +757,8 @@ static grpc_lb_policy *glb_create(grpc_exec_ctx *exec_ctx,
    * time, this should be changed to allow a list with no balancer addresses,
    * since the resolver might fail to return a balancer address even when
    * this is the right LB policy to use. */
-  arg = grpc_channel_args_find(args->args, GRPC_ARG_LB_ADDRESSES);
+  const grpc_arg *arg =
+      grpc_channel_args_find(args->args, GRPC_ARG_LB_ADDRESSES);
   GPR_ASSERT(arg != NULL && arg->type == GRPC_ARG_POINTER);
   grpc_lb_addresses *addresses = arg->value.pointer.p;
   size_t num_grpclb_addrs = 0;
@@ -767,13 +770,25 @@ static grpc_lb_policy *glb_create(grpc_exec_ctx *exec_ctx,
   glb_lb_policy *glb_policy = gpr_malloc(sizeof(*glb_policy));
   memset(glb_policy, 0, sizeof(*glb_policy));
 
+  /* Get server name. */
+  arg = grpc_channel_args_find(args->args, GRPC_ARG_SERVER_URI);
+  GPR_ASSERT(arg != NULL);
+  GPR_ASSERT(arg->type == GRPC_ARG_STRING);
+  grpc_uri *uri = grpc_uri_parse(arg->value.string, true);
+  GPR_ASSERT(uri->path[0] != '\0');
+  glb_policy->server_name =
+      gpr_strdup(uri->path[0] == '/' ? uri->path + 1 : uri->path);
+  if (grpc_lb_glb_trace) {
+    gpr_log(GPR_INFO, "Will use '%s' as the server name for LB request.",
+            glb_policy->server_name);
+  }
+  grpc_uri_destroy(uri);
+
   /* All input addresses in addresses come from a resolver that claims
    * they are LB services. It's the resolver's responsibility to make sure
-   * this
-   * policy is only instantiated and used in that case.
+   * this policy is only instantiated and used in that case.
    *
    * Create a client channel over them to communicate with a LB service */
-  glb_policy->server_name = gpr_strdup(server_name);
   glb_policy->cc_factory = args->client_channel_factory;
   glb_policy->args = grpc_channel_args_copy(args->args);
   GPR_ASSERT(glb_policy->cc_factory != NULL);
@@ -817,15 +832,20 @@ static grpc_lb_policy *glb_create(grpc_exec_ctx *exec_ctx,
    * We need the LB channel to return addresses with is_balancer=false
    * so that it does not wind up recursively using the grpclb LB policy,
    * as per the special case logic in client_channel.c.
+   *
+   * Finally, we also strip out the channel arg for the server URI,
+   * since that will be different for the LB channel than for the parent
+   * channel.  (The client channel factory will re-add this arg with
+   * the right value.)
    */
-  static const char *keys_to_remove[] = {GRPC_ARG_LB_POLICY_NAME,
-                                         GRPC_ARG_LB_ADDRESSES};
+  static const char *keys_to_remove[] = {
+      GRPC_ARG_LB_POLICY_NAME, GRPC_ARG_LB_ADDRESSES, GRPC_ARG_SERVER_URI};
   grpc_channel_args *new_args = grpc_channel_args_copy_and_remove(
       args->args, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove));
   glb_policy->lb_channel = grpc_client_channel_factory_create_channel(
       exec_ctx, glb_policy->cc_factory, target_uri_str,
       GRPC_CLIENT_CHANNEL_TYPE_LOAD_BALANCING, new_args);
-  grpc_channel_args_destroy(new_args);
+  grpc_channel_args_destroy(exec_ctx, new_args);
 
   gpr_free(target_uri_str);
   for (size_t i = 0; i < num_grpclb_addrs; i++) {
@@ -851,7 +871,7 @@ static void glb_destroy(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   GPR_ASSERT(glb_policy->pending_picks == NULL);
   GPR_ASSERT(glb_policy->pending_pings == NULL);
   gpr_free((void *)glb_policy->server_name);
-  grpc_channel_args_destroy(glb_policy->args);
+  grpc_channel_args_destroy(exec_ctx, glb_policy->args);
   grpc_channel_destroy(glb_policy->lb_channel);
   glb_policy->lb_channel = NULL;
   grpc_connectivity_state_destroy(exec_ctx, &glb_policy->state_tracker);
@@ -894,15 +914,15 @@ static void glb_shutdown(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   while (pp != NULL) {
     pending_pick *next = pp->next;
     *pp->target = NULL;
-    grpc_exec_ctx_sched(exec_ctx, &pp->wrapped_on_complete_arg.wrapper_closure,
-                        GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, &pp->wrapped_on_complete_arg.wrapper_closure,
+                       GRPC_ERROR_NONE);
     pp = next;
   }
 
   while (pping != NULL) {
     pending_ping *next = pping->next;
-    grpc_exec_ctx_sched(exec_ctx, &pping->wrapped_notify_arg.wrapper_closure,
-                        GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, &pping->wrapped_notify_arg.wrapper_closure,
+                       GRPC_ERROR_NONE);
     pping = next;
   }
 }
@@ -918,9 +938,9 @@ static void glb_cancel_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
     pending_pick *next = pp->next;
     if (pp->target == target) {
       *target = NULL;
-      grpc_exec_ctx_sched(
+      grpc_closure_sched(
           exec_ctx, &pp->wrapped_on_complete_arg.wrapper_closure,
-          GRPC_ERROR_CREATE_REFERENCING("Pick Cancelled", &error, 1), NULL);
+          GRPC_ERROR_CREATE_REFERENCING("Pick Cancelled", &error, 1));
     } else {
       pp->next = glb_policy->pending_picks;
       glb_policy->pending_picks = pp;
@@ -943,9 +963,9 @@ static void glb_cancel_picks(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
     pending_pick *next = pp->next;
     if ((pp->pick_args.initial_metadata_flags & initial_metadata_flags_mask) ==
         initial_metadata_flags_eq) {
-      grpc_exec_ctx_sched(
+      grpc_closure_sched(
           exec_ctx, &pp->wrapped_on_complete_arg.wrapper_closure,
-          GRPC_ERROR_CREATE_REFERENCING("Pick Cancelled", &error, 1), NULL);
+          GRPC_ERROR_CREATE_REFERENCING("Pick Cancelled", &error, 1));
     } else {
       pp->next = glb_policy->pending_picks;
       glb_policy->pending_picks = pp;
@@ -980,11 +1000,10 @@ static int glb_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
                     grpc_closure *on_complete) {
   if (pick_args->lb_token_mdelem_storage == NULL) {
     *target = NULL;
-    grpc_exec_ctx_sched(
+    grpc_closure_sched(
         exec_ctx, on_complete,
         GRPC_ERROR_CREATE("No mdelem storage for the LB token. Load reporting "
-                          "won't work without it. Failing"),
-        NULL);
+                          "won't work without it. Failing"));
     return 0;
   }
 
@@ -1003,7 +1022,8 @@ static int glb_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
     wrapped_rr_closure_arg *wc_arg = gpr_malloc(sizeof(wrapped_rr_closure_arg));
     memset(wc_arg, 0, sizeof(wrapped_rr_closure_arg));
 
-    grpc_closure_init(&wc_arg->wrapper_closure, wrapped_rr_closure, wc_arg);
+    grpc_closure_init(&wc_arg->wrapper_closure, wrapped_rr_closure, wc_arg,
+                      grpc_schedule_on_exec_ctx);
     wc_arg->rr_policy = glb_policy->rr_policy;
     wc_arg->target = target;
     wc_arg->wrapped_closure = on_complete;
@@ -1074,7 +1094,8 @@ static void lb_on_server_status_received(grpc_exec_ctx *exec_ctx, void *arg,
                                          grpc_error *error);
 static void lb_on_response_received(grpc_exec_ctx *exec_ctx, void *arg,
                                     grpc_error *error);
-static void lb_call_init_locked(glb_lb_policy *glb_policy) {
+static void lb_call_init_locked(grpc_exec_ctx *exec_ctx,
+                                glb_lb_policy *glb_policy) {
   GPR_ASSERT(glb_policy->server_name != NULL);
   GPR_ASSERT(glb_policy->server_name[0] != '\0');
   GPR_ASSERT(!glb_policy->shutting_down);
@@ -1083,7 +1104,7 @@ static void lb_call_init_locked(glb_lb_policy *glb_policy) {
    * glb_policy->base.interested_parties, which is comprised of the polling
    * entities from \a client_channel. */
   glb_policy->lb_call = grpc_channel_create_pollset_set_call(
-      glb_policy->lb_channel, NULL, GRPC_PROPAGATE_DEFAULTS,
+      exec_ctx, glb_policy->lb_channel, NULL, GRPC_PROPAGATE_DEFAULTS,
       glb_policy->base.interested_parties,
       "/grpc.lb.v1.LoadBalancer/BalanceLoad", glb_policy->server_name,
       glb_policy->deadline, NULL);
@@ -1096,20 +1117,25 @@ static void lb_call_init_locked(glb_lb_policy *glb_policy) {
   grpc_slice request_payload_slice = grpc_grpclb_request_encode(request);
   glb_policy->lb_request_payload =
       grpc_raw_byte_buffer_create(&request_payload_slice, 1);
-  grpc_slice_unref(request_payload_slice);
+  grpc_slice_unref_internal(exec_ctx, request_payload_slice);
   grpc_grpclb_request_destroy(request);
 
   glb_policy->lb_call_status_details = NULL;
   glb_policy->lb_call_status_details_capacity = 0;
 
   grpc_closure_init(&glb_policy->lb_on_server_status_received,
-                    lb_on_server_status_received, glb_policy);
+                    lb_on_server_status_received, glb_policy,
+                    grpc_schedule_on_exec_ctx);
   grpc_closure_init(&glb_policy->lb_on_response_received,
-                    lb_on_response_received, glb_policy);
-
-  gpr_backoff_init(&glb_policy->lb_call_backoff_state, BACKOFF_MULTIPLIER,
-                   BACKOFF_JITTER, BACKOFF_MIN_SECONDS * 1000,
-                   BACKOFF_MAX_SECONDS * 1000);
+                    lb_on_response_received, glb_policy,
+                    grpc_schedule_on_exec_ctx);
+
+  gpr_backoff_init(&glb_policy->lb_call_backoff_state,
+                   GRPC_GRPCLB_INITIAL_CONNECT_BACKOFF_SECONDS,
+                   GRPC_GRPCLB_RECONNECT_BACKOFF_MULTIPLIER,
+                   GRPC_GRPCLB_RECONNECT_JITTER,
+                   GRPC_GRPCLB_MIN_CONNECT_TIMEOUT_SECONDS * 1000,
+                   GRPC_GRPCLB_RECONNECT_MAX_BACKOFF_SECONDS * 1000);
 }
 
 static void lb_call_destroy_locked(glb_lb_policy *glb_policy) {
@@ -1132,7 +1158,7 @@ static void query_for_backends_locked(grpc_exec_ctx *exec_ctx,
   GPR_ASSERT(glb_policy->lb_channel != NULL);
   if (glb_policy->shutting_down) return;
 
-  lb_call_init_locked(glb_policy);
+  lb_call_init_locked(exec_ctx, glb_policy);
 
   if (grpc_lb_glb_trace) {
     gpr_log(GPR_INFO, "Query for backends (grpclb: %p, lb_call: %p)",
@@ -1217,7 +1243,7 @@ static void lb_on_response_received(grpc_exec_ctx *exec_ctx, void *arg,
         grpc_grpclb_response_parse_serverlist(response_slice);
     if (serverlist != NULL) {
       GPR_ASSERT(glb_policy->lb_call != NULL);
-      grpc_slice_unref(response_slice);
+      grpc_slice_unref_internal(exec_ctx, response_slice);
       if (grpc_lb_glb_trace) {
         gpr_log(GPR_INFO, "Serverlist with %lu servers received",
                 (unsigned long)serverlist->num_servers);
@@ -1261,7 +1287,7 @@ static void lb_on_response_received(grpc_exec_ctx *exec_ctx, void *arg,
     } else { /* serverlist == NULL */
       gpr_log(GPR_ERROR, "Invalid LB response received: '%s'. Ignoring.",
               grpc_dump_slice(response_slice, GPR_DUMP_ASCII | GPR_DUMP_HEX));
-      grpc_slice_unref(response_slice);
+      grpc_slice_unref_internal(exec_ctx, response_slice);
     }
 
     if (!glb_policy->shutting_down) {
@@ -1341,8 +1367,10 @@ static void lb_on_server_status_received(grpc_exec_ctx *exec_ctx, void *arg,
       }
     }
     GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "grpclb_retry_timer");
+    grpc_closure_init(&glb_policy->lb_on_call_retry, lb_call_on_retry_timer,
+                      glb_policy, grpc_schedule_on_exec_ctx);
     grpc_timer_init(exec_ctx, &glb_policy->lb_call_retry_timer, next_try,
-                    lb_call_on_retry_timer, glb_policy, now);
+                    &glb_policy->lb_on_call_retry, now);
   }
   gpr_mu_unlock(&glb_policy->mu);
   GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &glb_policy->base,
diff --git a/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c b/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c
index afecb716fb..e352e0396f 100644
--- a/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c
+++ b/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c
@@ -1,35 +1,3 @@
-/*
- *
- * Copyright 2016, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
 /* Automatically generated nanopb constant definitions */
 /* Generated by nanopb-0.3.7-dev */
 
diff --git a/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h b/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h
index e36d0966f8..725aa7e386 100644
--- a/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h
+++ b/src/core/ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h
@@ -1,35 +1,3 @@
-/*
- *
- * Copyright 2016, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
 /* Automatically generated nanopb header */
 /* Generated by nanopb-0.3.7-dev */
 
diff --git a/src/core/ext/lb_policy/pick_first/pick_first.c b/src/core/ext/lb_policy/pick_first/pick_first.c
index c69f773e78..821becff69 100644
--- a/src/core/ext/lb_policy/pick_first/pick_first.c
+++ b/src/core/ext/lb_policy/pick_first/pick_first.c
@@ -120,7 +120,7 @@ static void pf_shutdown(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   while (pp != NULL) {
     pending_pick *next = pp->next;
     *pp->target = NULL;
-    grpc_exec_ctx_sched(exec_ctx, pp->on_complete, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, pp->on_complete, GRPC_ERROR_NONE);
     gpr_free(pp);
     pp = next;
   }
@@ -138,9 +138,9 @@ static void pf_cancel_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
     pending_pick *next = pp->next;
     if (pp->target == target) {
       *target = NULL;
-      grpc_exec_ctx_sched(
+      grpc_closure_sched(
           exec_ctx, pp->on_complete,
-          GRPC_ERROR_CREATE_REFERENCING("Pick Cancelled", &error, 1), NULL);
+          GRPC_ERROR_CREATE_REFERENCING("Pick Cancelled", &error, 1));
       gpr_free(pp);
     } else {
       pp->next = p->pending_picks;
@@ -165,9 +165,9 @@ static void pf_cancel_picks(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
     pending_pick *next = pp->next;
     if ((pp->initial_metadata_flags & initial_metadata_flags_mask) ==
         initial_metadata_flags_eq) {
-      grpc_exec_ctx_sched(
+      grpc_closure_sched(
           exec_ctx, pp->on_complete,
-          GRPC_ERROR_CREATE_REFERENCING("Pick Cancelled", &error, 1), NULL);
+          GRPC_ERROR_CREATE_REFERENCING("Pick Cancelled", &error, 1));
       gpr_free(pp);
     } else {
       pp->next = p->pending_picks;
@@ -306,14 +306,15 @@ static void pf_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg,
         /* drop the pick list: we are connected now */
         GRPC_LB_POLICY_WEAK_REF(&p->base, "destroy_subchannels");
         gpr_atm_rel_store(&p->selected, (gpr_atm)selected);
-        grpc_exec_ctx_sched(exec_ctx,
-                            grpc_closure_create(destroy_subchannels, p),
-                            GRPC_ERROR_NONE, NULL);
+        grpc_closure_sched(exec_ctx,
+                           grpc_closure_create(destroy_subchannels, p,
+                                               grpc_schedule_on_exec_ctx),
+                           GRPC_ERROR_NONE);
         /* update any calls that were waiting for a pick */
         while ((pp = p->pending_picks)) {
           p->pending_picks = pp->next;
           *pp->target = GRPC_CONNECTED_SUBCHANNEL_REF(selected, "picked");
-          grpc_exec_ctx_sched(exec_ctx, pp->on_complete, GRPC_ERROR_NONE, NULL);
+          grpc_closure_sched(exec_ctx, pp->on_complete, GRPC_ERROR_NONE);
           gpr_free(pp);
         }
         grpc_connected_subchannel_notify_on_state_change(
@@ -366,8 +367,7 @@ static void pf_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg,
           while ((pp = p->pending_picks)) {
             p->pending_picks = pp->next;
             *pp->target = NULL;
-            grpc_exec_ctx_sched(exec_ctx, pp->on_complete, GRPC_ERROR_NONE,
-                                NULL);
+            grpc_closure_sched(exec_ctx, pp->on_complete, GRPC_ERROR_NONE);
             gpr_free(pp);
           }
           GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &p->base,
@@ -419,8 +419,7 @@ static void pf_ping_one(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
   if (selected) {
     grpc_connected_subchannel_ping(exec_ctx, selected, closure);
   } else {
-    grpc_exec_ctx_sched(exec_ctx, closure, GRPC_ERROR_CREATE("Not connected"),
-                        NULL);
+    grpc_closure_sched(exec_ctx, closure, GRPC_ERROR_CREATE("Not connected"));
   }
 }
 
@@ -438,15 +437,10 @@ static grpc_lb_policy *create_pick_first(grpc_exec_ctx *exec_ctx,
                                          grpc_lb_policy_args *args) {
   GPR_ASSERT(args->client_channel_factory != NULL);
 
-  /* Get server name. */
-  const grpc_arg *arg =
-      grpc_channel_args_find(args->args, GRPC_ARG_SERVER_NAME);
-  const char *server_name =
-      arg != NULL && arg->type == GRPC_ARG_STRING ? arg->value.string : NULL;
-
   /* Find the number of backend addresses. We ignore balancer
    * addresses, since we don't know how to handle them. */
-  arg = grpc_channel_args_find(args->args, GRPC_ARG_LB_ADDRESSES);
+  const grpc_arg *arg =
+      grpc_channel_args_find(args->args, GRPC_ARG_LB_ADDRESSES);
   GPR_ASSERT(arg != NULL && arg->type == GRPC_ARG_POINTER);
   grpc_lb_addresses *addresses = arg->value.pointer.p;
   size_t num_addrs = 0;
@@ -472,9 +466,6 @@ static grpc_lb_policy *create_pick_first(grpc_exec_ctx *exec_ctx,
     }
 
     memset(&sc_args, 0, sizeof(grpc_subchannel_args));
-    /* server_name will be copied as part of the subchannel creation. This makes
-     * the copying of server_name (a borrowed pointer) OK. */
-    sc_args.server_name = server_name;
     sc_args.addr = &addresses->addresses[i].address;
     sc_args.args = args->args;
 
@@ -493,7 +484,8 @@ static grpc_lb_policy *create_pick_first(grpc_exec_ctx *exec_ctx,
   p->num_subchannels = subchannel_idx;
 
   grpc_lb_policy_init(&p->base, &pick_first_lb_policy_vtable);
-  grpc_closure_init(&p->connectivity_changed, pf_connectivity_changed, p);
+  grpc_closure_init(&p->connectivity_changed, pf_connectivity_changed, p,
+                    grpc_schedule_on_exec_ctx);
   gpr_mu_init(&p->mu);
   return &p->base;
 }
diff --git a/src/core/ext/lb_policy/round_robin/round_robin.c b/src/core/ext/lb_policy/round_robin/round_robin.c
index 59f84054c4..cb679489c3 100644
--- a/src/core/ext/lb_policy/round_robin/round_robin.c
+++ b/src/core/ext/lb_policy/round_robin/round_robin.c
@@ -284,7 +284,7 @@ static void rr_destroy(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
     GRPC_SUBCHANNEL_UNREF(exec_ctx, sd->subchannel, "rr_destroy");
     if (sd->user_data != NULL) {
       GPR_ASSERT(sd->user_data_vtable != NULL);
-      sd->user_data_vtable->destroy(sd->user_data);
+      sd->user_data_vtable->destroy(exec_ctx, sd->user_data);
     }
     gpr_free(sd);
   }
@@ -321,8 +321,8 @@ static void rr_shutdown(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   while ((pp = p->pending_picks)) {
     p->pending_picks = pp->next;
     *pp->target = NULL;
-    grpc_exec_ctx_sched(exec_ctx, pp->on_complete,
-                        GRPC_ERROR_CREATE("Channel Shutdown"), NULL);
+    grpc_closure_sched(exec_ctx, pp->on_complete,
+                       GRPC_ERROR_CREATE("Channel Shutdown"));
     gpr_free(pp);
   }
   grpc_connectivity_state_set(
@@ -348,9 +348,9 @@ static void rr_cancel_pick(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
     pending_pick *next = pp->next;
     if (pp->target == target) {
       *target = NULL;
-      grpc_exec_ctx_sched(
+      grpc_closure_sched(
           exec_ctx, pp->on_complete,
-          GRPC_ERROR_CREATE_REFERENCING("Pick cancelled", &error, 1), NULL);
+          GRPC_ERROR_CREATE_REFERENCING("Pick cancelled", &error, 1));
       gpr_free(pp);
     } else {
       pp->next = p->pending_picks;
@@ -376,9 +376,9 @@ static void rr_cancel_picks(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
     if ((pp->initial_metadata_flags & initial_metadata_flags_mask) ==
         initial_metadata_flags_eq) {
       *pp->target = NULL;
-      grpc_exec_ctx_sched(
+      grpc_closure_sched(
           exec_ctx, pp->on_complete,
-          GRPC_ERROR_CREATE_REFERENCING("Pick cancelled", &error, 1), NULL);
+          GRPC_ERROR_CREATE_REFERENCING("Pick cancelled", &error, 1));
       gpr_free(pp);
     } else {
       pp->next = p->pending_picks;
@@ -581,7 +581,7 @@ static void rr_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg,
                   "[RR CONN CHANGED] TARGET <-- SUBCHANNEL %p (NODE %p)",
                   (void *)selected->subchannel, (void *)selected);
         }
-        grpc_exec_ctx_sched(exec_ctx, pp->on_complete, GRPC_ERROR_NONE, NULL);
+        grpc_closure_sched(exec_ctx, pp->on_complete, GRPC_ERROR_NONE);
         gpr_free(pp);
       }
       update_lb_connectivity_status(exec_ctx, sd, error);
@@ -634,7 +634,7 @@ static void rr_connectivity_changed(grpc_exec_ctx *exec_ctx, void *arg,
         while ((pp = p->pending_picks)) {
           p->pending_picks = pp->next;
           *pp->target = NULL;
-          grpc_exec_ctx_sched(exec_ctx, pp->on_complete, GRPC_ERROR_NONE, NULL);
+          grpc_closure_sched(exec_ctx, pp->on_complete, GRPC_ERROR_NONE);
           gpr_free(pp);
         }
       }
@@ -684,8 +684,8 @@ static void rr_ping_one(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol,
     GRPC_CONNECTED_SUBCHANNEL_UNREF(exec_ctx, target, "rr_picked");
   } else {
     gpr_mu_unlock(&p->mu);
-    grpc_exec_ctx_sched(exec_ctx, closure,
-                        GRPC_ERROR_CREATE("Round Robin not connected"), NULL);
+    grpc_closure_sched(exec_ctx, closure,
+                       GRPC_ERROR_CREATE("Round Robin not connected"));
   }
 }
 
@@ -703,15 +703,10 @@ static grpc_lb_policy *round_robin_create(grpc_exec_ctx *exec_ctx,
                                           grpc_lb_policy_args *args) {
   GPR_ASSERT(args->client_channel_factory != NULL);
 
-  /* Get server name. */
-  const grpc_arg *arg =
-      grpc_channel_args_find(args->args, GRPC_ARG_SERVER_NAME);
-  const char *server_name =
-      arg != NULL && arg->type == GRPC_ARG_STRING ? arg->value.string : NULL;
-
   /* Find the number of backend addresses. We ignore balancer
    * addresses, since we don't know how to handle them. */
-  arg = grpc_channel_args_find(args->args, GRPC_ARG_LB_ADDRESSES);
+  const grpc_arg *arg =
+      grpc_channel_args_find(args->args, GRPC_ARG_LB_ADDRESSES);
   GPR_ASSERT(arg != NULL && arg->type == GRPC_ARG_POINTER);
   grpc_lb_addresses *addresses = arg->value.pointer.p;
   size_t num_addrs = 0;
@@ -734,9 +729,6 @@ static grpc_lb_policy *round_robin_create(grpc_exec_ctx *exec_ctx,
     if (addresses->addresses[i].is_balancer) continue;
 
     memset(&sc_args, 0, sizeof(grpc_subchannel_args));
-    /* server_name will be copied as part of the subchannel creation. This makes
-     * the copying of server_name (a borrowed pointer) OK. */
-    sc_args.server_name = server_name;
     sc_args.addr = &addresses->addresses[i].address;
     sc_args.args = args->args;
 
@@ -757,7 +749,7 @@ static grpc_lb_policy *round_robin_create(grpc_exec_ctx *exec_ctx,
       }
       ++subchannel_idx;
       grpc_closure_init(&sd->connectivity_changed_closure,
-                        rr_connectivity_changed, sd);
+                        rr_connectivity_changed, sd, grpc_schedule_on_exec_ctx);
     }
   }
   if (subchannel_idx == 0) {
diff --git a/src/core/ext/load_reporting/load_reporting.c b/src/core/ext/load_reporting/load_reporting.c
index df1ea0ec9a..37b06a737f 100644
--- a/src/core/ext/load_reporting/load_reporting.c
+++ b/src/core/ext/load_reporting/load_reporting.c
@@ -53,7 +53,8 @@ static bool is_load_reporting_enabled(const grpc_channel_args *a) {
   return false;
 }
 
-static bool maybe_add_load_reporting_filter(grpc_channel_stack_builder *builder,
+static bool maybe_add_load_reporting_filter(grpc_exec_ctx *exec_ctx,
+                                            grpc_channel_stack_builder *builder,
                                             void *arg) {
   const grpc_channel_args *args =
       grpc_channel_stack_builder_get_channel_arguments(builder);
diff --git a/src/core/ext/load_reporting/load_reporting_filter.c b/src/core/ext/load_reporting/load_reporting_filter.c
index b810e20bb9..07ef10e6a8 100644
--- a/src/core/ext/load_reporting/load_reporting_filter.c
+++ b/src/core/ext/load_reporting/load_reporting_filter.c
@@ -68,7 +68,8 @@ typedef struct {
   grpc_exec_ctx *exec_ctx;
 } recv_md_filter_args;
 
-static grpc_mdelem *recv_md_filter(void *user_data, grpc_mdelem *md) {
+static grpc_mdelem *recv_md_filter(grpc_exec_ctx *exec_ctx, void *user_data,
+                                   grpc_mdelem *md) {
   recv_md_filter_args *a = user_data;
   grpc_call_element *elem = a->elem;
   call_data *calld = elem->call_data;
@@ -92,8 +93,8 @@ static void on_initial_md_ready(grpc_exec_ctx *exec_ctx, void *user_data,
     recv_md_filter_args a;
     a.elem = elem;
     a.exec_ctx = exec_ctx;
-    grpc_metadata_batch_filter(calld->recv_initial_metadata, recv_md_filter,
-                               &a);
+    grpc_metadata_batch_filter(exec_ctx, calld->recv_initial_metadata,
+                               recv_md_filter, &a);
     if (calld->service_method == NULL) {
       err =
           grpc_error_add_child(err, GRPC_ERROR_CREATE("Missing :path header"));
@@ -114,7 +115,8 @@ static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx,
   memset(calld, 0, sizeof(call_data));
 
   calld->id = (intptr_t)args->call_stack;
-  grpc_closure_init(&calld->on_initial_md_ready, on_initial_md_ready, elem);
+  grpc_closure_init(&calld->on_initial_md_ready, on_initial_md_ready, elem,
+                    grpc_schedule_on_exec_ctx);
 
   /* TODO(dgq): do something with the data
   channel_data *chand = elem->channel_data;
@@ -152,9 +154,9 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
 }
 
 /* Constructor for channel_data */
-static void init_channel_elem(grpc_exec_ctx *exec_ctx,
-                              grpc_channel_element *elem,
-                              grpc_channel_element_args *args) {
+static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
+                                     grpc_channel_element *elem,
+                                     grpc_channel_element_args *args) {
   GPR_ASSERT(!args->is_last);
 
   channel_data *chand = elem->channel_data;
@@ -171,6 +173,8 @@ static void init_channel_elem(grpc_exec_ctx *exec_ctx,
                                                 NULL,
                                                 NULL};
                                                 */
+
+  return GRPC_ERROR_NONE;
 }
 
 /* Destructor for channel data */
@@ -189,7 +193,8 @@ static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
   */
 }
 
-static grpc_mdelem *lr_trailing_md_filter(void *user_data, grpc_mdelem *md) {
+static grpc_mdelem *lr_trailing_md_filter(grpc_exec_ctx *exec_ctx,
+                                          void *user_data, grpc_mdelem *md) {
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
 
@@ -213,7 +218,7 @@ static void lr_start_transport_stream_op(grpc_exec_ctx *exec_ctx,
     calld->ops_recv_initial_metadata_ready = op->recv_initial_metadata_ready;
     op->recv_initial_metadata_ready = &calld->on_initial_md_ready;
   } else if (op->send_trailing_metadata) {
-    grpc_metadata_batch_filter(op->send_trailing_metadata,
+    grpc_metadata_batch_filter(exec_ctx, op->send_trailing_metadata,
                                lr_trailing_md_filter, elem);
   }
   grpc_call_next_op(exec_ctx, elem, op);
diff --git a/src/core/ext/resolver/README.md b/src/core/ext/resolver/README.md
new file mode 100644
index 0000000000..b0e234e96a
--- /dev/null
+++ b/src/core/ext/resolver/README.md
@@ -0,0 +1,4 @@
+# Resolver
+
+Implementations of various name resolution schemes.
+See the [naming spec](/doc/naming.md).
diff --git a/src/core/ext/resolver/dns/native/dns_resolver.c b/src/core/ext/resolver/dns/native/dns_resolver.c
index 665439f360..655d9dc586 100644
--- a/src/core/ext/resolver/dns/native/dns_resolver.c
+++ b/src/core/ext/resolver/dns/native/dns_resolver.c
@@ -46,10 +46,11 @@
 #include "src/core/lib/support/backoff.h"
 #include "src/core/lib/support/string.h"
 
-#define BACKOFF_MULTIPLIER 1.6
-#define BACKOFF_JITTER 0.2
-#define BACKOFF_MIN_SECONDS 1
-#define BACKOFF_MAX_SECONDS 120
+#define GRPC_DNS_MIN_CONNECT_TIMEOUT_SECONDS 1
+#define GRPC_DNS_INITIAL_CONNECT_BACKOFF_SECONDS 1
+#define GRPC_DNS_RECONNECT_BACKOFF_MULTIPLIER 1.6
+#define GRPC_DNS_RECONNECT_MAX_BACKOFF_SECONDS 120
+#define GRPC_DNS_RECONNECT_JITTER 0.2
 
 typedef struct {
   /** base class: must be first */
@@ -60,6 +61,8 @@ typedef struct {
   char *default_port;
   /** channel args. */
   grpc_channel_args *channel_args;
+  /** pollset_set to drive the name resolution process */
+  grpc_pollset_set *interested_parties;
 
   /** mutex guarding the rest of the state */
   gpr_mu mu;
@@ -78,6 +81,7 @@ typedef struct {
   /** retry timer */
   bool have_retry_timer;
   grpc_timer retry_timer;
+  grpc_closure on_retry;
   /** retry backoff state */
   gpr_backoff backoff_state;
 
@@ -109,8 +113,8 @@ static void dns_shutdown(grpc_exec_ctx *exec_ctx, grpc_resolver *resolver) {
   }
   if (r->next_completion != NULL) {
     *r->target_result = NULL;
-    grpc_exec_ctx_sched(exec_ctx, r->next_completion,
-                        GRPC_ERROR_CREATE("Resolver Shutdown"), NULL);
+    grpc_closure_sched(exec_ctx, r->next_completion,
+                       GRPC_ERROR_CREATE("Resolver Shutdown"));
     r->next_completion = NULL;
   }
   gpr_mu_unlock(&r->mu);
@@ -179,13 +183,13 @@ static void dns_on_resolved(grpc_exec_ctx *exec_ctx, void *arg,
     grpc_arg new_arg = grpc_lb_addresses_create_channel_arg(addresses);
     result = grpc_channel_args_copy_and_add(r->channel_args, &new_arg, 1);
     grpc_resolved_addresses_destroy(r->addresses);
-    grpc_lb_addresses_destroy(addresses);
+    grpc_lb_addresses_destroy(exec_ctx, addresses);
   } else {
     gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
     gpr_timespec next_try = gpr_backoff_step(&r->backoff_state, now);
     gpr_timespec timeout = gpr_time_sub(next_try, now);
     const char *msg = grpc_error_string(error);
-    gpr_log(GPR_DEBUG, "dns resolution failed: %s", msg);
+    gpr_log(GPR_INFO, "dns resolution failed (will retry): %s", msg);
     grpc_error_free_string(msg);
     GPR_ASSERT(!r->have_retry_timer);
     r->have_retry_timer = true;
@@ -196,11 +200,12 @@ static void dns_on_resolved(grpc_exec_ctx *exec_ctx, void *arg,
     } else {
       gpr_log(GPR_DEBUG, "retrying immediately");
     }
-    grpc_timer_init(exec_ctx, &r->retry_timer, next_try, dns_on_retry_timer, r,
-                    now);
+    grpc_closure_init(&r->on_retry, dns_on_retry_timer, r,
+                      grpc_schedule_on_exec_ctx);
+    grpc_timer_init(exec_ctx, &r->retry_timer, next_try, &r->on_retry, now);
   }
   if (r->resolved_result != NULL) {
-    grpc_channel_args_destroy(r->resolved_result);
+    grpc_channel_args_destroy(exec_ctx, r->resolved_result);
   }
   r->resolved_result = result;
   r->resolved_version++;
@@ -216,8 +221,10 @@ static void dns_start_resolving_locked(grpc_exec_ctx *exec_ctx,
   GPR_ASSERT(!r->resolving);
   r->resolving = true;
   r->addresses = NULL;
-  grpc_resolve_address(exec_ctx, r->name_to_resolve, r->default_port,
-                       grpc_closure_create(dns_on_resolved, r), &r->addresses);
+  grpc_resolve_address(
+      exec_ctx, r->name_to_resolve, r->default_port, r->interested_parties,
+      grpc_closure_create(dns_on_resolved, r, grpc_schedule_on_exec_ctx),
+      &r->addresses);
 }
 
 static void dns_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx,
@@ -227,7 +234,7 @@ static void dns_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx,
     *r->target_result = r->resolved_result == NULL
                             ? NULL
                             : grpc_channel_args_copy(r->resolved_result);
-    grpc_exec_ctx_sched(exec_ctx, r->next_completion, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
     r->next_completion = NULL;
     r->published_version = r->resolved_version;
   }
@@ -237,15 +244,17 @@ static void dns_destroy(grpc_exec_ctx *exec_ctx, grpc_resolver *gr) {
   dns_resolver *r = (dns_resolver *)gr;
   gpr_mu_destroy(&r->mu);
   if (r->resolved_result != NULL) {
-    grpc_channel_args_destroy(r->resolved_result);
+    grpc_channel_args_destroy(exec_ctx, r->resolved_result);
   }
+  grpc_pollset_set_destroy(r->interested_parties);
   gpr_free(r->name_to_resolve);
   gpr_free(r->default_port);
-  grpc_channel_args_destroy(r->channel_args);
+  grpc_channel_args_destroy(exec_ctx, r->channel_args);
   gpr_free(r);
 }
 
-static grpc_resolver *dns_create(grpc_resolver_args *args,
+static grpc_resolver *dns_create(grpc_exec_ctx *exec_ctx,
+                                 grpc_resolver_args *args,
                                  const char *default_port) {
   if (0 != strcmp(args->uri->authority, "")) {
     gpr_log(GPR_ERROR, "authority based dns uri's not supported");
@@ -263,14 +272,17 @@ static grpc_resolver *dns_create(grpc_resolver_args *args,
   grpc_resolver_init(&r->base, &dns_resolver_vtable);
   r->name_to_resolve = proxy_name == NULL ? gpr_strdup(path) : proxy_name;
   r->default_port = gpr_strdup(default_port);
-  grpc_arg server_name_arg;
-  server_name_arg.type = GRPC_ARG_STRING;
-  server_name_arg.key = GRPC_ARG_SERVER_NAME;
-  server_name_arg.value.string = (char *)path;
-  r->channel_args =
-      grpc_channel_args_copy_and_add(args->args, &server_name_arg, 1);
-  gpr_backoff_init(&r->backoff_state, BACKOFF_MULTIPLIER, BACKOFF_JITTER,
-                   BACKOFF_MIN_SECONDS * 1000, BACKOFF_MAX_SECONDS * 1000);
+  r->channel_args = grpc_channel_args_copy(args->args);
+  r->interested_parties = grpc_pollset_set_create();
+  if (args->pollset_set != NULL) {
+    grpc_pollset_set_add_pollset_set(exec_ctx, r->interested_parties,
+                                     args->pollset_set);
+  }
+  gpr_backoff_init(&r->backoff_state, GRPC_DNS_INITIAL_CONNECT_BACKOFF_SECONDS,
+                   GRPC_DNS_RECONNECT_BACKOFF_MULTIPLIER,
+                   GRPC_DNS_RECONNECT_JITTER,
+                   GRPC_DNS_MIN_CONNECT_TIMEOUT_SECONDS * 1000,
+                   GRPC_DNS_RECONNECT_MAX_BACKOFF_SECONDS * 1000);
   return &r->base;
 }
 
@@ -283,8 +295,9 @@ static void dns_factory_ref(grpc_resolver_factory *factory) {}
 static void dns_factory_unref(grpc_resolver_factory *factory) {}
 
 static grpc_resolver *dns_factory_create_resolver(
-    grpc_resolver_factory *factory, grpc_resolver_args *args) {
-  return dns_create(args, "https");
+    grpc_exec_ctx *exec_ctx, grpc_resolver_factory *factory,
+    grpc_resolver_args *args) {
+  return dns_create(exec_ctx, args, "https");
 }
 
 static char *dns_factory_get_default_host_name(grpc_resolver_factory *factory,
diff --git a/src/core/ext/resolver/sockaddr/sockaddr_resolver.c b/src/core/ext/resolver/sockaddr/sockaddr_resolver.c
index 26a650aadd..c146a627cb 100644
--- a/src/core/ext/resolver/sockaddr/sockaddr_resolver.c
+++ b/src/core/ext/resolver/sockaddr/sockaddr_resolver.c
@@ -47,6 +47,7 @@
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/iomgr/resolve_address.h"
 #include "src/core/lib/iomgr/unix_sockets_posix.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/string.h"
 
@@ -89,7 +90,7 @@ static void sockaddr_shutdown(grpc_exec_ctx *exec_ctx,
   gpr_mu_lock(&r->mu);
   if (r->next_completion != NULL) {
     *r->target_result = NULL;
-    grpc_exec_ctx_sched(exec_ctx, r->next_completion, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
     r->next_completion = NULL;
   }
   gpr_mu_unlock(&r->mu);
@@ -123,7 +124,7 @@ static void sockaddr_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx,
     grpc_arg arg = grpc_lb_addresses_create_channel_arg(r->addresses);
     *r->target_result =
         grpc_channel_args_copy_and_add(r->channel_args, &arg, 1);
-    grpc_exec_ctx_sched(exec_ctx, r->next_completion, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, r->next_completion, GRPC_ERROR_NONE);
     r->next_completion = NULL;
   }
 }
@@ -131,8 +132,8 @@ static void sockaddr_maybe_finish_next_locked(grpc_exec_ctx *exec_ctx,
 static void sockaddr_destroy(grpc_exec_ctx *exec_ctx, grpc_resolver *gr) {
   sockaddr_resolver *r = (sockaddr_resolver *)gr;
   gpr_mu_destroy(&r->mu);
-  grpc_lb_addresses_destroy(r->addresses);
-  grpc_channel_args_destroy(r->channel_args);
+  grpc_lb_addresses_destroy(exec_ctx, r->addresses);
+  grpc_channel_args_destroy(exec_ctx, r->channel_args);
   gpr_free(r);
 }
 
@@ -161,7 +162,8 @@ char *unix_get_default_authority(grpc_resolver_factory *factory,
 
 static void do_nothing(void *ignored) {}
 
-static grpc_resolver *sockaddr_create(grpc_resolver_args *args,
+static grpc_resolver *sockaddr_create(grpc_exec_ctx *exec_ctx,
+                                      grpc_resolver_args *args,
                                       int parse(grpc_uri *uri,
                                                 grpc_resolved_address *dst)) {
   if (0 != strcmp(args->uri->authority, "")) {
@@ -188,22 +190,17 @@ static grpc_resolver *sockaddr_create(grpc_resolver_args *args,
     gpr_free(part_str);
     if (errors_found) break;
   }
-  grpc_slice_buffer_destroy(&path_parts);
-  grpc_slice_unref(path_slice);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &path_parts);
+  grpc_slice_unref_internal(exec_ctx, path_slice);
   if (errors_found) {
-    grpc_lb_addresses_destroy(addresses);
+    grpc_lb_addresses_destroy(exec_ctx, addresses);
     return NULL;
   }
   /* Instantiate resolver. */
   sockaddr_resolver *r = gpr_malloc(sizeof(sockaddr_resolver));
   memset(r, 0, sizeof(*r));
   r->addresses = addresses;
-  grpc_arg server_name_arg;
-  server_name_arg.type = GRPC_ARG_STRING;
-  server_name_arg.key = GRPC_ARG_SERVER_NAME;
-  server_name_arg.value.string = args->uri->path;
-  r->channel_args =
-      grpc_channel_args_copy_and_add(args->args, &server_name_arg, 1);
+  r->channel_args = grpc_channel_args_copy(args->args);
   gpr_mu_init(&r->mu);
   grpc_resolver_init(&r->base, &sockaddr_resolver_vtable);
   return &r->base;
@@ -219,8 +216,9 @@ static void sockaddr_factory_unref(grpc_resolver_factory *factory) {}
 
 #define DECL_FACTORY(name)                                                  \
   static grpc_resolver *name##_factory_create_resolver(                     \
-      grpc_resolver_factory *factory, grpc_resolver_args *args) {           \
-    return sockaddr_create(args, parse_##name);                             \
+      grpc_exec_ctx *exec_ctx, grpc_resolver_factory *factory,              \
+      grpc_resolver_args *args) {                                           \
+    return sockaddr_create(exec_ctx, args, parse_##name);                   \
   }                                                                         \
   static const grpc_resolver_factory_vtable name##_factory_vtable = {       \
       sockaddr_factory_ref, sockaddr_factory_unref,                         \
diff --git a/src/core/ext/transport/README.md b/src/core/ext/transport/README.md
new file mode 100644
index 0000000000..2290568784
--- /dev/null
+++ b/src/core/ext/transport/README.md
@@ -0,0 +1 @@
+Transports for gRPC
diff --git a/src/core/ext/transport/chttp2/README.md b/src/core/ext/transport/chttp2/README.md
new file mode 100644
index 0000000000..8880a47460
--- /dev/null
+++ b/src/core/ext/transport/chttp2/README.md
@@ -0,0 +1 @@
+CHTTP2 - gRPC's implementation of a HTTP2 based transport
diff --git a/src/core/ext/transport/chttp2/client/chttp2_connector.c b/src/core/ext/transport/chttp2/client/chttp2_connector.c
new file mode 100644
index 0000000000..2c5dfaea60
--- /dev/null
+++ b/src/core/ext/transport/chttp2/client/chttp2_connector.c
@@ -0,0 +1,250 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/ext/transport/chttp2/client/chttp2_connector.h"
+
+#include <grpc/grpc.h>
+
+#include <string.h>
+
+#include <grpc/slice_buffer.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
+
+#include "src/core/ext/client_channel/connector.h"
+#include "src/core/ext/client_channel/http_connect_handshaker.h"
+#include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/channel/handshaker.h"
+#include "src/core/lib/channel/handshaker_registry.h"
+#include "src/core/lib/iomgr/tcp_client.h"
+#include "src/core/lib/slice/slice_internal.h"
+
+typedef struct {
+  grpc_connector base;
+
+  gpr_mu mu;
+  gpr_refcount refs;
+
+  bool shutdown;
+  bool connecting;
+
+  grpc_closure *notify;
+  grpc_connect_in_args args;
+  grpc_connect_out_args *result;
+  grpc_closure initial_string_sent;
+  grpc_slice_buffer initial_string_buffer;
+
+  grpc_endpoint *endpoint;  // Non-NULL until handshaking starts.
+
+  grpc_closure connected;
+
+  grpc_handshake_manager *handshake_mgr;
+} chttp2_connector;
+
+static void chttp2_connector_ref(grpc_connector *con) {
+  chttp2_connector *c = (chttp2_connector *)con;
+  gpr_ref(&c->refs);
+}
+
+static void chttp2_connector_unref(grpc_exec_ctx *exec_ctx,
+                                   grpc_connector *con) {
+  chttp2_connector *c = (chttp2_connector *)con;
+  if (gpr_unref(&c->refs)) {
+    /* c->initial_string_buffer does not need to be destroyed */
+    gpr_mu_destroy(&c->mu);
+    // If handshaking is not yet in progress, destroy the endpoint.
+    // Otherwise, the handshaker will do this for us.
+    if (c->endpoint != NULL) grpc_endpoint_destroy(exec_ctx, c->endpoint);
+    gpr_free(c);
+  }
+}
+
+static void chttp2_connector_shutdown(grpc_exec_ctx *exec_ctx,
+                                      grpc_connector *con) {
+  chttp2_connector *c = (chttp2_connector *)con;
+  gpr_mu_lock(&c->mu);
+  c->shutdown = true;
+  if (c->handshake_mgr != NULL) {
+    grpc_handshake_manager_shutdown(exec_ctx, c->handshake_mgr);
+  }
+  // If handshaking is not yet in progress, shutdown the endpoint.
+  // Otherwise, the handshaker will do this for us.
+  if (!c->connecting && c->endpoint != NULL) {
+    grpc_endpoint_shutdown(exec_ctx, c->endpoint);
+  }
+  gpr_mu_unlock(&c->mu);
+}
+
+static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
+                              grpc_error *error) {
+  grpc_handshaker_args *args = arg;
+  chttp2_connector *c = args->user_data;
+  gpr_mu_lock(&c->mu);
+  if (error != GRPC_ERROR_NONE || c->shutdown) {
+    if (error == GRPC_ERROR_NONE) {
+      error = GRPC_ERROR_CREATE("connector shutdown");
+      // We were shut down after handshaking completed successfully, so
+      // destroy the endpoint here.
+      // TODO(ctiller): It is currently necessary to shutdown endpoints
+      // before destroying them, even if we know that there are no
+      // pending read/write callbacks.  This should be fixed, at which
+      // point this can be removed.
+      grpc_endpoint_shutdown(exec_ctx, args->endpoint);
+      grpc_endpoint_destroy(exec_ctx, args->endpoint);
+      grpc_channel_args_destroy(exec_ctx, args->args);
+      grpc_slice_buffer_destroy_internal(exec_ctx, args->read_buffer);
+      gpr_free(args->read_buffer);
+    } else {
+      error = GRPC_ERROR_REF(error);
+    }
+    memset(c->result, 0, sizeof(*c->result));
+  } else {
+    c->result->transport =
+        grpc_create_chttp2_transport(exec_ctx, args->args, args->endpoint, 1);
+    GPR_ASSERT(c->result->transport);
+    grpc_chttp2_transport_start_reading(exec_ctx, c->result->transport,
+                                        args->read_buffer);
+    c->result->channel_args = args->args;
+  }
+  grpc_closure *notify = c->notify;
+  c->notify = NULL;
+  grpc_closure_sched(exec_ctx, notify, error);
+  grpc_handshake_manager_destroy(exec_ctx, c->handshake_mgr);
+  c->handshake_mgr = NULL;
+  gpr_mu_unlock(&c->mu);
+  chttp2_connector_unref(exec_ctx, (grpc_connector *)c);
+}
+
+static void start_handshake_locked(grpc_exec_ctx *exec_ctx,
+                                   chttp2_connector *c) {
+  c->handshake_mgr = grpc_handshake_manager_create();
+  grpc_handshakers_add(exec_ctx, HANDSHAKER_CLIENT, c->args.channel_args,
+                       c->handshake_mgr);
+  grpc_handshake_manager_do_handshake(
+      exec_ctx, c->handshake_mgr, c->endpoint, c->args.channel_args,
+      c->args.deadline, NULL /* acceptor */, on_handshake_done, c);
+  c->endpoint = NULL;  // Endpoint handed off to handshake manager.
+}
+
+static void on_initial_connect_string_sent(grpc_exec_ctx *exec_ctx, void *arg,
+                                           grpc_error *error) {
+  chttp2_connector *c = arg;
+  gpr_mu_lock(&c->mu);
+  if (error != GRPC_ERROR_NONE || c->shutdown) {
+    if (error == GRPC_ERROR_NONE) {
+      error = GRPC_ERROR_CREATE("connector shutdown");
+    } else {
+      error = GRPC_ERROR_REF(error);
+    }
+    memset(c->result, 0, sizeof(*c->result));
+    grpc_closure *notify = c->notify;
+    c->notify = NULL;
+    grpc_closure_sched(exec_ctx, notify, error);
+    gpr_mu_unlock(&c->mu);
+    chttp2_connector_unref(exec_ctx, arg);
+  } else {
+    start_handshake_locked(exec_ctx, c);
+    gpr_mu_unlock(&c->mu);
+  }
+}
+
+static void connected(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
+  chttp2_connector *c = arg;
+  gpr_mu_lock(&c->mu);
+  GPR_ASSERT(c->connecting);
+  c->connecting = false;
+  if (error != GRPC_ERROR_NONE || c->shutdown) {
+    if (error == GRPC_ERROR_NONE) {
+      error = GRPC_ERROR_CREATE("connector shutdown");
+    } else {
+      error = GRPC_ERROR_REF(error);
+    }
+    memset(c->result, 0, sizeof(*c->result));
+    grpc_closure *notify = c->notify;
+    c->notify = NULL;
+    grpc_closure_sched(exec_ctx, notify, error);
+    if (c->endpoint != NULL) grpc_endpoint_shutdown(exec_ctx, c->endpoint);
+    gpr_mu_unlock(&c->mu);
+    chttp2_connector_unref(exec_ctx, arg);
+  } else {
+    GPR_ASSERT(c->endpoint != NULL);
+    if (!GRPC_SLICE_IS_EMPTY(c->args.initial_connect_string)) {
+      grpc_closure_init(&c->initial_string_sent, on_initial_connect_string_sent,
+                        c, grpc_schedule_on_exec_ctx);
+      grpc_slice_buffer_init(&c->initial_string_buffer);
+      grpc_slice_buffer_add(&c->initial_string_buffer,
+                            c->args.initial_connect_string);
+      grpc_endpoint_write(exec_ctx, c->endpoint, &c->initial_string_buffer,
+                          &c->initial_string_sent);
+    } else {
+      start_handshake_locked(exec_ctx, c);
+    }
+    gpr_mu_unlock(&c->mu);
+  }
+}
+
+static void chttp2_connector_connect(grpc_exec_ctx *exec_ctx,
+                                     grpc_connector *con,
+                                     const grpc_connect_in_args *args,
+                                     grpc_connect_out_args *result,
+                                     grpc_closure *notify) {
+  chttp2_connector *c = (chttp2_connector *)con;
+  gpr_mu_lock(&c->mu);
+  GPR_ASSERT(c->notify == NULL);
+  c->notify = notify;
+  c->args = *args;
+  c->result = result;
+  GPR_ASSERT(c->endpoint == NULL);
+  chttp2_connector_ref(con);  // Ref taken for callback.
+  grpc_closure_init(&c->connected, connected, c, grpc_schedule_on_exec_ctx);
+  GPR_ASSERT(!c->connecting);
+  c->connecting = true;
+  grpc_tcp_client_connect(exec_ctx, &c->connected, &c->endpoint,
+                          args->interested_parties, args->channel_args,
+                          args->addr, args->deadline);
+  gpr_mu_unlock(&c->mu);
+}
+
+static const grpc_connector_vtable chttp2_connector_vtable = {
+    chttp2_connector_ref, chttp2_connector_unref, chttp2_connector_shutdown,
+    chttp2_connector_connect};
+
+grpc_connector *grpc_chttp2_connector_create() {
+  chttp2_connector *c = gpr_malloc(sizeof(*c));
+  memset(c, 0, sizeof(*c));
+  c->base.vtable = &chttp2_connector_vtable;
+  gpr_mu_init(&c->mu);
+  gpr_ref_init(&c->refs, 1);
+  return &c->base;
+}
diff --git a/src/core/ext/transport/chttp2/client/chttp2_connector.h b/src/core/ext/transport/chttp2/client/chttp2_connector.h
new file mode 100644
index 0000000000..f5d1025432
--- /dev/null
+++ b/src/core/ext/transport/chttp2/client/chttp2_connector.h
@@ -0,0 +1,41 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_EXT_TRANSPORT_CHTTP2_CLIENT_CHTTP2_CONNECTOR_H
+#define GRPC_CORE_EXT_TRANSPORT_CHTTP2_CLIENT_CHTTP2_CONNECTOR_H
+
+#include "src/core/ext/client_channel/connector.h"
+
+grpc_connector* grpc_chttp2_connector_create();
+
+#endif /* GRPC_CORE_EXT_TRANSPORT_CHTTP2_CLIENT_CHTTP2_CONNECTOR_H */
diff --git a/src/core/ext/transport/chttp2/client/insecure/channel_create.c b/src/core/ext/transport/chttp2/client/insecure/channel_create.c
index 8e03fd82c1..c9f4021216 100644
--- a/src/core/ext/transport/chttp2/client/insecure/channel_create.c
+++ b/src/core/ext/transport/chttp2/client/insecure/channel_create.c
@@ -33,138 +33,17 @@
 
 #include <grpc/grpc.h>
 
-#include <stdlib.h>
 #include <string.h>
 
-#include <grpc/slice.h>
-#include <grpc/slice_buffer.h>
 #include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
 
 #include "src/core/ext/client_channel/client_channel.h"
-#include "src/core/ext/client_channel/http_connect_handshaker.h"
-#include "src/core/ext/client_channel/resolver_registry.h"
-#include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
+#include "src/core/ext/transport/chttp2/client/chttp2_connector.h"
 #include "src/core/lib/channel/channel_args.h"
-#include "src/core/lib/channel/compress_filter.h"
-#include "src/core/lib/channel/handshaker.h"
-#include "src/core/lib/channel/http_client_filter.h"
-#include "src/core/lib/iomgr/tcp_client.h"
 #include "src/core/lib/surface/api_trace.h"
 #include "src/core/lib/surface/channel.h"
 
-//
-// connector
-//
-
-typedef struct {
-  grpc_connector base;
-  gpr_refcount refs;
-
-  grpc_closure *notify;
-  grpc_connect_in_args args;
-  grpc_connect_out_args *result;
-  grpc_closure initial_string_sent;
-  grpc_slice_buffer initial_string_buffer;
-
-  grpc_endpoint *tcp;
-
-  grpc_closure connected;
-
-  grpc_handshake_manager *handshake_mgr;
-} connector;
-
-static void connector_ref(grpc_connector *con) {
-  connector *c = (connector *)con;
-  gpr_ref(&c->refs);
-}
-
-static void connector_unref(grpc_exec_ctx *exec_ctx, grpc_connector *con) {
-  connector *c = (connector *)con;
-  if (gpr_unref(&c->refs)) {
-    /* c->initial_string_buffer does not need to be destroyed */
-    grpc_handshake_manager_destroy(exec_ctx, c->handshake_mgr);
-    gpr_free(c);
-  }
-}
-
-static void on_initial_connect_string_sent(grpc_exec_ctx *exec_ctx, void *arg,
-                                           grpc_error *error) {
-  connector_unref(exec_ctx, arg);
-}
-
-static void on_handshake_done(grpc_exec_ctx *exec_ctx, grpc_endpoint *endpoint,
-                              grpc_channel_args *args,
-                              grpc_slice_buffer *read_buffer, void *user_data,
-                              grpc_error *error) {
-  connector *c = user_data;
-  if (error != GRPC_ERROR_NONE) {
-    grpc_channel_args_destroy(args);
-    gpr_free(read_buffer);
-  } else {
-    c->result->transport =
-        grpc_create_chttp2_transport(exec_ctx, args, endpoint, 1);
-    GPR_ASSERT(c->result->transport);
-    grpc_chttp2_transport_start_reading(exec_ctx, c->result->transport,
-                                        read_buffer);
-    c->result->channel_args = args;
-  }
-  grpc_closure *notify = c->notify;
-  c->notify = NULL;
-  grpc_exec_ctx_sched(exec_ctx, notify, error, NULL);
-}
-
-static void connected(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
-  connector *c = arg;
-  grpc_endpoint *tcp = c->tcp;
-  if (tcp != NULL) {
-    if (!GRPC_SLICE_IS_EMPTY(c->args.initial_connect_string)) {
-      grpc_closure_init(&c->initial_string_sent, on_initial_connect_string_sent,
-                        c);
-      grpc_slice_buffer_init(&c->initial_string_buffer);
-      grpc_slice_buffer_add(&c->initial_string_buffer,
-                            c->args.initial_connect_string);
-      connector_ref(arg);
-      grpc_endpoint_write(exec_ctx, tcp, &c->initial_string_buffer,
-                          &c->initial_string_sent);
-    } else {
-      grpc_handshake_manager_do_handshake(
-          exec_ctx, c->handshake_mgr, tcp, c->args.channel_args,
-          c->args.deadline, NULL /* acceptor */, on_handshake_done, c);
-    }
-  } else {
-    memset(c->result, 0, sizeof(*c->result));
-    grpc_closure *notify = c->notify;
-    c->notify = NULL;
-    grpc_exec_ctx_sched(exec_ctx, notify, GRPC_ERROR_REF(error), NULL);
-  }
-}
-
-static void connector_shutdown(grpc_exec_ctx *exec_ctx, grpc_connector *con) {}
-
-static void connector_connect(grpc_exec_ctx *exec_ctx, grpc_connector *con,
-                              const grpc_connect_in_args *args,
-                              grpc_connect_out_args *result,
-                              grpc_closure *notify) {
-  connector *c = (connector *)con;
-  GPR_ASSERT(c->notify == NULL);
-  GPR_ASSERT(notify->cb);
-  c->notify = notify;
-  c->args = *args;
-  c->result = result;
-  c->tcp = NULL;
-  grpc_closure_init(&c->connected, connected, c);
-  grpc_tcp_client_connect(exec_ctx, &c->connected, &c->tcp,
-                          args->interested_parties, args->channel_args,
-                          args->addr, args->deadline);
-}
-
-static const grpc_connector_vtable connector_vtable = {
-    connector_ref, connector_unref, connector_shutdown, connector_connect};
-
-//
-// client_channel_factory
-//
-
 static void client_channel_factory_ref(
     grpc_client_channel_factory *cc_factory) {}
 
@@ -174,20 +53,9 @@ static void client_channel_factory_unref(
 static grpc_subchannel *client_channel_factory_create_subchannel(
     grpc_exec_ctx *exec_ctx, grpc_client_channel_factory *cc_factory,
     const grpc_subchannel_args *args) {
-  connector *c = gpr_malloc(sizeof(*c));
-  memset(c, 0, sizeof(*c));
-  c->base.vtable = &connector_vtable;
-  gpr_ref_init(&c->refs, 1);
-  c->handshake_mgr = grpc_handshake_manager_create();
-  char *proxy_name = grpc_get_http_proxy_server();
-  if (proxy_name != NULL) {
-    grpc_handshake_manager_add(
-        c->handshake_mgr,
-        grpc_http_connect_handshaker_create(proxy_name, args->server_name));
-    gpr_free(proxy_name);
-  }
-  grpc_subchannel *s = grpc_subchannel_create(exec_ctx, &c->base, args);
-  grpc_connector_unref(exec_ctx, &c->base);
+  grpc_connector *connector = grpc_chttp2_connector_create();
+  grpc_subchannel *s = grpc_subchannel_create(exec_ctx, connector, args);
+  grpc_connector_unref(exec_ctx, connector);
   return s;
 }
 
@@ -195,19 +63,15 @@ static grpc_channel *client_channel_factory_create_channel(
     grpc_exec_ctx *exec_ctx, grpc_client_channel_factory *cc_factory,
     const char *target, grpc_client_channel_type type,
     const grpc_channel_args *args) {
-  grpc_channel *channel =
-      grpc_channel_create(exec_ctx, target, args, GRPC_CLIENT_CHANNEL, NULL);
-  grpc_resolver *resolver = grpc_resolver_create(target, args);
-  if (!resolver) {
-    GRPC_CHANNEL_INTERNAL_UNREF(exec_ctx, channel,
-                                "client_channel_factory_create_channel");
-    return NULL;
-  }
-
-  grpc_client_channel_finish_initialization(
-      exec_ctx, grpc_channel_get_channel_stack(channel), resolver, cc_factory);
-  GRPC_RESOLVER_UNREF(exec_ctx, resolver, "create_channel");
-
+  // Add channel arg containing the server URI.
+  grpc_arg arg;
+  arg.type = GRPC_ARG_STRING;
+  arg.key = GRPC_ARG_SERVER_URI;
+  arg.value.string = (char *)target;
+  grpc_channel_args *new_args = grpc_channel_args_copy_and_add(args, &arg, 1);
+  grpc_channel *channel = grpc_channel_create(exec_ctx, target, new_args,
+                                              GRPC_CLIENT_CHANNEL, NULL);
+  grpc_channel_args_destroy(exec_ctx, new_args);
   return channel;
 }
 
@@ -230,16 +94,18 @@ grpc_channel *grpc_insecure_channel_create(const char *target,
   GRPC_API_TRACE(
       "grpc_insecure_channel_create(target=%p, args=%p, reserved=%p)", 3,
       (target, args, reserved));
-  GPR_ASSERT(!reserved);
-
-  grpc_client_channel_factory *factory =
-      (grpc_client_channel_factory *)&client_channel_factory;
+  GPR_ASSERT(reserved == NULL);
+  // Add channel arg containing the client channel factory.
+  grpc_arg arg =
+      grpc_client_channel_factory_create_channel_arg(&client_channel_factory);
+  grpc_channel_args *new_args = grpc_channel_args_copy_and_add(args, &arg, 1);
+  // Create channel.
   grpc_channel *channel = client_channel_factory_create_channel(
-      &exec_ctx, factory, target, GRPC_CLIENT_CHANNEL_TYPE_REGULAR, args);
-
-  grpc_client_channel_factory_unref(&exec_ctx, factory);
+      &exec_ctx, &client_channel_factory, target,
+      GRPC_CLIENT_CHANNEL_TYPE_REGULAR, new_args);
+  // Clean up.
+  grpc_channel_args_destroy(&exec_ctx, new_args);
   grpc_exec_ctx_finish(&exec_ctx);
-
   return channel != NULL ? channel : grpc_lame_client_channel_create(
                                          target, GRPC_STATUS_INTERNAL,
                                          "Failed to create client channel");
diff --git a/src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c b/src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c
index 1e5b1c22e3..f1069e2c57 100644
--- a/src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c
+++ b/src/core/ext/transport/chttp2/client/insecure/channel_create_posix.c
@@ -74,7 +74,7 @@ grpc_channel *grpc_insecure_channel_create_from_fd(
   GPR_ASSERT(transport);
   grpc_channel *channel = grpc_channel_create(
       &exec_ctx, target, final_args, GRPC_CLIENT_DIRECT_CHANNEL, transport);
-  grpc_channel_args_destroy(final_args);
+  grpc_channel_args_destroy(&exec_ctx, final_args);
   grpc_chttp2_transport_start_reading(&exec_ctx, transport, NULL);
 
   grpc_exec_ctx_finish(&exec_ctx);
diff --git a/src/core/ext/transport/chttp2/client/secure/secure_channel_create.c b/src/core/ext/transport/chttp2/client/secure/secure_channel_create.c
index 04c88a2d36..f979d9bad5 100644
--- a/src/core/ext/transport/chttp2/client/secure/secure_channel_create.c
+++ b/src/core/ext/transport/chttp2/client/secure/secure_channel_create.c
@@ -33,239 +33,31 @@
 
 #include <grpc/grpc.h>
 
-#include <stdlib.h>
 #include <string.h>
 
-#include <grpc/slice.h>
-#include <grpc/slice_buffer.h>
 #include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
 
 #include "src/core/ext/client_channel/client_channel.h"
-#include "src/core/ext/client_channel/http_connect_handshaker.h"
-#include "src/core/ext/client_channel/resolver_registry.h"
-#include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
+#include "src/core/ext/transport/chttp2/client/chttp2_connector.h"
 #include "src/core/lib/channel/channel_args.h"
-#include "src/core/lib/channel/handshaker.h"
-#include "src/core/lib/iomgr/tcp_client.h"
-#include "src/core/lib/security/context/security_context.h"
 #include "src/core/lib/security/credentials/credentials.h"
-#include "src/core/lib/security/transport/auth_filters.h"
+#include "src/core/lib/security/transport/security_connector.h"
 #include "src/core/lib/surface/api_trace.h"
 #include "src/core/lib/surface/channel.h"
-#include "src/core/lib/tsi/transport_security_interface.h"
-
-//
-// connector
-//
-
-typedef struct {
-  grpc_connector base;
-  gpr_refcount refs;
-
-  grpc_channel_security_connector *security_connector;
-
-  grpc_closure *notify;
-  grpc_connect_in_args args;
-  grpc_connect_out_args *result;
-  grpc_closure initial_string_sent;
-  grpc_slice_buffer initial_string_buffer;
-
-  gpr_mu mu;
-  grpc_endpoint *connecting_endpoint;
-  grpc_endpoint *newly_connecting_endpoint;
-
-  grpc_closure connected_closure;
-
-  grpc_handshake_manager *handshake_mgr;
-
-  // TODO(roth): Remove once we eliminate on_secure_handshake_done().
-  grpc_channel_args *tmp_args;
-} connector;
-
-static void connector_ref(grpc_connector *con) {
-  connector *c = (connector *)con;
-  gpr_ref(&c->refs);
-}
-
-static void connector_unref(grpc_exec_ctx *exec_ctx, grpc_connector *con) {
-  connector *c = (connector *)con;
-  if (gpr_unref(&c->refs)) {
-    /* c->initial_string_buffer does not need to be destroyed */
-    grpc_channel_args_destroy(c->tmp_args);
-    grpc_handshake_manager_destroy(exec_ctx, c->handshake_mgr);
-    gpr_free(c);
-  }
-}
-
-static void on_secure_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
-                                     grpc_security_status status,
-                                     grpc_endpoint *secure_endpoint,
-                                     grpc_auth_context *auth_context) {
-  connector *c = arg;
-  gpr_mu_lock(&c->mu);
-  grpc_error *error = GRPC_ERROR_NONE;
-  if (c->connecting_endpoint == NULL) {
-    memset(c->result, 0, sizeof(*c->result));
-    gpr_mu_unlock(&c->mu);
-  } else if (status != GRPC_SECURITY_OK) {
-    error = grpc_error_set_int(GRPC_ERROR_CREATE("Secure handshake failed"),
-                               GRPC_ERROR_INT_SECURITY_STATUS, status);
-    memset(c->result, 0, sizeof(*c->result));
-    c->connecting_endpoint = NULL;
-    gpr_mu_unlock(&c->mu);
-  } else {
-    grpc_arg auth_context_arg;
-    c->connecting_endpoint = NULL;
-    gpr_mu_unlock(&c->mu);
-    c->result->transport = grpc_create_chttp2_transport(
-        exec_ctx, c->args.channel_args, secure_endpoint, 1);
-    grpc_chttp2_transport_start_reading(exec_ctx, c->result->transport, NULL);
-    auth_context_arg = grpc_auth_context_to_arg(auth_context);
-    c->result->channel_args =
-        grpc_channel_args_copy_and_add(c->tmp_args, &auth_context_arg, 1);
-  }
-  grpc_closure *notify = c->notify;
-  c->notify = NULL;
-  grpc_exec_ctx_sched(exec_ctx, notify, error, NULL);
-}
-
-static void on_handshake_done(grpc_exec_ctx *exec_ctx, grpc_endpoint *endpoint,
-                              grpc_channel_args *args,
-                              grpc_slice_buffer *read_buffer, void *user_data,
-                              grpc_error *error) {
-  connector *c = user_data;
-  c->tmp_args = args;
-  if (error != GRPC_ERROR_NONE) {
-    gpr_free(read_buffer);
-    grpc_closure *notify = c->notify;
-    c->notify = NULL;
-    grpc_exec_ctx_sched(exec_ctx, notify, error, NULL);
-  } else {
-    // TODO(roth, jboeuf): Convert security connector handshaking to use new
-    // handshake API, and then move the code from on_secure_handshake_done()
-    // into this function.
-    grpc_channel_security_connector_do_handshake(
-        exec_ctx, c->security_connector, endpoint, read_buffer,
-        c->args.deadline, on_secure_handshake_done, c);
-  }
-}
-
-static void on_initial_connect_string_sent(grpc_exec_ctx *exec_ctx, void *arg,
-                                           grpc_error *error) {
-  connector *c = arg;
-  grpc_handshake_manager_do_handshake(
-      exec_ctx, c->handshake_mgr, c->connecting_endpoint, c->args.channel_args,
-      c->args.deadline, NULL /* acceptor */, on_handshake_done, c);
-}
-
-static void connected(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
-  connector *c = arg;
-  grpc_endpoint *tcp = c->newly_connecting_endpoint;
-  if (tcp != NULL) {
-    gpr_mu_lock(&c->mu);
-    GPR_ASSERT(c->connecting_endpoint == NULL);
-    c->connecting_endpoint = tcp;
-    gpr_mu_unlock(&c->mu);
-    if (!GRPC_SLICE_IS_EMPTY(c->args.initial_connect_string)) {
-      grpc_closure_init(&c->initial_string_sent, on_initial_connect_string_sent,
-                        c);
-      grpc_slice_buffer_init(&c->initial_string_buffer);
-      grpc_slice_buffer_add(&c->initial_string_buffer,
-                            c->args.initial_connect_string);
-      grpc_endpoint_write(exec_ctx, tcp, &c->initial_string_buffer,
-                          &c->initial_string_sent);
-    } else {
-      grpc_handshake_manager_do_handshake(
-          exec_ctx, c->handshake_mgr, tcp, c->args.channel_args,
-          c->args.deadline, NULL /* acceptor */, on_handshake_done, c);
-    }
-  } else {
-    memset(c->result, 0, sizeof(*c->result));
-    grpc_closure *notify = c->notify;
-    c->notify = NULL;
-    grpc_exec_ctx_sched(exec_ctx, notify, GRPC_ERROR_REF(error), NULL);
-  }
-}
-
-static void connector_shutdown(grpc_exec_ctx *exec_ctx, grpc_connector *con) {
-  connector *c = (connector *)con;
-  grpc_endpoint *ep;
-  gpr_mu_lock(&c->mu);
-  ep = c->connecting_endpoint;
-  c->connecting_endpoint = NULL;
-  gpr_mu_unlock(&c->mu);
-  if (ep) {
-    grpc_endpoint_shutdown(exec_ctx, ep);
-  }
-}
-
-static void connector_connect(grpc_exec_ctx *exec_ctx, grpc_connector *con,
-                              const grpc_connect_in_args *args,
-                              grpc_connect_out_args *result,
-                              grpc_closure *notify) {
-  connector *c = (connector *)con;
-  GPR_ASSERT(c->notify == NULL);
-  c->notify = notify;
-  c->args = *args;
-  c->result = result;
-  gpr_mu_lock(&c->mu);
-  GPR_ASSERT(c->connecting_endpoint == NULL);
-  gpr_mu_unlock(&c->mu);
-  grpc_closure_init(&c->connected_closure, connected, c);
-  grpc_tcp_client_connect(
-      exec_ctx, &c->connected_closure, &c->newly_connecting_endpoint,
-      args->interested_parties, args->channel_args, args->addr, args->deadline);
-}
-
-static const grpc_connector_vtable connector_vtable = {
-    connector_ref, connector_unref, connector_shutdown, connector_connect};
-
-//
-// client_channel_factory
-//
-
-typedef struct {
-  grpc_client_channel_factory base;
-  gpr_refcount refs;
-  grpc_channel_security_connector *security_connector;
-} client_channel_factory;
 
 static void client_channel_factory_ref(
-    grpc_client_channel_factory *cc_factory) {
-  client_channel_factory *f = (client_channel_factory *)cc_factory;
-  gpr_ref(&f->refs);
-}
+    grpc_client_channel_factory *cc_factory) {}
 
 static void client_channel_factory_unref(
-    grpc_exec_ctx *exec_ctx, grpc_client_channel_factory *cc_factory) {
-  client_channel_factory *f = (client_channel_factory *)cc_factory;
-  if (gpr_unref(&f->refs)) {
-    GRPC_SECURITY_CONNECTOR_UNREF(&f->security_connector->base,
-                                  "client_channel_factory");
-    gpr_free(f);
-  }
-}
+    grpc_exec_ctx *exec_ctx, grpc_client_channel_factory *cc_factory) {}
 
 static grpc_subchannel *client_channel_factory_create_subchannel(
     grpc_exec_ctx *exec_ctx, grpc_client_channel_factory *cc_factory,
     const grpc_subchannel_args *args) {
-  client_channel_factory *f = (client_channel_factory *)cc_factory;
-  connector *c = gpr_malloc(sizeof(*c));
-  memset(c, 0, sizeof(*c));
-  c->base.vtable = &connector_vtable;
-  c->security_connector = f->security_connector;
-  c->handshake_mgr = grpc_handshake_manager_create();
-  char *proxy_name = grpc_get_http_proxy_server();
-  if (proxy_name != NULL) {
-    grpc_handshake_manager_add(
-        c->handshake_mgr,
-        grpc_http_connect_handshaker_create(proxy_name, args->server_name));
-    gpr_free(proxy_name);
-  }
-  gpr_mu_init(&c->mu);
-  gpr_ref_init(&c->refs, 1);
-  grpc_subchannel *s = grpc_subchannel_create(exec_ctx, &c->base, args);
-  grpc_connector_unref(exec_ctx, &c->base);
+  grpc_connector *connector = grpc_chttp2_connector_create();
+  grpc_subchannel *s = grpc_subchannel_create(exec_ctx, connector, args);
+  grpc_connector_unref(exec_ctx, connector);
   return s;
 }
 
@@ -273,19 +65,15 @@ static grpc_channel *client_channel_factory_create_channel(
     grpc_exec_ctx *exec_ctx, grpc_client_channel_factory *cc_factory,
     const char *target, grpc_client_channel_type type,
     const grpc_channel_args *args) {
-  client_channel_factory *f = (client_channel_factory *)cc_factory;
-  grpc_channel *channel =
-      grpc_channel_create(exec_ctx, target, args, GRPC_CLIENT_CHANNEL, NULL);
-  grpc_resolver *resolver = grpc_resolver_create(target, args);
-  if (resolver != NULL) {
-    grpc_client_channel_finish_initialization(
-        exec_ctx, grpc_channel_get_channel_stack(channel), resolver, &f->base);
-    GRPC_RESOLVER_UNREF(exec_ctx, resolver, "create");
-  } else {
-    GRPC_CHANNEL_INTERNAL_UNREF(exec_ctx, channel,
-                                "client_channel_factory_create_channel");
-    channel = NULL;
-  }
+  // Add channel arg containing the server URI.
+  grpc_arg arg;
+  arg.type = GRPC_ARG_STRING;
+  arg.key = GRPC_ARG_SERVER_URI;
+  arg.value.string = (char *)target;
+  grpc_channel_args *new_args = grpc_channel_args_copy_and_add(args, &arg, 1);
+  grpc_channel *channel = grpc_channel_create(exec_ctx, target, new_args,
+                                              GRPC_CLIENT_CHANNEL, NULL);
+  grpc_channel_args_destroy(exec_ctx, new_args);
   return channel;
 }
 
@@ -294,6 +82,9 @@ static const grpc_client_channel_factory_vtable client_channel_factory_vtable =
      client_channel_factory_create_subchannel,
      client_channel_factory_create_channel};
 
+static grpc_client_channel_factory client_channel_factory = {
+    &client_channel_factory_vtable};
+
 /* Create a secure client channel:
    Asynchronously: - resolve target
                    - connect to it (trying alternatives as presented)
@@ -320,36 +111,32 @@ grpc_channel *grpc_secure_channel_create(grpc_channel_credentials *creds,
   grpc_channel_security_connector *security_connector;
   grpc_channel_args *new_args_from_connector;
   if (grpc_channel_credentials_create_security_connector(
-          creds, target, args, &security_connector, &new_args_from_connector) !=
-      GRPC_SECURITY_OK) {
+          &exec_ctx, creds, target, args, &security_connector,
+          &new_args_from_connector) != GRPC_SECURITY_OK) {
     grpc_exec_ctx_finish(&exec_ctx);
     return grpc_lame_client_channel_create(
         target, GRPC_STATUS_INTERNAL, "Failed to create security connector.");
   }
-  grpc_arg connector_arg =
-      grpc_security_connector_to_arg(&security_connector->base);
+  // Add channel args containing the client channel factory and security
+  // connector.
+  grpc_arg args_to_add[2];
+  args_to_add[0] =
+      grpc_client_channel_factory_create_channel_arg(&client_channel_factory);
+  args_to_add[1] = grpc_security_connector_to_arg(&security_connector->base);
   grpc_channel_args *new_args = grpc_channel_args_copy_and_add(
       new_args_from_connector != NULL ? new_args_from_connector : args,
-      &connector_arg, 1);
+      args_to_add, GPR_ARRAY_SIZE(args_to_add));
   if (new_args_from_connector != NULL) {
-    grpc_channel_args_destroy(new_args_from_connector);
+    grpc_channel_args_destroy(&exec_ctx, new_args_from_connector);
   }
-  // Create client channel factory.
-  client_channel_factory *f = gpr_malloc(sizeof(*f));
-  memset(f, 0, sizeof(*f));
-  f->base.vtable = &client_channel_factory_vtable;
-  gpr_ref_init(&f->refs, 1);
-  GRPC_SECURITY_CONNECTOR_REF(&security_connector->base,
-                              "grpc_secure_channel_create");
-  f->security_connector = security_connector;
   // Create channel.
   grpc_channel *channel = client_channel_factory_create_channel(
-      &exec_ctx, &f->base, target, GRPC_CLIENT_CHANNEL_TYPE_REGULAR, new_args);
+      &exec_ctx, &client_channel_factory, target,
+      GRPC_CLIENT_CHANNEL_TYPE_REGULAR, new_args);
   // Clean up.
-  GRPC_SECURITY_CONNECTOR_UNREF(&f->security_connector->base,
+  GRPC_SECURITY_CONNECTOR_UNREF(&exec_ctx, &security_connector->base,
                                 "secure_client_channel_factory_create_channel");
-  grpc_channel_args_destroy(new_args);
-  grpc_client_channel_factory_unref(&exec_ctx, &f->base);
+  grpc_channel_args_destroy(&exec_ctx, new_args);
   grpc_exec_ctx_finish(&exec_ctx);
   return channel; /* may be NULL */
 }
diff --git a/src/core/ext/transport/chttp2/server/chttp2_server.c b/src/core/ext/transport/chttp2/server/chttp2_server.c
new file mode 100644
index 0000000000..574d1a7710
--- /dev/null
+++ b/src/core/ext/transport/chttp2/server/chttp2_server.c
@@ -0,0 +1,342 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/ext/transport/chttp2/server/chttp2_server.h"
+
+#include <grpc/grpc.h>
+
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+#include <grpc/support/sync.h>
+#include <grpc/support/useful.h>
+
+#include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/channel/handshaker.h"
+#include "src/core/lib/channel/handshaker_registry.h"
+#include "src/core/lib/channel/http_server_filter.h"
+#include "src/core/lib/iomgr/endpoint.h"
+#include "src/core/lib/iomgr/resolve_address.h"
+#include "src/core/lib/iomgr/tcp_server.h"
+#include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/surface/api_trace.h"
+#include "src/core/lib/surface/server.h"
+
+typedef struct pending_handshake_manager_node {
+  grpc_handshake_manager *handshake_mgr;
+  struct pending_handshake_manager_node *next;
+} pending_handshake_manager_node;
+
+typedef struct {
+  grpc_server *server;
+  grpc_tcp_server *tcp_server;
+  grpc_channel_args *args;
+  gpr_mu mu;
+  bool shutdown;
+  grpc_closure tcp_server_shutdown_complete;
+  grpc_closure *server_destroy_listener_done;
+  pending_handshake_manager_node *pending_handshake_mgrs;
+} server_state;
+
+typedef struct {
+  server_state *server_state;
+  grpc_pollset *accepting_pollset;
+  grpc_tcp_server_acceptor *acceptor;
+  grpc_handshake_manager *handshake_mgr;
+} server_connection_state;
+
+static void pending_handshake_manager_add_locked(
+    server_state *state, grpc_handshake_manager *handshake_mgr) {
+  pending_handshake_manager_node *node = gpr_malloc(sizeof(*node));
+  node->handshake_mgr = handshake_mgr;
+  node->next = state->pending_handshake_mgrs;
+  state->pending_handshake_mgrs = node;
+}
+
+static void pending_handshake_manager_remove_locked(
+    server_state *state, grpc_handshake_manager *handshake_mgr) {
+  pending_handshake_manager_node **prev_node = &state->pending_handshake_mgrs;
+  for (pending_handshake_manager_node *node = state->pending_handshake_mgrs;
+       node != NULL; node = node->next) {
+    if (node->handshake_mgr == handshake_mgr) {
+      *prev_node = node->next;
+      gpr_free(node);
+      break;
+    }
+    prev_node = &node->next;
+  }
+}
+
+static void pending_handshake_manager_shutdown_locked(grpc_exec_ctx *exec_ctx,
+                                                      server_state *state) {
+  pending_handshake_manager_node *prev_node = NULL;
+  for (pending_handshake_manager_node *node = state->pending_handshake_mgrs;
+       node != NULL; node = node->next) {
+    grpc_handshake_manager_shutdown(exec_ctx, node->handshake_mgr);
+    gpr_free(prev_node);
+    prev_node = node;
+  }
+  gpr_free(prev_node);
+  state->pending_handshake_mgrs = NULL;
+}
+
+static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
+                              grpc_error *error) {
+  grpc_handshaker_args *args = arg;
+  server_connection_state *connection_state = args->user_data;
+  gpr_mu_lock(&connection_state->server_state->mu);
+  if (error != GRPC_ERROR_NONE || connection_state->server_state->shutdown) {
+    const char *error_str = grpc_error_string(error);
+    gpr_log(GPR_ERROR, "Handshaking failed: %s", error_str);
+    grpc_error_free_string(error_str);
+    if (error == GRPC_ERROR_NONE && args->endpoint != NULL) {
+      // We were shut down after handshaking completed successfully, so
+      // destroy the endpoint here.
+      // TODO(ctiller): It is currently necessary to shutdown endpoints
+      // before destroying them, even if we know that there are no
+      // pending read/write callbacks.  This should be fixed, at which
+      // point this can be removed.
+      grpc_endpoint_shutdown(exec_ctx, args->endpoint);
+      grpc_endpoint_destroy(exec_ctx, args->endpoint);
+      grpc_channel_args_destroy(exec_ctx, args->args);
+      grpc_slice_buffer_destroy_internal(exec_ctx, args->read_buffer);
+      gpr_free(args->read_buffer);
+    }
+  } else {
+    // If the handshaking succeeded but there is no endpoint, then the
+    // handshaker may have handed off the connection to some external
+    // code, so we can just clean up here without creating a transport.
+    if (args->endpoint != NULL) {
+      grpc_transport *transport =
+          grpc_create_chttp2_transport(exec_ctx, args->args, args->endpoint, 0);
+      grpc_server_setup_transport(
+          exec_ctx, connection_state->server_state->server, transport,
+          connection_state->accepting_pollset, args->args);
+      grpc_chttp2_transport_start_reading(exec_ctx, transport,
+                                          args->read_buffer);
+      grpc_channel_args_destroy(exec_ctx, args->args);
+    }
+  }
+  pending_handshake_manager_remove_locked(connection_state->server_state,
+                                          connection_state->handshake_mgr);
+  gpr_mu_unlock(&connection_state->server_state->mu);
+  grpc_handshake_manager_destroy(exec_ctx, connection_state->handshake_mgr);
+  grpc_tcp_server_unref(exec_ctx, connection_state->server_state->tcp_server);
+  gpr_free(connection_state->acceptor);
+  gpr_free(connection_state);
+}
+
+static void on_accept(grpc_exec_ctx *exec_ctx, void *arg, grpc_endpoint *tcp,
+                      grpc_pollset *accepting_pollset,
+                      grpc_tcp_server_acceptor *acceptor) {
+  server_state *state = arg;
+  gpr_mu_lock(&state->mu);
+  if (state->shutdown) {
+    gpr_mu_unlock(&state->mu);
+    grpc_endpoint_destroy(exec_ctx, tcp);
+    gpr_free(acceptor);
+    return;
+  }
+  grpc_handshake_manager *handshake_mgr = grpc_handshake_manager_create();
+  pending_handshake_manager_add_locked(state, handshake_mgr);
+  gpr_mu_unlock(&state->mu);
+  grpc_tcp_server_ref(state->tcp_server);
+  server_connection_state *connection_state =
+      gpr_malloc(sizeof(*connection_state));
+  connection_state->server_state = state;
+  connection_state->accepting_pollset = accepting_pollset;
+  connection_state->acceptor = acceptor;
+  connection_state->handshake_mgr = handshake_mgr;
+  grpc_handshakers_add(exec_ctx, HANDSHAKER_SERVER, state->args,
+                       connection_state->handshake_mgr);
+  // TODO(roth): We should really get this timeout value from channel
+  // args instead of hard-coding it.
+  const gpr_timespec deadline = gpr_time_add(
+      gpr_now(GPR_CLOCK_MONOTONIC), gpr_time_from_seconds(120, GPR_TIMESPAN));
+  grpc_handshake_manager_do_handshake(exec_ctx, connection_state->handshake_mgr,
+                                      tcp, state->args, deadline, acceptor,
+                                      on_handshake_done, connection_state);
+}
+
+/* Server callback: start listening on our ports */
+static void server_start_listener(grpc_exec_ctx *exec_ctx, grpc_server *server,
+                                  void *arg, grpc_pollset **pollsets,
+                                  size_t pollset_count) {
+  server_state *state = arg;
+  gpr_mu_lock(&state->mu);
+  state->shutdown = false;
+  gpr_mu_unlock(&state->mu);
+  grpc_tcp_server_start(exec_ctx, state->tcp_server, pollsets, pollset_count,
+                        on_accept, state);
+}
+
+static void tcp_server_shutdown_complete(grpc_exec_ctx *exec_ctx, void *arg,
+                                         grpc_error *error) {
+  server_state *state = arg;
+  /* ensure all threads have unlocked */
+  gpr_mu_lock(&state->mu);
+  grpc_closure *destroy_done = state->server_destroy_listener_done;
+  GPR_ASSERT(state->shutdown);
+  pending_handshake_manager_shutdown_locked(exec_ctx, state);
+  gpr_mu_unlock(&state->mu);
+  // Flush queued work before destroying handshaker factory, since that
+  // may do a synchronous unref.
+  grpc_exec_ctx_flush(exec_ctx);
+  if (destroy_done != NULL) {
+    destroy_done->cb(exec_ctx, destroy_done->cb_arg, GRPC_ERROR_REF(error));
+    grpc_exec_ctx_flush(exec_ctx);
+  }
+  grpc_channel_args_destroy(exec_ctx, state->args);
+  gpr_mu_destroy(&state->mu);
+  gpr_free(state);
+}
+
+/* Server callback: destroy the tcp listener (so we don't generate further
+   callbacks) */
+static void server_destroy_listener(grpc_exec_ctx *exec_ctx,
+                                    grpc_server *server, void *arg,
+                                    grpc_closure *destroy_done) {
+  server_state *state = arg;
+  gpr_mu_lock(&state->mu);
+  state->shutdown = true;
+  state->server_destroy_listener_done = destroy_done;
+  grpc_tcp_server *tcp_server = state->tcp_server;
+  gpr_mu_unlock(&state->mu);
+  grpc_tcp_server_shutdown_listeners(exec_ctx, tcp_server);
+  grpc_tcp_server_unref(exec_ctx, tcp_server);
+}
+
+grpc_error *grpc_chttp2_server_add_port(grpc_exec_ctx *exec_ctx,
+                                        grpc_server *server, const char *addr,
+                                        grpc_channel_args *args,
+                                        int *port_num) {
+  grpc_resolved_addresses *resolved = NULL;
+  grpc_tcp_server *tcp_server = NULL;
+  size_t i;
+  size_t count = 0;
+  int port_temp;
+  grpc_error *err = GRPC_ERROR_NONE;
+  server_state *state = NULL;
+  grpc_error **errors = NULL;
+
+  *port_num = -1;
+
+  /* resolve address */
+  err = grpc_blocking_resolve_address(addr, "https", &resolved);
+  if (err != GRPC_ERROR_NONE) {
+    goto error;
+  }
+  state = gpr_malloc(sizeof(*state));
+  memset(state, 0, sizeof(*state));
+  grpc_closure_init(&state->tcp_server_shutdown_complete,
+                    tcp_server_shutdown_complete, state,
+                    grpc_schedule_on_exec_ctx);
+  err = grpc_tcp_server_create(exec_ctx, &state->tcp_server_shutdown_complete,
+                               args, &tcp_server);
+  if (err != GRPC_ERROR_NONE) {
+    goto error;
+  }
+
+  state->server = server;
+  state->tcp_server = tcp_server;
+  state->args = args;
+  state->shutdown = true;
+  gpr_mu_init(&state->mu);
+
+  const size_t naddrs = resolved->naddrs;
+  errors = gpr_malloc(sizeof(*errors) * naddrs);
+  for (i = 0; i < naddrs; i++) {
+    errors[i] =
+        grpc_tcp_server_add_port(tcp_server, &resolved->addrs[i], &port_temp);
+    if (errors[i] == GRPC_ERROR_NONE) {
+      if (*port_num == -1) {
+        *port_num = port_temp;
+      } else {
+        GPR_ASSERT(*port_num == port_temp);
+      }
+      count++;
+    }
+  }
+  if (count == 0) {
+    char *msg;
+    gpr_asprintf(&msg, "No address added out of total %" PRIuPTR " resolved",
+                 naddrs);
+    err = GRPC_ERROR_CREATE_REFERENCING(msg, errors, naddrs);
+    gpr_free(msg);
+    goto error;
+  } else if (count != naddrs) {
+    char *msg;
+    gpr_asprintf(&msg, "Only %" PRIuPTR
+                       " addresses added out of total %" PRIuPTR " resolved",
+                 count, naddrs);
+    err = GRPC_ERROR_CREATE_REFERENCING(msg, errors, naddrs);
+    gpr_free(msg);
+
+    const char *warning_message = grpc_error_string(err);
+    gpr_log(GPR_INFO, "WARNING: %s", warning_message);
+    grpc_error_free_string(warning_message);
+    /* we managed to bind some addresses: continue */
+  }
+  grpc_resolved_addresses_destroy(resolved);
+
+  /* Register with the server only upon success */
+  grpc_server_add_listener(exec_ctx, server, state, server_start_listener,
+                           server_destroy_listener);
+  goto done;
+
+/* Error path: cleanup and return */
+error:
+  GPR_ASSERT(err != GRPC_ERROR_NONE);
+  if (resolved) {
+    grpc_resolved_addresses_destroy(resolved);
+  }
+  if (tcp_server) {
+    grpc_tcp_server_unref(exec_ctx, tcp_server);
+  } else {
+    grpc_channel_args_destroy(exec_ctx, args);
+    gpr_free(state);
+  }
+  *port_num = 0;
+
+done:
+  if (errors != NULL) {
+    for (i = 0; i < naddrs; i++) {
+      GRPC_ERROR_UNREF(errors[i]);
+    }
+    gpr_free(errors);
+  }
+  return err;
+}
diff --git a/src/core/ext/transport/chttp2/server/chttp2_server.h b/src/core/ext/transport/chttp2/server/chttp2_server.h
new file mode 100644
index 0000000000..2581ebaae9
--- /dev/null
+++ b/src/core/ext/transport/chttp2/server/chttp2_server.h
@@ -0,0 +1,47 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_EXT_TRANSPORT_CHTTP2_SERVER_CHTTP2_SERVER_H
+#define GRPC_CORE_EXT_TRANSPORT_CHTTP2_SERVER_CHTTP2_SERVER_H
+
+#include <grpc/impl/codegen/grpc_types.h>
+
+#include "src/core/lib/iomgr/exec_ctx.h"
+
+/// Adds a port to \a server.  Sets \a port_num to the port number.
+/// Takes ownership of \a args.
+grpc_error *grpc_chttp2_server_add_port(grpc_exec_ctx *exec_ctx,
+                                        grpc_server *server, const char *addr,
+                                        grpc_channel_args *args, int *port_num);
+
+#endif /* GRPC_CORE_EXT_TRANSPORT_CHTTP2_SERVER_CHTTP2_SERVER_H */
diff --git a/src/core/ext/transport/chttp2/server/insecure/server_chttp2.c b/src/core/ext/transport/chttp2/server/insecure/server_chttp2.c
index c18d618f96..bf5026bea6 100644
--- a/src/core/ext/transport/chttp2/server/insecure/server_chttp2.c
+++ b/src/core/ext/transport/chttp2/server/insecure/server_chttp2.c
@@ -33,180 +33,27 @@
 
 #include <grpc/grpc.h>
 
-#include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
-#include <grpc/support/string_util.h>
-#include <grpc/support/useful.h>
 
-#include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
+#include "src/core/ext/transport/chttp2/server/chttp2_server.h"
 #include "src/core/lib/channel/channel_args.h"
-#include "src/core/lib/channel/handshaker.h"
-#include "src/core/lib/channel/http_server_filter.h"
-#include "src/core/lib/iomgr/resolve_address.h"
-#include "src/core/lib/iomgr/tcp_server.h"
 #include "src/core/lib/surface/api_trace.h"
 #include "src/core/lib/surface/server.h"
 
-typedef struct server_connect_state {
-  grpc_server *server;
-  grpc_pollset *accepting_pollset;
-  grpc_tcp_server_acceptor *acceptor;
-  grpc_handshake_manager *handshake_mgr;
-} server_connect_state;
-
-static void on_handshake_done(grpc_exec_ctx *exec_ctx, grpc_endpoint *endpoint,
-                              grpc_channel_args *args,
-                              grpc_slice_buffer *read_buffer, void *user_data,
-                              grpc_error *error) {
-  server_connect_state *state = user_data;
-  if (error != GRPC_ERROR_NONE) {
-    const char *error_str = grpc_error_string(error);
-    gpr_log(GPR_ERROR, "Handshaking failed: %s", error_str);
-    grpc_error_free_string(error_str);
-    GRPC_ERROR_UNREF(error);
-    grpc_handshake_manager_shutdown(exec_ctx, state->handshake_mgr);
-    gpr_free(read_buffer);
-  } else {
-    // Beware that the call to grpc_create_chttp2_transport() has to happen
-    // before grpc_tcp_server_destroy(). This is fine here, but similar code
-    // asynchronously doing a handshake instead of calling
-    // grpc_tcp_server_start() (as in server_secure_chttp2.c) needs to add
-    // synchronization to avoid this case.
-    grpc_transport *transport =
-        grpc_create_chttp2_transport(exec_ctx, args, endpoint, 0);
-    grpc_server_setup_transport(exec_ctx, state->server, transport,
-                                state->accepting_pollset,
-                                grpc_server_get_channel_args(state->server));
-    grpc_chttp2_transport_start_reading(exec_ctx, transport, read_buffer);
-  }
-  // Clean up.
-  grpc_channel_args_destroy(args);
-  grpc_handshake_manager_destroy(exec_ctx, state->handshake_mgr);
-  gpr_free(state);
-}
-
-static void on_accept(grpc_exec_ctx *exec_ctx, void *server, grpc_endpoint *tcp,
-                      grpc_pollset *accepting_pollset,
-                      grpc_tcp_server_acceptor *acceptor) {
-  server_connect_state *state = gpr_malloc(sizeof(server_connect_state));
-  state->server = server;
-  state->accepting_pollset = accepting_pollset;
-  state->acceptor = acceptor;
-  state->handshake_mgr = grpc_handshake_manager_create();
-  // TODO(roth): We should really get this timeout value from channel
-  // args instead of hard-coding it.
-  const gpr_timespec deadline = gpr_time_add(
-      gpr_now(GPR_CLOCK_MONOTONIC), gpr_time_from_seconds(120, GPR_TIMESPAN));
-  grpc_handshake_manager_do_handshake(
-      exec_ctx, state->handshake_mgr, tcp, grpc_server_get_channel_args(server),
-      deadline, acceptor, on_handshake_done, state);
-}
-
-/* Server callback: start listening on our ports */
-static void start(grpc_exec_ctx *exec_ctx, grpc_server *server, void *tcpp,
-                  grpc_pollset **pollsets, size_t pollset_count) {
-  grpc_tcp_server *tcp = tcpp;
-  grpc_tcp_server_start(exec_ctx, tcp, pollsets, pollset_count, on_accept,
-                        server);
-}
-
-/* Server callback: destroy the tcp listener (so we don't generate further
-   callbacks) */
-static void destroy(grpc_exec_ctx *exec_ctx, grpc_server *server, void *tcpp,
-                    grpc_closure *destroy_done) {
-  grpc_tcp_server *tcp = tcpp;
-  grpc_tcp_server_shutdown_listeners(exec_ctx, tcp);
-  grpc_tcp_server_unref(exec_ctx, tcp);
-  grpc_exec_ctx_sched(exec_ctx, destroy_done, GRPC_ERROR_NONE, NULL);
-}
-
 int grpc_server_add_insecure_http2_port(grpc_server *server, const char *addr) {
-  grpc_resolved_addresses *resolved = NULL;
-  grpc_tcp_server *tcp = NULL;
-  size_t i;
-  size_t count = 0;
-  int port_num = -1;
-  int port_temp;
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  grpc_error *err = GRPC_ERROR_NONE;
-
+  int port_num = 0;
   GRPC_API_TRACE("grpc_server_add_insecure_http2_port(server=%p, addr=%s)", 2,
                  (server, addr));
-
-  grpc_error **errors = NULL;
-  err = grpc_blocking_resolve_address(addr, "https", &resolved);
-  if (err != GRPC_ERROR_NONE) {
-    goto error;
-  }
-
-  err = grpc_tcp_server_create(&exec_ctx, NULL,
-                               grpc_server_get_channel_args(server), &tcp);
+  grpc_error *err = grpc_chttp2_server_add_port(
+      &exec_ctx, server, addr,
+      grpc_channel_args_copy(grpc_server_get_channel_args(server)), &port_num);
   if (err != GRPC_ERROR_NONE) {
-    goto error;
-  }
-
-  const size_t naddrs = resolved->naddrs;
-  errors = gpr_malloc(sizeof(*errors) * naddrs);
-  for (i = 0; i < naddrs; i++) {
-    errors[i] = grpc_tcp_server_add_port(tcp, &resolved->addrs[i], &port_temp);
-    if (errors[i] == GRPC_ERROR_NONE) {
-      if (port_num == -1) {
-        port_num = port_temp;
-      } else {
-        GPR_ASSERT(port_num == port_temp);
-      }
-      count++;
-    }
+    const char *msg = grpc_error_string(err);
+    gpr_log(GPR_ERROR, "%s", msg);
+    grpc_error_free_string(msg);
+    GRPC_ERROR_UNREF(err);
   }
-  if (count == 0) {
-    char *msg;
-    gpr_asprintf(&msg, "No address added out of total %" PRIuPTR " resolved",
-                 naddrs);
-    err = GRPC_ERROR_CREATE_REFERENCING(msg, errors, naddrs);
-    gpr_free(msg);
-    goto error;
-  } else if (count != naddrs) {
-    char *msg;
-    gpr_asprintf(&msg, "Only %" PRIuPTR
-                       " addresses added out of total %" PRIuPTR " resolved",
-                 count, naddrs);
-    err = GRPC_ERROR_CREATE_REFERENCING(msg, errors, naddrs);
-    gpr_free(msg);
-
-    const char *warning_message = grpc_error_string(err);
-    gpr_log(GPR_INFO, "WARNING: %s", warning_message);
-    grpc_error_free_string(warning_message);
-    /* we managed to bind some addresses: continue */
-  }
-  grpc_resolved_addresses_destroy(resolved);
-
-  /* Register with the server only upon success */
-  grpc_server_add_listener(&exec_ctx, server, tcp, start, destroy);
-  goto done;
-
-/* Error path: cleanup and return */
-error:
-  GPR_ASSERT(err != GRPC_ERROR_NONE);
-  if (resolved) {
-    grpc_resolved_addresses_destroy(resolved);
-  }
-  if (tcp) {
-    grpc_tcp_server_unref(&exec_ctx, tcp);
-  }
-  port_num = 0;
-
-  const char *msg = grpc_error_string(err);
-  gpr_log(GPR_ERROR, "%s", msg);
-  grpc_error_free_string(msg);
-  GRPC_ERROR_UNREF(err);
-
-done:
   grpc_exec_ctx_finish(&exec_ctx);
-  if (errors != NULL) {
-    for (i = 0; i < naddrs; i++) {
-      GRPC_ERROR_UNREF(errors[i]);
-    }
-  }
-  gpr_free(errors);
   return port_num;
 }
diff --git a/src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c b/src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c
index aa2ecf5743..f46e849932 100644
--- a/src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c
+++ b/src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c
@@ -62,7 +62,7 @@ void grpc_server_add_insecure_channel_from_fd(grpc_server *server,
   grpc_endpoint *server_endpoint =
       grpc_tcp_create(grpc_fd_create(fd, name), resource_quota,
                       GRPC_TCP_DEFAULT_READ_SLICE_SIZE, name);
-  grpc_resource_quota_internal_unref(&exec_ctx, resource_quota);
+  grpc_resource_quota_unref_internal(&exec_ctx, resource_quota);
 
   gpr_free(name);
 
diff --git a/src/core/ext/transport/chttp2/server/secure/server_secure_chttp2.c b/src/core/ext/transport/chttp2/server/secure/server_secure_chttp2.c
index 942638ad7f..395c79a71d 100644
--- a/src/core/ext/transport/chttp2/server/secure/server_secure_chttp2.c
+++ b/src/core/ext/transport/chttp2/server/secure/server_secure_chttp2.c
@@ -38,218 +38,35 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
-#include <grpc/support/sync.h>
-#include <grpc/support/useful.h>
+
+#include "src/core/ext/transport/chttp2/server/chttp2_server.h"
+
 #include "src/core/ext/transport/chttp2/transport/chttp2_transport.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/handshaker.h"
-#include "src/core/lib/channel/http_server_filter.h"
-#include "src/core/lib/iomgr/endpoint.h"
-#include "src/core/lib/iomgr/resolve_address.h"
-#include "src/core/lib/iomgr/tcp_server.h"
 #include "src/core/lib/security/context/security_context.h"
 #include "src/core/lib/security/credentials/credentials.h"
-#include "src/core/lib/security/transport/auth_filters.h"
-#include "src/core/lib/security/transport/security_connector.h"
 #include "src/core/lib/surface/api_trace.h"
 #include "src/core/lib/surface/server.h"
 
-typedef struct server_secure_state {
-  grpc_server *server;
-  grpc_tcp_server *tcp;
-  grpc_server_security_connector *sc;
-  grpc_server_credentials *creds;
-  bool is_shutdown;
-  gpr_mu mu;
-  grpc_closure tcp_server_shutdown_complete;
-  grpc_closure *server_destroy_listener_done;
-} server_secure_state;
-
-typedef struct server_secure_connect {
-  server_secure_state *server_state;
-  grpc_pollset *accepting_pollset;
-  grpc_tcp_server_acceptor *acceptor;
-  grpc_handshake_manager *handshake_mgr;
-  // TODO(roth): Remove the following two fields when we eliminate
-  // grpc_server_security_connector_do_handshake().
-  gpr_timespec deadline;
-  grpc_channel_args *args;
-} server_secure_connect;
-
-static void on_secure_handshake_done(grpc_exec_ctx *exec_ctx, void *statep,
-                                     grpc_security_status status,
-                                     grpc_endpoint *secure_endpoint,
-                                     grpc_auth_context *auth_context) {
-  server_secure_connect *connection_state = statep;
-  if (status == GRPC_SECURITY_OK) {
-    if (secure_endpoint) {
-      gpr_mu_lock(&connection_state->server_state->mu);
-      if (!connection_state->server_state->is_shutdown) {
-        grpc_transport *transport = grpc_create_chttp2_transport(
-            exec_ctx, grpc_server_get_channel_args(
-                          connection_state->server_state->server),
-            secure_endpoint, 0);
-        grpc_arg args_to_add[2];
-        args_to_add[0] = grpc_server_credentials_to_arg(
-            connection_state->server_state->creds);
-        args_to_add[1] = grpc_auth_context_to_arg(auth_context);
-        grpc_channel_args *args_copy = grpc_channel_args_copy_and_add(
-            connection_state->args, args_to_add, GPR_ARRAY_SIZE(args_to_add));
-        grpc_server_setup_transport(
-            exec_ctx, connection_state->server_state->server, transport,
-            connection_state->accepting_pollset, args_copy);
-        grpc_channel_args_destroy(args_copy);
-        grpc_chttp2_transport_start_reading(exec_ctx, transport, NULL);
-      } else {
-        /* We need to consume this here, because the server may already have
-         * gone away. */
-        grpc_endpoint_destroy(exec_ctx, secure_endpoint);
-      }
-      gpr_mu_unlock(&connection_state->server_state->mu);
-    }
-  } else {
-    gpr_log(GPR_ERROR, "Secure transport failed with error %d", status);
-  }
-  grpc_channel_args_destroy(connection_state->args);
-  grpc_tcp_server_unref(exec_ctx, connection_state->server_state->tcp);
-  gpr_free(connection_state);
-}
-
-static void on_handshake_done(grpc_exec_ctx *exec_ctx, grpc_endpoint *endpoint,
-                              grpc_channel_args *args,
-                              grpc_slice_buffer *read_buffer, void *user_data,
-                              grpc_error *error) {
-  server_secure_connect *connection_state = user_data;
-  if (error != GRPC_ERROR_NONE) {
-    const char *error_str = grpc_error_string(error);
-    gpr_log(GPR_ERROR, "Handshaking failed: %s", error_str);
-    grpc_error_free_string(error_str);
-    GRPC_ERROR_UNREF(error);
-    grpc_channel_args_destroy(args);
-    gpr_free(read_buffer);
-    grpc_handshake_manager_shutdown(exec_ctx, connection_state->handshake_mgr);
-    grpc_handshake_manager_destroy(exec_ctx, connection_state->handshake_mgr);
-    grpc_tcp_server_unref(exec_ctx, connection_state->server_state->tcp);
-    gpr_free(connection_state);
-    return;
-  }
-  grpc_handshake_manager_destroy(exec_ctx, connection_state->handshake_mgr);
-  connection_state->handshake_mgr = NULL;
-  // TODO(roth, jboeuf): Convert security connector handshaking to use new
-  // handshake API, and then move the code from on_secure_handshake_done()
-  // into this function.
-  connection_state->args = args;
-  grpc_server_security_connector_do_handshake(
-      exec_ctx, connection_state->server_state->sc, connection_state->acceptor,
-      endpoint, read_buffer, connection_state->deadline,
-      on_secure_handshake_done, connection_state);
-}
-
-static void on_accept(grpc_exec_ctx *exec_ctx, void *statep, grpc_endpoint *tcp,
-                      grpc_pollset *accepting_pollset,
-                      grpc_tcp_server_acceptor *acceptor) {
-  server_secure_state *server_state = statep;
-  server_secure_connect *connection_state = NULL;
-  gpr_mu_lock(&server_state->mu);
-  if (server_state->is_shutdown) {
-    gpr_mu_unlock(&server_state->mu);
-    grpc_endpoint_destroy(exec_ctx, tcp);
-    return;
-  }
-  gpr_mu_unlock(&server_state->mu);
-  grpc_tcp_server_ref(server_state->tcp);
-  connection_state = gpr_malloc(sizeof(*connection_state));
-  connection_state->server_state = server_state;
-  connection_state->accepting_pollset = accepting_pollset;
-  connection_state->acceptor = acceptor;
-  connection_state->handshake_mgr = grpc_handshake_manager_create();
-  // TODO(roth): We should really get this timeout value from channel
-  // args instead of hard-coding it.
-  connection_state->deadline = gpr_time_add(
-      gpr_now(GPR_CLOCK_MONOTONIC), gpr_time_from_seconds(120, GPR_TIMESPAN));
-  grpc_handshake_manager_do_handshake(
-      exec_ctx, connection_state->handshake_mgr, tcp,
-      grpc_server_get_channel_args(connection_state->server_state->server),
-      connection_state->deadline, acceptor, on_handshake_done,
-      connection_state);
-}
-
-/* Server callback: start listening on our ports */
-static void server_start_listener(grpc_exec_ctx *exec_ctx, grpc_server *server,
-                                  void *statep, grpc_pollset **pollsets,
-                                  size_t pollset_count) {
-  server_secure_state *server_state = statep;
-  gpr_mu_lock(&server_state->mu);
-  server_state->is_shutdown = false;
-  gpr_mu_unlock(&server_state->mu);
-  grpc_tcp_server_start(exec_ctx, server_state->tcp, pollsets, pollset_count,
-                        on_accept, server_state);
-}
-
-static void tcp_server_shutdown_complete(grpc_exec_ctx *exec_ctx, void *statep,
-                                         grpc_error *error) {
-  server_secure_state *server_state = statep;
-  /* ensure all threads have unlocked */
-  gpr_mu_lock(&server_state->mu);
-  grpc_closure *destroy_done = server_state->server_destroy_listener_done;
-  GPR_ASSERT(server_state->is_shutdown);
-  gpr_mu_unlock(&server_state->mu);
-  /* clean up */
-  grpc_server_security_connector_shutdown(exec_ctx, server_state->sc);
-
-  /* Flush queued work before a synchronous unref. */
-  grpc_exec_ctx_flush(exec_ctx);
-  GRPC_SECURITY_CONNECTOR_UNREF(&server_state->sc->base, "server");
-  grpc_server_credentials_unref(server_state->creds);
-
-  if (destroy_done != NULL) {
-    destroy_done->cb(exec_ctx, destroy_done->cb_arg, GRPC_ERROR_REF(error));
-    grpc_exec_ctx_flush(exec_ctx);
-  }
-  gpr_free(server_state);
-}
-
-static void server_destroy_listener(grpc_exec_ctx *exec_ctx,
-                                    grpc_server *server, void *statep,
-                                    grpc_closure *callback) {
-  server_secure_state *server_state = statep;
-  grpc_tcp_server *tcp;
-  gpr_mu_lock(&server_state->mu);
-  server_state->is_shutdown = true;
-  server_state->server_destroy_listener_done = callback;
-  tcp = server_state->tcp;
-  gpr_mu_unlock(&server_state->mu);
-  grpc_tcp_server_shutdown_listeners(exec_ctx, tcp);
-  grpc_tcp_server_unref(exec_ctx, server_state->tcp);
-}
-
 int grpc_server_add_secure_http2_port(grpc_server *server, const char *addr,
                                       grpc_server_credentials *creds) {
-  grpc_resolved_addresses *resolved = NULL;
-  grpc_tcp_server *tcp = NULL;
-  server_secure_state *server_state = NULL;
-  size_t i;
-  size_t count = 0;
-  int port_num = -1;
-  int port_temp;
-  grpc_security_status status = GRPC_SECURITY_ERROR;
-  grpc_server_security_connector *sc = NULL;
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_error *err = GRPC_ERROR_NONE;
-  grpc_error **errors = NULL;
-
+  grpc_server_security_connector *sc = NULL;
+  int port_num = 0;
   GRPC_API_TRACE(
       "grpc_server_add_secure_http2_port("
       "server=%p, addr=%s, creds=%p)",
       3, (server, addr, creds));
-
-  /* create security context */
+  // Create security context.
   if (creds == NULL) {
     err = GRPC_ERROR_CREATE(
         "No credentials specified for secure server port (creds==NULL)");
-    goto error;
+    goto done;
   }
-  status = grpc_server_credentials_create_security_connector(creds, &sc);
+  grpc_security_status status =
+      grpc_server_credentials_create_security_connector(&exec_ctx, creds, &sc);
   if (status != GRPC_SECURITY_OK) {
     char *msg;
     gpr_asprintf(&msg,
@@ -258,107 +75,27 @@ int grpc_server_add_secure_http2_port(grpc_server *server, const char *addr,
     err = grpc_error_set_int(GRPC_ERROR_CREATE(msg),
                              GRPC_ERROR_INT_SECURITY_STATUS, status);
     gpr_free(msg);
-    goto error;
+    goto done;
   }
-  sc->channel_args = grpc_server_get_channel_args(server);
-
-  /* resolve address */
-  err = grpc_blocking_resolve_address(addr, "https", &resolved);
-  if (err != GRPC_ERROR_NONE) {
-    goto error;
+  // Create channel args.
+  grpc_arg args_to_add[2];
+  args_to_add[0] = grpc_server_credentials_to_arg(creds);
+  args_to_add[1] = grpc_security_connector_to_arg(&sc->base);
+  grpc_channel_args *args =
+      grpc_channel_args_copy_and_add(grpc_server_get_channel_args(server),
+                                     args_to_add, GPR_ARRAY_SIZE(args_to_add));
+  // Add server port.
+  err = grpc_chttp2_server_add_port(&exec_ctx, server, addr, args, &port_num);
+done:
+  if (sc != NULL) {
+    GRPC_SECURITY_CONNECTOR_UNREF(&exec_ctx, &sc->base, "server");
   }
-  server_state = gpr_malloc(sizeof(*server_state));
-  memset(server_state, 0, sizeof(*server_state));
-  grpc_closure_init(&server_state->tcp_server_shutdown_complete,
-                    tcp_server_shutdown_complete, server_state);
-  err = grpc_tcp_server_create(&exec_ctx,
-                               &server_state->tcp_server_shutdown_complete,
-                               grpc_server_get_channel_args(server), &tcp);
+  grpc_exec_ctx_finish(&exec_ctx);
   if (err != GRPC_ERROR_NONE) {
-    goto error;
+    const char *msg = grpc_error_string(err);
+    gpr_log(GPR_ERROR, "%s", msg);
+    grpc_error_free_string(msg);
+    GRPC_ERROR_UNREF(err);
   }
-
-  server_state->server = server;
-  server_state->tcp = tcp;
-  server_state->sc = sc;
-  server_state->creds = grpc_server_credentials_ref(creds);
-  server_state->is_shutdown = true;
-  gpr_mu_init(&server_state->mu);
-
-  errors = gpr_malloc(sizeof(*errors) * resolved->naddrs);
-  for (i = 0; i < resolved->naddrs; i++) {
-    errors[i] = grpc_tcp_server_add_port(tcp, &resolved->addrs[i], &port_temp);
-    if (errors[i] == GRPC_ERROR_NONE) {
-      if (port_num == -1) {
-        port_num = port_temp;
-      } else {
-        GPR_ASSERT(port_num == port_temp);
-      }
-      count++;
-    }
-  }
-  if (count == 0) {
-    char *msg;
-    gpr_asprintf(&msg, "No address added out of total %" PRIuPTR " resolved",
-                 resolved->naddrs);
-    err = GRPC_ERROR_CREATE_REFERENCING(msg, errors, resolved->naddrs);
-    gpr_free(msg);
-    goto error;
-  } else if (count != resolved->naddrs) {
-    char *msg;
-    gpr_asprintf(&msg, "Only %" PRIuPTR
-                       " addresses added out of total %" PRIuPTR " resolved",
-                 count, resolved->naddrs);
-    err = GRPC_ERROR_CREATE_REFERENCING(msg, errors, resolved->naddrs);
-    gpr_free(msg);
-
-    const char *warning_message = grpc_error_string(err);
-    gpr_log(GPR_INFO, "WARNING: %s", warning_message);
-    grpc_error_free_string(warning_message);
-    /* we managed to bind some addresses: continue */
-  } else {
-    for (i = 0; i < resolved->naddrs; i++) {
-      GRPC_ERROR_UNREF(errors[i]);
-    }
-  }
-  gpr_free(errors);
-  errors = NULL;
-  grpc_resolved_addresses_destroy(resolved);
-
-  /* Register with the server only upon success */
-  grpc_server_add_listener(&exec_ctx, server, server_state,
-                           server_start_listener, server_destroy_listener);
-
-  grpc_exec_ctx_finish(&exec_ctx);
   return port_num;
-
-/* Error path: cleanup and return */
-error:
-  GPR_ASSERT(err != GRPC_ERROR_NONE);
-  if (errors != NULL) {
-    for (i = 0; i < resolved->naddrs; i++) {
-      GRPC_ERROR_UNREF(errors[i]);
-    }
-    gpr_free(errors);
-  }
-  if (resolved) {
-    grpc_resolved_addresses_destroy(resolved);
-  }
-  if (tcp) {
-    grpc_tcp_server_unref(&exec_ctx, tcp);
-  } else {
-    if (sc) {
-      grpc_exec_ctx_flush(&exec_ctx);
-      GRPC_SECURITY_CONNECTOR_UNREF(&sc->base, "server");
-    }
-    if (server_state) {
-      gpr_free(server_state);
-    }
-  }
-  grpc_exec_ctx_finish(&exec_ctx);
-  const char *msg = grpc_error_string(err);
-  GRPC_ERROR_UNREF(err);
-  gpr_log(GPR_ERROR, "%s", msg);
-  grpc_error_free_string(msg);
-  return 0;
 }
diff --git a/src/core/ext/transport/chttp2/transport/bin_decoder.c b/src/core/ext/transport/chttp2/transport/bin_decoder.c
index 3eef80b557..8db36e4a7f 100644
--- a/src/core/ext/transport/chttp2/transport/bin_decoder.c
+++ b/src/core/ext/transport/chttp2/transport/bin_decoder.c
@@ -34,6 +34,7 @@
 #include "src/core/ext/transport/chttp2/transport/bin_decoder.h"
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/string.h"
 
@@ -143,7 +144,8 @@ bool grpc_base64_decode_partial(struct grpc_base64_decode_context *ctx) {
   return true;
 }
 
-grpc_slice grpc_chttp2_base64_decode(grpc_slice input) {
+grpc_slice grpc_chttp2_base64_decode(grpc_exec_ctx *exec_ctx,
+                                     grpc_slice input) {
   size_t input_length = GRPC_SLICE_LENGTH(input);
   size_t output_length = input_length / 4 * 3;
   struct grpc_base64_decode_context ctx;
@@ -179,7 +181,7 @@ grpc_slice grpc_chttp2_base64_decode(grpc_slice input) {
     char *s = grpc_dump_slice(input, GPR_DUMP_ASCII);
     gpr_log(GPR_ERROR, "Base64 decoding failed, input string:\n%s\n", s);
     gpr_free(s);
-    grpc_slice_unref(output);
+    grpc_slice_unref_internal(exec_ctx, output);
     return gpr_empty_slice();
   }
   GPR_ASSERT(ctx.output_cur == GRPC_SLICE_END_PTR(output));
@@ -187,7 +189,8 @@ grpc_slice grpc_chttp2_base64_decode(grpc_slice input) {
   return output;
 }
 
-grpc_slice grpc_chttp2_base64_decode_with_length(grpc_slice input,
+grpc_slice grpc_chttp2_base64_decode_with_length(grpc_exec_ctx *exec_ctx,
+                                                 grpc_slice input,
                                                  size_t output_length) {
   size_t input_length = GRPC_SLICE_LENGTH(input);
   grpc_slice output = grpc_slice_malloc(output_length);
@@ -200,7 +203,7 @@ grpc_slice grpc_chttp2_base64_decode_with_length(grpc_slice input,
             "grpc_chttp2_base64_decode_with_length has a length of %d, which "
             "has a tail of 1 byte.\n",
             (int)input_length);
-    grpc_slice_unref(output);
+    grpc_slice_unref_internal(exec_ctx, output);
     return gpr_empty_slice();
   }
 
@@ -210,7 +213,7 @@ grpc_slice grpc_chttp2_base64_decode_with_length(grpc_slice input,
             "than the max possible output length %d.\n",
             (int)output_length,
             (int)(input_length / 4 * 3 + tail_xtra[input_length % 4]));
-    grpc_slice_unref(output);
+    grpc_slice_unref_internal(exec_ctx, output);
     return gpr_empty_slice();
   }
 
@@ -224,7 +227,7 @@ grpc_slice grpc_chttp2_base64_decode_with_length(grpc_slice input,
     char *s = grpc_dump_slice(input, GPR_DUMP_ASCII);
     gpr_log(GPR_ERROR, "Base64 decoding failed, input string:\n%s\n", s);
     gpr_free(s);
-    grpc_slice_unref(output);
+    grpc_slice_unref_internal(exec_ctx, output);
     return gpr_empty_slice();
   }
   GPR_ASSERT(ctx.output_cur == GRPC_SLICE_END_PTR(output));
diff --git a/src/core/ext/transport/chttp2/transport/bin_decoder.h b/src/core/ext/transport/chttp2/transport/bin_decoder.h
index 83a90be519..48ffb2ae3b 100644
--- a/src/core/ext/transport/chttp2/transport/bin_decoder.h
+++ b/src/core/ext/transport/chttp2/transport/bin_decoder.h
@@ -55,12 +55,13 @@ bool grpc_base64_decode_partial(struct grpc_base64_decode_context *ctx);
 
 /* base64 decode a slice with pad chars. Returns a new slice, does not take
    ownership of the input. Returns an empty slice if decoding is failed. */
-grpc_slice grpc_chttp2_base64_decode(grpc_slice input);
+grpc_slice grpc_chttp2_base64_decode(grpc_exec_ctx *exec_ctx, grpc_slice input);
 
 /* base64 decode a slice without pad chars, data length is needed. Returns a new
    slice, does not take ownership of the input. Returns an empty slice if
    decoding is failed. */
-grpc_slice grpc_chttp2_base64_decode_with_length(grpc_slice input,
+grpc_slice grpc_chttp2_base64_decode_with_length(grpc_exec_ctx *exec_ctx,
+                                                 grpc_slice input,
                                                  size_t output_length);
 
 #endif /* GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_BIN_DECODER_H */
diff --git a/src/core/ext/transport/chttp2/transport/bin_encoder.h b/src/core/ext/transport/chttp2/transport/bin_encoder.h
index 9e143b46e2..477559d0e2 100644
--- a/src/core/ext/transport/chttp2/transport/bin_encoder.h
+++ b/src/core/ext/transport/chttp2/transport/bin_encoder.h
@@ -47,7 +47,7 @@ grpc_slice grpc_chttp2_huffman_compress(grpc_slice input);
 /* equivalent to:
    grpc_slice x = grpc_chttp2_base64_encode(input);
    grpc_slice y = grpc_chttp2_huffman_compress(x);
-   grpc_slice_unref(x);
+   grpc_slice_unref_internal(exec_ctx, x);
    return y; */
 grpc_slice grpc_chttp2_base64_encode_and_huffman_compress_impl(
     grpc_slice input);
diff --git a/src/core/ext/transport/chttp2/transport/chttp2_transport.c b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
index 4e3c7ff681..8fe12a2690 100644
--- a/src/core/ext/transport/chttp2/transport/chttp2_transport.c
+++ b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
@@ -47,10 +47,12 @@
 #include "src/core/ext/transport/chttp2/transport/http2_errors.h"
 #include "src/core/ext/transport/chttp2/transport/internal.h"
 #include "src/core/ext/transport/chttp2/transport/status_conversion.h"
+#include "src/core/ext/transport/chttp2/transport/varint.h"
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/http/parser.h"
 #include "src/core/lib/iomgr/workqueue.h"
 #include "src/core/lib/profiling/timers.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/transport/static_metadata.h"
@@ -73,20 +75,14 @@ static const grpc_transport_vtable vtable;
 static void write_action_begin_locked(grpc_exec_ctx *exec_ctx, void *t,
                                       grpc_error *error);
 static void write_action(grpc_exec_ctx *exec_ctx, void *t, grpc_error *error);
-static void write_action_end(grpc_exec_ctx *exec_ctx, void *t,
-                             grpc_error *error);
 static void write_action_end_locked(grpc_exec_ctx *exec_ctx, void *t,
                                     grpc_error *error);
 
-static void read_action_begin(grpc_exec_ctx *exec_ctx, void *t,
-                              grpc_error *error);
 static void read_action_locked(grpc_exec_ctx *exec_ctx, void *t,
                                grpc_error *error);
 
 static void complete_fetch_locked(grpc_exec_ctx *exec_ctx, void *gs,
                                   grpc_error *error);
-static void complete_fetch(grpc_exec_ctx *exec_ctx, void *gs,
-                           grpc_error *error);
 /** Set a transport level setting, and push it to our peer */
 static void push_setting(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                          grpc_chttp2_setting_id id, uint32_t value);
@@ -111,16 +107,9 @@ static void incoming_byte_stream_update_flow_control(grpc_exec_ctx *exec_ctx,
 static void incoming_byte_stream_destroy_locked(grpc_exec_ctx *exec_ctx,
                                                 void *byte_stream,
                                                 grpc_error *error_ignored);
-static void fail_pending_writes(grpc_exec_ctx *exec_ctx,
-                                grpc_chttp2_transport *t, grpc_chttp2_stream *s,
-                                grpc_error *error);
 
-static void benign_reclaimer(grpc_exec_ctx *exec_ctx, void *t,
-                             grpc_error *error);
 static void benign_reclaimer_locked(grpc_exec_ctx *exec_ctx, void *t,
                                     grpc_error *error);
-static void destructive_reclaimer(grpc_exec_ctx *exec_ctx, void *t,
-                                  grpc_error *error);
 static void destructive_reclaimer_locked(grpc_exec_ctx *exec_ctx, void *t,
                                          grpc_error *error);
 
@@ -144,13 +133,13 @@ static void destruct_transport(grpc_exec_ctx *exec_ctx,
 
   grpc_endpoint_destroy(exec_ctx, t->ep);
 
-  grpc_slice_buffer_destroy(&t->qbuf);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &t->qbuf);
 
-  grpc_slice_buffer_destroy(&t->outbuf);
-  grpc_chttp2_hpack_compressor_destroy(&t->hpack_compressor);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &t->outbuf);
+  grpc_chttp2_hpack_compressor_destroy(exec_ctx, &t->hpack_compressor);
 
-  grpc_slice_buffer_destroy(&t->read_buffer);
-  grpc_chttp2_hpack_parser_destroy(&t->hpack_parser);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &t->read_buffer);
+  grpc_chttp2_hpack_parser_destroy(exec_ctx, &t->hpack_parser);
   grpc_chttp2_goaway_parser_destroy(&t->goaway_parser);
 
   for (i = 0; i < STREAM_LIST_COUNT; i++) {
@@ -169,8 +158,8 @@ static void destruct_transport(grpc_exec_ctx *exec_ctx,
      and maybe they hold resources that need to be freed */
   while (t->pings.next != &t->pings) {
     grpc_chttp2_outstanding_ping *ping = t->pings.next;
-    grpc_exec_ctx_sched(exec_ctx, ping->on_recv,
-                        GRPC_ERROR_CREATE("Transport closed"), NULL);
+    grpc_closure_sched(exec_ctx, ping->on_recv,
+                       GRPC_ERROR_CREATE("Transport closed"));
     ping->next->prev = ping->prev;
     ping->prev->next = ping->next;
     gpr_free(ping);
@@ -249,21 +238,18 @@ static void init_transport(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   grpc_slice_buffer_init(&t->outbuf);
   grpc_chttp2_hpack_compressor_init(&t->hpack_compressor);
 
-  grpc_closure_init(&t->write_action_begin_locked, write_action_begin_locked,
-                    t);
-  grpc_closure_init(&t->write_action, write_action, t);
-  grpc_closure_init(&t->write_action_end, write_action_end, t);
-  grpc_closure_init(&t->write_action_end_locked, write_action_end_locked, t);
-  grpc_closure_init(&t->read_action_begin, read_action_begin, t);
-  grpc_closure_init(&t->read_action_locked, read_action_locked, t);
-  grpc_closure_init(&t->benign_reclaimer, benign_reclaimer, t);
-  grpc_closure_init(&t->destructive_reclaimer, destructive_reclaimer, t);
-  grpc_closure_init(&t->benign_reclaimer_locked, benign_reclaimer_locked, t);
+  grpc_closure_init(&t->write_action, write_action, t,
+                    grpc_schedule_on_exec_ctx);
+  grpc_closure_init(&t->read_action_locked, read_action_locked, t,
+                    grpc_combiner_scheduler(t->combiner, false));
+  grpc_closure_init(&t->benign_reclaimer_locked, benign_reclaimer_locked, t,
+                    grpc_combiner_scheduler(t->combiner, false));
   grpc_closure_init(&t->destructive_reclaimer_locked,
-                    destructive_reclaimer_locked, t);
+                    destructive_reclaimer_locked, t,
+                    grpc_combiner_scheduler(t->combiner, false));
 
   grpc_chttp2_goaway_parser_init(&t->goaway_parser);
-  grpc_chttp2_hpack_parser_init(&t->hpack_parser);
+  grpc_chttp2_hpack_parser_init(exec_ctx, &t->hpack_parser);
 
   grpc_slice_buffer_init(&t->read_buffer);
 
@@ -398,9 +384,10 @@ static void destroy_transport_locked(grpc_exec_ctx *exec_ctx, void *tp,
 
 static void destroy_transport(grpc_exec_ctx *exec_ctx, grpc_transport *gt) {
   grpc_chttp2_transport *t = (grpc_chttp2_transport *)gt;
-  grpc_combiner_execute(exec_ctx, t->combiner,
-                        grpc_closure_create(destroy_transport_locked, t),
-                        GRPC_ERROR_NONE, false);
+  grpc_closure_sched(exec_ctx, grpc_closure_create(
+                                   destroy_transport_locked, t,
+                                   grpc_combiner_scheduler(t->combiner, false)),
+                     GRPC_ERROR_NONE);
 }
 
 static void close_transport_locked(grpc_exec_ctx *exec_ctx,
@@ -474,8 +461,8 @@ static int init_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
   grpc_chttp2_data_parser_init(&s->data_parser);
   grpc_slice_buffer_init(&s->flow_controlled_buffer);
   s->deadline = gpr_inf_future(GPR_CLOCK_MONOTONIC);
-  grpc_closure_init(&s->complete_fetch, complete_fetch, s);
-  grpc_closure_init(&s->complete_fetch_locked, complete_fetch_locked, s);
+  grpc_closure_init(&s->complete_fetch_locked, complete_fetch_locked, s,
+                    grpc_schedule_on_exec_ctx);
 
   GRPC_CHTTP2_REF_TRANSPORT(t, "stream");
 
@@ -530,9 +517,11 @@ static void destroy_stream_locked(grpc_exec_ctx *exec_ctx, void *sp,
   GPR_ASSERT(s->recv_message_ready == NULL);
   GPR_ASSERT(s->recv_trailing_metadata_finished == NULL);
   grpc_chttp2_data_parser_destroy(exec_ctx, &s->data_parser);
-  grpc_chttp2_incoming_metadata_buffer_destroy(&s->metadata_buffer[0]);
-  grpc_chttp2_incoming_metadata_buffer_destroy(&s->metadata_buffer[1]);
-  grpc_slice_buffer_destroy(&s->flow_controlled_buffer);
+  grpc_chttp2_incoming_metadata_buffer_destroy(exec_ctx,
+                                               &s->metadata_buffer[0]);
+  grpc_chttp2_incoming_metadata_buffer_destroy(exec_ctx,
+                                               &s->metadata_buffer[1]);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &s->flow_controlled_buffer);
   GRPC_ERROR_UNREF(s->read_closed_error);
   GRPC_ERROR_UNREF(s->write_closed_error);
 
@@ -550,9 +539,10 @@ static void destroy_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
   grpc_chttp2_stream *s = (grpc_chttp2_stream *)gs;
 
   s->destroy_stream_arg = and_free_memory;
-  grpc_closure_init(&s->destroy_stream, destroy_stream_locked, s);
-  grpc_combiner_execute(exec_ctx, t->combiner, &s->destroy_stream,
-                        GRPC_ERROR_NONE, false);
+  grpc_closure_sched(
+      exec_ctx, grpc_closure_init(&s->destroy_stream, destroy_stream_locked, s,
+                                  grpc_combiner_scheduler(t->combiner, false)),
+      GRPC_ERROR_NONE);
   GPR_TIMER_END("destroy_stream", 0);
 }
 
@@ -602,11 +592,13 @@ static void set_write_state(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
                                  write_state_name(t->write_state),
                                  write_state_name(st), reason));
   t->write_state = st;
-  if (st == GRPC_CHTTP2_WRITE_STATE_IDLE &&
-      t->close_transport_on_writes_finished != NULL) {
-    grpc_error *err = t->close_transport_on_writes_finished;
-    t->close_transport_on_writes_finished = NULL;
-    close_transport_locked(exec_ctx, t, err);
+  if (st == GRPC_CHTTP2_WRITE_STATE_IDLE) {
+    grpc_closure_list_sched(exec_ctx, &t->run_after_write);
+    if (t->close_transport_on_writes_finished != NULL) {
+      grpc_error *err = t->close_transport_on_writes_finished;
+      t->close_transport_on_writes_finished = NULL;
+      close_transport_locked(exec_ctx, t, err);
+    }
   }
 }
 
@@ -619,9 +611,12 @@ void grpc_chttp2_initiate_write(grpc_exec_ctx *exec_ctx,
     case GRPC_CHTTP2_WRITE_STATE_IDLE:
       set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_WRITING, reason);
       GRPC_CHTTP2_REF_TRANSPORT(t, "writing");
-      grpc_combiner_execute_finally(exec_ctx, t->combiner,
-                                    &t->write_action_begin_locked,
-                                    GRPC_ERROR_NONE, covered_by_poller);
+      grpc_closure_sched(
+          exec_ctx,
+          grpc_closure_init(
+              &t->write_action_begin_locked, write_action_begin_locked, t,
+              grpc_combiner_finally_scheduler(t->combiner, covered_by_poller)),
+          GRPC_ERROR_NONE);
       break;
     case GRPC_CHTTP2_WRITE_STATE_WRITING:
       set_write_state(
@@ -663,7 +658,7 @@ static void write_action_begin_locked(grpc_exec_ctx *exec_ctx, void *gt,
   if (!t->closed && grpc_chttp2_begin_write(exec_ctx, t)) {
     set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_WRITING,
                     "begin writing");
-    grpc_exec_ctx_sched(exec_ctx, &t->write_action, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, &t->write_action, GRPC_ERROR_NONE);
   } else {
     set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_IDLE,
                     "begin writing nothing");
@@ -675,19 +670,13 @@ static void write_action_begin_locked(grpc_exec_ctx *exec_ctx, void *gt,
 static void write_action(grpc_exec_ctx *exec_ctx, void *gt, grpc_error *error) {
   grpc_chttp2_transport *t = gt;
   GPR_TIMER_BEGIN("write_action", 0);
-  grpc_endpoint_write(exec_ctx, t->ep, &t->outbuf, &t->write_action_end);
+  grpc_endpoint_write(
+      exec_ctx, t->ep, &t->outbuf,
+      grpc_closure_init(&t->write_action_end_locked, write_action_end_locked, t,
+                        grpc_combiner_scheduler(t->combiner, false)));
   GPR_TIMER_END("write_action", 0);
 }
 
-static void write_action_end(grpc_exec_ctx *exec_ctx, void *gt,
-                             grpc_error *error) {
-  grpc_chttp2_transport *t = gt;
-  GPR_TIMER_BEGIN("write_action_end", 0);
-  grpc_combiner_execute(exec_ctx, t->combiner, &t->write_action_end_locked,
-                        GRPC_ERROR_REF(error), false);
-  GPR_TIMER_END("write_action_end", 0);
-}
-
 static void write_action_end_locked(grpc_exec_ctx *exec_ctx, void *tp,
                                     grpc_error *error) {
   GPR_TIMER_BEGIN("terminate_writing_with_lock", 0);
@@ -704,8 +693,6 @@ static void write_action_end_locked(grpc_exec_ctx *exec_ctx, void *tp,
     }
   }
 
-  grpc_chttp2_end_write(exec_ctx, t, GRPC_ERROR_REF(error));
-
   switch (t->write_state) {
     case GRPC_CHTTP2_WRITE_STATE_IDLE:
       GPR_UNREACHABLE_CODE(break);
@@ -719,21 +706,29 @@ static void write_action_end_locked(grpc_exec_ctx *exec_ctx, void *tp,
       set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_WRITING,
                       "continue writing [!covered]");
       GRPC_CHTTP2_REF_TRANSPORT(t, "writing");
-      grpc_combiner_execute_finally(exec_ctx, t->combiner,
-                                    &t->write_action_begin_locked,
-                                    GRPC_ERROR_NONE, false);
+      grpc_closure_run(
+          exec_ctx,
+          grpc_closure_init(
+              &t->write_action_begin_locked, write_action_begin_locked, t,
+              grpc_combiner_finally_scheduler(t->combiner, false)),
+          GRPC_ERROR_NONE);
       break;
     case GRPC_CHTTP2_WRITE_STATE_WRITING_WITH_MORE_AND_COVERED_BY_POLLER:
       GPR_TIMER_MARK("state=writing_stale_with_poller", 0);
       set_write_state(exec_ctx, t, GRPC_CHTTP2_WRITE_STATE_WRITING,
                       "continue writing [covered]");
       GRPC_CHTTP2_REF_TRANSPORT(t, "writing");
-      grpc_combiner_execute_finally(exec_ctx, t->combiner,
-                                    &t->write_action_begin_locked,
-                                    GRPC_ERROR_NONE, true);
+      grpc_closure_run(
+          exec_ctx,
+          grpc_closure_init(&t->write_action_begin_locked,
+                            write_action_begin_locked, t,
+                            grpc_combiner_finally_scheduler(t->combiner, true)),
+          GRPC_ERROR_NONE);
       break;
   }
 
+  grpc_chttp2_end_write(exec_ctx, t, GRPC_ERROR_REF(error));
+
   GRPC_CHTTP2_UNREF_TRANSPORT(exec_ctx, t, "writing");
   GPR_TIMER_END("terminate_writing_with_lock", 0);
 }
@@ -761,7 +756,7 @@ void grpc_chttp2_add_incoming_goaway(grpc_exec_ctx *exec_ctx,
   char *msg = grpc_dump_slice(goaway_text, GPR_DUMP_HEX | GPR_DUMP_ASCII);
   GRPC_CHTTP2_IF_TRACING(
       gpr_log(GPR_DEBUG, "got goaway [%d]: %s", goaway_error, msg));
-  grpc_slice_unref(goaway_text);
+  grpc_slice_unref_internal(exec_ctx, goaway_text);
   t->seen_goaway = 1;
   /* lie: use transient failure from the transport to indicate goaway has been
    * received */
@@ -823,7 +818,14 @@ static void maybe_start_some_streams(grpc_exec_ctx *exec_ctx,
   }
 }
 
+/* Flag that this closure barrier wants stats to be updated before finishing */
 #define CLOSURE_BARRIER_STATS_BIT (1 << 0)
+/* Flag that this closure barrier may be covering a write in a pollset, and so
+   we should not complete this closure until we can prove that the write got
+   scheduled */
+#define CLOSURE_BARRIER_MAY_COVER_WRITE (1 << 1)
+/* First bit of the reference count, stored in the high order bits (with the low
+   bits being used for flags defined above) */
 #define CLOSURE_BARRIER_FIRST_REF_BIT (1 << 16)
 
 static grpc_closure *add_closure_barrier(grpc_closure *closure) {
@@ -850,6 +852,16 @@ void grpc_chttp2_complete_closure_step(grpc_exec_ctx *exec_ctx,
     return;
   }
   closure->next_data.scratch -= CLOSURE_BARRIER_FIRST_REF_BIT;
+  if (grpc_http_trace) {
+    const char *errstr = grpc_error_string(error);
+    gpr_log(GPR_DEBUG,
+            "complete_closure_step: %p refs=%d flags=0x%04x desc=%s err=%s",
+            closure,
+            (int)(closure->next_data.scratch / CLOSURE_BARRIER_FIRST_REF_BIT),
+            (int)(closure->next_data.scratch % CLOSURE_BARRIER_FIRST_REF_BIT),
+            desc, errstr);
+    grpc_error_free_string(errstr);
+  }
   if (error != GRPC_ERROR_NONE) {
     if (closure->error_data.error == GRPC_ERROR_NONE) {
       closure->error_data.error =
@@ -866,7 +878,13 @@ void grpc_chttp2_complete_closure_step(grpc_exec_ctx *exec_ctx,
       grpc_transport_move_stats(&s->stats, s->collecting_stats);
       s->collecting_stats = NULL;
     }
-    grpc_closure_run(exec_ctx, closure, closure->error_data.error);
+    if ((t->write_state == GRPC_CHTTP2_WRITE_STATE_IDLE) ||
+        !(closure->next_data.scratch & CLOSURE_BARRIER_MAY_COVER_WRITE)) {
+      grpc_closure_run(exec_ctx, closure, closure->error_data.error);
+    } else {
+      grpc_closure_list_append(&t->run_after_write, closure,
+                               closure->error_data.error);
+    }
   }
 }
 
@@ -943,15 +961,6 @@ static void complete_fetch_locked(grpc_exec_ctx *exec_ctx, void *gs,
   }
 }
 
-static void complete_fetch(grpc_exec_ctx *exec_ctx, void *gs,
-                           grpc_error *error) {
-  grpc_chttp2_stream *s = gs;
-  grpc_chttp2_transport *t = s->t;
-  grpc_combiner_execute(exec_ctx, t->combiner, &s->complete_fetch_locked,
-                        GRPC_ERROR_REF(error),
-                        s->complete_fetch_covered_by_poller);
-}
-
 static void do_nothing(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {}
 
 static void log_metadata(const grpc_metadata_batch *md_batch, uint32_t id,
@@ -987,7 +996,8 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
 
   grpc_closure *on_complete = op->on_complete;
   if (on_complete == NULL) {
-    on_complete = grpc_closure_create(do_nothing, NULL);
+    on_complete =
+        grpc_closure_create(do_nothing, NULL, grpc_schedule_on_exec_ctx);
   }
 
   /* use final_data as a barrier until enqueue time; the inital counter is
@@ -1011,6 +1021,7 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
 
   if (op->send_initial_metadata != NULL) {
     GPR_ASSERT(s->send_initial_metadata_finished == NULL);
+    on_complete->next_data.scratch |= CLOSURE_BARRIER_MAY_COVER_WRITE;
     s->send_initial_metadata_finished = add_closure_barrier(on_complete);
     s->send_initial_metadata = op->send_initial_metadata;
     const size_t metadata_size =
@@ -1064,6 +1075,7 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
   }
 
   if (op->send_message != NULL) {
+    on_complete->next_data.scratch |= CLOSURE_BARRIER_MAY_COVER_WRITE;
     s->fetching_send_message_finished = add_closure_barrier(op->on_complete);
     if (s->write_closed) {
       grpc_chttp2_complete_closure_step(
@@ -1101,6 +1113,7 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
 
   if (op->send_trailing_metadata != NULL) {
     GPR_ASSERT(s->send_trailing_metadata_finished == NULL);
+    on_complete->next_data.scratch |= CLOSURE_BARRIER_MAY_COVER_WRITE;
     s->send_trailing_metadata_finished = add_closure_barrier(on_complete);
     s->send_trailing_metadata = op->send_trailing_metadata;
     const size_t metadata_size =
@@ -1187,13 +1200,15 @@ static void perform_stream_op(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
     gpr_free(str);
   }
 
-  grpc_closure_init(&op->transport_private.closure, perform_stream_op_locked,
-                    op);
   op->transport_private.args[0] = gt;
   op->transport_private.args[1] = gs;
   GRPC_CHTTP2_STREAM_REF(s, "perform_stream_op");
-  grpc_combiner_execute(exec_ctx, t->combiner, &op->transport_private.closure,
-                        GRPC_ERROR_NONE, op->covered_by_poller);
+  grpc_closure_sched(
+      exec_ctx,
+      grpc_closure_init(
+          &op->transport_private.closure, perform_stream_op_locked, op,
+          grpc_combiner_scheduler(t->combiner, op->covered_by_poller)),
+      GRPC_ERROR_NONE);
   GPR_TIMER_END("perform_stream_op", 0);
 }
 
@@ -1222,7 +1237,7 @@ void grpc_chttp2_ack_ping(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
   grpc_chttp2_outstanding_ping *ping;
   for (ping = t->pings.next; ping != &t->pings; ping = ping->next) {
     if (0 == memcmp(opaque_8bytes, ping->id, 8)) {
-      grpc_exec_ctx_sched(exec_ctx, ping->on_recv, GRPC_ERROR_NONE, NULL);
+      grpc_closure_sched(exec_ctx, ping->on_recv, GRPC_ERROR_NONE);
       ping->next->prev = ping->prev;
       ping->prev->next = ping->next;
       gpr_free(ping);
@@ -1260,7 +1275,7 @@ static void perform_transport_op_locked(grpc_exec_ctx *exec_ctx,
   if (op->send_goaway) {
     send_goaway(exec_ctx, t,
                 grpc_chttp2_grpc_status_to_http2_error(op->goaway_status),
-                grpc_slice_ref(*op->goaway_message));
+                grpc_slice_ref_internal(*op->goaway_message));
   }
 
   if (op->set_accept_stream) {
@@ -1296,11 +1311,12 @@ static void perform_transport_op(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
   char *msg = grpc_transport_op_string(op);
   gpr_free(msg);
   op->transport_private.args[0] = gt;
-  grpc_closure_init(&op->transport_private.closure, perform_transport_op_locked,
-                    op);
   GRPC_CHTTP2_REF_TRANSPORT(t, "transport_op");
-  grpc_combiner_execute(exec_ctx, t->combiner, &op->transport_private.closure,
-                        GRPC_ERROR_NONE, false);
+  grpc_closure_sched(
+      exec_ctx, grpc_closure_init(&op->transport_private.closure,
+                                  perform_transport_op_locked, op,
+                                  grpc_combiner_scheduler(t->combiner, false)),
+      GRPC_ERROR_NONE);
 }
 
 /*******************************************************************************
@@ -1490,21 +1506,22 @@ void grpc_chttp2_fake_status(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
     char status_string[GPR_LTOA_MIN_BUFSIZE];
     gpr_ltoa(status, status_string);
     grpc_chttp2_incoming_metadata_buffer_add(
-        &s->metadata_buffer[1],
-        grpc_mdelem_from_metadata_strings(
-            GRPC_MDSTR_GRPC_STATUS, grpc_mdstr_from_string(status_string)));
+        &s->metadata_buffer[1], grpc_mdelem_from_metadata_strings(
+                                    exec_ctx, GRPC_MDSTR_GRPC_STATUS,
+                                    grpc_mdstr_from_string(status_string)));
     if (slice) {
       grpc_chttp2_incoming_metadata_buffer_add(
           &s->metadata_buffer[1],
           grpc_mdelem_from_metadata_strings(
-              GRPC_MDSTR_GRPC_MESSAGE,
-              grpc_mdstr_from_slice(grpc_slice_ref(*slice))));
+              exec_ctx, GRPC_MDSTR_GRPC_MESSAGE,
+              grpc_mdstr_from_slice(exec_ctx,
+                                    grpc_slice_ref_internal(*slice))));
     }
     s->published_metadata[1] = GRPC_METADATA_SYNTHESIZED_FROM_FAKE;
     grpc_chttp2_maybe_complete_recv_trailing_metadata(exec_ctx, t, s);
   }
   if (slice) {
-    grpc_slice_unref(*slice);
+    grpc_slice_unref_internal(exec_ctx, *slice);
   }
 }
 
@@ -1534,9 +1551,9 @@ static grpc_error *removal_error(grpc_error *extra_error, grpc_chttp2_stream *s,
   return error;
 }
 
-static void fail_pending_writes(grpc_exec_ctx *exec_ctx,
-                                grpc_chttp2_transport *t, grpc_chttp2_stream *s,
-                                grpc_error *error) {
+void grpc_chttp2_fail_pending_writes(grpc_exec_ctx *exec_ctx,
+                                     grpc_chttp2_transport *t,
+                                     grpc_chttp2_stream *s, grpc_error *error) {
   error =
       removal_error(error, s, "Pending writes failed due to stream closure");
   s->send_initial_metadata = NULL;
@@ -1590,13 +1607,16 @@ void grpc_chttp2_mark_stream_closed(grpc_exec_ctx *exec_ctx,
   if (close_writes && !s->write_closed) {
     s->write_closed_error = GRPC_ERROR_REF(error);
     s->write_closed = true;
-    fail_pending_writes(exec_ctx, t, s, GRPC_ERROR_REF(error));
+    grpc_chttp2_fail_pending_writes(exec_ctx, t, s, GRPC_ERROR_REF(error));
     grpc_chttp2_maybe_complete_recv_trailing_metadata(exec_ctx, t, s);
   }
   if (s->read_closed && s->write_closed) {
     if (s->id != 0) {
       remove_stream(exec_ctx, t, s->id,
                     removal_error(GRPC_ERROR_REF(error), s, "Stream removed"));
+    } else {
+      /* Purge streams waiting on concurrency still waiting for id assignment */
+      grpc_chttp2_list_remove_waiting_for_concurrency(t, s);
     }
     GRPC_CHTTP2_STREAM_UNREF(exec_ctx, s, "chttp2");
   }
@@ -1657,8 +1677,9 @@ static void close_from_api(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
 
     if (optional_message != NULL) {
       size_t msg_len = strlen(optional_message);
-      GPR_ASSERT(msg_len < 127);
-      message_pfx = grpc_slice_malloc(15);
+      GPR_ASSERT(msg_len <= UINT32_MAX);
+      uint32_t msg_len_len = GRPC_CHTTP2_VARINT_LENGTH((uint32_t)msg_len, 0);
+      message_pfx = grpc_slice_malloc(14 + msg_len_len);
       p = GRPC_SLICE_START_PTR(message_pfx);
       *p++ = 0x40;
       *p++ = 12; /* len(grpc-message) */
@@ -1674,7 +1695,9 @@ static void close_from_api(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
       *p++ = 'a';
       *p++ = 'g';
       *p++ = 'e';
-      *p++ = (uint8_t)msg_len;
+      GRPC_CHTTP2_WRITE_VARINT((uint32_t)msg_len, 0, 0, p,
+                               (uint32_t)msg_len_len);
+      p += msg_len_len;
       GPR_ASSERT(p == GRPC_SLICE_END_PTR(message_pfx));
       len += (uint32_t)GRPC_SLICE_LENGTH(message_pfx);
       len += (uint32_t)msg_len;
@@ -1773,19 +1796,6 @@ static void update_global_window(void *args, uint32_t id, void *stream) {
  * INPUT PROCESSING - PARSING
  */
 
-static void read_action_begin(grpc_exec_ctx *exec_ctx, void *tp,
-                              grpc_error *error) {
-  /* Control flow:
-     reading_action_locked ->
-       (parse_unlocked -> post_parse_locked)? ->
-       post_reading_action_locked */
-  GPR_TIMER_BEGIN("reading_action", 0);
-  grpc_chttp2_transport *t = tp;
-  grpc_combiner_execute(exec_ctx, t->combiner, &t->read_action_locked,
-                        GRPC_ERROR_REF(error), false);
-  GPR_TIMER_END("reading_action", 0);
-}
-
 static grpc_error *try_http_parsing(grpc_exec_ctx *exec_ctx,
                                     grpc_chttp2_transport *t) {
   grpc_http_parser parser;
@@ -1882,10 +1892,11 @@ static void read_action_locked(grpc_exec_ctx *exec_ctx, void *tp,
     keep_reading = true;
     GRPC_CHTTP2_REF_TRANSPORT(t, "keep_reading");
   }
-  grpc_slice_buffer_reset_and_unref(&t->read_buffer);
+  grpc_slice_buffer_reset_and_unref_internal(exec_ctx, &t->read_buffer);
 
   if (keep_reading) {
-    grpc_endpoint_read(exec_ctx, t->ep, &t->read_buffer, &t->read_action_begin);
+    grpc_endpoint_read(exec_ctx, t->ep, &t->read_buffer,
+                       &t->read_action_locked);
     GRPC_CHTTP2_UNREF_TRANSPORT(exec_ctx, t, "keep_reading");
   } else {
     GRPC_CHTTP2_UNREF_TRANSPORT(exec_ctx, t, "reading_action");
@@ -1936,7 +1947,7 @@ static void incoming_byte_stream_unref(grpc_exec_ctx *exec_ctx,
                                        grpc_chttp2_incoming_byte_stream *bs) {
   if (gpr_unref(&bs->refs)) {
     GRPC_ERROR_UNREF(bs->error);
-    grpc_slice_buffer_destroy(&bs->slices);
+    grpc_slice_buffer_destroy_internal(exec_ctx, &bs->slices);
     gpr_mu_destroy(&bs->slice_mu);
     gpr_free(bs);
   }
@@ -2022,10 +2033,12 @@ static int incoming_byte_stream_next(grpc_exec_ctx *exec_ctx,
   bs->next_action.slice = slice;
   bs->next_action.max_size_hint = max_size_hint;
   bs->next_action.on_complete = on_complete;
-  grpc_closure_init(&bs->next_action.closure, incoming_byte_stream_next_locked,
-                    bs);
-  grpc_combiner_execute(exec_ctx, bs->transport->combiner,
-                        &bs->next_action.closure, GRPC_ERROR_NONE, false);
+  grpc_closure_sched(
+      exec_ctx,
+      grpc_closure_init(
+          &bs->next_action.closure, incoming_byte_stream_next_locked, bs,
+          grpc_combiner_scheduler(bs->transport->combiner, false)),
+      GRPC_ERROR_NONE);
   GPR_TIMER_END("incoming_byte_stream_next", 0);
   return 0;
 }
@@ -2047,10 +2060,12 @@ static void incoming_byte_stream_destroy(grpc_exec_ctx *exec_ctx,
   GPR_TIMER_BEGIN("incoming_byte_stream_destroy", 0);
   grpc_chttp2_incoming_byte_stream *bs =
       (grpc_chttp2_incoming_byte_stream *)byte_stream;
-  grpc_closure_init(&bs->destroy_action, incoming_byte_stream_destroy_locked,
-                    bs);
-  grpc_combiner_execute(exec_ctx, bs->transport->combiner, &bs->destroy_action,
-                        GRPC_ERROR_NONE, false);
+  grpc_closure_sched(
+      exec_ctx,
+      grpc_closure_init(
+          &bs->destroy_action, incoming_byte_stream_destroy_locked, bs,
+          grpc_combiner_scheduler(bs->transport->combiner, false)),
+      GRPC_ERROR_NONE);
   GPR_TIMER_END("incoming_byte_stream_destroy", 0);
 }
 
@@ -2058,7 +2073,7 @@ static void incoming_byte_stream_publish_error(
     grpc_exec_ctx *exec_ctx, grpc_chttp2_incoming_byte_stream *bs,
     grpc_error *error) {
   GPR_ASSERT(error != GRPC_ERROR_NONE);
-  grpc_exec_ctx_sched(exec_ctx, bs->on_next, GRPC_ERROR_REF(error), NULL);
+  grpc_closure_sched(exec_ctx, bs->on_next, GRPC_ERROR_REF(error));
   bs->on_next = NULL;
   GRPC_ERROR_UNREF(bs->error);
   bs->error = error;
@@ -2075,7 +2090,7 @@ void grpc_chttp2_incoming_byte_stream_push(grpc_exec_ctx *exec_ctx,
     bs->remaining_bytes -= (uint32_t)GRPC_SLICE_LENGTH(slice);
     if (bs->on_next != NULL) {
       *bs->next = slice;
-      grpc_exec_ctx_sched(exec_ctx, bs->on_next, GRPC_ERROR_NONE, NULL);
+      grpc_closure_sched(exec_ctx, bs->on_next, GRPC_ERROR_NONE);
       bs->on_next = NULL;
     } else {
       grpc_slice_buffer_add(&bs->slices, slice);
@@ -2143,7 +2158,7 @@ static void post_benign_reclaimer(grpc_exec_ctx *exec_ctx,
     GRPC_CHTTP2_REF_TRANSPORT(t, "benign_reclaimer");
     grpc_resource_user_post_reclaimer(exec_ctx,
                                       grpc_endpoint_get_resource_user(t->ep),
-                                      false, &t->benign_reclaimer);
+                                      false, &t->benign_reclaimer_locked);
   }
 }
 
@@ -2154,24 +2169,10 @@ static void post_destructive_reclaimer(grpc_exec_ctx *exec_ctx,
     GRPC_CHTTP2_REF_TRANSPORT(t, "destructive_reclaimer");
     grpc_resource_user_post_reclaimer(exec_ctx,
                                       grpc_endpoint_get_resource_user(t->ep),
-                                      true, &t->destructive_reclaimer);
+                                      true, &t->destructive_reclaimer_locked);
   }
 }
 
-static void benign_reclaimer(grpc_exec_ctx *exec_ctx, void *arg,
-                             grpc_error *error) {
-  grpc_chttp2_transport *t = arg;
-  grpc_combiner_execute(exec_ctx, t->combiner, &t->benign_reclaimer_locked,
-                        GRPC_ERROR_REF(error), false);
-}
-
-static void destructive_reclaimer(grpc_exec_ctx *exec_ctx, void *arg,
-                                  grpc_error *error) {
-  grpc_chttp2_transport *t = arg;
-  grpc_combiner_execute(exec_ctx, t->combiner, &t->destructive_reclaimer_locked,
-                        GRPC_ERROR_REF(error), false);
-}
-
 static void benign_reclaimer_locked(grpc_exec_ctx *exec_ctx, void *arg,
                                     grpc_error *error) {
   grpc_chttp2_transport *t = arg;
@@ -2352,5 +2353,5 @@ void grpc_chttp2_transport_start_reading(grpc_exec_ctx *exec_ctx,
     grpc_slice_buffer_move_into(read_buffer, &t->read_buffer);
     gpr_free(read_buffer);
   }
-  read_action_begin(exec_ctx, t, GRPC_ERROR_NONE);
+  grpc_closure_sched(exec_ctx, &t->read_action_locked, GRPC_ERROR_NONE);
 }
diff --git a/src/core/ext/transport/chttp2/transport/frame_rst_stream.c b/src/core/ext/transport/chttp2/transport/frame_rst_stream.c
index b4c5ed769b..20043f5fbf 100644
--- a/src/core/ext/transport/chttp2/transport/frame_rst_stream.c
+++ b/src/core/ext/transport/chttp2/transport/frame_rst_stream.c
@@ -109,7 +109,7 @@ grpc_error *grpc_chttp2_rst_stream_parser_parse(grpc_exec_ctx *exec_ctx,
                       (((uint32_t)p->reason_bytes[2]) << 8) |
                       (((uint32_t)p->reason_bytes[3]));
     grpc_error *error = GRPC_ERROR_NONE;
-    if (reason != GRPC_CHTTP2_NO_ERROR) {
+    if (reason != GRPC_CHTTP2_NO_ERROR || s->header_frames_received < 2) {
       error = grpc_error_set_int(GRPC_ERROR_CREATE("RST_STREAM"),
                                  GRPC_ERROR_INT_HTTP2_ERROR, (intptr_t)reason);
       grpc_status_code status_code = grpc_chttp2_http2_error_to_grpc_status(
diff --git a/src/core/ext/transport/chttp2/transport/hpack_encoder.c b/src/core/ext/transport/chttp2/transport/hpack_encoder.c
index eb68fe3138..49a8326f62 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_encoder.c
+++ b/src/core/ext/transport/chttp2/transport/hpack_encoder.c
@@ -48,6 +48,7 @@
 #include "src/core/ext/transport/chttp2/transport/bin_encoder.h"
 #include "src/core/ext/transport/chttp2/transport/hpack_table.h"
 #include "src/core/ext/transport/chttp2/transport/varint.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/transport/metadata.h"
 #include "src/core/lib/transport/static_metadata.h"
 #include "src/core/lib/transport/timeout_encoding.h"
@@ -183,7 +184,8 @@ static void evict_entry(grpc_chttp2_hpack_compressor *c) {
 }
 
 /* add an element to the decoder table */
-static void add_elem(grpc_chttp2_hpack_compressor *c, grpc_mdelem *elem) {
+static void add_elem(grpc_exec_ctx *exec_ctx, grpc_chttp2_hpack_compressor *c,
+                     grpc_mdelem *elem) {
   uint32_t key_hash = elem->key->hash;
   uint32_t elem_hash = GRPC_MDSTR_KV_HASH(key_hash, elem->value->hash);
   uint32_t new_index = c->tail_remote_index + c->table_elems + 1;
@@ -227,12 +229,12 @@ static void add_elem(grpc_chttp2_hpack_compressor *c, grpc_mdelem *elem) {
   } else if (c->indices_elems[HASH_FRAGMENT_2(elem_hash)] <
              c->indices_elems[HASH_FRAGMENT_3(elem_hash)]) {
     /* not there: replace oldest */
-    GRPC_MDELEM_UNREF(c->entries_elems[HASH_FRAGMENT_2(elem_hash)]);
+    GRPC_MDELEM_UNREF(exec_ctx, c->entries_elems[HASH_FRAGMENT_2(elem_hash)]);
     c->entries_elems[HASH_FRAGMENT_2(elem_hash)] = GRPC_MDELEM_REF(elem);
     c->indices_elems[HASH_FRAGMENT_2(elem_hash)] = new_index;
   } else {
     /* not there: replace oldest */
-    GRPC_MDELEM_UNREF(c->entries_elems[HASH_FRAGMENT_3(elem_hash)]);
+    GRPC_MDELEM_UNREF(exec_ctx, c->entries_elems[HASH_FRAGMENT_3(elem_hash)]);
     c->entries_elems[HASH_FRAGMENT_3(elem_hash)] = GRPC_MDELEM_REF(elem);
     c->indices_elems[HASH_FRAGMENT_3(elem_hash)] = new_index;
   }
@@ -251,11 +253,11 @@ static void add_elem(grpc_chttp2_hpack_compressor *c, grpc_mdelem *elem) {
     c->indices_keys[HASH_FRAGMENT_3(key_hash)] = new_index;
   } else if (c->indices_keys[HASH_FRAGMENT_2(key_hash)] <
              c->indices_keys[HASH_FRAGMENT_3(key_hash)]) {
-    GRPC_MDSTR_UNREF(c->entries_keys[HASH_FRAGMENT_2(key_hash)]);
+    GRPC_MDSTR_UNREF(exec_ctx, c->entries_keys[HASH_FRAGMENT_2(key_hash)]);
     c->entries_keys[HASH_FRAGMENT_2(key_hash)] = GRPC_MDSTR_REF(elem->key);
     c->indices_keys[HASH_FRAGMENT_2(key_hash)] = new_index;
   } else {
-    GRPC_MDSTR_UNREF(c->entries_keys[HASH_FRAGMENT_3(key_hash)]);
+    GRPC_MDSTR_UNREF(exec_ctx, c->entries_keys[HASH_FRAGMENT_3(key_hash)]);
     c->entries_keys[HASH_FRAGMENT_3(key_hash)] = GRPC_MDSTR_REF(elem->key);
     c->indices_keys[HASH_FRAGMENT_3(key_hash)] = new_index;
   }
@@ -294,7 +296,7 @@ static void emit_lithdr_incidx(grpc_chttp2_hpack_compressor *c,
                            add_tiny_header_data(st, len_pfx), len_pfx);
   GRPC_CHTTP2_WRITE_VARINT((uint32_t)len_val, 1, huffman_prefix,
                            add_tiny_header_data(st, len_val_len), len_val_len);
-  add_header_data(st, grpc_slice_ref(value_slice));
+  add_header_data(st, grpc_slice_ref_internal(value_slice));
 }
 
 static void emit_lithdr_noidx(grpc_chttp2_hpack_compressor *c,
@@ -311,7 +313,7 @@ static void emit_lithdr_noidx(grpc_chttp2_hpack_compressor *c,
                            add_tiny_header_data(st, len_pfx), len_pfx);
   GRPC_CHTTP2_WRITE_VARINT((uint32_t)len_val, 1, huffman_prefix,
                            add_tiny_header_data(st, len_val_len), len_val_len);
-  add_header_data(st, grpc_slice_ref(value_slice));
+  add_header_data(st, grpc_slice_ref_internal(value_slice));
 }
 
 static void emit_lithdr_incidx_v(grpc_chttp2_hpack_compressor *c,
@@ -327,10 +329,10 @@ static void emit_lithdr_incidx_v(grpc_chttp2_hpack_compressor *c,
   *add_tiny_header_data(st, 1) = 0x40;
   GRPC_CHTTP2_WRITE_VARINT(len_key, 1, 0x00,
                            add_tiny_header_data(st, len_key_len), len_key_len);
-  add_header_data(st, grpc_slice_ref(elem->key->slice));
+  add_header_data(st, grpc_slice_ref_internal(elem->key->slice));
   GRPC_CHTTP2_WRITE_VARINT(len_val, 1, huffman_prefix,
                            add_tiny_header_data(st, len_val_len), len_val_len);
-  add_header_data(st, grpc_slice_ref(value_slice));
+  add_header_data(st, grpc_slice_ref_internal(value_slice));
 }
 
 static void emit_lithdr_noidx_v(grpc_chttp2_hpack_compressor *c,
@@ -346,10 +348,10 @@ static void emit_lithdr_noidx_v(grpc_chttp2_hpack_compressor *c,
   *add_tiny_header_data(st, 1) = 0x00;
   GRPC_CHTTP2_WRITE_VARINT(len_key, 1, 0x00,
                            add_tiny_header_data(st, len_key_len), len_key_len);
-  add_header_data(st, grpc_slice_ref(elem->key->slice));
+  add_header_data(st, grpc_slice_ref_internal(elem->key->slice));
   GRPC_CHTTP2_WRITE_VARINT(len_val, 1, huffman_prefix,
                            add_tiny_header_data(st, len_val_len), len_val_len);
-  add_header_data(st, grpc_slice_ref(value_slice));
+  add_header_data(st, grpc_slice_ref_internal(value_slice));
 }
 
 static void emit_advertise_table_size_change(grpc_chttp2_hpack_compressor *c,
@@ -366,8 +368,8 @@ static uint32_t dynidx(grpc_chttp2_hpack_compressor *c, uint32_t elem_index) {
 }
 
 /* encode an mdelem */
-static void hpack_enc(grpc_chttp2_hpack_compressor *c, grpc_mdelem *elem,
-                      framer_state *st) {
+static void hpack_enc(grpc_exec_ctx *exec_ctx, grpc_chttp2_hpack_compressor *c,
+                      grpc_mdelem *elem, framer_state *st) {
   uint32_t key_hash = elem->key->hash;
   uint32_t elem_hash = GRPC_MDSTR_KV_HASH(key_hash, elem->value->hash);
   size_t decoder_space_usage;
@@ -417,7 +419,7 @@ static void hpack_enc(grpc_chttp2_hpack_compressor *c, grpc_mdelem *elem,
     /* HIT: key (first cuckoo hash) */
     if (should_add_elem) {
       emit_lithdr_incidx(c, dynidx(c, indices_key), elem, st);
-      add_elem(c, elem);
+      add_elem(exec_ctx, c, elem);
       return;
     } else {
       emit_lithdr_noidx(c, dynidx(c, indices_key), elem, st);
@@ -432,7 +434,7 @@ static void hpack_enc(grpc_chttp2_hpack_compressor *c, grpc_mdelem *elem,
     /* HIT: key (first cuckoo hash) */
     if (should_add_elem) {
       emit_lithdr_incidx(c, dynidx(c, indices_key), elem, st);
-      add_elem(c, elem);
+      add_elem(exec_ctx, c, elem);
       return;
     } else {
       emit_lithdr_noidx(c, dynidx(c, indices_key), elem, st);
@@ -445,7 +447,7 @@ static void hpack_enc(grpc_chttp2_hpack_compressor *c, grpc_mdelem *elem,
 
   if (should_add_elem) {
     emit_lithdr_incidx_v(c, elem, st);
-    add_elem(c, elem);
+    add_elem(exec_ctx, c, elem);
     return;
   } else {
     emit_lithdr_noidx_v(c, elem, st);
@@ -457,16 +459,17 @@ static void hpack_enc(grpc_chttp2_hpack_compressor *c, grpc_mdelem *elem,
 #define STRLEN_LIT(x) (sizeof(x) - 1)
 #define TIMEOUT_KEY "grpc-timeout"
 
-static void deadline_enc(grpc_chttp2_hpack_compressor *c, gpr_timespec deadline,
+static void deadline_enc(grpc_exec_ctx *exec_ctx,
+                         grpc_chttp2_hpack_compressor *c, gpr_timespec deadline,
                          framer_state *st) {
   char timeout_str[GRPC_HTTP2_TIMEOUT_ENCODE_MIN_BUFSIZE];
   grpc_mdelem *mdelem;
   grpc_http2_encode_timeout(
       gpr_time_sub(deadline, gpr_now(deadline.clock_type)), timeout_str);
   mdelem = grpc_mdelem_from_metadata_strings(
-      GRPC_MDSTR_GRPC_TIMEOUT, grpc_mdstr_from_string(timeout_str));
-  hpack_enc(c, mdelem, st);
-  GRPC_MDELEM_UNREF(mdelem);
+      exec_ctx, GRPC_MDSTR_GRPC_TIMEOUT, grpc_mdstr_from_string(timeout_str));
+  hpack_enc(exec_ctx, c, mdelem, st);
+  GRPC_MDELEM_UNREF(exec_ctx, mdelem);
 }
 
 static uint32_t elems_for_bytes(uint32_t bytes) { return (bytes + 31) / 32; }
@@ -483,11 +486,12 @@ void grpc_chttp2_hpack_compressor_init(grpc_chttp2_hpack_compressor *c) {
          sizeof(*c->table_elem_size) * c->cap_table_elems);
 }
 
-void grpc_chttp2_hpack_compressor_destroy(grpc_chttp2_hpack_compressor *c) {
+void grpc_chttp2_hpack_compressor_destroy(grpc_exec_ctx *exec_ctx,
+                                          grpc_chttp2_hpack_compressor *c) {
   int i;
   for (i = 0; i < GRPC_CHTTP2_HPACKC_NUM_VALUES; i++) {
-    if (c->entries_keys[i]) GRPC_MDSTR_UNREF(c->entries_keys[i]);
-    if (c->entries_elems[i]) GRPC_MDELEM_UNREF(c->entries_elems[i]);
+    if (c->entries_keys[i]) GRPC_MDSTR_UNREF(exec_ctx, c->entries_keys[i]);
+    if (c->entries_elems[i]) GRPC_MDELEM_UNREF(exec_ctx, c->entries_elems[i]);
   }
   gpr_free(c->table_elem_size);
 }
@@ -542,7 +546,8 @@ void grpc_chttp2_hpack_compressor_set_max_table_size(
   }
 }
 
-void grpc_chttp2_encode_header(grpc_chttp2_hpack_compressor *c,
+void grpc_chttp2_encode_header(grpc_exec_ctx *exec_ctx,
+                               grpc_chttp2_hpack_compressor *c,
                                uint32_t stream_id,
                                grpc_metadata_batch *metadata, int is_eof,
                                size_t max_frame_size,
@@ -571,11 +576,11 @@ void grpc_chttp2_encode_header(grpc_chttp2_hpack_compressor *c,
   }
   grpc_metadata_batch_assert_ok(metadata);
   for (l = metadata->list.head; l; l = l->next) {
-    hpack_enc(c, l->md, &st);
+    hpack_enc(exec_ctx, c, l->md, &st);
   }
   deadline = metadata->deadline;
   if (gpr_time_cmp(deadline, gpr_inf_future(deadline.clock_type)) != 0) {
-    deadline_enc(c, deadline, &st);
+    deadline_enc(exec_ctx, c, deadline, &st);
   }
 
   finish_frame(&st, 1, is_eof);
diff --git a/src/core/ext/transport/chttp2/transport/hpack_encoder.h b/src/core/ext/transport/chttp2/transport/hpack_encoder.h
index bcbd675ca2..3a35496ec8 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_encoder.h
+++ b/src/core/ext/transport/chttp2/transport/hpack_encoder.h
@@ -83,13 +83,15 @@ typedef struct {
 } grpc_chttp2_hpack_compressor;
 
 void grpc_chttp2_hpack_compressor_init(grpc_chttp2_hpack_compressor *c);
-void grpc_chttp2_hpack_compressor_destroy(grpc_chttp2_hpack_compressor *c);
+void grpc_chttp2_hpack_compressor_destroy(grpc_exec_ctx *exec_ctx,
+                                          grpc_chttp2_hpack_compressor *c);
 void grpc_chttp2_hpack_compressor_set_max_table_size(
     grpc_chttp2_hpack_compressor *c, uint32_t max_table_size);
 void grpc_chttp2_hpack_compressor_set_max_usable_size(
     grpc_chttp2_hpack_compressor *c, uint32_t max_table_size);
 
-void grpc_chttp2_encode_header(grpc_chttp2_hpack_compressor *c, uint32_t id,
+void grpc_chttp2_encode_header(grpc_exec_ctx *exec_ctx,
+                               grpc_chttp2_hpack_compressor *c, uint32_t id,
                                grpc_metadata_batch *metadata, int is_eof,
                                size_t max_frame_size,
                                grpc_transport_one_way_stats *stats,
diff --git a/src/core/ext/transport/chttp2/transport/hpack_parser.c b/src/core/ext/transport/chttp2/transport/hpack_parser.c
index 6a9200b8db..8b91cc760b 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_parser.c
+++ b/src/core/ext/transport/chttp2/transport/hpack_parser.c
@@ -670,11 +670,11 @@ static const uint8_t inverse_base64[256] = {
 static grpc_error *on_hdr(grpc_exec_ctx *exec_ctx, grpc_chttp2_hpack_parser *p,
                           grpc_mdelem *md, int add_to_table) {
   if (add_to_table) {
-    grpc_error *err = grpc_chttp2_hptbl_add(&p->table, md);
+    grpc_error *err = grpc_chttp2_hptbl_add(exec_ctx, &p->table, md);
     if (err != GRPC_ERROR_NONE) return err;
   }
   if (p->on_header == NULL) {
-    GRPC_MDELEM_UNREF(md);
+    GRPC_MDELEM_UNREF(exec_ctx, md);
     return GRPC_ERROR_CREATE("on_header callback not set");
   }
   p->on_header(exec_ctx, p->on_header_user_data, md);
@@ -815,10 +815,10 @@ static grpc_error *finish_lithdr_incidx(grpc_exec_ctx *exec_ctx,
                                         const uint8_t *end) {
   grpc_mdelem *md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
   GPR_ASSERT(md != NULL); /* handled in string parsing */
-  grpc_error *err = on_hdr(
-      exec_ctx, p, grpc_mdelem_from_metadata_strings(GRPC_MDSTR_REF(md->key),
-                                                     take_string(p, &p->value)),
-      1);
+  grpc_error *err = on_hdr(exec_ctx, p, grpc_mdelem_from_metadata_strings(
+                                            exec_ctx, GRPC_MDSTR_REF(md->key),
+                                            take_string(p, &p->value)),
+                           1);
   if (err != GRPC_ERROR_NONE) return parse_error(exec_ctx, p, cur, end, err);
   return parse_begin(exec_ctx, p, cur, end);
 }
@@ -828,10 +828,10 @@ static grpc_error *finish_lithdr_incidx_v(grpc_exec_ctx *exec_ctx,
                                           grpc_chttp2_hpack_parser *p,
                                           const uint8_t *cur,
                                           const uint8_t *end) {
-  grpc_error *err = on_hdr(
-      exec_ctx, p, grpc_mdelem_from_metadata_strings(take_string(p, &p->key),
-                                                     take_string(p, &p->value)),
-      1);
+  grpc_error *err = on_hdr(exec_ctx, p, grpc_mdelem_from_metadata_strings(
+                                            exec_ctx, take_string(p, &p->key),
+                                            take_string(p, &p->value)),
+                           1);
   if (err != GRPC_ERROR_NONE) return parse_error(exec_ctx, p, cur, end, err);
   return parse_begin(exec_ctx, p, cur, end);
 }
@@ -883,10 +883,10 @@ static grpc_error *finish_lithdr_notidx(grpc_exec_ctx *exec_ctx,
                                         const uint8_t *end) {
   grpc_mdelem *md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
   GPR_ASSERT(md != NULL); /* handled in string parsing */
-  grpc_error *err = on_hdr(
-      exec_ctx, p, grpc_mdelem_from_metadata_strings(GRPC_MDSTR_REF(md->key),
-                                                     take_string(p, &p->value)),
-      0);
+  grpc_error *err = on_hdr(exec_ctx, p, grpc_mdelem_from_metadata_strings(
+                                            exec_ctx, GRPC_MDSTR_REF(md->key),
+                                            take_string(p, &p->value)),
+                           0);
   if (err != GRPC_ERROR_NONE) return parse_error(exec_ctx, p, cur, end, err);
   return parse_begin(exec_ctx, p, cur, end);
 }
@@ -896,10 +896,10 @@ static grpc_error *finish_lithdr_notidx_v(grpc_exec_ctx *exec_ctx,
                                           grpc_chttp2_hpack_parser *p,
                                           const uint8_t *cur,
                                           const uint8_t *end) {
-  grpc_error *err = on_hdr(
-      exec_ctx, p, grpc_mdelem_from_metadata_strings(take_string(p, &p->key),
-                                                     take_string(p, &p->value)),
-      0);
+  grpc_error *err = on_hdr(exec_ctx, p, grpc_mdelem_from_metadata_strings(
+                                            exec_ctx, take_string(p, &p->key),
+                                            take_string(p, &p->value)),
+                           0);
   if (err != GRPC_ERROR_NONE) return parse_error(exec_ctx, p, cur, end, err);
   return parse_begin(exec_ctx, p, cur, end);
 }
@@ -951,10 +951,10 @@ static grpc_error *finish_lithdr_nvridx(grpc_exec_ctx *exec_ctx,
                                         const uint8_t *end) {
   grpc_mdelem *md = grpc_chttp2_hptbl_lookup(&p->table, p->index);
   GPR_ASSERT(md != NULL); /* handled in string parsing */
-  grpc_error *err = on_hdr(
-      exec_ctx, p, grpc_mdelem_from_metadata_strings(GRPC_MDSTR_REF(md->key),
-                                                     take_string(p, &p->value)),
-      0);
+  grpc_error *err = on_hdr(exec_ctx, p, grpc_mdelem_from_metadata_strings(
+                                            exec_ctx, GRPC_MDSTR_REF(md->key),
+                                            take_string(p, &p->value)),
+                           0);
   if (err != GRPC_ERROR_NONE) return parse_error(exec_ctx, p, cur, end, err);
   return parse_begin(exec_ctx, p, cur, end);
 }
@@ -964,10 +964,10 @@ static grpc_error *finish_lithdr_nvridx_v(grpc_exec_ctx *exec_ctx,
                                           grpc_chttp2_hpack_parser *p,
                                           const uint8_t *cur,
                                           const uint8_t *end) {
-  grpc_error *err = on_hdr(
-      exec_ctx, p, grpc_mdelem_from_metadata_strings(take_string(p, &p->key),
-                                                     take_string(p, &p->value)),
-      0);
+  grpc_error *err = on_hdr(exec_ctx, p, grpc_mdelem_from_metadata_strings(
+                                            exec_ctx, take_string(p, &p->key),
+                                            take_string(p, &p->value)),
+                           0);
   if (err != GRPC_ERROR_NONE) return parse_error(exec_ctx, p, cur, end, err);
   return parse_begin(exec_ctx, p, cur, end);
 }
@@ -1020,7 +1020,7 @@ static grpc_error *finish_max_tbl_size(grpc_exec_ctx *exec_ctx,
     gpr_log(GPR_INFO, "MAX TABLE SIZE: %d", p->index);
   }
   grpc_error *err =
-      grpc_chttp2_hptbl_set_current_table_size(&p->table, p->index);
+      grpc_chttp2_hptbl_set_current_table_size(exec_ctx, &p->table, p->index);
   if (err != GRPC_ERROR_NONE) return parse_error(exec_ctx, p, cur, end, err);
   return parse_begin(exec_ctx, p, cur, end);
 }
@@ -1534,7 +1534,8 @@ static grpc_error *parse_value_string_with_literal_key(
 
 /* PUBLIC INTERFACE */
 
-void grpc_chttp2_hpack_parser_init(grpc_chttp2_hpack_parser *p) {
+void grpc_chttp2_hpack_parser_init(grpc_exec_ctx *exec_ctx,
+                                   grpc_chttp2_hpack_parser *p) {
   p->on_header = NULL;
   p->on_header_user_data = NULL;
   p->state = parse_begin;
@@ -1546,7 +1547,7 @@ void grpc_chttp2_hpack_parser_init(grpc_chttp2_hpack_parser *p) {
   p->value.length = 0;
   p->dynamic_table_update_allowed = 2;
   p->last_error = GRPC_ERROR_NONE;
-  grpc_chttp2_hptbl_init(&p->table);
+  grpc_chttp2_hptbl_init(exec_ctx, &p->table);
 }
 
 void grpc_chttp2_hpack_parser_set_has_priority(grpc_chttp2_hpack_parser *p) {
@@ -1554,8 +1555,9 @@ void grpc_chttp2_hpack_parser_set_has_priority(grpc_chttp2_hpack_parser *p) {
   p->state = parse_stream_dep0;
 }
 
-void grpc_chttp2_hpack_parser_destroy(grpc_chttp2_hpack_parser *p) {
-  grpc_chttp2_hptbl_destroy(&p->table);
+void grpc_chttp2_hpack_parser_destroy(grpc_exec_ctx *exec_ctx,
+                                      grpc_chttp2_hpack_parser *p) {
+  grpc_chttp2_hptbl_destroy(exec_ctx, &p->table);
   GRPC_ERROR_UNREF(p->last_error);
   gpr_free(p->key.str);
   gpr_free(p->value.str);
@@ -1634,10 +1636,11 @@ grpc_error *grpc_chttp2_header_parser_parse(grpc_exec_ctx *exec_ctx,
              however -- it might be that we receive a RST_STREAM following this
              and can avoid the extra write */
           GRPC_CHTTP2_STREAM_REF(s, "final_rst");
-          grpc_combiner_execute_finally(
-              exec_ctx, t->combiner,
-              grpc_closure_create(force_client_rst_stream, s), GRPC_ERROR_NONE,
-              false);
+          grpc_closure_sched(
+              exec_ctx, grpc_closure_create(force_client_rst_stream, s,
+                                            grpc_combiner_finally_scheduler(
+                                                t->combiner, false)),
+              GRPC_ERROR_NONE);
         }
         grpc_chttp2_mark_stream_closed(exec_ctx, t, s, true, false,
                                        GRPC_ERROR_NONE);
diff --git a/src/core/ext/transport/chttp2/transport/hpack_parser.h b/src/core/ext/transport/chttp2/transport/hpack_parser.h
index a39bf466cd..52ccf1e7a7 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_parser.h
+++ b/src/core/ext/transport/chttp2/transport/hpack_parser.h
@@ -99,8 +99,10 @@ struct grpc_chttp2_hpack_parser {
   grpc_chttp2_hptbl table;
 };
 
-void grpc_chttp2_hpack_parser_init(grpc_chttp2_hpack_parser *p);
-void grpc_chttp2_hpack_parser_destroy(grpc_chttp2_hpack_parser *p);
+void grpc_chttp2_hpack_parser_init(grpc_exec_ctx *exec_ctx,
+                                   grpc_chttp2_hpack_parser *p);
+void grpc_chttp2_hpack_parser_destroy(grpc_exec_ctx *exec_ctx,
+                                      grpc_chttp2_hpack_parser *p);
 
 void grpc_chttp2_hpack_parser_set_has_priority(grpc_chttp2_hpack_parser *p);
 
diff --git a/src/core/ext/transport/chttp2/transport/hpack_table.c b/src/core/ext/transport/chttp2/transport/hpack_table.c
index 2dc793d304..26d4036d49 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_table.c
+++ b/src/core/ext/transport/chttp2/transport/hpack_table.c
@@ -179,7 +179,7 @@ static uint32_t entries_for_bytes(uint32_t bytes) {
          GRPC_CHTTP2_HPACK_ENTRY_OVERHEAD;
 }
 
-void grpc_chttp2_hptbl_init(grpc_chttp2_hptbl *tbl) {
+void grpc_chttp2_hptbl_init(grpc_exec_ctx *exec_ctx, grpc_chttp2_hptbl *tbl) {
   size_t i;
 
   memset(tbl, 0, sizeof(*tbl));
@@ -190,18 +190,20 @@ void grpc_chttp2_hptbl_init(grpc_chttp2_hptbl *tbl) {
   tbl->ents = gpr_malloc(sizeof(*tbl->ents) * tbl->cap_entries);
   memset(tbl->ents, 0, sizeof(*tbl->ents) * tbl->cap_entries);
   for (i = 1; i <= GRPC_CHTTP2_LAST_STATIC_ENTRY; i++) {
-    tbl->static_ents[i - 1] =
-        grpc_mdelem_from_strings(static_table[i].key, static_table[i].value);
+    tbl->static_ents[i - 1] = grpc_mdelem_from_strings(
+        exec_ctx, static_table[i].key, static_table[i].value);
   }
 }
 
-void grpc_chttp2_hptbl_destroy(grpc_chttp2_hptbl *tbl) {
+void grpc_chttp2_hptbl_destroy(grpc_exec_ctx *exec_ctx,
+                               grpc_chttp2_hptbl *tbl) {
   size_t i;
   for (i = 0; i < GRPC_CHTTP2_LAST_STATIC_ENTRY; i++) {
-    GRPC_MDELEM_UNREF(tbl->static_ents[i]);
+    GRPC_MDELEM_UNREF(exec_ctx, tbl->static_ents[i]);
   }
   for (i = 0; i < tbl->num_ents; i++) {
-    GRPC_MDELEM_UNREF(tbl->ents[(tbl->first_ent + i) % tbl->cap_entries]);
+    GRPC_MDELEM_UNREF(exec_ctx,
+                      tbl->ents[(tbl->first_ent + i) % tbl->cap_entries]);
   }
   gpr_free(tbl->ents);
 }
@@ -224,7 +226,7 @@ grpc_mdelem *grpc_chttp2_hptbl_lookup(const grpc_chttp2_hptbl *tbl,
 }
 
 /* Evict one element from the table */
-static void evict1(grpc_chttp2_hptbl *tbl) {
+static void evict1(grpc_exec_ctx *exec_ctx, grpc_chttp2_hptbl *tbl) {
   grpc_mdelem *first_ent = tbl->ents[tbl->first_ent];
   size_t elem_bytes = GRPC_SLICE_LENGTH(first_ent->key->slice) +
                       GRPC_SLICE_LENGTH(first_ent->value->slice) +
@@ -233,7 +235,7 @@ static void evict1(grpc_chttp2_hptbl *tbl) {
   tbl->mem_used -= (uint32_t)elem_bytes;
   tbl->first_ent = ((tbl->first_ent + 1) % tbl->cap_entries);
   tbl->num_ents--;
-  GRPC_MDELEM_UNREF(first_ent);
+  GRPC_MDELEM_UNREF(exec_ctx, first_ent);
 }
 
 static void rebuild_ents(grpc_chttp2_hptbl *tbl, uint32_t new_cap) {
@@ -249,7 +251,8 @@ static void rebuild_ents(grpc_chttp2_hptbl *tbl, uint32_t new_cap) {
   tbl->first_ent = 0;
 }
 
-void grpc_chttp2_hptbl_set_max_bytes(grpc_chttp2_hptbl *tbl,
+void grpc_chttp2_hptbl_set_max_bytes(grpc_exec_ctx *exec_ctx,
+                                     grpc_chttp2_hptbl *tbl,
                                      uint32_t max_bytes) {
   if (tbl->max_bytes == max_bytes) {
     return;
@@ -258,12 +261,13 @@ void grpc_chttp2_hptbl_set_max_bytes(grpc_chttp2_hptbl *tbl,
     gpr_log(GPR_DEBUG, "Update hpack parser max size to %d", max_bytes);
   }
   while (tbl->mem_used > max_bytes) {
-    evict1(tbl);
+    evict1(exec_ctx, tbl);
   }
   tbl->max_bytes = max_bytes;
 }
 
-grpc_error *grpc_chttp2_hptbl_set_current_table_size(grpc_chttp2_hptbl *tbl,
+grpc_error *grpc_chttp2_hptbl_set_current_table_size(grpc_exec_ctx *exec_ctx,
+                                                     grpc_chttp2_hptbl *tbl,
                                                      uint32_t bytes) {
   if (tbl->current_table_bytes == bytes) {
     return GRPC_ERROR_NONE;
@@ -281,7 +285,7 @@ grpc_error *grpc_chttp2_hptbl_set_current_table_size(grpc_chttp2_hptbl *tbl,
     gpr_log(GPR_DEBUG, "Update hpack parser table size to %d", bytes);
   }
   while (tbl->mem_used > bytes) {
-    evict1(tbl);
+    evict1(exec_ctx, tbl);
   }
   tbl->current_table_bytes = bytes;
   tbl->max_entries = entries_for_bytes(bytes);
@@ -296,7 +300,8 @@ grpc_error *grpc_chttp2_hptbl_set_current_table_size(grpc_chttp2_hptbl *tbl,
   return GRPC_ERROR_NONE;
 }
 
-grpc_error *grpc_chttp2_hptbl_add(grpc_chttp2_hptbl *tbl, grpc_mdelem *md) {
+grpc_error *grpc_chttp2_hptbl_add(grpc_exec_ctx *exec_ctx,
+                                  grpc_chttp2_hptbl *tbl, grpc_mdelem *md) {
   /* determine how many bytes of buffer this entry represents */
   size_t elem_bytes = GRPC_SLICE_LENGTH(md->key->slice) +
                       GRPC_SLICE_LENGTH(md->value->slice) +
@@ -326,14 +331,14 @@ grpc_error *grpc_chttp2_hptbl_add(grpc_chttp2_hptbl *tbl, grpc_mdelem *md) {
      * empty table.
      */
     while (tbl->num_ents) {
-      evict1(tbl);
+      evict1(exec_ctx, tbl);
     }
     return GRPC_ERROR_NONE;
   }
 
   /* evict entries to ensure no overflow */
   while (elem_bytes > (size_t)tbl->current_table_bytes - tbl->mem_used) {
-    evict1(tbl);
+    evict1(exec_ctx, tbl);
   }
 
   /* copy the finalized entry in */
diff --git a/src/core/ext/transport/chttp2/transport/hpack_table.h b/src/core/ext/transport/chttp2/transport/hpack_table.h
index 2ca130e64b..144574ef06 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_table.h
+++ b/src/core/ext/transport/chttp2/transport/hpack_table.h
@@ -84,18 +84,21 @@ typedef struct {
 } grpc_chttp2_hptbl;
 
 /* initialize a hpack table */
-void grpc_chttp2_hptbl_init(grpc_chttp2_hptbl *tbl);
-void grpc_chttp2_hptbl_destroy(grpc_chttp2_hptbl *tbl);
-void grpc_chttp2_hptbl_set_max_bytes(grpc_chttp2_hptbl *tbl,
+void grpc_chttp2_hptbl_init(grpc_exec_ctx *exec_ctx, grpc_chttp2_hptbl *tbl);
+void grpc_chttp2_hptbl_destroy(grpc_exec_ctx *exec_ctx, grpc_chttp2_hptbl *tbl);
+void grpc_chttp2_hptbl_set_max_bytes(grpc_exec_ctx *exec_ctx,
+                                     grpc_chttp2_hptbl *tbl,
                                      uint32_t max_bytes);
-grpc_error *grpc_chttp2_hptbl_set_current_table_size(grpc_chttp2_hptbl *tbl,
+grpc_error *grpc_chttp2_hptbl_set_current_table_size(grpc_exec_ctx *exec_ctx,
+                                                     grpc_chttp2_hptbl *tbl,
                                                      uint32_t bytes);
 
 /* lookup a table entry based on its hpack index */
 grpc_mdelem *grpc_chttp2_hptbl_lookup(const grpc_chttp2_hptbl *tbl,
                                       uint32_t index);
 /* add a table entry to the index */
-grpc_error *grpc_chttp2_hptbl_add(grpc_chttp2_hptbl *tbl,
+grpc_error *grpc_chttp2_hptbl_add(grpc_exec_ctx *exec_ctx,
+                                  grpc_chttp2_hptbl *tbl,
                                   grpc_mdelem *md) GRPC_MUST_USE_RESULT;
 /* Find a key/value pair in the table... returns the index in the table of the
    most similar entry, or 0 if the value was not found */
diff --git a/src/core/ext/transport/chttp2/transport/incoming_metadata.c b/src/core/ext/transport/chttp2/transport/incoming_metadata.c
index 3e463a7995..5d1094999c 100644
--- a/src/core/ext/transport/chttp2/transport/incoming_metadata.c
+++ b/src/core/ext/transport/chttp2/transport/incoming_metadata.c
@@ -46,11 +46,11 @@ void grpc_chttp2_incoming_metadata_buffer_init(
 }
 
 void grpc_chttp2_incoming_metadata_buffer_destroy(
-    grpc_chttp2_incoming_metadata_buffer *buffer) {
+    grpc_exec_ctx *exec_ctx, grpc_chttp2_incoming_metadata_buffer *buffer) {
   size_t i;
   if (!buffer->published) {
     for (i = 0; i < buffer->count; i++) {
-      GRPC_MDELEM_UNREF(buffer->elems[i].md);
+      GRPC_MDELEM_UNREF(exec_ctx, buffer->elems[i].md);
     }
   }
   gpr_free(buffer->elems);
diff --git a/src/core/ext/transport/chttp2/transport/incoming_metadata.h b/src/core/ext/transport/chttp2/transport/incoming_metadata.h
index df4343b93e..7a0c4da15f 100644
--- a/src/core/ext/transport/chttp2/transport/incoming_metadata.h
+++ b/src/core/ext/transport/chttp2/transport/incoming_metadata.h
@@ -49,7 +49,7 @@ typedef struct {
 void grpc_chttp2_incoming_metadata_buffer_init(
     grpc_chttp2_incoming_metadata_buffer *buffer);
 void grpc_chttp2_incoming_metadata_buffer_destroy(
-    grpc_chttp2_incoming_metadata_buffer *buffer);
+    grpc_exec_ctx *exec_ctx, grpc_chttp2_incoming_metadata_buffer *buffer);
 void grpc_chttp2_incoming_metadata_buffer_publish(
     grpc_chttp2_incoming_metadata_buffer *buffer, grpc_metadata_batch *batch);
 
diff --git a/src/core/ext/transport/chttp2/transport/internal.h b/src/core/ext/transport/chttp2/transport/internal.h
index b74233d992..a52acbacdb 100644
--- a/src/core/ext/transport/chttp2/transport/internal.h
+++ b/src/core/ext/transport/chttp2/transport/internal.h
@@ -212,10 +212,8 @@ struct grpc_chttp2_transport {
 
   grpc_closure write_action_begin_locked;
   grpc_closure write_action;
-  grpc_closure write_action_end;
   grpc_closure write_action_end_locked;
 
-  grpc_closure read_action_begin;
   grpc_closure read_action_locked;
 
   /** incoming read bytes */
@@ -327,16 +325,17 @@ struct grpc_chttp2_transport {
    */
   grpc_error *close_transport_on_writes_finished;
 
+  /* a list of closures to run after writes are finished */
+  grpc_closure_list run_after_write;
+
   /* buffer pool state */
   /** have we scheduled a benign cleanup? */
   bool benign_reclaimer_registered;
   /** have we scheduled a destructive cleanup? */
   bool destructive_reclaimer_registered;
   /** benign cleanup closure */
-  grpc_closure benign_reclaimer;
   grpc_closure benign_reclaimer_locked;
   /** destructive cleanup closure */
-  grpc_closure destructive_reclaimer;
   grpc_closure destructive_reclaimer_locked;
 };
 
@@ -493,6 +492,8 @@ void grpc_chttp2_list_add_waiting_for_concurrency(grpc_chttp2_transport *t,
                                                   grpc_chttp2_stream *s);
 int grpc_chttp2_list_pop_waiting_for_concurrency(grpc_chttp2_transport *t,
                                                  grpc_chttp2_stream **s);
+void grpc_chttp2_list_remove_waiting_for_concurrency(grpc_chttp2_transport *t,
+                                                     grpc_chttp2_stream *s);
 
 void grpc_chttp2_list_add_stalled_by_transport(grpc_chttp2_transport *t,
                                                grpc_chttp2_stream *s);
@@ -689,4 +690,8 @@ void grpc_chttp2_maybe_complete_recv_trailing_metadata(grpc_exec_ctx *exec_ctx,
                                                        grpc_chttp2_transport *t,
                                                        grpc_chttp2_stream *s);
 
+void grpc_chttp2_fail_pending_writes(grpc_exec_ctx *exec_ctx,
+                                     grpc_chttp2_transport *t,
+                                     grpc_chttp2_stream *s, grpc_error *error);
+
 #endif /* GRPC_CORE_EXT_TRANSPORT_CHTTP2_TRANSPORT_INTERNAL_H */
diff --git a/src/core/ext/transport/chttp2/transport/parsing.c b/src/core/ext/transport/chttp2/transport/parsing.c
index 5efb49751c..4fb5dc7bd2 100644
--- a/src/core/ext/transport/chttp2/transport/parsing.c
+++ b/src/core/ext/transport/chttp2/transport/parsing.c
@@ -336,7 +336,7 @@ static grpc_error *skip_parser(grpc_exec_ctx *exec_ctx, void *parser,
 }
 
 static void skip_header(grpc_exec_ctx *exec_ctx, void *tp, grpc_mdelem *md) {
-  GRPC_MDELEM_UNREF(md);
+  GRPC_MDELEM_UNREF(exec_ctx, md);
 }
 
 static grpc_error *init_skip_frame_parser(grpc_exec_ctx *exec_ctx,
@@ -477,7 +477,7 @@ static void on_initial_header(grpc_exec_ctx *exec_ctx, void *tp,
     grpc_chttp2_incoming_metadata_buffer_set_deadline(
         &s->metadata_buffer[0],
         gpr_time_add(gpr_now(GPR_CLOCK_MONOTONIC), *cached_timeout));
-    GRPC_MDELEM_UNREF(md);
+    GRPC_MDELEM_UNREF(exec_ctx, md);
   } else {
     const size_t new_size = s->metadata_buffer[0].size + GRPC_MDELEM_LENGTH(md);
     const size_t metadata_size_limit =
@@ -495,7 +495,7 @@ static void on_initial_header(grpc_exec_ctx *exec_ctx, void *tp,
               GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_RESOURCE_EXHAUSTED));
       grpc_chttp2_parsing_become_skip_parser(exec_ctx, t);
       s->seen_error = true;
-      GRPC_MDELEM_UNREF(md);
+      GRPC_MDELEM_UNREF(exec_ctx, md);
     } else {
       grpc_chttp2_incoming_metadata_buffer_add(&s->metadata_buffer[0], md);
     }
@@ -538,7 +538,7 @@ static void on_trailing_header(grpc_exec_ctx *exec_ctx, void *tp,
             GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_RESOURCE_EXHAUSTED));
     grpc_chttp2_parsing_become_skip_parser(exec_ctx, t);
     s->seen_error = true;
-    GRPC_MDELEM_UNREF(md);
+    GRPC_MDELEM_UNREF(exec_ctx, md);
   } else {
     grpc_chttp2_incoming_metadata_buffer_add(&s->metadata_buffer[1], md);
   }
@@ -712,7 +712,7 @@ static grpc_error *init_settings_frame_parser(grpc_exec_ctx *exec_ctx,
     memcpy(t->settings[GRPC_ACKED_SETTINGS], t->settings[GRPC_SENT_SETTINGS],
            GRPC_CHTTP2_NUM_SETTINGS * sizeof(uint32_t));
     grpc_chttp2_hptbl_set_max_bytes(
-        &t->hpack_parser.table,
+        exec_ctx, &t->hpack_parser.table,
         t->settings[GRPC_ACKED_SETTINGS]
                    [GRPC_CHTTP2_SETTINGS_HEADER_TABLE_SIZE]);
     t->sent_local_settings = 0;
diff --git a/src/core/ext/transport/chttp2/transport/stream_lists.c b/src/core/ext/transport/chttp2/transport/stream_lists.c
index 6d25b3ae57..a60264cc51 100644
--- a/src/core/ext/transport/chttp2/transport/stream_lists.c
+++ b/src/core/ext/transport/chttp2/transport/stream_lists.c
@@ -158,6 +158,11 @@ int grpc_chttp2_list_pop_waiting_for_concurrency(grpc_chttp2_transport *t,
   return stream_list_pop(t, s, GRPC_CHTTP2_LIST_WAITING_FOR_CONCURRENCY);
 }
 
+void grpc_chttp2_list_remove_waiting_for_concurrency(grpc_chttp2_transport *t,
+                                                     grpc_chttp2_stream *s) {
+  stream_list_maybe_remove(t, s, GRPC_CHTTP2_LIST_WAITING_FOR_CONCURRENCY);
+}
+
 void grpc_chttp2_list_add_stalled_by_transport(grpc_chttp2_transport *t,
                                                grpc_chttp2_stream *s) {
   stream_list_add(t, s, GRPC_CHTTP2_LIST_STALLED_BY_TRANSPORT);
diff --git a/src/core/ext/transport/chttp2/transport/writing.c b/src/core/ext/transport/chttp2/transport/writing.c
index 139e7387c4..ef2010af7b 100644
--- a/src/core/ext/transport/chttp2/transport/writing.c
+++ b/src/core/ext/transport/chttp2/transport/writing.c
@@ -39,6 +39,7 @@
 
 #include "src/core/ext/transport/chttp2/transport/http2_errors.h"
 #include "src/core/lib/profiling/timers.h"
+#include "src/core/lib/slice/slice_internal.h"
 
 static void add_to_write_list(grpc_chttp2_write_cb **list,
                               grpc_chttp2_write_cb *cb) {
@@ -119,7 +120,7 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
     /* send initial metadata if it's available */
     if (!sent_initial_metadata && s->send_initial_metadata) {
       grpc_chttp2_encode_header(
-          &t->hpack_compressor, s->id, s->send_initial_metadata, 0,
+          exec_ctx, &t->hpack_compressor, s->id, s->send_initial_metadata, 0,
           t->settings[GRPC_ACKED_SETTINGS][GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
           &s->stats.outgoing, &t->outbuf);
       s->send_initial_metadata = NULL;
@@ -186,9 +187,9 @@ bool grpc_chttp2_begin_write(grpc_exec_ctx *exec_ctx,
                                   &s->stats.outgoing, &t->outbuf);
         } else {
           grpc_chttp2_encode_header(
-              &t->hpack_compressor, s->id, s->send_trailing_metadata, true,
-              t->settings[GRPC_ACKED_SETTINGS]
-                         [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
+              exec_ctx, &t->hpack_compressor, s->id, s->send_trailing_metadata,
+              true, t->settings[GRPC_ACKED_SETTINGS]
+                               [GRPC_CHTTP2_SETTINGS_MAX_FRAME_SIZE],
               &s->stats.outgoing, &t->outbuf);
         }
         s->send_trailing_metadata = NULL;
@@ -254,7 +255,7 @@ void grpc_chttp2_end_write(grpc_exec_ctx *exec_ctx, grpc_chttp2_transport *t,
     }
     GRPC_CHTTP2_STREAM_UNREF(exec_ctx, s, "chttp2_writing:end");
   }
-  grpc_slice_buffer_reset_and_unref(&t->outbuf);
+  grpc_slice_buffer_reset_and_unref_internal(exec_ctx, &t->outbuf);
   GRPC_ERROR_UNREF(error);
   GPR_TIMER_END("grpc_chttp2_end_write", 0);
 }
diff --git a/src/core/ext/transport/cronet/transport/cronet_transport.c b/src/core/ext/transport/cronet/transport/cronet_transport.c
index a4c110101e..296c406324 100644
--- a/src/core/ext/transport/cronet/transport/cronet_transport.c
+++ b/src/core/ext/transport/cronet/transport/cronet_transport.c
@@ -149,6 +149,9 @@ struct write_state {
 struct op_state {
   bool state_op_done[OP_NUM_OPS];
   bool state_callback_received[OP_NUM_OPS];
+  bool fail_state;
+  bool flush_read;
+  grpc_error *cancel_error;
   /* data structure for storing data coming from server */
   struct read_state rs;
   /* data structure for storing data going to the server */
@@ -248,6 +251,12 @@ static void free_read_buffer(stream_obj *s) {
   }
 }
 
+static grpc_error *make_error_with_desc(int error_code, const char *desc) {
+  grpc_error *error = GRPC_ERROR_CREATE(desc);
+  error = grpc_error_set_int(error, GRPC_ERROR_INT_GRPC_STATUS, error_code);
+  return error;
+}
+
 /*
   Add a new stream op to op storage.
 */
@@ -418,6 +427,7 @@ static void on_response_headers_received(
     cronet_bidirectional_stream *stream,
     const cronet_bidirectional_stream_header_array *headers,
     const char *negotiated_protocol) {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   CRONET_LOG(GPR_DEBUG, "R: on_response_headers_received(%p, %p, %s)", stream,
              headers, negotiated_protocol);
   stream_obj *s = (stream_obj *)stream->annotation;
@@ -429,11 +439,24 @@ static void on_response_headers_received(
     grpc_chttp2_incoming_metadata_buffer_add(
         &s->state.rs.initial_metadata,
         grpc_mdelem_from_metadata_strings(
-            grpc_mdstr_from_string(headers->headers[i].key),
+            &exec_ctx, grpc_mdstr_from_string(headers->headers[i].key),
             grpc_mdstr_from_string(headers->headers[i].value)));
   }
   s->state.state_callback_received[OP_RECV_INITIAL_METADATA] = true;
+  if (!(s->state.state_op_done[OP_CANCEL_ERROR] ||
+        s->state.state_callback_received[OP_FAILED])) {
+    /* Do an extra read to trigger on_succeeded() callback in case connection
+     is closed */
+    GPR_ASSERT(s->state.rs.length_field_received == false);
+    s->state.rs.read_buffer = s->state.rs.grpc_header_bytes;
+    s->state.rs.received_bytes = 0;
+    s->state.rs.remaining_bytes = GRPC_HEADER_SIZE_IN_BYTES;
+    CRONET_LOG(GPR_DEBUG, "cronet_bidirectional_stream_read(%p)", s->cbs);
+    cronet_bidirectional_stream_read(s->cbs, s->state.rs.read_buffer,
+                                     s->state.rs.remaining_bytes);
+  }
   gpr_mu_unlock(&s->mu);
+  grpc_exec_ctx_finish(&exec_ctx);
   execute_from_storage(s);
 }
 
@@ -464,7 +487,11 @@ static void on_read_completed(cronet_bidirectional_stream *stream, char *data,
              count);
   gpr_mu_lock(&s->mu);
   s->state.state_callback_received[OP_RECV_MESSAGE] = true;
-  if (count > 0) {
+  if (count > 0 && s->state.flush_read) {
+    CRONET_LOG(GPR_DEBUG, "cronet_bidirectional_stream_read(%p)", s->cbs);
+    cronet_bidirectional_stream_read(s->cbs, s->state.rs.read_buffer, 4096);
+    gpr_mu_unlock(&s->mu);
+  } else if (count > 0) {
     s->state.rs.received_bytes += count;
     s->state.rs.remaining_bytes -= count;
     if (s->state.rs.remaining_bytes > 0) {
@@ -479,6 +506,10 @@ static void on_read_completed(cronet_bidirectional_stream *stream, char *data,
       execute_from_storage(s);
     }
   } else {
+    if (s->state.flush_read) {
+      gpr_free(s->state.rs.read_buffer);
+      s->state.rs.read_buffer = NULL;
+    }
     s->state.rs.read_stream_closed = true;
     gpr_mu_unlock(&s->mu);
     execute_from_storage(s);
@@ -491,6 +522,7 @@ static void on_read_completed(cronet_bidirectional_stream *stream, char *data,
 static void on_response_trailers_received(
     cronet_bidirectional_stream *stream,
     const cronet_bidirectional_stream_header_array *trailers) {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   CRONET_LOG(GPR_DEBUG, "R: on_response_trailers_received(%p,%p)", stream,
              trailers);
   stream_obj *s = (stream_obj *)stream->annotation;
@@ -505,13 +537,32 @@ static void on_response_trailers_received(
     grpc_chttp2_incoming_metadata_buffer_add(
         &s->state.rs.trailing_metadata,
         grpc_mdelem_from_metadata_strings(
-            grpc_mdstr_from_string(trailers->headers[i].key),
+            &exec_ctx, grpc_mdstr_from_string(trailers->headers[i].key),
             grpc_mdstr_from_string(trailers->headers[i].value)));
     s->state.rs.trailing_metadata_valid = true;
+    if (0 == strcmp(trailers->headers[i].key, "grpc-status") &&
+        0 != strcmp(trailers->headers[i].value, "0")) {
+      s->state.fail_state = true;
+    }
   }
   s->state.state_callback_received[OP_RECV_TRAILING_METADATA] = true;
-  gpr_mu_unlock(&s->mu);
-  execute_from_storage(s);
+  /* Send a EOS when server terminates the stream (testServerFinishesRequest) to
+   * trigger on_succeeded */
+  if (!s->state.state_op_done[OP_SEND_TRAILING_METADATA] &&
+      !(s->state.state_op_done[OP_CANCEL_ERROR] ||
+        s->state.state_callback_received[OP_FAILED])) {
+    CRONET_LOG(GPR_DEBUG, "cronet_bidirectional_stream_write (%p, 0)", s->cbs);
+    s->state.state_callback_received[OP_SEND_MESSAGE] = false;
+    cronet_bidirectional_stream_write(s->cbs, "", 0, true);
+    s->state.state_op_done[OP_SEND_TRAILING_METADATA] = true;
+
+    gpr_mu_unlock(&s->mu);
+    grpc_exec_ctx_finish(&exec_ctx);
+  } else {
+    gpr_mu_unlock(&s->mu);
+    grpc_exec_ctx_finish(&exec_ctx);
+    execute_from_storage(s);
+  }
 }
 
 /*
@@ -632,9 +683,9 @@ static bool op_can_be_run(grpc_transport_stream_op *curr_op,
   /* When call is canceled, every op can be run, except under following
   conditions
   */
-  bool is_canceled_of_failed = stream_state->state_op_done[OP_CANCEL_ERROR] ||
+  bool is_canceled_or_failed = stream_state->state_op_done[OP_CANCEL_ERROR] ||
                                stream_state->state_callback_received[OP_FAILED];
-  if (is_canceled_of_failed) {
+  if (is_canceled_or_failed) {
     if (op_id == OP_SEND_INITIAL_METADATA) result = false;
     if (op_id == OP_SEND_MESSAGE) result = false;
     if (op_id == OP_SEND_TRAILING_METADATA) result = false;
@@ -778,16 +829,10 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
       op_can_be_run(stream_op, stream_state, &oas->state,
                     OP_SEND_INITIAL_METADATA)) {
     CRONET_LOG(GPR_DEBUG, "running: %p OP_SEND_INITIAL_METADATA", oas);
-    /* This OP is the beginning. Reset various states */
-    memset(&s->header_array, 0, sizeof(s->header_array));
-    memset(&stream_state->rs, 0, sizeof(stream_state->rs));
-    memset(&stream_state->ws, 0, sizeof(stream_state->ws));
-    memset(stream_state->state_op_done, 0, sizeof(stream_state->state_op_done));
-    memset(stream_state->state_callback_received, 0,
-           sizeof(stream_state->state_callback_received));
     /* Start new cronet stream. It is destroyed in on_succeeded, on_canceled,
      * on_failed */
     GPR_ASSERT(s->cbs == NULL);
+    GPR_ASSERT(!stream_state->state_op_done[OP_SEND_INITIAL_METADATA]);
     s->cbs = cronet_bidirectional_stream_create(s->curr_ct.engine, s->curr_gs,
                                                 &cronet_callbacks);
     CRONET_LOG(GPR_DEBUG, "%p = cronet_bidirectional_stream_create()", s->cbs);
@@ -808,15 +853,18 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
              op_can_be_run(stream_op, stream_state, &oas->state,
                            OP_RECV_INITIAL_METADATA)) {
     CRONET_LOG(GPR_DEBUG, "running: %p  OP_RECV_INITIAL_METADATA", oas);
-    if (stream_state->state_op_done[OP_CANCEL_ERROR] ||
-        stream_state->state_callback_received[OP_FAILED]) {
-      grpc_exec_ctx_sched(exec_ctx, stream_op->recv_initial_metadata_ready,
-                          GRPC_ERROR_CANCELLED, NULL);
+    if (stream_state->state_op_done[OP_CANCEL_ERROR]) {
+      grpc_closure_sched(exec_ctx, stream_op->recv_initial_metadata_ready,
+                         GRPC_ERROR_CANCELLED);
+    } else if (stream_state->state_callback_received[OP_FAILED]) {
+      grpc_closure_sched(
+          exec_ctx, stream_op->recv_initial_metadata_ready,
+          make_error_with_desc(GRPC_STATUS_UNAVAILABLE, "Unavailable."));
     } else {
       grpc_chttp2_incoming_metadata_buffer_publish(
           &oas->s->state.rs.initial_metadata, stream_op->recv_initial_metadata);
-      grpc_exec_ctx_sched(exec_ctx, stream_op->recv_initial_metadata_ready,
-                          GRPC_ERROR_NONE, NULL);
+      grpc_closure_sched(exec_ctx, stream_op->recv_initial_metadata_ready,
+                         GRPC_ERROR_NONE);
     }
     stream_state->state_op_done[OP_RECV_INITIAL_METADATA] = true;
     result = ACTION_TAKEN_NO_CALLBACK;
@@ -865,19 +913,27 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
              op_can_be_run(stream_op, stream_state, &oas->state,
                            OP_RECV_MESSAGE)) {
     CRONET_LOG(GPR_DEBUG, "running: %p  OP_RECV_MESSAGE", oas);
-    if (stream_state->state_op_done[OP_CANCEL_ERROR] ||
-        stream_state->state_callback_received[OP_FAILED]) {
-      CRONET_LOG(GPR_DEBUG, "Stream is either cancelled or failed.");
-      grpc_exec_ctx_sched(exec_ctx, stream_op->recv_message_ready,
-                          GRPC_ERROR_CANCELLED, NULL);
+    if (stream_state->state_op_done[OP_CANCEL_ERROR]) {
+      CRONET_LOG(GPR_DEBUG, "Stream is cancelled.");
+      grpc_closure_sched(exec_ctx, stream_op->recv_message_ready,
+                         GRPC_ERROR_CANCELLED);
+      stream_state->state_op_done[OP_RECV_MESSAGE] = true;
+      result = ACTION_TAKEN_NO_CALLBACK;
+    } else if (stream_state->state_callback_received[OP_FAILED]) {
+      CRONET_LOG(GPR_DEBUG, "Stream failed.");
+      grpc_closure_sched(
+          exec_ctx, stream_op->recv_message_ready,
+          make_error_with_desc(GRPC_STATUS_UNAVAILABLE, "Unavailable."));
       stream_state->state_op_done[OP_RECV_MESSAGE] = true;
+      result = ACTION_TAKEN_NO_CALLBACK;
     } else if (stream_state->rs.read_stream_closed == true) {
       /* No more data will be received */
       CRONET_LOG(GPR_DEBUG, "read stream closed");
-      grpc_exec_ctx_sched(exec_ctx, stream_op->recv_message_ready,
-                          GRPC_ERROR_NONE, NULL);
+      grpc_closure_sched(exec_ctx, stream_op->recv_message_ready,
+                         GRPC_ERROR_NONE);
       stream_state->state_op_done[OP_RECV_MESSAGE] = true;
       oas->state.state_op_done[OP_RECV_MESSAGE] = true;
+      result = ACTION_TAKEN_NO_CALLBACK;
     } else if (stream_state->rs.length_field_received == false) {
       if (stream_state->rs.received_bytes == GRPC_HEADER_SIZE_IN_BYTES &&
           stream_state->rs.remaining_bytes == 0) {
@@ -907,8 +963,8 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
                                         &stream_state->rs.read_slice_buffer, 0);
           *((grpc_byte_buffer **)stream_op->recv_message) =
               (grpc_byte_buffer *)&stream_state->rs.sbs;
-          grpc_exec_ctx_sched(exec_ctx, stream_op->recv_message_ready,
-                              GRPC_ERROR_NONE, NULL);
+          grpc_closure_sched(exec_ctx, stream_op->recv_message_ready,
+                             GRPC_ERROR_NONE);
           stream_state->state_op_done[OP_RECV_MESSAGE] = true;
           oas->state.state_op_done[OP_RECV_MESSAGE] = true;
           result = ACTION_TAKEN_NO_CALLBACK;
@@ -942,14 +998,19 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
                                     &stream_state->rs.read_slice_buffer, 0);
       *((grpc_byte_buffer **)stream_op->recv_message) =
           (grpc_byte_buffer *)&stream_state->rs.sbs;
-      grpc_exec_ctx_sched(exec_ctx, stream_op->recv_message_ready,
-                          GRPC_ERROR_NONE, NULL);
+      grpc_closure_sched(exec_ctx, stream_op->recv_message_ready,
+                         GRPC_ERROR_NONE);
       stream_state->state_op_done[OP_RECV_MESSAGE] = true;
       oas->state.state_op_done[OP_RECV_MESSAGE] = true;
-      /* Clear read state of the stream, so next read op (if it were to come)
-       * will work */
-      stream_state->rs.received_bytes = stream_state->rs.remaining_bytes =
-          stream_state->rs.length_field_received = 0;
+      /* Do an extra read to trigger on_succeeded() callback in case connection
+         is closed */
+      stream_state->rs.read_buffer = stream_state->rs.grpc_header_bytes;
+      stream_state->rs.received_bytes = 0;
+      stream_state->rs.remaining_bytes = GRPC_HEADER_SIZE_IN_BYTES;
+      stream_state->rs.length_field_received = false;
+      CRONET_LOG(GPR_DEBUG, "cronet_bidirectional_stream_read(%p)", s->cbs);
+      cronet_bidirectional_stream_read(s->cbs, stream_state->rs.read_buffer,
+                                       stream_state->rs.remaining_bytes);
       result = ACTION_TAKEN_NO_CALLBACK;
     }
   } else if (stream_op->recv_trailing_metadata &&
@@ -986,23 +1047,30 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
     CRONET_LOG(GPR_DEBUG, "W: cronet_bidirectional_stream_cancel(%p)", s->cbs);
     if (s->cbs) {
       cronet_bidirectional_stream_cancel(s->cbs);
+      result = ACTION_TAKEN_WITH_CALLBACK;
+    } else {
+      result = ACTION_TAKEN_NO_CALLBACK;
     }
     stream_state->state_op_done[OP_CANCEL_ERROR] = true;
-    result = ACTION_TAKEN_WITH_CALLBACK;
+    if (!stream_state->cancel_error) {
+      stream_state->cancel_error = GRPC_ERROR_REF(stream_op->cancel_error);
+    }
   } else if (stream_op->on_complete &&
              op_can_be_run(stream_op, stream_state, &oas->state,
                            OP_ON_COMPLETE)) {
     CRONET_LOG(GPR_DEBUG, "running: %p  OP_ON_COMPLETE", oas);
-    if (stream_state->state_op_done[OP_CANCEL_ERROR] ||
-        stream_state->state_callback_received[OP_FAILED]) {
-      grpc_exec_ctx_sched(exec_ctx, stream_op->on_complete,
-                          GRPC_ERROR_CANCELLED, NULL);
+    if (stream_state->state_op_done[OP_CANCEL_ERROR]) {
+      grpc_closure_sched(exec_ctx, stream_op->on_complete,
+                         GRPC_ERROR_REF(stream_state->cancel_error));
+    } else if (stream_state->state_callback_received[OP_FAILED]) {
+      grpc_closure_sched(
+          exec_ctx, stream_op->on_complete,
+          make_error_with_desc(GRPC_STATUS_UNAVAILABLE, "Unavailable."));
     } else {
       /* All actions in this stream_op are complete. Call the on_complete
        * callback
        */
-      grpc_exec_ctx_sched(exec_ctx, stream_op->on_complete, GRPC_ERROR_NONE,
-                          NULL);
+      grpc_closure_sched(exec_ctx, stream_op->on_complete, GRPC_ERROR_NONE);
     }
     oas->state.state_op_done[OP_ON_COMPLETE] = true;
     oas->done = true;
@@ -1017,6 +1085,15 @@ static enum e_op_result execute_stream_op(grpc_exec_ctx *exec_ctx,
       make a note */
     if (stream_op->recv_message)
       stream_state->state_op_done[OP_RECV_MESSAGE_AND_ON_COMPLETE] = true;
+  } else if (stream_state->fail_state && !stream_state->flush_read) {
+    CRONET_LOG(GPR_DEBUG, "running: %p  flush read", oas);
+    if (stream_state->rs.read_buffer &&
+        stream_state->rs.read_buffer != stream_state->rs.grpc_header_bytes) {
+      gpr_free(stream_state->rs.read_buffer);
+      stream_state->rs.read_buffer = NULL;
+    }
+    stream_state->rs.read_buffer = gpr_malloc(4096);
+    stream_state->flush_read = true;
   } else {
     result = NO_ACTION_POSSIBLE;
   }
@@ -1042,6 +1119,8 @@ static int init_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
   memset(s->state.state_op_done, 0, sizeof(s->state.state_op_done));
   memset(s->state.state_callback_received, 0,
          sizeof(s->state.state_callback_received));
+  s->state.fail_state = s->state.flush_read = false;
+  s->state.cancel_error = NULL;
   gpr_mu_init(&s->mu);
   return 0;
 }
@@ -1088,7 +1167,10 @@ static void perform_stream_op(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
 }
 
 static void destroy_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
-                           grpc_stream *gs, void *and_free_memory) {}
+                           grpc_stream *gs, void *and_free_memory) {
+  stream_obj *s = (stream_obj *)gs;
+  GRPC_ERROR_UNREF(s->state.cancel_error);
+}
 
 static void destroy_transport(grpc_exec_ctx *exec_ctx, grpc_transport *gt) {}
 
diff --git a/src/core/lib/README.md b/src/core/lib/README.md
new file mode 100644
index 0000000000..69b6bce2d9
--- /dev/null
+++ b/src/core/lib/README.md
@@ -0,0 +1,6 @@
+Required elements of gRPC Core: Each module in this directory is required to
+build gRPC. If it's possible to envisage a configuration where code is not
+required, then that code belongs in ext/ instead.
+
+NOTE: The movement of code between lib and ext is an ongoing effort, so this
+directory currently contains too much of the core library.
diff --git a/src/core/lib/channel/README.md b/src/core/lib/channel/README.md
new file mode 100644
index 0000000000..2dfcfe6e66
--- /dev/null
+++ b/src/core/lib/channel/README.md
@@ -0,0 +1,4 @@
+# Channel
+
+Provides channel/call stack implementation, and implementation of common filters
+for that implementation.
diff --git a/src/core/lib/channel/channel_args.c b/src/core/lib/channel/channel_args.c
index 401a2ad4fe..1a099ac437 100644
--- a/src/core/lib/channel/channel_args.c
+++ b/src/core/lib/channel/channel_args.c
@@ -184,7 +184,7 @@ grpc_channel_args *grpc_channel_args_normalize(const grpc_channel_args *a) {
   return b;
 }
 
-void grpc_channel_args_destroy(grpc_channel_args *a) {
+void grpc_channel_args_destroy(grpc_exec_ctx *exec_ctx, grpc_channel_args *a) {
   size_t i;
   if (!a) return;
   for (i = 0; i < a->num_args; i++) {
@@ -195,7 +195,8 @@ void grpc_channel_args_destroy(grpc_channel_args *a) {
       case GRPC_ARG_INTEGER:
         break;
       case GRPC_ARG_POINTER:
-        a->args[i].value.pointer.vtable->destroy(a->args[i].value.pointer.p);
+        a->args[i].value.pointer.vtable->destroy(exec_ctx,
+                                                 a->args[i].value.pointer.p);
         break;
     }
     gpr_free(a->args[i].key);
@@ -249,7 +250,8 @@ static int find_compression_algorithm_states_bitset(const grpc_channel_args *a,
 }
 
 grpc_channel_args *grpc_channel_args_compression_algorithm_set_state(
-    grpc_channel_args **a, grpc_compression_algorithm algorithm, int state) {
+    grpc_exec_ctx *exec_ctx, grpc_channel_args **a,
+    grpc_compression_algorithm algorithm, int state) {
   int *states_arg = NULL;
   grpc_channel_args *result = *a;
   const int states_arg_found =
@@ -282,7 +284,7 @@ grpc_channel_args *grpc_channel_args_compression_algorithm_set_state(
       GPR_BITCLEAR((unsigned *)&tmp.value.integer, algorithm);
     }
     result = grpc_channel_args_copy_and_add(*a, &tmp, 1);
-    grpc_channel_args_destroy(*a);
+    grpc_channel_args_destroy(exec_ctx, *a);
     *a = result;
   }
   return result;
diff --git a/src/core/lib/channel/channel_args.h b/src/core/lib/channel/channel_args.h
index 88fc0e37a3..5c7d31f8bb 100644
--- a/src/core/lib/channel/channel_args.h
+++ b/src/core/lib/channel/channel_args.h
@@ -68,7 +68,7 @@ grpc_channel_args *grpc_channel_args_merge(const grpc_channel_args *a,
                                            const grpc_channel_args *b);
 
 /** Destroy arguments created by \a grpc_channel_args_copy */
-void grpc_channel_args_destroy(grpc_channel_args *a);
+void grpc_channel_args_destroy(grpc_exec_ctx *exec_ctx, grpc_channel_args *a);
 
 /** Returns the compression algorithm set in \a a. */
 grpc_compression_algorithm grpc_channel_args_get_compression_algorithm(
@@ -88,7 +88,8 @@ grpc_channel_args *grpc_channel_args_set_compression_algorithm(
  * modified to point to the returned instance (which may be different from the
  * input value of \a a). */
 grpc_channel_args *grpc_channel_args_compression_algorithm_set_state(
-    grpc_channel_args **a, grpc_compression_algorithm algorithm, int enabled);
+    grpc_exec_ctx *exec_ctx, grpc_channel_args **a,
+    grpc_compression_algorithm algorithm, int enabled);
 
 /** Returns the bitset representing the support state (true for enabled, false
  * for disabled) for compression algorithms.
diff --git a/src/core/lib/channel/channel_stack.c b/src/core/lib/channel/channel_stack.c
index 999ad5f507..8f08b427fb 100644
--- a/src/core/lib/channel/channel_stack.c
+++ b/src/core/lib/channel/channel_stack.c
@@ -102,13 +102,11 @@ grpc_call_element *grpc_call_stack_element(grpc_call_stack *call_stack,
   return CALL_ELEMS_FROM_STACK(call_stack) + index;
 }
 
-void grpc_channel_stack_init(grpc_exec_ctx *exec_ctx, int initial_refs,
-                             grpc_iomgr_cb_func destroy, void *destroy_arg,
-                             const grpc_channel_filter **filters,
-                             size_t filter_count,
-                             const grpc_channel_args *channel_args,
-                             grpc_transport *optional_transport,
-                             const char *name, grpc_channel_stack *stack) {
+grpc_error *grpc_channel_stack_init(
+    grpc_exec_ctx *exec_ctx, int initial_refs, grpc_iomgr_cb_func destroy,
+    void *destroy_arg, const grpc_channel_filter **filters, size_t filter_count,
+    const grpc_channel_args *channel_args, grpc_transport *optional_transport,
+    const char *name, grpc_channel_stack *stack) {
   size_t call_size =
       ROUND_UP_TO_ALIGNMENT_SIZE(sizeof(grpc_call_stack)) +
       ROUND_UP_TO_ALIGNMENT_SIZE(filter_count * sizeof(grpc_call_element));
@@ -126,6 +124,7 @@ void grpc_channel_stack_init(grpc_exec_ctx *exec_ctx, int initial_refs,
       ROUND_UP_TO_ALIGNMENT_SIZE(filter_count * sizeof(grpc_channel_element));
 
   /* init per-filter data */
+  grpc_error *first_error = GRPC_ERROR_NONE;
   for (i = 0; i < filter_count; i++) {
     args.channel_stack = stack;
     args.channel_args = channel_args;
@@ -134,7 +133,15 @@ void grpc_channel_stack_init(grpc_exec_ctx *exec_ctx, int initial_refs,
     args.is_last = i == (filter_count - 1);
     elems[i].filter = filters[i];
     elems[i].channel_data = user_data;
-    elems[i].filter->init_channel_elem(exec_ctx, &elems[i], &args);
+    grpc_error *error =
+        elems[i].filter->init_channel_elem(exec_ctx, &elems[i], &args);
+    if (error != GRPC_ERROR_NONE) {
+      if (first_error == GRPC_ERROR_NONE) {
+        first_error = error;
+      } else {
+        GRPC_ERROR_UNREF(error);
+      }
+    }
     user_data += ROUND_UP_TO_ALIGNMENT_SIZE(filters[i]->sizeof_channel_data);
     call_size += ROUND_UP_TO_ALIGNMENT_SIZE(filters[i]->sizeof_call_data);
   }
@@ -144,6 +151,7 @@ void grpc_channel_stack_init(grpc_exec_ctx *exec_ctx, int initial_refs,
              grpc_channel_stack_size(filters, filter_count));
 
   stack->call_stack_size = call_size;
+  return first_error;
 }
 
 void grpc_channel_stack_destroy(grpc_exec_ctx *exec_ctx,
@@ -289,7 +297,8 @@ void grpc_call_element_send_cancel(grpc_exec_ctx *exec_ctx,
   grpc_transport_stream_op *op = gpr_malloc(sizeof(*op));
   memset(op, 0, sizeof(*op));
   op->cancel_error = GRPC_ERROR_CANCELLED;
-  op->on_complete = grpc_closure_create(destroy_op, op);
+  op->on_complete =
+      grpc_closure_create(destroy_op, op, grpc_schedule_on_exec_ctx);
   elem->filter->start_transport_stream_op(exec_ctx, elem, op);
 }
 
@@ -299,8 +308,9 @@ void grpc_call_element_send_cancel_with_message(grpc_exec_ctx *exec_ctx,
                                                 grpc_slice *optional_message) {
   grpc_transport_stream_op *op = gpr_malloc(sizeof(*op));
   memset(op, 0, sizeof(*op));
-  op->on_complete = grpc_closure_create(destroy_op, op);
-  grpc_transport_stream_op_add_cancellation_with_message(op, status,
+  op->on_complete =
+      grpc_closure_create(destroy_op, op, grpc_schedule_on_exec_ctx);
+  grpc_transport_stream_op_add_cancellation_with_message(exec_ctx, op, status,
                                                          optional_message);
   elem->filter->start_transport_stream_op(exec_ctx, elem, op);
 }
@@ -311,7 +321,8 @@ void grpc_call_element_send_close_with_message(grpc_exec_ctx *exec_ctx,
                                                grpc_slice *optional_message) {
   grpc_transport_stream_op *op = gpr_malloc(sizeof(*op));
   memset(op, 0, sizeof(*op));
-  op->on_complete = grpc_closure_create(destroy_op, op);
-  grpc_transport_stream_op_add_close(op, status, optional_message);
+  op->on_complete =
+      grpc_closure_create(destroy_op, op, grpc_schedule_on_exec_ctx);
+  grpc_transport_stream_op_add_close(exec_ctx, op, status, optional_message);
   elem->filter->start_transport_stream_op(exec_ctx, elem, op);
 }
diff --git a/src/core/lib/channel/channel_stack.h b/src/core/lib/channel/channel_stack.h
index 004643d45f..d9d3a85233 100644
--- a/src/core/lib/channel/channel_stack.h
+++ b/src/core/lib/channel/channel_stack.h
@@ -34,6 +34,13 @@
 #ifndef GRPC_CORE_LIB_CHANNEL_CHANNEL_STACK_H
 #define GRPC_CORE_LIB_CHANNEL_CHANNEL_STACK_H
 
+//////////////////////////////////////////////////////////////////////////////
+// IMPORTANT NOTE:
+//
+// When you update this API, please make the corresponding changes to
+// the C++ API in src/cpp/common/channel_filter.{h,cc}
+//////////////////////////////////////////////////////////////////////////////
+
 /* A channel filter defines how operations on a channel are implemented.
    Channel filters are chained together to create full channels, and if those
    chains are linear, then channel stacks provide a mechanism to minimize
@@ -146,8 +153,9 @@ typedef struct {
      is_first, is_last designate this elements position in the stack, and are
      useful for asserting correct configuration by upper layer code.
      The filter does not need to do any chaining */
-  void (*init_channel_elem)(grpc_exec_ctx *exec_ctx, grpc_channel_element *elem,
-                            grpc_channel_element_args *args);
+  grpc_error *(*init_channel_elem)(grpc_exec_ctx *exec_ctx,
+                                   grpc_channel_element *elem,
+                                   grpc_channel_element_args *args);
   /* Destroy per channel data.
      The filter does not need to do any chaining */
   void (*destroy_channel_elem)(grpc_exec_ctx *exec_ctx,
@@ -214,12 +222,11 @@ grpc_call_element *grpc_call_stack_element(grpc_call_stack *stack, size_t i);
 size_t grpc_channel_stack_size(const grpc_channel_filter **filters,
                                size_t filter_count);
 /* Initialize a channel stack given some filters */
-void grpc_channel_stack_init(grpc_exec_ctx *exec_ctx, int initial_refs,
-                             grpc_iomgr_cb_func destroy, void *destroy_arg,
-                             const grpc_channel_filter **filters,
-                             size_t filter_count, const grpc_channel_args *args,
-                             grpc_transport *optional_transport,
-                             const char *name, grpc_channel_stack *stack);
+grpc_error *grpc_channel_stack_init(
+    grpc_exec_ctx *exec_ctx, int initial_refs, grpc_iomgr_cb_func destroy,
+    void *destroy_arg, const grpc_channel_filter **filters, size_t filter_count,
+    const grpc_channel_args *args, grpc_transport *optional_transport,
+    const char *name, grpc_channel_stack *stack);
 /* Destroy a channel stack */
 void grpc_channel_stack_destroy(grpc_exec_ctx *exec_ctx,
                                 grpc_channel_stack *stack);
diff --git a/src/core/lib/channel/channel_stack_builder.c b/src/core/lib/channel/channel_stack_builder.c
index eda4968f48..5f9e3b4539 100644
--- a/src/core/lib/channel/channel_stack_builder.c
+++ b/src/core/lib/channel/channel_stack_builder.c
@@ -138,9 +138,10 @@ void grpc_channel_stack_builder_set_name(grpc_channel_stack_builder *builder,
 }
 
 void grpc_channel_stack_builder_set_channel_arguments(
-    grpc_channel_stack_builder *builder, const grpc_channel_args *args) {
+    grpc_exec_ctx *exec_ctx, grpc_channel_stack_builder *builder,
+    const grpc_channel_args *args) {
   if (builder->args != NULL) {
-    grpc_channel_args_destroy(builder->args);
+    grpc_channel_args_destroy(exec_ctx, builder->args);
   }
   builder->args = grpc_channel_args_copy(args);
 }
@@ -213,7 +214,8 @@ bool grpc_channel_stack_builder_add_filter_after(
   return true;
 }
 
-void grpc_channel_stack_builder_destroy(grpc_channel_stack_builder *builder) {
+void grpc_channel_stack_builder_destroy(grpc_exec_ctx *exec_ctx,
+                                        grpc_channel_stack_builder *builder) {
   filter_node *p = builder->begin.next;
   while (p != &builder->end) {
     filter_node *next = p->next;
@@ -221,17 +223,16 @@ void grpc_channel_stack_builder_destroy(grpc_channel_stack_builder *builder) {
     p = next;
   }
   if (builder->args != NULL) {
-    grpc_channel_args_destroy(builder->args);
+    grpc_channel_args_destroy(exec_ctx, builder->args);
   }
   gpr_free(builder->target);
   gpr_free(builder);
 }
 
-void *grpc_channel_stack_builder_finish(grpc_exec_ctx *exec_ctx,
-                                        grpc_channel_stack_builder *builder,
-                                        size_t prefix_bytes, int initial_refs,
-                                        grpc_iomgr_cb_func destroy,
-                                        void *destroy_arg) {
+grpc_error *grpc_channel_stack_builder_finish(
+    grpc_exec_ctx *exec_ctx, grpc_channel_stack_builder *builder,
+    size_t prefix_bytes, int initial_refs, grpc_iomgr_cb_func destroy,
+    void *destroy_arg, void **result) {
   // count the number of filters
   size_t num_filters = 0;
   for (filter_node *p = builder->begin.next; p != &builder->end; p = p->next) {
@@ -250,28 +251,35 @@ void *grpc_channel_stack_builder_finish(grpc_exec_ctx *exec_ctx,
   size_t channel_stack_size = grpc_channel_stack_size(filters, num_filters);
 
   // allocate memory, with prefix_bytes followed by channel_stack_size
-  char *result = gpr_malloc(prefix_bytes + channel_stack_size);
+  *result = gpr_malloc(prefix_bytes + channel_stack_size);
   // fetch a pointer to the channel stack
   grpc_channel_stack *channel_stack =
-      (grpc_channel_stack *)(result + prefix_bytes);
+      (grpc_channel_stack *)((char *)(*result) + prefix_bytes);
   // and initialize it
-  grpc_channel_stack_init(exec_ctx, initial_refs, destroy,
-                          destroy_arg == NULL ? result : destroy_arg, filters,
-                          num_filters, builder->args, builder->transport,
-                          builder->name, channel_stack);
-
-  // run post-initialization functions
-  i = 0;
-  for (filter_node *p = builder->begin.next; p != &builder->end; p = p->next) {
-    if (p->init != NULL) {
-      p->init(channel_stack, grpc_channel_stack_element(channel_stack, i),
-              p->init_arg);
+  grpc_error *error = grpc_channel_stack_init(
+      exec_ctx, initial_refs, destroy,
+      destroy_arg == NULL ? *result : destroy_arg, filters, num_filters,
+      builder->args, builder->transport, builder->name, channel_stack);
+
+  if (error != GRPC_ERROR_NONE) {
+    grpc_channel_stack_destroy(exec_ctx, channel_stack);
+    gpr_free(*result);
+    *result = NULL;
+  } else {
+    // run post-initialization functions
+    i = 0;
+    for (filter_node *p = builder->begin.next; p != &builder->end;
+         p = p->next) {
+      if (p->init != NULL) {
+        p->init(channel_stack, grpc_channel_stack_element(channel_stack, i),
+                p->init_arg);
+      }
+      i++;
     }
-    i++;
   }
 
-  grpc_channel_stack_builder_destroy(builder);
+  grpc_channel_stack_builder_destroy(exec_ctx, builder);
   gpr_free((grpc_channel_filter **)filters);
 
-  return result;
+  return error;
 }
diff --git a/src/core/lib/channel/channel_stack_builder.h b/src/core/lib/channel/channel_stack_builder.h
index 4a00f7bfdb..8adf38e27b 100644
--- a/src/core/lib/channel/channel_stack_builder.h
+++ b/src/core/lib/channel/channel_stack_builder.h
@@ -73,7 +73,8 @@ grpc_transport *grpc_channel_stack_builder_get_transport(
 
 /// Set channel arguments: copies args
 void grpc_channel_stack_builder_set_channel_arguments(
-    grpc_channel_stack_builder *builder, const grpc_channel_args *args);
+    grpc_exec_ctx *exec_ctx, grpc_channel_stack_builder *builder,
+    const grpc_channel_args *args);
 
 /// Return a borrowed pointer to the channel arguments
 const grpc_channel_args *grpc_channel_stack_builder_get_channel_arguments(
@@ -146,19 +147,19 @@ bool grpc_channel_stack_builder_append_filter(
 void grpc_channel_stack_builder_iterator_destroy(
     grpc_channel_stack_builder_iterator *iterator);
 
-/// Destroy the builder, return the freshly minted channel stack
+/// Destroy the builder, return the freshly minted channel stack in \a result.
 /// Allocates \a prefix_bytes bytes before the channel stack
 /// Returns the base pointer of the allocated block
 /// \a initial_refs, \a destroy, \a destroy_arg are as per
 /// grpc_channel_stack_init
-void *grpc_channel_stack_builder_finish(grpc_exec_ctx *exec_ctx,
-                                        grpc_channel_stack_builder *builder,
-                                        size_t prefix_bytes, int initial_refs,
-                                        grpc_iomgr_cb_func destroy,
-                                        void *destroy_arg);
+grpc_error *grpc_channel_stack_builder_finish(
+    grpc_exec_ctx *exec_ctx, grpc_channel_stack_builder *builder,
+    size_t prefix_bytes, int initial_refs, grpc_iomgr_cb_func destroy,
+    void *destroy_arg, void **result);
 
 /// Destroy the builder without creating a channel stack
-void grpc_channel_stack_builder_destroy(grpc_channel_stack_builder *builder);
+void grpc_channel_stack_builder_destroy(grpc_exec_ctx *exec_ctx,
+                                        grpc_channel_stack_builder *builder);
 
 extern int grpc_trace_channel_stack_builder;
 
diff --git a/src/core/lib/channel/compress_filter.c b/src/core/lib/channel/compress_filter.c
index 2874d63fc7..337c194b79 100644
--- a/src/core/lib/channel/compress_filter.c
+++ b/src/core/lib/channel/compress_filter.c
@@ -44,6 +44,7 @@
 #include "src/core/lib/compression/algorithm_metadata.h"
 #include "src/core/lib/compression/message_compress.h"
 #include "src/core/lib/profiling/timers.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/transport/static_metadata.h"
 
@@ -82,7 +83,8 @@ typedef struct channel_data {
 /** For each \a md element from the incoming metadata, filter out the entry for
  * "grpc-encoding", using its value to populate the call data's
  * compression_algorithm field. */
-static grpc_mdelem *compression_md_filter(void *user_data, grpc_mdelem *md) {
+static grpc_mdelem *compression_md_filter(grpc_exec_ctx *exec_ctx,
+                                          void *user_data, grpc_mdelem *md) {
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
   channel_data *channeld = elem->channel_data;
@@ -130,12 +132,14 @@ static int skip_compression(grpc_call_element *elem, uint32_t flags) {
 
 /** Filter initial metadata */
 static void process_send_initial_metadata(
-    grpc_call_element *elem, grpc_metadata_batch *initial_metadata) {
+    grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
+    grpc_metadata_batch *initial_metadata) {
   call_data *calld = elem->call_data;
   channel_data *channeld = elem->channel_data;
   /* Parse incoming request for compression. If any, it'll be available
    * at calld->compression_algorithm */
-  grpc_metadata_batch_filter(initial_metadata, compression_md_filter, elem);
+  grpc_metadata_batch_filter(exec_ctx, initial_metadata, compression_md_filter,
+                             elem);
   if (!calld->has_compression_algorithm) {
     /* If no algorithm was found in the metadata and we aren't
      * exceptionally skipping compression, fall back to the channel
@@ -161,7 +165,7 @@ static void continue_send_message(grpc_exec_ctx *exec_ctx,
 static void send_done(grpc_exec_ctx *exec_ctx, void *elemp, grpc_error *error) {
   grpc_call_element *elem = elemp;
   call_data *calld = elem->call_data;
-  grpc_slice_buffer_reset_and_unref(&calld->slices);
+  grpc_slice_buffer_reset_and_unref_internal(exec_ctx, &calld->slices);
   calld->post_send->cb(exec_ctx, calld->post_send->cb_arg, error);
 }
 
@@ -171,8 +175,8 @@ static void finish_send_message(grpc_exec_ctx *exec_ctx,
   int did_compress;
   grpc_slice_buffer tmp;
   grpc_slice_buffer_init(&tmp);
-  did_compress =
-      grpc_msg_compress(calld->compression_algorithm, &calld->slices, &tmp);
+  did_compress = grpc_msg_compress(exec_ctx, calld->compression_algorithm,
+                                   &calld->slices, &tmp);
   if (did_compress) {
     if (grpc_compression_trace) {
       char *algo_name;
@@ -199,7 +203,7 @@ static void finish_send_message(grpc_exec_ctx *exec_ctx,
     }
   }
 
-  grpc_slice_buffer_destroy(&tmp);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &tmp);
 
   grpc_slice_buffer_stream_init(&calld->replacement_stream, &calld->slices,
                                 calld->send_flags);
@@ -243,7 +247,7 @@ static void compress_start_transport_stream_op(grpc_exec_ctx *exec_ctx,
   GPR_TIMER_BEGIN("compress_start_transport_stream_op", 0);
 
   if (op->send_initial_metadata) {
-    process_send_initial_metadata(elem, op->send_initial_metadata);
+    process_send_initial_metadata(exec_ctx, elem, op->send_initial_metadata);
   }
   if (op->send_message != NULL &&
       !skip_compression(elem, op->send_message->flags)) {
@@ -269,8 +273,10 @@ static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx,
   /* initialize members */
   grpc_slice_buffer_init(&calld->slices);
   calld->has_compression_algorithm = 0;
-  grpc_closure_init(&calld->got_slice, got_slice, elem);
-  grpc_closure_init(&calld->send_done, send_done, elem);
+  grpc_closure_init(&calld->got_slice, got_slice, elem,
+                    grpc_schedule_on_exec_ctx);
+  grpc_closure_init(&calld->send_done, send_done, elem,
+                    grpc_schedule_on_exec_ctx);
 
   return GRPC_ERROR_NONE;
 }
@@ -281,13 +287,13 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
                               void *ignored) {
   /* grab pointers to our data from the call element */
   call_data *calld = elem->call_data;
-  grpc_slice_buffer_destroy(&calld->slices);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &calld->slices);
 }
 
 /* Constructor for channel_data */
-static void init_channel_elem(grpc_exec_ctx *exec_ctx,
-                              grpc_channel_element *elem,
-                              grpc_channel_element_args *args) {
+static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
+                                     grpc_channel_element *elem,
+                                     grpc_channel_element_args *args) {
   channel_data *channeld = elem->channel_data;
 
   channeld->enabled_algorithms_bitset =
@@ -315,6 +321,7 @@ static void init_channel_elem(grpc_exec_ctx *exec_ctx,
   }
 
   GPR_ASSERT(!args->is_last);
+  return GRPC_ERROR_NONE;
 }
 
 /* Destructor for channel data */
diff --git a/src/core/lib/channel/connected_channel.c b/src/core/lib/channel/connected_channel.c
index 038e819f72..ccc0619e1c 100644
--- a/src/core/lib/channel/connected_channel.c
+++ b/src/core/lib/channel/connected_channel.c
@@ -114,12 +114,13 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
 }
 
 /* Constructor for channel_data */
-static void init_channel_elem(grpc_exec_ctx *exec_ctx,
-                              grpc_channel_element *elem,
-                              grpc_channel_element_args *args) {
+static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
+                                     grpc_channel_element *elem,
+                                     grpc_channel_element_args *args) {
   channel_data *cd = (channel_data *)elem->channel_data;
   GPR_ASSERT(args->is_last);
   cd->transport = NULL;
+  return GRPC_ERROR_NONE;
 }
 
 /* Destructor for channel_data */
@@ -170,7 +171,8 @@ static void bind_transport(grpc_channel_stack *channel_stack,
   channel_stack->call_stack_size += grpc_transport_stream_size(t);
 }
 
-bool grpc_add_connected_filter(grpc_channel_stack_builder *builder,
+bool grpc_add_connected_filter(grpc_exec_ctx *exec_ctx,
+                               grpc_channel_stack_builder *builder,
                                void *arg_must_be_null) {
   GPR_ASSERT(arg_must_be_null == NULL);
   grpc_transport *t = grpc_channel_stack_builder_get_transport(builder);
diff --git a/src/core/lib/channel/connected_channel.h b/src/core/lib/channel/connected_channel.h
index 3142d647b7..3585c0ecbc 100644
--- a/src/core/lib/channel/connected_channel.h
+++ b/src/core/lib/channel/connected_channel.h
@@ -36,7 +36,8 @@
 
 #include "src/core/lib/channel/channel_stack_builder.h"
 
-bool grpc_add_connected_filter(grpc_channel_stack_builder *builder,
+bool grpc_add_connected_filter(grpc_exec_ctx *exec_ctx,
+                               grpc_channel_stack_builder *builder,
                                void *arg_must_be_null);
 
 #endif /* GRPC_CORE_LIB_CHANNEL_CONNECTED_CHANNEL_H */
diff --git a/src/core/lib/channel/context.h b/src/core/lib/channel/context.h
index 071c5f695c..6c931ad28a 100644
--- a/src/core/lib/channel/context.h
+++ b/src/core/lib/channel/context.h
@@ -47,6 +47,9 @@ typedef enum {
   /// Value is a \a census_context.
   GRPC_CONTEXT_TRACING,
 
+  /// Reserved for traffic_class_context.
+  GRPC_CONTEXT_TRAFFIC,
+
   GRPC_CONTEXT_COUNT
 } grpc_context_index;
 
diff --git a/src/core/lib/channel/deadline_filter.c b/src/core/lib/channel/deadline_filter.c
index 0e703d8d27..a45a4d4b82 100644
--- a/src/core/lib/channel/deadline_filter.c
+++ b/src/core/lib/channel/deadline_filter.c
@@ -41,6 +41,7 @@
 
 #include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/iomgr/timer.h"
+#include "src/core/lib/slice/slice_internal.h"
 
 //
 // grpc_deadline_state
@@ -58,7 +59,7 @@ static void timer_callback(grpc_exec_ctx* exec_ctx, void* arg,
     grpc_slice msg = grpc_slice_from_static_string("Deadline Exceeded");
     grpc_call_element_send_cancel_with_message(
         exec_ctx, elem, GRPC_STATUS_DEADLINE_EXCEEDED, &msg);
-    grpc_slice_unref(msg);
+    grpc_slice_unref_internal(exec_ctx, msg);
   }
   GRPC_CALL_STACK_UNREF(exec_ctx, deadline_state->call_stack, "deadline_timer");
 }
@@ -82,8 +83,11 @@ static void start_timer_if_needed_locked(grpc_exec_ctx* exec_ctx,
     // Take a reference to the call stack, to be owned by the timer.
     GRPC_CALL_STACK_REF(deadline_state->call_stack, "deadline_timer");
     deadline_state->timer_pending = true;
-    grpc_timer_init(exec_ctx, &deadline_state->timer, deadline, timer_callback,
-                    elem, gpr_now(GPR_CLOCK_MONOTONIC));
+    grpc_closure_init(&deadline_state->timer_callback, timer_callback, elem,
+                      grpc_schedule_on_exec_ctx);
+    grpc_timer_init(exec_ctx, &deadline_state->timer, deadline,
+                    &deadline_state->timer_callback,
+                    gpr_now(GPR_CLOCK_MONOTONIC));
   }
 }
 static void start_timer_if_needed(grpc_exec_ctx* exec_ctx,
@@ -123,7 +127,8 @@ static void on_complete(grpc_exec_ctx* exec_ctx, void* arg, grpc_error* error) {
 static void inject_on_complete_cb(grpc_deadline_state* deadline_state,
                                   grpc_transport_stream_op* op) {
   deadline_state->next_on_complete = op->on_complete;
-  grpc_closure_init(&deadline_state->on_complete, on_complete, deadline_state);
+  grpc_closure_init(&deadline_state->on_complete, on_complete, deadline_state,
+                    grpc_schedule_on_exec_ctx);
   op->on_complete = &deadline_state->on_complete;
 }
 
@@ -172,8 +177,9 @@ void grpc_deadline_state_start(grpc_exec_ctx* exec_ctx, grpc_call_element* elem,
     struct start_timer_after_init_state* state = gpr_malloc(sizeof(*state));
     state->elem = elem;
     state->deadline = deadline;
-    grpc_closure_init(&state->closure, start_timer_after_init, state);
-    grpc_exec_ctx_sched(exec_ctx, &state->closure, GRPC_ERROR_NONE, NULL);
+    grpc_closure_init(&state->closure, start_timer_after_init, state,
+                      grpc_schedule_on_exec_ctx);
+    grpc_closure_sched(exec_ctx, &state->closure, GRPC_ERROR_NONE);
   }
 }
 
@@ -207,10 +213,11 @@ void grpc_deadline_state_client_start_transport_stream_op(
 //
 
 // Constructor for channel_data.  Used for both client and server filters.
-static void init_channel_elem(grpc_exec_ctx* exec_ctx,
-                              grpc_channel_element* elem,
-                              grpc_channel_element_args* args) {
+static grpc_error* init_channel_elem(grpc_exec_ctx* exec_ctx,
+                                     grpc_channel_element* elem,
+                                     grpc_channel_element_args* args) {
   GPR_ASSERT(!args->is_last);
+  return GRPC_ERROR_NONE;
 }
 
 // Destructor for channel_data.  Used for both client and server filters.
@@ -289,7 +296,8 @@ static void server_start_transport_stream_op(grpc_exec_ctx* exec_ctx,
       calld->next_recv_initial_metadata_ready = op->recv_initial_metadata_ready;
       calld->recv_initial_metadata = op->recv_initial_metadata;
       grpc_closure_init(&calld->recv_initial_metadata_ready,
-                        recv_initial_metadata_ready, elem);
+                        recv_initial_metadata_ready, elem,
+                        grpc_schedule_on_exec_ctx);
       op->recv_initial_metadata_ready = &calld->recv_initial_metadata_ready;
     }
     // Make sure we know when the call is complete, so that we can cancel
diff --git a/src/core/lib/channel/deadline_filter.h b/src/core/lib/channel/deadline_filter.h
index 716a852565..bd2b84f79e 100644
--- a/src/core/lib/channel/deadline_filter.h
+++ b/src/core/lib/channel/deadline_filter.h
@@ -46,6 +46,7 @@ typedef struct grpc_deadline_state {
   bool timer_pending;
   // The deadline timer.
   grpc_timer timer;
+  grpc_closure timer_callback;
   // Closure to invoke when the call is complete.
   // We use this to cancel the timer.
   grpc_closure on_complete;
diff --git a/src/core/lib/channel/handshaker.c b/src/core/lib/channel/handshaker.c
index a45a39981c..c052ca5385 100644
--- a/src/core/lib/channel/handshaker.c
+++ b/src/core/lib/channel/handshaker.c
@@ -38,12 +38,13 @@
 
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/handshaker.h"
+#include "src/core/lib/iomgr/timer.h"
 
 //
 // grpc_handshaker
 //
 
-void grpc_handshaker_init(const struct grpc_handshaker_vtable* vtable,
+void grpc_handshaker_init(const grpc_handshaker_vtable* vtable,
                           grpc_handshaker* handshaker) {
   handshaker->vtable = vtable;
 }
@@ -60,45 +61,44 @@ void grpc_handshaker_shutdown(grpc_exec_ctx* exec_ctx,
 
 void grpc_handshaker_do_handshake(grpc_exec_ctx* exec_ctx,
                                   grpc_handshaker* handshaker,
-                                  grpc_endpoint* endpoint,
-                                  grpc_channel_args* args,
-                                  grpc_slice_buffer* read_buffer,
-                                  gpr_timespec deadline,
                                   grpc_tcp_server_acceptor* acceptor,
-                                  grpc_handshaker_done_cb cb, void* user_data) {
-  handshaker->vtable->do_handshake(exec_ctx, handshaker, endpoint, args,
-                                   read_buffer, deadline, acceptor, cb,
-                                   user_data);
+                                  grpc_closure* on_handshake_done,
+                                  grpc_handshaker_args* args) {
+  handshaker->vtable->do_handshake(exec_ctx, handshaker, acceptor,
+                                   on_handshake_done, args);
 }
 
 //
 // grpc_handshake_manager
 //
 
-// State used while chaining handshakers.
-struct grpc_handshaker_state {
-  // The index of the handshaker to invoke next.
-  size_t index;
-  // The deadline for all handshakers.
-  gpr_timespec deadline;
-  // The acceptor to call the handshakers with.
-  grpc_tcp_server_acceptor* acceptor;
-  // The final callback and user_data to invoke after the last handshaker.
-  grpc_handshaker_done_cb final_cb;
-  void* final_user_data;
-};
-
 struct grpc_handshake_manager {
+  gpr_mu mu;
+  gpr_refcount refs;
+  bool shutdown;
   // An array of handshakers added via grpc_handshake_manager_add().
   size_t count;
   grpc_handshaker** handshakers;
-  // State used while chaining handshakers.
-  struct grpc_handshaker_state* state;
+  // The index of the handshaker to invoke next and closure to invoke it.
+  size_t index;
+  grpc_closure call_next_handshaker;
+  // The acceptor to call the handshakers with.
+  grpc_tcp_server_acceptor* acceptor;
+  // Deadline timer across all handshakers.
+  grpc_timer deadline_timer;
+  grpc_closure on_timeout;
+  // The final callback and user_data to invoke after the last handshaker.
+  grpc_closure on_handshake_done;
+  void* user_data;
+  // Handshaker args.
+  grpc_handshaker_args args;
 };
 
 grpc_handshake_manager* grpc_handshake_manager_create() {
   grpc_handshake_manager* mgr = gpr_malloc(sizeof(grpc_handshake_manager));
   memset(mgr, 0, sizeof(*mgr));
+  gpr_mu_init(&mgr->mu);
+  gpr_ref_init(&mgr->refs, 1);
   return mgr;
 }
 
@@ -106,6 +106,7 @@ static bool is_power_of_2(size_t n) { return (n & (n - 1)) == 0; }
 
 void grpc_handshake_manager_add(grpc_handshake_manager* mgr,
                                 grpc_handshaker* handshaker) {
+  gpr_mu_lock(&mgr->mu);
   // To avoid allocating memory for each handshaker we add, we double
   // the number of elements every time we need more.
   size_t realloc_count = 0;
@@ -119,85 +120,121 @@ void grpc_handshake_manager_add(grpc_handshake_manager* mgr,
         gpr_realloc(mgr->handshakers, realloc_count * sizeof(grpc_handshaker*));
   }
   mgr->handshakers[mgr->count++] = handshaker;
+  gpr_mu_unlock(&mgr->mu);
+}
+
+static void grpc_handshake_manager_unref(grpc_exec_ctx* exec_ctx,
+                                         grpc_handshake_manager* mgr) {
+  if (gpr_unref(&mgr->refs)) {
+    for (size_t i = 0; i < mgr->count; ++i) {
+      grpc_handshaker_destroy(exec_ctx, mgr->handshakers[i]);
+    }
+    gpr_free(mgr->handshakers);
+    gpr_mu_destroy(&mgr->mu);
+    gpr_free(mgr);
+  }
 }
 
 void grpc_handshake_manager_destroy(grpc_exec_ctx* exec_ctx,
                                     grpc_handshake_manager* mgr) {
-  for (size_t i = 0; i < mgr->count; ++i) {
-    grpc_handshaker_destroy(exec_ctx, mgr->handshakers[i]);
-  }
-  gpr_free(mgr->handshakers);
-  gpr_free(mgr);
+  grpc_handshake_manager_unref(exec_ctx, mgr);
 }
 
 void grpc_handshake_manager_shutdown(grpc_exec_ctx* exec_ctx,
                                      grpc_handshake_manager* mgr) {
-  for (size_t i = 0; i < mgr->count; ++i) {
-    grpc_handshaker_shutdown(exec_ctx, mgr->handshakers[i]);
+  gpr_mu_lock(&mgr->mu);
+  // Shutdown the handshaker that's currently in progress, if any.
+  if (!mgr->shutdown && mgr->index > 0) {
+    mgr->shutdown = true;
+    grpc_handshaker_shutdown(exec_ctx, mgr->handshakers[mgr->index - 1]);
   }
-  if (mgr->state != NULL) {
-    gpr_free(mgr->state);
-    mgr->state = NULL;
+  gpr_mu_unlock(&mgr->mu);
+}
+
+// Helper function to call either the next handshaker or the
+// on_handshake_done callback.
+// Returns true if we've scheduled the on_handshake_done callback.
+static bool call_next_handshaker_locked(grpc_exec_ctx* exec_ctx,
+                                        grpc_handshake_manager* mgr,
+                                        grpc_error* error) {
+  GPR_ASSERT(mgr->index <= mgr->count);
+  // If we got an error or we've been shut down or we're exiting early or
+  // we've finished the last handshaker, invoke the on_handshake_done
+  // callback.  Otherwise, call the next handshaker.
+  if (error != GRPC_ERROR_NONE || mgr->shutdown || mgr->args.exit_early ||
+      mgr->index == mgr->count) {
+    // Cancel deadline timer, since we're invoking the on_handshake_done
+    // callback now.
+    grpc_timer_cancel(exec_ctx, &mgr->deadline_timer);
+    grpc_closure_sched(exec_ctx, &mgr->on_handshake_done, error);
+    mgr->shutdown = true;
+  } else {
+    grpc_handshaker_do_handshake(exec_ctx, mgr->handshakers[mgr->index],
+                                 mgr->acceptor, &mgr->call_next_handshaker,
+                                 &mgr->args);
   }
+  ++mgr->index;
+  return mgr->shutdown;
 }
 
 // A function used as the handshaker-done callback when chaining
 // handshakers together.
-static void call_next_handshaker(grpc_exec_ctx* exec_ctx,
-                                 grpc_endpoint* endpoint,
-                                 grpc_channel_args* args,
-                                 grpc_slice_buffer* read_buffer,
-                                 void* user_data, grpc_error* error) {
-  grpc_handshake_manager* mgr = user_data;
-  GPR_ASSERT(mgr->state != NULL);
-  GPR_ASSERT(mgr->state->index < mgr->count);
-  // If we got an error, skip all remaining handshakers and invoke the
-  // caller-supplied callback immediately.
-  if (error != GRPC_ERROR_NONE) {
-    mgr->state->final_cb(exec_ctx, endpoint, args, read_buffer,
-                         mgr->state->final_user_data, error);
-    return;
+static void call_next_handshaker(grpc_exec_ctx* exec_ctx, void* arg,
+                                 grpc_error* error) {
+  grpc_handshake_manager* mgr = arg;
+  gpr_mu_lock(&mgr->mu);
+  bool done = call_next_handshaker_locked(exec_ctx, mgr, GRPC_ERROR_REF(error));
+  gpr_mu_unlock(&mgr->mu);
+  // If we're invoked the final callback, we won't be coming back
+  // to this function, so we can release our reference to the
+  // handshake manager.
+  if (done) {
+    grpc_handshake_manager_unref(exec_ctx, mgr);
   }
-  grpc_handshaker_done_cb cb = call_next_handshaker;
-  // If this is the last handshaker, use the caller-supplied callback
-  // and user_data instead of chaining back to this function again.
-  if (mgr->state->index == mgr->count - 1) {
-    cb = mgr->state->final_cb;
-    user_data = mgr->state->final_user_data;
-  }
-  // Invoke handshaker.
-  grpc_handshaker_do_handshake(
-      exec_ctx, mgr->handshakers[mgr->state->index], endpoint, args,
-      read_buffer, mgr->state->deadline, mgr->state->acceptor, cb, user_data);
-  ++mgr->state->index;
-  // If this is the last handshaker, clean up state.
-  if (mgr->state->index == mgr->count) {
-    gpr_free(mgr->state);
-    mgr->state = NULL;
+}
+
+// Callback invoked when deadline is exceeded.
+static void on_timeout(grpc_exec_ctx* exec_ctx, void* arg, grpc_error* error) {
+  grpc_handshake_manager* mgr = arg;
+  if (error == GRPC_ERROR_NONE) {  // Timer fired, rather than being cancelled.
+    grpc_handshake_manager_shutdown(exec_ctx, mgr);
   }
+  grpc_handshake_manager_unref(exec_ctx, mgr);
 }
 
 void grpc_handshake_manager_do_handshake(
     grpc_exec_ctx* exec_ctx, grpc_handshake_manager* mgr,
-    grpc_endpoint* endpoint, const grpc_channel_args* args,
+    grpc_endpoint* endpoint, const grpc_channel_args* channel_args,
     gpr_timespec deadline, grpc_tcp_server_acceptor* acceptor,
-    grpc_handshaker_done_cb cb, void* user_data) {
-  grpc_channel_args* args_copy = grpc_channel_args_copy(args);
-  grpc_slice_buffer* read_buffer = gpr_malloc(sizeof(*read_buffer));
-  grpc_slice_buffer_init(read_buffer);
-  if (mgr->count == 0) {
-    // No handshakers registered, so we just immediately call the done
-    // callback with the passed-in endpoint.
-    cb(exec_ctx, endpoint, args_copy, read_buffer, user_data, GRPC_ERROR_NONE);
-  } else {
-    GPR_ASSERT(mgr->state == NULL);
-    mgr->state = gpr_malloc(sizeof(struct grpc_handshaker_state));
-    memset(mgr->state, 0, sizeof(*mgr->state));
-    mgr->state->deadline = deadline;
-    mgr->state->acceptor = acceptor;
-    mgr->state->final_cb = cb;
-    mgr->state->final_user_data = user_data;
-    call_next_handshaker(exec_ctx, endpoint, args_copy, read_buffer, mgr,
-                         GRPC_ERROR_NONE);
+    grpc_iomgr_cb_func on_handshake_done, void* user_data) {
+  gpr_mu_lock(&mgr->mu);
+  GPR_ASSERT(mgr->index == 0);
+  GPR_ASSERT(!mgr->shutdown);
+  // Construct handshaker args.  These will be passed through all
+  // handshakers and eventually be freed by the on_handshake_done callback.
+  mgr->args.endpoint = endpoint;
+  mgr->args.args = grpc_channel_args_copy(channel_args);
+  mgr->args.user_data = user_data;
+  mgr->args.read_buffer = gpr_malloc(sizeof(*mgr->args.read_buffer));
+  grpc_slice_buffer_init(mgr->args.read_buffer);
+  // Initialize state needed for calling handshakers.
+  mgr->acceptor = acceptor;
+  grpc_closure_init(&mgr->call_next_handshaker, call_next_handshaker, mgr,
+                    grpc_schedule_on_exec_ctx);
+  grpc_closure_init(&mgr->on_handshake_done, on_handshake_done, &mgr->args,
+                    grpc_schedule_on_exec_ctx);
+  // Start deadline timer, which owns a ref.
+  gpr_ref(&mgr->refs);
+  grpc_closure_init(&mgr->on_timeout, on_timeout, mgr,
+                    grpc_schedule_on_exec_ctx);
+  grpc_timer_init(exec_ctx, &mgr->deadline_timer,
+                  gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC),
+                  &mgr->on_timeout, gpr_now(GPR_CLOCK_MONOTONIC));
+  // Start first handshaker, which also owns a ref.
+  gpr_ref(&mgr->refs);
+  bool done = call_next_handshaker_locked(exec_ctx, mgr, GRPC_ERROR_NONE);
+  gpr_mu_unlock(&mgr->mu);
+  if (done) {
+    grpc_handshake_manager_unref(exec_ctx, mgr);
   }
 }
diff --git a/src/core/lib/channel/handshaker.h b/src/core/lib/channel/handshaker.h
index f8a36c6473..450b7adaee 100644
--- a/src/core/lib/channel/handshaker.h
+++ b/src/core/lib/channel/handshaker.h
@@ -54,15 +54,33 @@
 
 typedef struct grpc_handshaker grpc_handshaker;
 
-/// Callback type invoked when a handshaker is done.
-/// Takes ownership of \a args and \a read_buffer.
-typedef void (*grpc_handshaker_done_cb)(grpc_exec_ctx* exec_ctx,
-                                        grpc_endpoint* endpoint,
-                                        grpc_channel_args* args,
-                                        grpc_slice_buffer* read_buffer,
-                                        void* user_data, grpc_error* error);
-
-struct grpc_handshaker_vtable {
+/// Arguments passed through handshakers and to the on_handshake_done callback.
+///
+/// For handshakers, all members are input/output parameters; for
+/// example, a handshaker may read from or write to \a endpoint and
+/// then later replace it with a wrapped endpoint.  Similarly, a
+/// handshaker may modify \a args.
+///
+/// A handshaker takes ownership of the members while a handshake is in
+/// progress.  Upon failure or shutdown of an in-progress handshaker,
+/// the handshaker is responsible for destroying the members and setting
+/// them to NULL before invoking the on_handshake_done callback.
+///
+/// For the on_handshake_done callback, all members are input arguments,
+/// which the callback takes ownership of.
+typedef struct {
+  grpc_endpoint* endpoint;
+  grpc_channel_args* args;
+  grpc_slice_buffer* read_buffer;
+  // A handshaker may set this to true before invoking on_handshake_done
+  // to indicate that subsequent handshakers should be skipped.
+  bool exit_early;
+  // User data passed through the handshake manager.  Not used by
+  // individual handshakers.
+  void* user_data;
+} grpc_handshaker_args;
+
+typedef struct {
   /// Destroys the handshaker.
   void (*destroy)(grpc_exec_ctx* exec_ctx, grpc_handshaker* handshaker);
 
@@ -70,43 +88,35 @@ struct grpc_handshaker_vtable {
   /// aborted in the middle).
   void (*shutdown)(grpc_exec_ctx* exec_ctx, grpc_handshaker* handshaker);
 
-  /// Performs handshaking.  When finished, calls \a cb with \a user_data.
-  /// Takes ownership of \a args.
-  /// Takes ownership of \a read_buffer, which contains leftover bytes read
-  /// from the endpoint by the previous handshaker.
+  /// Performs handshaking, modifying \a args as needed (e.g., to
+  /// replace \a endpoint with a wrapped endpoint).
+  /// When finished, invokes \a on_handshake_done.
   /// \a acceptor will be NULL for client-side handshakers.
   void (*do_handshake)(grpc_exec_ctx* exec_ctx, grpc_handshaker* handshaker,
-                       grpc_endpoint* endpoint, grpc_channel_args* args,
-                       grpc_slice_buffer* read_buffer, gpr_timespec deadline,
                        grpc_tcp_server_acceptor* acceptor,
-                       grpc_handshaker_done_cb cb, void* user_data);
-};
+                       grpc_closure* on_handshake_done,
+                       grpc_handshaker_args* args);
+} grpc_handshaker_vtable;
 
 /// Base struct.  To subclass, make this the first member of the
 /// implementation struct.
 struct grpc_handshaker {
-  const struct grpc_handshaker_vtable* vtable;
+  const grpc_handshaker_vtable* vtable;
 };
 
 /// Called by concrete implementations to initialize the base struct.
-void grpc_handshaker_init(const struct grpc_handshaker_vtable* vtable,
+void grpc_handshaker_init(const grpc_handshaker_vtable* vtable,
                           grpc_handshaker* handshaker);
 
-/// Convenient wrappers for invoking methods via the vtable.
-/// These probably do not need to be called from anywhere but
-/// grpc_handshake_manager.
 void grpc_handshaker_destroy(grpc_exec_ctx* exec_ctx,
                              grpc_handshaker* handshaker);
 void grpc_handshaker_shutdown(grpc_exec_ctx* exec_ctx,
                               grpc_handshaker* handshaker);
 void grpc_handshaker_do_handshake(grpc_exec_ctx* exec_ctx,
                                   grpc_handshaker* handshaker,
-                                  grpc_endpoint* endpoint,
-                                  grpc_channel_args* args,
-                                  grpc_slice_buffer* read_buffer,
-                                  gpr_timespec deadline,
                                   grpc_tcp_server_acceptor* acceptor,
-                                  grpc_handshaker_done_cb cb, void* user_data);
+                                  grpc_closure* on_handshake_done,
+                                  grpc_handshaker_args* args);
 
 ///
 /// grpc_handshake_manager
@@ -134,15 +144,21 @@ void grpc_handshake_manager_shutdown(grpc_exec_ctx* exec_ctx,
                                      grpc_handshake_manager* mgr);
 
 /// Invokes handshakers in the order they were added.
-/// Does NOT take ownership of \a args.  Instead, makes a copy before
+/// Takes ownership of \a endpoint, and then passes that ownership to
+/// the \a on_handshake_done callback.
+/// Does NOT take ownership of \a channel_args.  Instead, makes a copy before
 /// invoking the first handshaker.
 /// \a acceptor will be NULL for client-side handshakers.
-/// Invokes \a cb with \a user_data after either a handshaker fails or
-/// all handshakers have completed successfully.
+///
+/// When done, invokes \a on_handshake_done with a grpc_handshaker_args
+/// object as its argument.  If the callback is invoked with error !=
+/// GRPC_ERROR_NONE, then handshaking failed and the handshaker has done
+/// the necessary clean-up.  Otherwise, the callback takes ownership of
+/// the arguments.
 void grpc_handshake_manager_do_handshake(
     grpc_exec_ctx* exec_ctx, grpc_handshake_manager* mgr,
-    grpc_endpoint* endpoint, const grpc_channel_args* args,
+    grpc_endpoint* endpoint, const grpc_channel_args* channel_args,
     gpr_timespec deadline, grpc_tcp_server_acceptor* acceptor,
-    grpc_handshaker_done_cb cb, void* user_data);
+    grpc_iomgr_cb_func on_handshake_done, void* user_data);
 
 #endif /* GRPC_CORE_LIB_CHANNEL_HANDSHAKER_H */
diff --git a/src/core/lib/channel/handshaker_factory.c b/src/core/lib/channel/handshaker_factory.c
new file mode 100644
index 0000000000..3c30a4e1d2
--- /dev/null
+++ b/src/core/lib/channel/handshaker_factory.c
@@ -0,0 +1,54 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/lib/channel/handshaker_factory.h"
+
+#include <grpc/support/log.h>
+
+void grpc_handshaker_factory_add_handshakers(
+    grpc_exec_ctx *exec_ctx, grpc_handshaker_factory *handshaker_factory,
+    const grpc_channel_args *args, grpc_handshake_manager *handshake_mgr) {
+  if (handshaker_factory != NULL) {
+    GPR_ASSERT(handshaker_factory->vtable != NULL);
+    handshaker_factory->vtable->add_handshakers(exec_ctx, handshaker_factory,
+                                                args, handshake_mgr);
+  }
+}
+
+void grpc_handshaker_factory_destroy(
+    grpc_exec_ctx *exec_ctx, grpc_handshaker_factory *handshaker_factory) {
+  if (handshaker_factory != NULL) {
+    GPR_ASSERT(handshaker_factory->vtable != NULL);
+    handshaker_factory->vtable->destroy(exec_ctx, handshaker_factory);
+  }
+}
diff --git a/src/core/lib/channel/handshaker_factory.h b/src/core/lib/channel/handshaker_factory.h
new file mode 100644
index 0000000000..1984546104
--- /dev/null
+++ b/src/core/lib/channel/handshaker_factory.h
@@ -0,0 +1,66 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_CHANNEL_HANDSHAKER_FACTORY_H
+#define GRPC_CORE_LIB_CHANNEL_HANDSHAKER_FACTORY_H
+
+#include <grpc/impl/codegen/grpc_types.h>
+
+#include "src/core/lib/channel/handshaker.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
+
+// A handshaker factory is used to create handshakers.
+
+typedef struct grpc_handshaker_factory grpc_handshaker_factory;
+
+typedef struct {
+  void (*add_handshakers)(grpc_exec_ctx *exec_ctx,
+                          grpc_handshaker_factory *handshaker_factory,
+                          const grpc_channel_args *args,
+                          grpc_handshake_manager *handshake_mgr);
+  void (*destroy)(grpc_exec_ctx *exec_ctx,
+                  grpc_handshaker_factory *handshaker_factory);
+} grpc_handshaker_factory_vtable;
+
+struct grpc_handshaker_factory {
+  const grpc_handshaker_factory_vtable *vtable;
+};
+
+void grpc_handshaker_factory_add_handshakers(
+    grpc_exec_ctx *exec_ctx, grpc_handshaker_factory *handshaker_factory,
+    const grpc_channel_args *args, grpc_handshake_manager *handshake_mgr);
+
+void grpc_handshaker_factory_destroy(
+    grpc_exec_ctx *exec_ctx, grpc_handshaker_factory *handshaker_factory);
+
+#endif /* GRPC_CORE_LIB_CHANNEL_HANDSHAKER_FACTORY_H */
diff --git a/src/core/lib/channel/handshaker_registry.c b/src/core/lib/channel/handshaker_registry.c
new file mode 100644
index 0000000000..2e5f04064c
--- /dev/null
+++ b/src/core/lib/channel/handshaker_registry.c
@@ -0,0 +1,113 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/lib/channel/handshaker_registry.h"
+
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+
+//
+// grpc_handshaker_factory_list
+//
+
+typedef struct {
+  grpc_handshaker_factory** list;
+  size_t num_factories;
+} grpc_handshaker_factory_list;
+
+static void grpc_handshaker_factory_list_register(
+    grpc_handshaker_factory_list* list, bool at_start,
+    grpc_handshaker_factory* factory) {
+  list->list = gpr_realloc(
+      list->list, (list->num_factories + 1) * sizeof(grpc_handshaker_factory*));
+  if (at_start) {
+    memmove(list->list + 1, list->list,
+            sizeof(grpc_handshaker_factory*) * list->num_factories);
+    list->list[0] = factory;
+  } else {
+    list->list[list->num_factories] = factory;
+  }
+  ++list->num_factories;
+}
+
+static void grpc_handshaker_factory_list_add_handshakers(
+    grpc_exec_ctx* exec_ctx, grpc_handshaker_factory_list* list,
+    const grpc_channel_args* args, grpc_handshake_manager* handshake_mgr) {
+  for (size_t i = 0; i < list->num_factories; ++i) {
+    grpc_handshaker_factory_add_handshakers(exec_ctx, list->list[i], args,
+                                            handshake_mgr);
+  }
+}
+
+static void grpc_handshaker_factory_list_destroy(
+    grpc_exec_ctx* exec_ctx, grpc_handshaker_factory_list* list) {
+  for (size_t i = 0; i < list->num_factories; ++i) {
+    grpc_handshaker_factory_destroy(exec_ctx, list->list[i]);
+  }
+  gpr_free(list->list);
+}
+
+//
+// plugin
+//
+
+static grpc_handshaker_factory_list
+    g_handshaker_factory_lists[NUM_HANDSHAKER_TYPES];
+
+void grpc_handshaker_factory_registry_init() {
+  memset(g_handshaker_factory_lists, 0, sizeof(g_handshaker_factory_lists));
+}
+
+void grpc_handshaker_factory_registry_shutdown(grpc_exec_ctx* exec_ctx) {
+  for (size_t i = 0; i < NUM_HANDSHAKER_TYPES; ++i) {
+    grpc_handshaker_factory_list_destroy(exec_ctx,
+                                         &g_handshaker_factory_lists[i]);
+  }
+}
+
+void grpc_handshaker_factory_register(bool at_start,
+                                      grpc_handshaker_type handshaker_type,
+                                      grpc_handshaker_factory* factory) {
+  grpc_handshaker_factory_list_register(
+      &g_handshaker_factory_lists[handshaker_type], at_start, factory);
+}
+
+void grpc_handshakers_add(grpc_exec_ctx* exec_ctx,
+                          grpc_handshaker_type handshaker_type,
+                          const grpc_channel_args* args,
+                          grpc_handshake_manager* handshake_mgr) {
+  grpc_handshaker_factory_list_add_handshakers(
+      exec_ctx, &g_handshaker_factory_lists[handshaker_type], args,
+      handshake_mgr);
+}
diff --git a/src/core/lib/channel/handshaker_registry.h b/src/core/lib/channel/handshaker_registry.h
new file mode 100644
index 0000000000..53c1b173af
--- /dev/null
+++ b/src/core/lib/channel/handshaker_registry.h
@@ -0,0 +1,63 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_CHANNEL_HANDSHAKER_REGISTRY_H
+#define GRPC_CORE_LIB_CHANNEL_HANDSHAKER_REGISTRY_H
+
+#include <grpc/impl/codegen/grpc_types.h>
+
+#include "src/core/lib/channel/handshaker_factory.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
+
+typedef enum {
+  HANDSHAKER_CLIENT = 0,
+  HANDSHAKER_SERVER,
+  NUM_HANDSHAKER_TYPES,  // Must be last.
+} grpc_handshaker_type;
+
+void grpc_handshaker_factory_registry_init();
+void grpc_handshaker_factory_registry_shutdown(grpc_exec_ctx* exec_ctx);
+
+/// Registers a new handshaker factory.  Takes ownership.
+/// If \a at_start is true, the new handshaker will be at the beginning of
+/// the list.  Otherwise, it will be added to the end.
+void grpc_handshaker_factory_register(bool at_start,
+                                      grpc_handshaker_type handshaker_type,
+                                      grpc_handshaker_factory* factory);
+
+void grpc_handshakers_add(grpc_exec_ctx* exec_ctx,
+                          grpc_handshaker_type handshaker_type,
+                          const grpc_channel_args* args,
+                          grpc_handshake_manager* handshake_mgr);
+
+#endif /* GRPC_CORE_LIB_CHANNEL_HANDSHAKER_REGISTRY_H */
diff --git a/src/core/lib/channel/http_client_filter.c b/src/core/lib/channel/http_client_filter.c
index fd8b46afcb..d154450988 100644
--- a/src/core/lib/channel/http_client_filter.c
+++ b/src/core/lib/channel/http_client_filter.c
@@ -37,6 +37,7 @@
 #include <string.h>
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/slice/percent_encoding.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/transport/static_metadata.h"
 #include "src/core/lib/transport/transport_impl.h"
@@ -92,13 +93,9 @@ typedef struct channel_data {
   size_t max_payload_size_for_get;
 } channel_data;
 
-typedef struct {
-  grpc_call_element *elem;
-  grpc_exec_ctx *exec_ctx;
-} client_recv_filter_args;
-
-static grpc_mdelem *client_recv_filter(void *user_data, grpc_mdelem *md) {
-  client_recv_filter_args *a = user_data;
+static grpc_mdelem *client_recv_filter(grpc_exec_ctx *exec_ctx, void *user_data,
+                                       grpc_mdelem *md) {
+  grpc_call_element *elem = user_data;
   if (md == GRPC_MDELEM_STATUS_200) {
     return NULL;
   } else if (md->key == GRPC_MDSTR_STATUS) {
@@ -107,18 +104,19 @@ static grpc_mdelem *client_recv_filter(void *user_data, grpc_mdelem *md) {
                  grpc_mdstr_as_c_string(md->value));
     grpc_slice message = grpc_slice_from_copied_string(message_string);
     gpr_free(message_string);
-    grpc_call_element_send_close_with_message(a->exec_ctx, a->elem,
+    grpc_call_element_send_close_with_message(exec_ctx, elem,
                                               GRPC_STATUS_CANCELLED, &message);
     return NULL;
   } else if (md->key == GRPC_MDSTR_GRPC_MESSAGE) {
     grpc_slice pct_decoded_msg =
         grpc_permissive_percent_decode_slice(md->value->slice);
     if (grpc_slice_is_equivalent(pct_decoded_msg, md->value->slice)) {
-      grpc_slice_unref(pct_decoded_msg);
+      grpc_slice_unref_internal(exec_ctx, pct_decoded_msg);
       return md;
     } else {
       return grpc_mdelem_from_metadata_strings(
-          GRPC_MDSTR_GRPC_MESSAGE, grpc_mdstr_from_slice(pct_decoded_msg));
+          exec_ctx, GRPC_MDSTR_GRPC_MESSAGE,
+          grpc_mdstr_from_slice(exec_ctx, pct_decoded_msg));
     }
   } else if (md == GRPC_MDELEM_CONTENT_TYPE_APPLICATION_SLASH_GRPC) {
     return NULL;
@@ -147,11 +145,8 @@ static void hc_on_recv_initial_metadata(grpc_exec_ctx *exec_ctx,
                                         void *user_data, grpc_error *error) {
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
-  client_recv_filter_args a;
-  a.elem = elem;
-  a.exec_ctx = exec_ctx;
-  grpc_metadata_batch_filter(calld->recv_initial_metadata, client_recv_filter,
-                             &a);
+  grpc_metadata_batch_filter(exec_ctx, calld->recv_initial_metadata,
+                             client_recv_filter, elem);
   grpc_closure_run(exec_ctx, calld->on_done_recv_initial_metadata,
                    GRPC_ERROR_REF(error));
 }
@@ -160,11 +155,8 @@ static void hc_on_recv_trailing_metadata(grpc_exec_ctx *exec_ctx,
                                          void *user_data, grpc_error *error) {
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
-  client_recv_filter_args a;
-  a.elem = elem;
-  a.exec_ctx = exec_ctx;
-  grpc_metadata_batch_filter(calld->recv_trailing_metadata, client_recv_filter,
-                             &a);
+  grpc_metadata_batch_filter(exec_ctx, calld->recv_trailing_metadata,
+                             client_recv_filter, elem);
   grpc_closure_run(exec_ctx, calld->on_done_recv_trailing_metadata,
                    GRPC_ERROR_REF(error));
 }
@@ -183,11 +175,12 @@ static void hc_on_complete(grpc_exec_ctx *exec_ctx, void *user_data,
 static void send_done(grpc_exec_ctx *exec_ctx, void *elemp, grpc_error *error) {
   grpc_call_element *elem = elemp;
   call_data *calld = elem->call_data;
-  grpc_slice_buffer_reset_and_unref(&calld->slices);
+  grpc_slice_buffer_reset_and_unref_internal(exec_ctx, &calld->slices);
   calld->post_send->cb(exec_ctx, calld->post_send->cb_arg, error);
 }
 
-static grpc_mdelem *client_strip_filter(void *user_data, grpc_mdelem *md) {
+static grpc_mdelem *client_strip_filter(grpc_exec_ctx *exec_ctx,
+                                        void *user_data, grpc_mdelem *md) {
   /* eat the things we'd like to set ourselves */
   if (md->key == GRPC_MDSTR_METHOD) return NULL;
   if (md->key == GRPC_MDSTR_SCHEME) return NULL;
@@ -275,7 +268,7 @@ static void hc_mutate_op(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
         /* when all the send_message data is available, then create a MDELEM and
         append to headers */
         grpc_mdelem *payload_bin = grpc_mdelem_from_metadata_strings(
-            GRPC_MDSTR_GRPC_PAYLOAD_BIN,
+            exec_ctx, GRPC_MDSTR_GRPC_PAYLOAD_BIN,
             grpc_mdstr_from_buffer(calld->payload_bytes,
                                    op->send_message->length));
         grpc_metadata_batch_add_tail(op->send_initial_metadata,
@@ -292,8 +285,8 @@ static void hc_mutate_op(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
       }
     }
 
-    grpc_metadata_batch_filter(op->send_initial_metadata, client_strip_filter,
-                               elem);
+    grpc_metadata_batch_filter(exec_ctx, op->send_initial_metadata,
+                               client_strip_filter, elem);
     /* Send : prefixed headers, which have to be before any application
        layer headers. */
     grpc_metadata_batch_add_head(op->send_initial_metadata, &calld->method,
@@ -352,12 +345,17 @@ static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx,
   calld->send_message_blocked = false;
   grpc_slice_buffer_init(&calld->slices);
   grpc_closure_init(&calld->hc_on_recv_initial_metadata,
-                    hc_on_recv_initial_metadata, elem);
+                    hc_on_recv_initial_metadata, elem,
+                    grpc_schedule_on_exec_ctx);
   grpc_closure_init(&calld->hc_on_recv_trailing_metadata,
-                    hc_on_recv_trailing_metadata, elem);
-  grpc_closure_init(&calld->hc_on_complete, hc_on_complete, elem);
-  grpc_closure_init(&calld->got_slice, got_slice, elem);
-  grpc_closure_init(&calld->send_done, send_done, elem);
+                    hc_on_recv_trailing_metadata, elem,
+                    grpc_schedule_on_exec_ctx);
+  grpc_closure_init(&calld->hc_on_complete, hc_on_complete, elem,
+                    grpc_schedule_on_exec_ctx);
+  grpc_closure_init(&calld->got_slice, got_slice, elem,
+                    grpc_schedule_on_exec_ctx);
+  grpc_closure_init(&calld->send_done, send_done, elem,
+                    grpc_schedule_on_exec_ctx);
   return GRPC_ERROR_NONE;
 }
 
@@ -366,7 +364,7 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
                               const grpc_call_final_info *final_info,
                               void *ignored) {
   call_data *calld = elem->call_data;
-  grpc_slice_buffer_destroy(&calld->slices);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &calld->slices);
 }
 
 static grpc_mdelem *scheme_from_args(const grpc_channel_args *args) {
@@ -457,9 +455,9 @@ static grpc_mdstr *user_agent_from_args(const grpc_channel_args *args,
 }
 
 /* Constructor for channel_data */
-static void init_channel_elem(grpc_exec_ctx *exec_ctx,
-                              grpc_channel_element *elem,
-                              grpc_channel_element_args *args) {
+static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
+                                     grpc_channel_element *elem,
+                                     grpc_channel_element_args *args) {
   channel_data *chand = elem->channel_data;
   GPR_ASSERT(!args->is_last);
   GPR_ASSERT(args->optional_transport != NULL);
@@ -467,16 +465,17 @@ static void init_channel_elem(grpc_exec_ctx *exec_ctx,
   chand->max_payload_size_for_get =
       max_payload_size_from_args(args->channel_args);
   chand->user_agent = grpc_mdelem_from_metadata_strings(
-      GRPC_MDSTR_USER_AGENT,
+      exec_ctx, GRPC_MDSTR_USER_AGENT,
       user_agent_from_args(args->channel_args,
                            args->optional_transport->vtable->name));
+  return GRPC_ERROR_NONE;
 }
 
 /* Destructor for channel data */
 static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
                                  grpc_channel_element *elem) {
   channel_data *chand = elem->channel_data;
-  GRPC_MDELEM_UNREF(chand->user_agent);
+  GRPC_MDELEM_UNREF(exec_ctx, chand->user_agent);
 }
 
 const grpc_channel_filter grpc_http_client_filter = {
diff --git a/src/core/lib/channel/http_server_filter.c b/src/core/lib/channel/http_server_filter.c
index b42ff06039..f508231238 100644
--- a/src/core/lib/channel/http_server_filter.c
+++ b/src/core/lib/channel/http_server_filter.c
@@ -38,6 +38,7 @@
 #include <string.h>
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/slice/percent_encoding.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/transport/static_metadata.h"
 
 #define EXPECTED_CONTENT_TYPE "application/grpc"
@@ -82,31 +83,28 @@ typedef struct call_data {
 
 typedef struct channel_data { uint8_t unused; } channel_data;
 
-typedef struct {
-  grpc_call_element *elem;
-  grpc_exec_ctx *exec_ctx;
-} server_filter_args;
-
-static grpc_mdelem *server_filter_outgoing_metadata(void *user_data,
+static grpc_mdelem *server_filter_outgoing_metadata(grpc_exec_ctx *exec_ctx,
+                                                    void *user_data,
                                                     grpc_mdelem *md) {
   if (md->key == GRPC_MDSTR_GRPC_MESSAGE) {
     grpc_slice pct_encoded_msg = grpc_percent_encode_slice(
         md->value->slice, grpc_compatible_percent_encoding_unreserved_bytes);
     if (grpc_slice_is_equivalent(pct_encoded_msg, md->value->slice)) {
-      grpc_slice_unref(pct_encoded_msg);
+      grpc_slice_unref_internal(exec_ctx, pct_encoded_msg);
       return md;
     } else {
       return grpc_mdelem_from_metadata_strings(
-          GRPC_MDSTR_GRPC_MESSAGE, grpc_mdstr_from_slice(pct_encoded_msg));
+          exec_ctx, GRPC_MDSTR_GRPC_MESSAGE,
+          grpc_mdstr_from_slice(exec_ctx, pct_encoded_msg));
     }
   } else {
     return md;
   }
 }
 
-static grpc_mdelem *server_filter(void *user_data, grpc_mdelem *md) {
-  server_filter_args *a = user_data;
-  grpc_call_element *elem = a->elem;
+static grpc_mdelem *server_filter(grpc_exec_ctx *exec_ctx, void *user_data,
+                                  grpc_mdelem *md) {
+  grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
 
   /* Check if it is one of the headers we care about. */
@@ -157,7 +155,7 @@ static grpc_mdelem *server_filter(void *user_data, grpc_mdelem *md) {
     /* swallow it and error everything out. */
     /* TODO(klempner): We ought to generate more descriptive error messages
        on the wire here. */
-    grpc_call_element_send_cancel(a->exec_ctx, elem);
+    grpc_call_element_send_cancel(exec_ctx, elem);
     return NULL;
   } else if (md->key == GRPC_MDSTR_PATH) {
     if (calld->seen_path) {
@@ -173,7 +171,7 @@ static grpc_mdelem *server_filter(void *user_data, grpc_mdelem *md) {
     /* translate host to :authority since :authority may be
        omitted */
     grpc_mdelem *authority = grpc_mdelem_from_metadata_strings(
-        GRPC_MDSTR_AUTHORITY, GRPC_MDSTR_REF(md->value));
+        exec_ctx, GRPC_MDSTR_AUTHORITY, GRPC_MDSTR_REF(md->value));
     calld->seen_authority = 1;
     return authority;
   } else if (md->key == GRPC_MDSTR_GRPC_PAYLOAD_BIN) {
@@ -181,7 +179,7 @@ static grpc_mdelem *server_filter(void *user_data, grpc_mdelem *md) {
        header field */
     calld->seen_payload_bin = 1;
     grpc_slice_buffer_add(&calld->read_slice_buffer,
-                          grpc_slice_ref(md->value->slice));
+                          grpc_slice_ref_internal(md->value->slice));
     grpc_slice_buffer_stream_init(&calld->read_stream,
                                   &calld->read_slice_buffer, 0);
     return NULL;
@@ -195,10 +193,8 @@ static void hs_on_recv(grpc_exec_ctx *exec_ctx, void *user_data,
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
   if (err == GRPC_ERROR_NONE) {
-    server_filter_args a;
-    a.elem = elem;
-    a.exec_ctx = exec_ctx;
-    grpc_metadata_batch_filter(calld->recv_initial_metadata, server_filter, &a);
+    grpc_metadata_batch_filter(exec_ctx, calld->recv_initial_metadata,
+                               server_filter, elem);
     /* Have we seen the required http2 transport headers?
        (:method, :scheme, content-type, with :path and :authority covered
        at the channel level right now) */
@@ -310,9 +306,8 @@ static void hs_mutate_op(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
   }
 
   if (op->send_trailing_metadata) {
-    server_filter_args a = {elem, exec_ctx};
-    grpc_metadata_batch_filter(op->send_trailing_metadata,
-                               server_filter_outgoing_metadata, &a);
+    grpc_metadata_batch_filter(exec_ctx, op->send_trailing_metadata,
+                               server_filter_outgoing_metadata, elem);
   }
 }
 
@@ -334,9 +329,12 @@ static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx,
   call_data *calld = elem->call_data;
   /* initialize members */
   memset(calld, 0, sizeof(*calld));
-  grpc_closure_init(&calld->hs_on_recv, hs_on_recv, elem);
-  grpc_closure_init(&calld->hs_on_complete, hs_on_complete, elem);
-  grpc_closure_init(&calld->hs_recv_message_ready, hs_recv_message_ready, elem);
+  grpc_closure_init(&calld->hs_on_recv, hs_on_recv, elem,
+                    grpc_schedule_on_exec_ctx);
+  grpc_closure_init(&calld->hs_on_complete, hs_on_complete, elem,
+                    grpc_schedule_on_exec_ctx);
+  grpc_closure_init(&calld->hs_recv_message_ready, hs_recv_message_ready, elem,
+                    grpc_schedule_on_exec_ctx);
   grpc_slice_buffer_init(&calld->read_slice_buffer);
   return GRPC_ERROR_NONE;
 }
@@ -346,14 +344,15 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
                               const grpc_call_final_info *final_info,
                               void *ignored) {
   call_data *calld = elem->call_data;
-  grpc_slice_buffer_destroy(&calld->read_slice_buffer);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &calld->read_slice_buffer);
 }
 
 /* Constructor for channel_data */
-static void init_channel_elem(grpc_exec_ctx *exec_ctx,
-                              grpc_channel_element *elem,
-                              grpc_channel_element_args *args) {
+static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
+                                     grpc_channel_element *elem,
+                                     grpc_channel_element_args *args) {
   GPR_ASSERT(!args->is_last);
+  return GRPC_ERROR_NONE;
 }
 
 /* Destructor for channel data */
diff --git a/src/core/lib/channel/message_size_filter.c b/src/core/lib/channel/message_size_filter.c
index 1cf68d790d..862090b371 100644
--- a/src/core/lib/channel/message_size_filter.c
+++ b/src/core/lib/channel/message_size_filter.c
@@ -54,8 +54,12 @@ static void* message_size_limits_copy(void* value) {
   return new_value;
 }
 
+static void message_size_limits_free(grpc_exec_ctx* exec_ctx, void* value) {
+  gpr_free(value);
+}
+
 static const grpc_mdstr_hash_table_vtable message_size_limits_vtable = {
-    gpr_free, message_size_limits_copy};
+    message_size_limits_free, message_size_limits_copy};
 
 static void* message_size_limits_create_from_json(const grpc_json* json) {
   int max_request_message_bytes = -1;
@@ -124,7 +128,7 @@ static void recv_message_ready(grpc_exec_ctx* exec_ctx, void* user_data,
     gpr_free(message_string);
   }
   // Invoke the next callback.
-  grpc_exec_ctx_sched(exec_ctx, calld->next_recv_message_ready, error, NULL);
+  grpc_closure_sched(exec_ctx, calld->next_recv_message_ready, error);
 }
 
 // Start transport stream op.
@@ -160,7 +164,8 @@ static grpc_error* init_call_elem(grpc_exec_ctx* exec_ctx,
   channel_data* chand = elem->channel_data;
   call_data* calld = elem->call_data;
   calld->next_recv_message_ready = NULL;
-  grpc_closure_init(&calld->recv_message_ready, recv_message_ready, elem);
+  grpc_closure_init(&calld->recv_message_ready, recv_message_ready, elem,
+                    grpc_schedule_on_exec_ctx);
   // Get max sizes from channel data, then merge in per-method config values.
   // Note: Per-method config is only available on the client, so we
   // apply the max request size to the send limit and the max response
@@ -168,8 +173,8 @@ static grpc_error* init_call_elem(grpc_exec_ctx* exec_ctx,
   calld->max_send_size = chand->max_send_size;
   calld->max_recv_size = chand->max_recv_size;
   if (chand->method_limit_table != NULL) {
-    message_size_limits* limits =
-        grpc_method_config_table_get(chand->method_limit_table, args->path);
+    message_size_limits* limits = grpc_method_config_table_get(
+        exec_ctx, chand->method_limit_table, args->path);
     if (limits != NULL) {
       if (limits->max_send_size >= 0 &&
           (limits->max_send_size < calld->max_send_size ||
@@ -192,9 +197,9 @@ static void destroy_call_elem(grpc_exec_ctx* exec_ctx, grpc_call_element* elem,
                               void* ignored) {}
 
 // Constructor for channel_data.
-static void init_channel_elem(grpc_exec_ctx* exec_ctx,
-                              grpc_channel_element* elem,
-                              grpc_channel_element_args* args) {
+static grpc_error* init_channel_elem(grpc_exec_ctx* exec_ctx,
+                                     grpc_channel_element* elem,
+                                     grpc_channel_element_args* args) {
   GPR_ASSERT(!args->is_last);
   channel_data* chand = elem->channel_data;
   memset(chand, 0, sizeof(*chand));
@@ -226,18 +231,19 @@ static void init_channel_elem(grpc_exec_ctx* exec_ctx,
     if (service_config != NULL) {
       chand->method_limit_table =
           grpc_service_config_create_method_config_table(
-              service_config, message_size_limits_create_from_json,
+              exec_ctx, service_config, message_size_limits_create_from_json,
               &message_size_limits_vtable);
       grpc_service_config_destroy(service_config);
     }
   }
+  return GRPC_ERROR_NONE;
 }
 
 // Destructor for channel_data.
 static void destroy_channel_elem(grpc_exec_ctx* exec_ctx,
                                  grpc_channel_element* elem) {
   channel_data* chand = elem->channel_data;
-  grpc_mdstr_hash_table_unref(chand->method_limit_table);
+  grpc_mdstr_hash_table_unref(exec_ctx, chand->method_limit_table);
 }
 
 const grpc_channel_filter grpc_message_size_filter = {
diff --git a/src/core/lib/compression/message_compress.c b/src/core/lib/compression/message_compress.c
index 6c245acf61..49beb953b0 100644
--- a/src/core/lib/compression/message_compress.c
+++ b/src/core/lib/compression/message_compress.c
@@ -40,10 +40,12 @@
 
 #include <zlib.h>
 
+#include "src/core/lib/slice/slice_internal.h"
+
 #define OUTPUT_BLOCK_SIZE 1024
 
-static int zlib_body(z_stream* zs, grpc_slice_buffer* input,
-                     grpc_slice_buffer* output,
+static int zlib_body(grpc_exec_ctx* exec_ctx, z_stream* zs,
+                     grpc_slice_buffer* input, grpc_slice_buffer* output,
                      int (*flate)(z_stream* zs, int flush)) {
   int r;
   int flush;
@@ -87,7 +89,7 @@ static int zlib_body(z_stream* zs, grpc_slice_buffer* input,
   return 1;
 
 error:
-  grpc_slice_unref(outbuf);
+  grpc_slice_unref_internal(exec_ctx, outbuf);
   return 0;
 }
 
@@ -97,8 +99,8 @@ static void* zalloc_gpr(void* opaque, unsigned int items, unsigned int size) {
 
 static void zfree_gpr(void* opaque, void* address) { gpr_free(address); }
 
-static int zlib_compress(grpc_slice_buffer* input, grpc_slice_buffer* output,
-                         int gzip) {
+static int zlib_compress(grpc_exec_ctx* exec_ctx, grpc_slice_buffer* input,
+                         grpc_slice_buffer* output, int gzip) {
   z_stream zs;
   int r;
   size_t i;
@@ -110,10 +112,11 @@ static int zlib_compress(grpc_slice_buffer* input, grpc_slice_buffer* output,
   r = deflateInit2(&zs, Z_DEFAULT_COMPRESSION, Z_DEFLATED, 15 | (gzip ? 16 : 0),
                    8, Z_DEFAULT_STRATEGY);
   GPR_ASSERT(r == Z_OK);
-  r = zlib_body(&zs, input, output, deflate) && output->length < input->length;
+  r = zlib_body(exec_ctx, &zs, input, output, deflate) &&
+      output->length < input->length;
   if (!r) {
     for (i = count_before; i < output->count; i++) {
-      grpc_slice_unref(output->slices[i]);
+      grpc_slice_unref_internal(exec_ctx, output->slices[i]);
     }
     output->count = count_before;
     output->length = length_before;
@@ -122,8 +125,8 @@ static int zlib_compress(grpc_slice_buffer* input, grpc_slice_buffer* output,
   return r;
 }
 
-static int zlib_decompress(grpc_slice_buffer* input, grpc_slice_buffer* output,
-                           int gzip) {
+static int zlib_decompress(grpc_exec_ctx* exec_ctx, grpc_slice_buffer* input,
+                           grpc_slice_buffer* output, int gzip) {
   z_stream zs;
   int r;
   size_t i;
@@ -134,10 +137,10 @@ static int zlib_decompress(grpc_slice_buffer* input, grpc_slice_buffer* output,
   zs.zfree = zfree_gpr;
   r = inflateInit2(&zs, 15 | (gzip ? 16 : 0));
   GPR_ASSERT(r == Z_OK);
-  r = zlib_body(&zs, input, output, inflate);
+  r = zlib_body(exec_ctx, &zs, input, output, inflate);
   if (!r) {
     for (i = count_before; i < output->count; i++) {
-      grpc_slice_unref(output->slices[i]);
+      grpc_slice_unref_internal(exec_ctx, output->slices[i]);
     }
     output->count = count_before;
     output->length = length_before;
@@ -149,12 +152,13 @@ static int zlib_decompress(grpc_slice_buffer* input, grpc_slice_buffer* output,
 static int copy(grpc_slice_buffer* input, grpc_slice_buffer* output) {
   size_t i;
   for (i = 0; i < input->count; i++) {
-    grpc_slice_buffer_add(output, grpc_slice_ref(input->slices[i]));
+    grpc_slice_buffer_add(output, grpc_slice_ref_internal(input->slices[i]));
   }
   return 1;
 }
 
-static int compress_inner(grpc_compression_algorithm algorithm,
+static int compress_inner(grpc_exec_ctx* exec_ctx,
+                          grpc_compression_algorithm algorithm,
                           grpc_slice_buffer* input, grpc_slice_buffer* output) {
   switch (algorithm) {
     case GRPC_COMPRESS_NONE:
@@ -162,9 +166,9 @@ static int compress_inner(grpc_compression_algorithm algorithm,
          rely on that here */
       return 0;
     case GRPC_COMPRESS_DEFLATE:
-      return zlib_compress(input, output, 0);
+      return zlib_compress(exec_ctx, input, output, 0);
     case GRPC_COMPRESS_GZIP:
-      return zlib_compress(input, output, 1);
+      return zlib_compress(exec_ctx, input, output, 1);
     case GRPC_COMPRESS_ALGORITHMS_COUNT:
       break;
   }
@@ -172,24 +176,26 @@ static int compress_inner(grpc_compression_algorithm algorithm,
   return 0;
 }
 
-int grpc_msg_compress(grpc_compression_algorithm algorithm,
+int grpc_msg_compress(grpc_exec_ctx* exec_ctx,
+                      grpc_compression_algorithm algorithm,
                       grpc_slice_buffer* input, grpc_slice_buffer* output) {
-  if (!compress_inner(algorithm, input, output)) {
+  if (!compress_inner(exec_ctx, algorithm, input, output)) {
     copy(input, output);
     return 0;
   }
   return 1;
 }
 
-int grpc_msg_decompress(grpc_compression_algorithm algorithm,
+int grpc_msg_decompress(grpc_exec_ctx* exec_ctx,
+                        grpc_compression_algorithm algorithm,
                         grpc_slice_buffer* input, grpc_slice_buffer* output) {
   switch (algorithm) {
     case GRPC_COMPRESS_NONE:
       return copy(input, output);
     case GRPC_COMPRESS_DEFLATE:
-      return zlib_decompress(input, output, 0);
+      return zlib_decompress(exec_ctx, input, output, 0);
     case GRPC_COMPRESS_GZIP:
-      return zlib_decompress(input, output, 1);
+      return zlib_decompress(exec_ctx, input, output, 1);
     case GRPC_COMPRESS_ALGORITHMS_COUNT:
       break;
   }
diff --git a/src/core/lib/compression/message_compress.h b/src/core/lib/compression/message_compress.h
index 448d36a863..7bd3d98607 100644
--- a/src/core/lib/compression/message_compress.h
+++ b/src/core/lib/compression/message_compress.h
@@ -40,13 +40,15 @@
 /* compress 'input' to 'output' using 'algorithm'.
    On success, appends compressed slices to output and returns 1.
    On failure, appends uncompressed slices to output and returns 0. */
-int grpc_msg_compress(grpc_compression_algorithm algorithm,
+int grpc_msg_compress(grpc_exec_ctx* exec_ctx,
+                      grpc_compression_algorithm algorithm,
                       grpc_slice_buffer* input, grpc_slice_buffer* output);
 
 /* decompress 'input' to 'output' using 'algorithm'.
    On success, appends slices to output and returns 1.
    On failure, output is unchanged, and returns 0. */
-int grpc_msg_decompress(grpc_compression_algorithm algorithm,
+int grpc_msg_decompress(grpc_exec_ctx* exec_ctx,
+                        grpc_compression_algorithm algorithm,
                         grpc_slice_buffer* input, grpc_slice_buffer* output);
 
 #endif /* GRPC_CORE_LIB_COMPRESSION_MESSAGE_COMPRESS_H */
diff --git a/src/core/lib/http/httpcli.c b/src/core/lib/http/httpcli.c
index fdb8abaa2d..fb2108987b 100644
--- a/src/core/lib/http/httpcli.c
+++ b/src/core/lib/http/httpcli.c
@@ -47,6 +47,7 @@
 #include "src/core/lib/iomgr/resolve_address.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
 #include "src/core/lib/iomgr/tcp_client.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/support/string.h"
 
 typedef struct {
@@ -103,7 +104,7 @@ static void finish(grpc_exec_ctx *exec_ctx, internal_request *req,
                    grpc_error *error) {
   grpc_polling_entity_del_from_pollset_set(exec_ctx, req->pollent,
                                            req->context->pollset_set);
-  grpc_exec_ctx_sched(exec_ctx, req->on_done, error, NULL);
+  grpc_closure_sched(exec_ctx, req->on_done, error);
   grpc_http_parser_destroy(&req->parser);
   if (req->addresses != NULL) {
     grpc_resolved_addresses_destroy(req->addresses);
@@ -111,14 +112,14 @@ static void finish(grpc_exec_ctx *exec_ctx, internal_request *req,
   if (req->ep != NULL) {
     grpc_endpoint_destroy(exec_ctx, req->ep);
   }
-  grpc_slice_unref(req->request_text);
+  grpc_slice_unref_internal(exec_ctx, req->request_text);
   gpr_free(req->host);
   gpr_free(req->ssl_host_override);
   grpc_iomgr_unregister_object(&req->iomgr_obj);
-  grpc_slice_buffer_destroy(&req->incoming);
-  grpc_slice_buffer_destroy(&req->outgoing);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &req->incoming);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &req->outgoing);
   GRPC_ERROR_UNREF(req->overall_error);
-  grpc_resource_quota_internal_unref(exec_ctx, req->resource_quota);
+  grpc_resource_quota_unref_internal(exec_ctx, req->resource_quota);
   gpr_free(req);
 }
 
@@ -178,7 +179,7 @@ static void done_write(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
 }
 
 static void start_write(grpc_exec_ctx *exec_ctx, internal_request *req) {
-  grpc_slice_ref(req->request_text);
+  grpc_slice_ref_internal(req->request_text);
   grpc_slice_buffer_add(&req->outgoing, req->request_text);
   grpc_endpoint_write(exec_ctx, req->ep, &req->outgoing, &req->done_write);
 }
@@ -224,7 +225,8 @@ static void next_address(grpc_exec_ctx *exec_ctx, internal_request *req,
     return;
   }
   addr = &req->addresses->addrs[req->next_address++];
-  grpc_closure_init(&req->connected, on_connected, req);
+  grpc_closure_init(&req->connected, on_connected, req,
+                    grpc_schedule_on_exec_ctx);
   grpc_arg arg;
   arg.key = GRPC_ARG_RESOURCE_QUOTA;
   arg.type = GRPC_ARG_POINTER;
@@ -265,9 +267,10 @@ static void internal_request_begin(grpc_exec_ctx *exec_ctx,
   req->context = context;
   req->pollent = pollent;
   req->overall_error = GRPC_ERROR_NONE;
-  req->resource_quota = grpc_resource_quota_internal_ref(resource_quota);
-  grpc_closure_init(&req->on_read, on_read, req);
-  grpc_closure_init(&req->done_write, done_write, req);
+  req->resource_quota = grpc_resource_quota_ref_internal(resource_quota);
+  grpc_closure_init(&req->on_read, on_read, req, grpc_schedule_on_exec_ctx);
+  grpc_closure_init(&req->done_write, done_write, req,
+                    grpc_schedule_on_exec_ctx);
   grpc_slice_buffer_init(&req->incoming);
   grpc_slice_buffer_init(&req->outgoing);
   grpc_iomgr_register_object(&req->iomgr_obj, name);
@@ -277,8 +280,11 @@ static void internal_request_begin(grpc_exec_ctx *exec_ctx,
   GPR_ASSERT(pollent);
   grpc_polling_entity_add_to_pollset_set(exec_ctx, req->pollent,
                                          req->context->pollset_set);
-  grpc_resolve_address(exec_ctx, request->host, req->handshaker->default_port,
-                       grpc_closure_create(on_resolved, req), &req->addresses);
+  grpc_resolve_address(
+      exec_ctx, request->host, req->handshaker->default_port,
+      req->context->pollset_set,
+      grpc_closure_create(on_resolved, req, grpc_schedule_on_exec_ctx),
+      &req->addresses);
 }
 
 void grpc_httpcli_get(grpc_exec_ctx *exec_ctx, grpc_httpcli_context *context,
diff --git a/src/core/lib/http/httpcli_security_connector.c b/src/core/lib/http/httpcli_security_connector.c
index 24d264c32a..440817c5a6 100644
--- a/src/core/lib/http/httpcli_security_connector.c
+++ b/src/core/lib/http/httpcli_security_connector.c
@@ -38,7 +38,10 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
-#include "src/core/lib/security/transport/handshake.h"
+
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/security/transport/security_handshaker.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/tsi/ssl_transport_security.h"
 
@@ -48,7 +51,8 @@ typedef struct {
   char *secure_peer_name;
 } grpc_httpcli_ssl_channel_security_connector;
 
-static void httpcli_ssl_destroy(grpc_security_connector *sc) {
+static void httpcli_ssl_destroy(grpc_exec_ctx *exec_ctx,
+                                grpc_security_connector *sc) {
   grpc_httpcli_ssl_channel_security_connector *c =
       (grpc_httpcli_ssl_channel_security_connector *)sc;
   if (c->handshaker_factory != NULL) {
@@ -58,52 +62,43 @@ static void httpcli_ssl_destroy(grpc_security_connector *sc) {
   gpr_free(sc);
 }
 
-static void httpcli_ssl_do_handshake(grpc_exec_ctx *exec_ctx,
-                                     grpc_channel_security_connector *sc,
-                                     grpc_endpoint *nonsecure_endpoint,
-                                     grpc_slice_buffer *read_buffer,
-                                     gpr_timespec deadline,
-                                     grpc_security_handshake_done_cb cb,
-                                     void *user_data) {
+static void httpcli_ssl_add_handshakers(grpc_exec_ctx *exec_ctx,
+                                        grpc_channel_security_connector *sc,
+                                        grpc_handshake_manager *handshake_mgr) {
   grpc_httpcli_ssl_channel_security_connector *c =
       (grpc_httpcli_ssl_channel_security_connector *)sc;
-  tsi_result result = TSI_OK;
-  tsi_handshaker *handshaker;
-  if (c->handshaker_factory == NULL) {
-    gpr_free(read_buffer);
-    cb(exec_ctx, user_data, GRPC_SECURITY_ERROR, NULL, NULL);
-    return;
-  }
-  result = tsi_ssl_handshaker_factory_create_handshaker(
-      c->handshaker_factory, c->secure_peer_name, &handshaker);
-  if (result != TSI_OK) {
-    gpr_log(GPR_ERROR, "Handshaker creation failed with error %s.",
-            tsi_result_to_string(result));
-    gpr_free(read_buffer);
-    cb(exec_ctx, user_data, GRPC_SECURITY_ERROR, NULL, NULL);
-  } else {
-    grpc_do_security_handshake(exec_ctx, handshaker, &sc->base, true,
-                               nonsecure_endpoint, read_buffer, deadline, cb,
-                               user_data);
+  tsi_handshaker *handshaker = NULL;
+  if (c->handshaker_factory != NULL) {
+    tsi_result result = tsi_ssl_handshaker_factory_create_handshaker(
+        c->handshaker_factory, c->secure_peer_name, &handshaker);
+    if (result != TSI_OK) {
+      gpr_log(GPR_ERROR, "Handshaker creation failed with error %s.",
+              tsi_result_to_string(result));
+    }
   }
+  grpc_handshake_manager_add(
+      handshake_mgr,
+      grpc_security_handshaker_create(exec_ctx, handshaker, &sc->base));
 }
 
 static void httpcli_ssl_check_peer(grpc_exec_ctx *exec_ctx,
                                    grpc_security_connector *sc, tsi_peer peer,
-                                   grpc_security_peer_check_cb cb,
-                                   void *user_data) {
+                                   grpc_auth_context **auth_context,
+                                   grpc_closure *on_peer_checked) {
   grpc_httpcli_ssl_channel_security_connector *c =
       (grpc_httpcli_ssl_channel_security_connector *)sc;
-  grpc_security_status status = GRPC_SECURITY_OK;
+  grpc_error *error = GRPC_ERROR_NONE;
 
   /* Check the peer name. */
   if (c->secure_peer_name != NULL &&
       !tsi_ssl_peer_matches_name(&peer, c->secure_peer_name)) {
-    gpr_log(GPR_ERROR, "Peer name %s is not in peer certificate",
-            c->secure_peer_name);
-    status = GRPC_SECURITY_ERROR;
+    char *msg;
+    gpr_asprintf(&msg, "Peer name %s is not in peer certificate",
+                 c->secure_peer_name);
+    error = GRPC_ERROR_CREATE(msg);
+    gpr_free(msg);
   }
-  cb(exec_ctx, user_data, status, NULL);
+  grpc_closure_sched(exec_ctx, on_peer_checked, error);
   tsi_peer_destruct(&peer);
 }
 
@@ -111,8 +106,9 @@ static grpc_security_connector_vtable httpcli_ssl_vtable = {
     httpcli_ssl_destroy, httpcli_ssl_check_peer};
 
 static grpc_security_status httpcli_ssl_channel_security_connector_create(
-    const unsigned char *pem_root_certs, size_t pem_root_certs_size,
-    const char *secure_peer_name, grpc_channel_security_connector **sc) {
+    grpc_exec_ctx *exec_ctx, const unsigned char *pem_root_certs,
+    size_t pem_root_certs_size, const char *secure_peer_name,
+    grpc_channel_security_connector **sc) {
   tsi_result result = TSI_OK;
   grpc_httpcli_ssl_channel_security_connector *c;
 
@@ -136,11 +132,11 @@ static grpc_security_status httpcli_ssl_channel_security_connector_create(
   if (result != TSI_OK) {
     gpr_log(GPR_ERROR, "Handshaker factory creation failed with %s.",
             tsi_result_to_string(result));
-    httpcli_ssl_destroy(&c->base.base);
+    httpcli_ssl_destroy(exec_ctx, &c->base.base);
     *sc = NULL;
     return GRPC_SECURITY_ERROR;
   }
-  c->base.do_handshake = httpcli_ssl_do_handshake;
+  c->base.add_handshakers = httpcli_ssl_add_handshakers;
   *sc = &c->base;
   return GRPC_SECURITY_OK;
 }
@@ -150,19 +146,25 @@ static grpc_security_status httpcli_ssl_channel_security_connector_create(
 typedef struct {
   void (*func)(grpc_exec_ctx *exec_ctx, void *arg, grpc_endpoint *endpoint);
   void *arg;
+  grpc_handshake_manager *handshake_mgr;
 } on_done_closure;
 
-static void on_secure_transport_setup_done(grpc_exec_ctx *exec_ctx, void *rp,
-                                           grpc_security_status status,
-                                           grpc_endpoint *secure_endpoint,
-                                           grpc_auth_context *auth_context) {
-  on_done_closure *c = rp;
-  if (status != GRPC_SECURITY_OK) {
-    gpr_log(GPR_ERROR, "Secure transport setup failed with error %d.", status);
+static void on_handshake_done(grpc_exec_ctx *exec_ctx, void *arg,
+                              grpc_error *error) {
+  grpc_handshaker_args *args = arg;
+  on_done_closure *c = args->user_data;
+  if (error != GRPC_ERROR_NONE) {
+    const char *msg = grpc_error_string(error);
+    gpr_log(GPR_ERROR, "Secure transport setup failed: %s", msg);
+    grpc_error_free_string(msg);
     c->func(exec_ctx, c->arg, NULL);
   } else {
-    c->func(exec_ctx, c->arg, secure_endpoint);
+    grpc_channel_args_destroy(exec_ctx, args->args);
+    grpc_slice_buffer_destroy_internal(exec_ctx, args->read_buffer);
+    gpr_free(args->read_buffer);
+    c->func(exec_ctx, c->arg, args->endpoint);
   }
+  grpc_handshake_manager_destroy(exec_ctx, c->handshake_mgr);
   gpr_free(c);
 }
 
@@ -183,12 +185,16 @@ static void ssl_handshake(grpc_exec_ctx *exec_ctx, void *arg,
   }
   c->func = on_done;
   c->arg = arg;
+  c->handshake_mgr = grpc_handshake_manager_create();
   GPR_ASSERT(httpcli_ssl_channel_security_connector_create(
-                 pem_root_certs, pem_root_certs_size, host, &sc) ==
+                 exec_ctx, pem_root_certs, pem_root_certs_size, host, &sc) ==
              GRPC_SECURITY_OK);
-  grpc_channel_security_connector_do_handshake(
-      exec_ctx, sc, tcp, NULL, deadline, on_secure_transport_setup_done, c);
-  GRPC_SECURITY_CONNECTOR_UNREF(&sc->base, "httpcli");
+  grpc_channel_security_connector_add_handshakers(exec_ctx, sc,
+                                                  c->handshake_mgr);
+  grpc_handshake_manager_do_handshake(
+      exec_ctx, c->handshake_mgr, tcp, NULL /* channel_args */, deadline,
+      NULL /* acceptor */, on_handshake_done, c /* user_data */);
+  GRPC_SECURITY_CONNECTOR_UNREF(exec_ctx, &sc->base, "httpcli");
 }
 
 const grpc_httpcli_handshaker grpc_httpcli_ssl = {"https", ssl_handshake};
diff --git a/src/core/lib/iomgr/README.md b/src/core/lib/iomgr/README.md
new file mode 100644
index 0000000000..9b22b76ceb
--- /dev/null
+++ b/src/core/lib/iomgr/README.md
@@ -0,0 +1,6 @@
+# iomgr
+
+Platform abstractions for I/O (mostly network).
+
+Provides abstractions over TCP/UDP I/O, file loading, polling, and concurrency
+management for various operating systems.
diff --git a/src/core/lib/iomgr/closure.c b/src/core/lib/iomgr/closure.c
index c6ddc76732..da0ec878a3 100644
--- a/src/core/lib/iomgr/closure.c
+++ b/src/core/lib/iomgr/closure.c
@@ -37,10 +37,13 @@
 
 #include "src/core/lib/profiling/timers.h"
 
-void grpc_closure_init(grpc_closure *closure, grpc_iomgr_cb_func cb,
-                       void *cb_arg) {
+grpc_closure *grpc_closure_init(grpc_closure *closure, grpc_iomgr_cb_func cb,
+                                void *cb_arg,
+                                grpc_closure_scheduler *scheduler) {
   closure->cb = cb;
   closure->cb_arg = cb_arg;
+  closure->scheduler = scheduler;
+  return closure;
 }
 
 void grpc_closure_list_init(grpc_closure_list *closure_list) {
@@ -105,11 +108,12 @@ static void closure_wrapper(grpc_exec_ctx *exec_ctx, void *arg,
   cb(exec_ctx, cb_arg, error);
 }
 
-grpc_closure *grpc_closure_create(grpc_iomgr_cb_func cb, void *cb_arg) {
+grpc_closure *grpc_closure_create(grpc_iomgr_cb_func cb, void *cb_arg,
+                                  grpc_closure_scheduler *scheduler) {
   wrapped_closure *wc = gpr_malloc(sizeof(*wc));
   wc->cb = cb;
   wc->cb_arg = cb_arg;
-  grpc_closure_init(&wc->wrapper, closure_wrapper, wc);
+  grpc_closure_init(&wc->wrapper, closure_wrapper, wc, scheduler);
   return &wc->wrapper;
 }
 
@@ -117,8 +121,30 @@ void grpc_closure_run(grpc_exec_ctx *exec_ctx, grpc_closure *c,
                       grpc_error *error) {
   GPR_TIMER_BEGIN("grpc_closure_run", 0);
   if (c != NULL) {
-    c->cb(exec_ctx, c->cb_arg, error);
+    c->scheduler->vtable->run(exec_ctx, c, error);
+  } else {
+    GRPC_ERROR_UNREF(error);
   }
-  GRPC_ERROR_UNREF(error);
   GPR_TIMER_END("grpc_closure_run", 0);
 }
+
+void grpc_closure_sched(grpc_exec_ctx *exec_ctx, grpc_closure *c,
+                        grpc_error *error) {
+  GPR_TIMER_BEGIN("grpc_closure_sched", 0);
+  if (c != NULL) {
+    c->scheduler->vtable->sched(exec_ctx, c, error);
+  } else {
+    GRPC_ERROR_UNREF(error);
+  }
+  GPR_TIMER_END("grpc_closure_sched", 0);
+}
+
+void grpc_closure_list_sched(grpc_exec_ctx *exec_ctx, grpc_closure_list *list) {
+  grpc_closure *c = list->head;
+  while (c != NULL) {
+    grpc_closure *next = c->next_data.next;
+    c->scheduler->vtable->sched(exec_ctx, c, c->error_data.error);
+    c = next;
+  }
+  list->head = list->tail = NULL;
+}
diff --git a/src/core/lib/iomgr/closure.h b/src/core/lib/iomgr/closure.h
index 2b4b271eaa..ee386fbc76 100644
--- a/src/core/lib/iomgr/closure.h
+++ b/src/core/lib/iomgr/closure.h
@@ -35,6 +35,8 @@
 #define GRPC_CORE_LIB_IOMGR_CLOSURE_H
 
 #include <grpc/support/port_platform.h>
+
+#include <grpc/impl/codegen/exec_ctx_fwd.h>
 #include <stdbool.h>
 #include "src/core/lib/iomgr/error.h"
 #include "src/core/lib/support/mpscq.h"
@@ -42,10 +44,6 @@
 struct grpc_closure;
 typedef struct grpc_closure grpc_closure;
 
-/* forward declaration for exec_ctx.h */
-struct grpc_exec_ctx;
-typedef struct grpc_exec_ctx grpc_exec_ctx;
-
 typedef struct grpc_closure_list {
   grpc_closure *head;
   grpc_closure *tail;
@@ -59,6 +57,22 @@ typedef struct grpc_closure_list {
 typedef void (*grpc_iomgr_cb_func)(grpc_exec_ctx *exec_ctx, void *arg,
                                    grpc_error *error);
 
+typedef struct grpc_closure_scheduler grpc_closure_scheduler;
+
+typedef struct grpc_closure_scheduler_vtable {
+  /* NOTE: for all these functions, closure->scheduler == the scheduler that was
+           used to find this vtable */
+  void (*run)(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
+              grpc_error *error);
+  void (*sched)(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
+                grpc_error *error);
+} grpc_closure_scheduler_vtable;
+
+/** Abstract type that can schedule closures for execution */
+struct grpc_closure_scheduler {
+  const grpc_closure_scheduler_vtable *vtable;
+};
+
 /** A closure over a grpc_iomgr_cb_func. */
 struct grpc_closure {
   /** Once queued, next indicates the next queued closure; before then, scratch
@@ -75,6 +89,10 @@ struct grpc_closure {
   /** Arguments to be passed to "cb". */
   void *cb_arg;
 
+  /** Scheduler to schedule against: NULL to schedule against current execution
+      context */
+  grpc_closure_scheduler *scheduler;
+
   /** Once queued, the result of the closure. Before then: scratch space */
   union {
     grpc_error *error;
@@ -82,12 +100,14 @@ struct grpc_closure {
   } error_data;
 };
 
-/** Initializes \a closure with \a cb and \a cb_arg. */
-void grpc_closure_init(grpc_closure *closure, grpc_iomgr_cb_func cb,
-                       void *cb_arg);
+/** Initializes \a closure with \a cb and \a cb_arg. Returns \a closure. */
+grpc_closure *grpc_closure_init(grpc_closure *closure, grpc_iomgr_cb_func cb,
+                                void *cb_arg,
+                                grpc_closure_scheduler *scheduler);
 
 /* Create a heap allocated closure: try to avoid except for very rare events */
-grpc_closure *grpc_closure_create(grpc_iomgr_cb_func cb, void *cb_arg);
+grpc_closure *grpc_closure_create(grpc_iomgr_cb_func cb, void *cb_arg,
+                                  grpc_closure_scheduler *scheduler);
 
 #define GRPC_CLOSURE_LIST_INIT \
   { NULL, NULL }
@@ -115,4 +135,13 @@ bool grpc_closure_list_empty(grpc_closure_list list);
 void grpc_closure_run(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
                       grpc_error *error);
 
+/** Schedule a closure to be run. Does not need to be run from a safe point. */
+void grpc_closure_sched(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
+                        grpc_error *error);
+
+/** Schedule all closures in a list to be run. Does not need to be run from a
+ * safe point. */
+void grpc_closure_list_sched(grpc_exec_ctx *exec_ctx,
+                             grpc_closure_list *closure_list);
+
 #endif /* GRPC_CORE_LIB_IOMGR_CLOSURE_H */
diff --git a/src/core/lib/iomgr/combiner.c b/src/core/lib/iomgr/combiner.c
index 60ee14eb23..c26a73b2b7 100644
--- a/src/core/lib/iomgr/combiner.c
+++ b/src/core/lib/iomgr/combiner.c
@@ -56,6 +56,10 @@ int grpc_combiner_trace = 0;
 struct grpc_combiner {
   grpc_combiner *next_combiner_on_this_exec_ctx;
   grpc_workqueue *optional_workqueue;
+  grpc_closure_scheduler uncovered_scheduler;
+  grpc_closure_scheduler covered_scheduler;
+  grpc_closure_scheduler uncovered_finally_scheduler;
+  grpc_closure_scheduler covered_finally_scheduler;
   gpr_mpscq queue;
   // state is:
   // lower bit - zero if orphaned (STATE_UNORPHANED)
@@ -70,6 +74,26 @@ struct grpc_combiner {
   grpc_closure offload;
 };
 
+static void combiner_exec_uncovered(grpc_exec_ctx *exec_ctx,
+                                    grpc_closure *closure, grpc_error *error);
+static void combiner_exec_covered(grpc_exec_ctx *exec_ctx,
+                                  grpc_closure *closure, grpc_error *error);
+static void combiner_finally_exec_uncovered(grpc_exec_ctx *exec_ctx,
+                                            grpc_closure *closure,
+                                            grpc_error *error);
+static void combiner_finally_exec_covered(grpc_exec_ctx *exec_ctx,
+                                          grpc_closure *closure,
+                                          grpc_error *error);
+
+static const grpc_closure_scheduler_vtable scheduler_uncovered = {
+    combiner_exec_uncovered, combiner_exec_uncovered};
+static const grpc_closure_scheduler_vtable scheduler_covered = {
+    combiner_exec_covered, combiner_exec_covered};
+static const grpc_closure_scheduler_vtable finally_scheduler_uncovered = {
+    combiner_finally_exec_uncovered, combiner_finally_exec_uncovered};
+static const grpc_closure_scheduler_vtable finally_scheduler_covered = {
+    combiner_finally_exec_covered, combiner_finally_exec_covered};
+
 static void offload(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error);
 
 typedef struct {
@@ -90,17 +114,28 @@ static bool is_covered_by_poller(grpc_combiner *lock) {
          gpr_atm_acq_load(&lock->elements_covered_by_poller) > 0;
 }
 
+#define IS_COVERED_BY_POLLER_FMT "(final=%d elems=%" PRIdPTR ")->%d"
+#define IS_COVERED_BY_POLLER_ARGS(lock)                      \
+  (lock)->final_list_covered_by_poller,                      \
+      gpr_atm_acq_load(&(lock)->elements_covered_by_poller), \
+      is_covered_by_poller((lock))
+
 grpc_combiner *grpc_combiner_create(grpc_workqueue *optional_workqueue) {
   grpc_combiner *lock = gpr_malloc(sizeof(*lock));
   lock->next_combiner_on_this_exec_ctx = NULL;
   lock->time_to_execute_final_list = false;
   lock->optional_workqueue = optional_workqueue;
   lock->final_list_covered_by_poller = false;
+  lock->uncovered_scheduler.vtable = &scheduler_uncovered;
+  lock->covered_scheduler.vtable = &scheduler_covered;
+  lock->uncovered_finally_scheduler.vtable = &finally_scheduler_uncovered;
+  lock->covered_finally_scheduler.vtable = &finally_scheduler_covered;
   gpr_atm_no_barrier_store(&lock->state, STATE_UNORPHANED);
   gpr_atm_no_barrier_store(&lock->elements_covered_by_poller, 0);
   gpr_mpscq_init(&lock->queue);
   grpc_closure_list_init(&lock->final_list);
-  grpc_closure_init(&lock->offload, offload, lock);
+  grpc_closure_init(&lock->offload, offload, lock,
+                    grpc_workqueue_scheduler(lock->optional_workqueue));
   GRPC_COMBINER_TRACE(gpr_log(GPR_DEBUG, "C:%p create", lock));
   return lock;
 }
@@ -142,9 +177,9 @@ static void push_first_on_exec_ctx(grpc_exec_ctx *exec_ctx,
   }
 }
 
-void grpc_combiner_execute(grpc_exec_ctx *exec_ctx, grpc_combiner *lock,
-                           grpc_closure *cl, grpc_error *error,
-                           bool covered_by_poller) {
+static void combiner_exec(grpc_exec_ctx *exec_ctx, grpc_combiner *lock,
+                          grpc_closure *cl, grpc_error *error,
+                          bool covered_by_poller) {
   GPR_TIMER_BEGIN("combiner.execute", 0);
   gpr_atm last = gpr_atm_full_fetch_add(&lock->state, STATE_ELEM_COUNT_LOW_BIT);
   GRPC_COMBINER_TRACE(gpr_log(
@@ -165,6 +200,24 @@ void grpc_combiner_execute(grpc_exec_ctx *exec_ctx, grpc_combiner *lock,
   GPR_TIMER_END("combiner.execute", 0);
 }
 
+#define COMBINER_FROM_CLOSURE_SCHEDULER(closure, scheduler_name) \
+  ((grpc_combiner *)(((char *)((closure)->scheduler)) -          \
+                     offsetof(grpc_combiner, scheduler_name)))
+
+static void combiner_exec_uncovered(grpc_exec_ctx *exec_ctx, grpc_closure *cl,
+                                    grpc_error *error) {
+  combiner_exec(exec_ctx,
+                COMBINER_FROM_CLOSURE_SCHEDULER(cl, uncovered_scheduler), cl,
+                error, false);
+}
+
+static void combiner_exec_covered(grpc_exec_ctx *exec_ctx, grpc_closure *cl,
+                                  grpc_error *error) {
+  combiner_exec(exec_ctx,
+                COMBINER_FROM_CLOSURE_SCHEDULER(cl, covered_scheduler), cl,
+                error, true);
+}
+
 static void move_next(grpc_exec_ctx *exec_ctx) {
   exec_ctx->active_combiner =
       exec_ctx->active_combiner->next_combiner_on_this_exec_ctx;
@@ -182,8 +235,7 @@ static void queue_offload(grpc_exec_ctx *exec_ctx, grpc_combiner *lock) {
   move_next(exec_ctx);
   GRPC_COMBINER_TRACE(gpr_log(GPR_DEBUG, "C:%p queue_offload --> %p", lock,
                               lock->optional_workqueue));
-  grpc_workqueue_enqueue(exec_ctx, lock->optional_workqueue, &lock->offload,
-                         GRPC_ERROR_NONE);
+  grpc_closure_sched(exec_ctx, &lock->offload, GRPC_ERROR_NONE);
 }
 
 bool grpc_combiner_continue_exec_ctx(grpc_exec_ctx *exec_ctx) {
@@ -197,9 +249,10 @@ bool grpc_combiner_continue_exec_ctx(grpc_exec_ctx *exec_ctx) {
   GRPC_COMBINER_TRACE(
       gpr_log(GPR_DEBUG,
               "C:%p grpc_combiner_continue_exec_ctx workqueue=%p "
-              "is_covered_by_poller=%d exec_ctx_ready_to_finish=%d "
+              "is_covered_by_poller=" IS_COVERED_BY_POLLER_FMT
+              " exec_ctx_ready_to_finish=%d "
               "time_to_execute_final_list=%d",
-              lock, lock->optional_workqueue, is_covered_by_poller(lock),
+              lock, lock->optional_workqueue, IS_COVERED_BY_POLLER_ARGS(lock),
               grpc_exec_ctx_ready_to_finish(exec_ctx),
               lock->time_to_execute_final_list));
 
@@ -305,23 +358,22 @@ bool grpc_combiner_continue_exec_ctx(grpc_exec_ctx *exec_ctx) {
 }
 
 static void enqueue_finally(grpc_exec_ctx *exec_ctx, void *closure,
-                            grpc_error *error) {
-  grpc_combiner_execute_finally(exec_ctx, exec_ctx->active_combiner, closure,
-                                GRPC_ERROR_REF(error), false);
-}
+                            grpc_error *error);
 
-void grpc_combiner_execute_finally(grpc_exec_ctx *exec_ctx, grpc_combiner *lock,
-                                   grpc_closure *closure, grpc_error *error,
-                                   bool covered_by_poller) {
+static void combiner_execute_finally(grpc_exec_ctx *exec_ctx,
+                                     grpc_combiner *lock, grpc_closure *closure,
+                                     grpc_error *error,
+                                     bool covered_by_poller) {
   GRPC_COMBINER_TRACE(gpr_log(
       GPR_DEBUG, "C:%p grpc_combiner_execute_finally c=%p; ac=%p; cov=%d", lock,
       closure, exec_ctx->active_combiner, covered_by_poller));
   GPR_TIMER_BEGIN("combiner.execute_finally", 0);
   if (exec_ctx->active_combiner != lock) {
     GPR_TIMER_MARK("slowpath", 0);
-    grpc_combiner_execute(exec_ctx, lock,
-                          grpc_closure_create(enqueue_finally, closure), error,
-                          false);
+    grpc_closure_sched(
+        exec_ctx, grpc_closure_create(enqueue_finally, closure,
+                                      grpc_combiner_scheduler(lock, false)),
+        error);
     GPR_TIMER_END("combiner.execute_finally", 0);
     return;
   }
@@ -335,3 +387,36 @@ void grpc_combiner_execute_finally(grpc_exec_ctx *exec_ctx, grpc_combiner *lock,
   grpc_closure_list_append(&lock->final_list, closure, error);
   GPR_TIMER_END("combiner.execute_finally", 0);
 }
+
+static void enqueue_finally(grpc_exec_ctx *exec_ctx, void *closure,
+                            grpc_error *error) {
+  combiner_execute_finally(exec_ctx, exec_ctx->active_combiner, closure,
+                           GRPC_ERROR_REF(error), false);
+}
+
+static void combiner_finally_exec_uncovered(grpc_exec_ctx *exec_ctx,
+                                            grpc_closure *cl,
+                                            grpc_error *error) {
+  combiner_execute_finally(exec_ctx, COMBINER_FROM_CLOSURE_SCHEDULER(
+                                         cl, uncovered_finally_scheduler),
+                           cl, error, false);
+}
+
+static void combiner_finally_exec_covered(grpc_exec_ctx *exec_ctx,
+                                          grpc_closure *cl, grpc_error *error) {
+  combiner_execute_finally(
+      exec_ctx, COMBINER_FROM_CLOSURE_SCHEDULER(cl, covered_finally_scheduler),
+      cl, error, true);
+}
+
+grpc_closure_scheduler *grpc_combiner_scheduler(grpc_combiner *combiner,
+                                                bool covered_by_poller) {
+  return covered_by_poller ? &combiner->covered_scheduler
+                           : &combiner->uncovered_scheduler;
+}
+
+grpc_closure_scheduler *grpc_combiner_finally_scheduler(
+    grpc_combiner *combiner, bool covered_by_poller) {
+  return covered_by_poller ? &combiner->covered_finally_scheduler
+                           : &combiner->uncovered_finally_scheduler;
+}
diff --git a/src/core/lib/iomgr/combiner.h b/src/core/lib/iomgr/combiner.h
index d04eeed83a..81dff85d40 100644
--- a/src/core/lib/iomgr/combiner.h
+++ b/src/core/lib/iomgr/combiner.h
@@ -50,14 +50,12 @@
 grpc_combiner *grpc_combiner_create(grpc_workqueue *optional_workqueue);
 // Destroy the lock
 void grpc_combiner_destroy(grpc_exec_ctx *exec_ctx, grpc_combiner *lock);
-// Execute \a action within the lock.
-void grpc_combiner_execute(grpc_exec_ctx *exec_ctx, grpc_combiner *lock,
-                           grpc_closure *closure, grpc_error *error,
-                           bool covered_by_poller);
-// Execute \a action within the lock just prior to unlocking.
-void grpc_combiner_execute_finally(grpc_exec_ctx *exec_ctx, grpc_combiner *lock,
-                                   grpc_closure *closure, grpc_error *error,
-                                   bool covered_by_poller);
+// Fetch a scheduler to schedule closures against
+grpc_closure_scheduler *grpc_combiner_scheduler(grpc_combiner *lock,
+                                                bool covered_by_poller);
+// Scheduler to execute \a action within the lock just prior to unlocking.
+grpc_closure_scheduler *grpc_combiner_finally_scheduler(grpc_combiner *lock,
+                                                        bool covered_by_poller);
 
 bool grpc_combiner_continue_exec_ctx(grpc_exec_ctx *exec_ctx);
 
diff --git a/src/core/lib/iomgr/ev_epoll_linux.c b/src/core/lib/iomgr/ev_epoll_linux.c
index 07fbfd849e..d6664aead2 100644
--- a/src/core/lib/iomgr/ev_epoll_linux.c
+++ b/src/core/lib/iomgr/ev_epoll_linux.c
@@ -31,7 +31,6 @@
  *
  */
 
-#include <grpc/grpc_posix.h>
 #include "src/core/lib/iomgr/port.h"
 
 /* This polling engine is only relevant on linux kernels supporting epoll() */
@@ -69,6 +68,9 @@ static int grpc_polling_trace = 0; /* Disabled by default */
     gpr_log(GPR_INFO, (fmt), __VA_ARGS__); \
   }
 
+/* Uncomment the following enable extra checks on poll_object operations */
+/* #define PO_DEBUG */
+
 static int grpc_wakeup_signal = -1;
 static bool is_grpc_wakeup_signal_initialized = false;
 
@@ -95,10 +97,42 @@ void grpc_use_signal(int signum) {
 
 struct polling_island;
 
+typedef enum {
+  POLL_OBJ_FD,
+  POLL_OBJ_POLLSET,
+  POLL_OBJ_POLLSET_SET
+} poll_obj_type;
+
+typedef struct poll_obj {
+#ifdef PO_DEBUG
+  poll_obj_type obj_type;
+#endif
+  gpr_mu mu;
+  struct polling_island *pi;
+} poll_obj;
+
+const char *poll_obj_string(poll_obj_type po_type) {
+  switch (po_type) {
+    case POLL_OBJ_FD:
+      return "fd";
+    case POLL_OBJ_POLLSET:
+      return "pollset";
+    case POLL_OBJ_POLLSET_SET:
+      return "pollset_set";
+  }
+
+  GPR_UNREACHABLE_CODE(return "UNKNOWN");
+}
+
 /*******************************************************************************
  * Fd Declarations
  */
+
+#define FD_FROM_PO(po) ((grpc_fd *)(po))
+
 struct grpc_fd {
+  poll_obj po;
+
   int fd;
   /* refst format:
        bit 0    : 1=Active / 0=Orphaned
@@ -106,8 +140,6 @@ struct grpc_fd {
      Ref/Unref by two to avoid altering the orphaned bit */
   gpr_atm refst;
 
-  gpr_mu mu;
-
   /* Indicates that the fd is shutdown and that any pending read/write closures
      should fail */
   bool shutdown;
@@ -120,9 +152,6 @@ struct grpc_fd {
   grpc_closure *read_closure;
   grpc_closure *write_closure;
 
-  /* The polling island to which this fd belongs to (protected by mu) */
-  struct polling_island *polling_island;
-
   struct grpc_fd *freelist_next;
   grpc_closure *on_done_closure;
 
@@ -172,6 +201,8 @@ static void fd_global_shutdown(void);
 
 /* This is also used as grpc_workqueue (by directly casing it) */
 typedef struct polling_island {
+  grpc_closure_scheduler workqueue_scheduler;
+
   gpr_mu mu;
   /* Ref count. Use PI_ADD_REF() and PI_UNREF() macros to increment/decrement
      the refcount.
@@ -225,41 +256,21 @@ struct grpc_pollset_worker {
 };
 
 struct grpc_pollset {
-  gpr_mu mu;
+  poll_obj po;
+
   grpc_pollset_worker root_worker;
   bool kicked_without_pollers;
 
   bool shutting_down;          /* Is the pollset shutting down ? */
   bool finish_shutdown_called; /* Is the 'finish_shutdown_locked()' called ? */
   grpc_closure *shutdown_done; /* Called after after shutdown is complete */
-
-  /* The polling island to which this pollset belongs to */
-  struct polling_island *polling_island;
 };
 
 /*******************************************************************************
  * Pollset-set Declarations
  */
-/* TODO: sreek - Change the pollset_set implementation such that a pollset_set
- * directly points to a polling_island (and adding an fd/pollset/pollset_set to
- * the current pollset_set would result in polling island merges. This would
- * remove the need to maintain fd_count here. This will also significantly
- * simplify the grpc_fd structure since we would no longer need to explicitly
- * maintain the orphaned state */
 struct grpc_pollset_set {
-  gpr_mu mu;
-
-  size_t pollset_count;
-  size_t pollset_capacity;
-  grpc_pollset **pollsets;
-
-  size_t pollset_set_count;
-  size_t pollset_set_capacity;
-  struct grpc_pollset_set **pollset_sets;
-
-  size_t fd_count;
-  size_t fd_capacity;
-  grpc_fd **fds;
+  poll_obj po;
 };
 
 /*******************************************************************************
@@ -295,6 +306,8 @@ static __thread polling_island *g_current_thread_polling_island;
 
 /* Forward declaration */
 static void polling_island_delete(grpc_exec_ctx *exec_ctx, polling_island *pi);
+static void workqueue_enqueue(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
+                              grpc_error *error);
 
 #ifdef GRPC_TSAN
 /* Currently TSAN may incorrectly flag data races between epoll_ctl and
@@ -307,6 +320,9 @@ static void polling_island_delete(grpc_exec_ctx *exec_ctx, polling_island *pi);
 gpr_atm g_epoll_sync;
 #endif /* defined(GRPC_TSAN) */
 
+static const grpc_closure_scheduler_vtable workqueue_scheduler_vtable = {
+    workqueue_enqueue, workqueue_enqueue};
+
 static void pi_add_ref(polling_island *pi);
 static void pi_unref(grpc_exec_ctx *exec_ctx, polling_island *pi);
 
@@ -519,6 +535,7 @@ static polling_island *polling_island_create(grpc_exec_ctx *exec_ctx,
   *error = GRPC_ERROR_NONE;
 
   pi = gpr_malloc(sizeof(*pi));
+  pi->workqueue_scheduler.vtable = &workqueue_scheduler_vtable;
   gpr_mu_init(&pi->mu);
   pi->fd_cnt = 0;
   pi->fd_capacity = 0;
@@ -790,10 +807,10 @@ static polling_island *polling_island_merge(polling_island *p,
   return q;
 }
 
-static void workqueue_enqueue(grpc_exec_ctx *exec_ctx,
-                              grpc_workqueue *workqueue, grpc_closure *closure,
+static void workqueue_enqueue(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
                               grpc_error *error) {
   GPR_TIMER_BEGIN("workqueue.enqueue", 0);
+  grpc_workqueue *workqueue = (grpc_workqueue *)closure->scheduler;
   /* take a ref to the workqueue: otherwise it can happen that whatever events
    * this kicks off ends up destroying the workqueue before this function
    * completes */
@@ -810,6 +827,12 @@ static void workqueue_enqueue(grpc_exec_ctx *exec_ctx,
   GPR_TIMER_END("workqueue.enqueue", 0);
 }
 
+static grpc_closure_scheduler *workqueue_scheduler(grpc_workqueue *workqueue) {
+  polling_island *pi = (polling_island *)workqueue;
+  return workqueue == NULL ? grpc_schedule_on_exec_ctx
+                           : &pi->workqueue_scheduler;
+}
+
 static grpc_error *polling_island_global_init() {
   grpc_error *error = GRPC_ERROR_NONE;
 
@@ -915,7 +938,7 @@ static void fd_global_shutdown(void) {
   while (fd_freelist != NULL) {
     grpc_fd *fd = fd_freelist;
     fd_freelist = fd_freelist->freelist_next;
-    gpr_mu_destroy(&fd->mu);
+    gpr_mu_destroy(&fd->po.mu);
     gpr_free(fd);
   }
   gpr_mu_destroy(&fd_freelist_mu);
@@ -933,13 +956,17 @@ static grpc_fd *fd_create(int fd, const char *name) {
 
   if (new_fd == NULL) {
     new_fd = gpr_malloc(sizeof(grpc_fd));
-    gpr_mu_init(&new_fd->mu);
+    gpr_mu_init(&new_fd->po.mu);
   }
 
-  /* Note: It is not really needed to get the new_fd->mu lock here. If this is a
-     newly created fd (or an fd we got from the freelist), no one else would be
-     holding a lock to it anyway. */
-  gpr_mu_lock(&new_fd->mu);
+  /* Note: It is not really needed to get the new_fd->po.mu lock here. If this
+   * is a newly created fd (or an fd we got from the freelist), no one else
+   * would be holding a lock to it anyway. */
+  gpr_mu_lock(&new_fd->po.mu);
+  new_fd->po.pi = NULL;
+#ifdef PO_DEBUG
+  new_fd->po.obj_type = POLL_OBJ_FD;
+#endif
 
   gpr_atm_rel_store(&new_fd->refst, (gpr_atm)1);
   new_fd->fd = fd;
@@ -947,12 +974,11 @@ static grpc_fd *fd_create(int fd, const char *name) {
   new_fd->orphaned = false;
   new_fd->read_closure = CLOSURE_NOT_READY;
   new_fd->write_closure = CLOSURE_NOT_READY;
-  new_fd->polling_island = NULL;
   new_fd->freelist_next = NULL;
   new_fd->on_done_closure = NULL;
   new_fd->read_notifier_pollset = NULL;
 
-  gpr_mu_unlock(&new_fd->mu);
+  gpr_mu_unlock(&new_fd->po.mu);
 
   char *fd_name;
   gpr_asprintf(&fd_name, "%s fd=%d", name, fd);
@@ -964,17 +990,13 @@ static grpc_fd *fd_create(int fd, const char *name) {
   return new_fd;
 }
 
-static bool fd_is_orphaned(grpc_fd *fd) {
-  return (gpr_atm_acq_load(&fd->refst) & 1) == 0;
-}
-
 static int fd_wrapped_fd(grpc_fd *fd) {
   int ret_fd = -1;
-  gpr_mu_lock(&fd->mu);
+  gpr_mu_lock(&fd->po.mu);
   if (!fd->orphaned) {
     ret_fd = fd->fd;
   }
-  gpr_mu_unlock(&fd->mu);
+  gpr_mu_unlock(&fd->po.mu);
 
   return ret_fd;
 }
@@ -986,7 +1008,7 @@ static void fd_orphan(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
   grpc_error *error = GRPC_ERROR_NONE;
   polling_island *unref_pi = NULL;
 
-  gpr_mu_lock(&fd->mu);
+  gpr_mu_lock(&fd->po.mu);
   fd->on_done_closure = on_done;
 
   /* If release_fd is not NULL, we should be relinquishing control of the file
@@ -1006,25 +1028,24 @@ static void fd_orphan(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
 
   /* Remove the fd from the polling island:
      - Get a lock on the latest polling island (i.e the last island in the
-       linked list pointed by fd->polling_island). This is the island that
+       linked list pointed by fd->po.pi). This is the island that
        would actually contain the fd
      - Remove the fd from the latest polling island
      - Unlock the latest polling island
-     - Set fd->polling_island to NULL (but remove the ref on the polling island
+     - Set fd->po.pi to NULL (but remove the ref on the polling island
        before doing this.) */
-  if (fd->polling_island != NULL) {
-    polling_island *pi_latest = polling_island_lock(fd->polling_island);
+  if (fd->po.pi != NULL) {
+    polling_island *pi_latest = polling_island_lock(fd->po.pi);
     polling_island_remove_fd_locked(pi_latest, fd, is_fd_closed, &error);
     gpr_mu_unlock(&pi_latest->mu);
 
-    unref_pi = fd->polling_island;
-    fd->polling_island = NULL;
+    unref_pi = fd->po.pi;
+    fd->po.pi = NULL;
   }
 
-  grpc_exec_ctx_sched(exec_ctx, fd->on_done_closure, GRPC_ERROR_REF(error),
-                      NULL);
+  grpc_closure_sched(exec_ctx, fd->on_done_closure, GRPC_ERROR_REF(error));
 
-  gpr_mu_unlock(&fd->mu);
+  gpr_mu_unlock(&fd->po.mu);
   UNREF_BY(fd, 2, reason); /* Drop the reference */
   if (unref_pi != NULL) {
     /* Unref stale polling island here, outside the fd lock above.
@@ -1048,16 +1069,14 @@ static grpc_error *fd_shutdown_error(bool shutdown) {
 static void notify_on_locked(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
                              grpc_closure **st, grpc_closure *closure) {
   if (fd->shutdown) {
-    grpc_exec_ctx_sched(exec_ctx, closure, GRPC_ERROR_CREATE("FD shutdown"),
-                        NULL);
+    grpc_closure_sched(exec_ctx, closure, GRPC_ERROR_CREATE("FD shutdown"));
   } else if (*st == CLOSURE_NOT_READY) {
     /* not ready ==> switch to a waiting state by setting the closure */
     *st = closure;
   } else if (*st == CLOSURE_READY) {
     /* already ready ==> queue the closure to run immediately */
     *st = CLOSURE_NOT_READY;
-    grpc_exec_ctx_sched(exec_ctx, closure, fd_shutdown_error(fd->shutdown),
-                        NULL);
+    grpc_closure_sched(exec_ctx, closure, fd_shutdown_error(fd->shutdown));
   } else {
     /* upcallptr was set to a different closure.  This is an error! */
     gpr_log(GPR_ERROR,
@@ -1079,7 +1098,7 @@ static int set_ready_locked(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
     return 0;
   } else {
     /* waiting ==> queue closure */
-    grpc_exec_ctx_sched(exec_ctx, *st, fd_shutdown_error(fd->shutdown), NULL);
+    grpc_closure_sched(exec_ctx, *st, fd_shutdown_error(fd->shutdown));
     *st = CLOSURE_NOT_READY;
     return 1;
   }
@@ -1089,23 +1108,23 @@ static grpc_pollset *fd_get_read_notifier_pollset(grpc_exec_ctx *exec_ctx,
                                                   grpc_fd *fd) {
   grpc_pollset *notifier = NULL;
 
-  gpr_mu_lock(&fd->mu);
+  gpr_mu_lock(&fd->po.mu);
   notifier = fd->read_notifier_pollset;
-  gpr_mu_unlock(&fd->mu);
+  gpr_mu_unlock(&fd->po.mu);
 
   return notifier;
 }
 
 static bool fd_is_shutdown(grpc_fd *fd) {
-  gpr_mu_lock(&fd->mu);
+  gpr_mu_lock(&fd->po.mu);
   const bool r = fd->shutdown;
-  gpr_mu_unlock(&fd->mu);
+  gpr_mu_unlock(&fd->po.mu);
   return r;
 }
 
 /* Might be called multiple times */
 static void fd_shutdown(grpc_exec_ctx *exec_ctx, grpc_fd *fd) {
-  gpr_mu_lock(&fd->mu);
+  gpr_mu_lock(&fd->po.mu);
   /* Do the actual shutdown only once */
   if (!fd->shutdown) {
     fd->shutdown = true;
@@ -1116,28 +1135,28 @@ static void fd_shutdown(grpc_exec_ctx *exec_ctx, grpc_fd *fd) {
     set_ready_locked(exec_ctx, fd, &fd->read_closure);
     set_ready_locked(exec_ctx, fd, &fd->write_closure);
   }
-  gpr_mu_unlock(&fd->mu);
+  gpr_mu_unlock(&fd->po.mu);
 }
 
 static void fd_notify_on_read(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
                               grpc_closure *closure) {
-  gpr_mu_lock(&fd->mu);
+  gpr_mu_lock(&fd->po.mu);
   notify_on_locked(exec_ctx, fd, &fd->read_closure, closure);
-  gpr_mu_unlock(&fd->mu);
+  gpr_mu_unlock(&fd->po.mu);
 }
 
 static void fd_notify_on_write(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
                                grpc_closure *closure) {
-  gpr_mu_lock(&fd->mu);
+  gpr_mu_lock(&fd->po.mu);
   notify_on_locked(exec_ctx, fd, &fd->write_closure, closure);
-  gpr_mu_unlock(&fd->mu);
+  gpr_mu_unlock(&fd->po.mu);
 }
 
 static grpc_workqueue *fd_get_workqueue(grpc_fd *fd) {
-  gpr_mu_lock(&fd->mu);
-  grpc_workqueue *workqueue = GRPC_WORKQUEUE_REF(
-      (grpc_workqueue *)fd->polling_island, "fd_get_workqueue");
-  gpr_mu_unlock(&fd->mu);
+  gpr_mu_lock(&fd->po.mu);
+  grpc_workqueue *workqueue =
+      GRPC_WORKQUEUE_REF((grpc_workqueue *)fd->po.pi, "fd_get_workqueue");
+  gpr_mu_unlock(&fd->po.mu);
   return workqueue;
 }
 
@@ -1277,8 +1296,12 @@ static grpc_error *kick_poller(void) {
 }
 
 static void pollset_init(grpc_pollset *pollset, gpr_mu **mu) {
-  gpr_mu_init(&pollset->mu);
-  *mu = &pollset->mu;
+  gpr_mu_init(&pollset->po.mu);
+  *mu = &pollset->po.mu;
+  pollset->po.pi = NULL;
+#ifdef PO_DEBUG
+  pollset->po.obj_type = POLL_OBJ_POLLSET;
+#endif
 
   pollset->root_worker.next = pollset->root_worker.prev = &pollset->root_worker;
   pollset->kicked_without_pollers = false;
@@ -1286,8 +1309,6 @@ static void pollset_init(grpc_pollset *pollset, gpr_mu **mu) {
   pollset->shutting_down = false;
   pollset->finish_shutdown_called = false;
   pollset->shutdown_done = NULL;
-
-  pollset->polling_island = NULL;
 }
 
 /* Convert a timespec to milliseconds:
@@ -1317,26 +1338,26 @@ static int poll_deadline_to_millis_timeout(gpr_timespec deadline,
 
 static void fd_become_readable(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
                                grpc_pollset *notifier) {
-  /* Need the fd->mu since we might be racing with fd_notify_on_read */
-  gpr_mu_lock(&fd->mu);
+  /* Need the fd->po.mu since we might be racing with fd_notify_on_read */
+  gpr_mu_lock(&fd->po.mu);
   set_ready_locked(exec_ctx, fd, &fd->read_closure);
   fd->read_notifier_pollset = notifier;
-  gpr_mu_unlock(&fd->mu);
+  gpr_mu_unlock(&fd->po.mu);
 }
 
 static void fd_become_writable(grpc_exec_ctx *exec_ctx, grpc_fd *fd) {
-  /* Need the fd->mu since we might be racing with fd_notify_on_write */
-  gpr_mu_lock(&fd->mu);
+  /* Need the fd->po.mu since we might be racing with fd_notify_on_write */
+  gpr_mu_lock(&fd->po.mu);
   set_ready_locked(exec_ctx, fd, &fd->write_closure);
-  gpr_mu_unlock(&fd->mu);
+  gpr_mu_unlock(&fd->po.mu);
 }
 
 static void pollset_release_polling_island(grpc_exec_ctx *exec_ctx,
                                            grpc_pollset *ps, char *reason) {
-  if (ps->polling_island != NULL) {
-    PI_UNREF(exec_ctx, ps->polling_island, reason);
+  if (ps->po.pi != NULL) {
+    PI_UNREF(exec_ctx, ps->po.pi, reason);
   }
-  ps->polling_island = NULL;
+  ps->po.pi = NULL;
 }
 
 static void finish_shutdown_locked(grpc_exec_ctx *exec_ctx,
@@ -1346,12 +1367,12 @@ static void finish_shutdown_locked(grpc_exec_ctx *exec_ctx,
 
   pollset->finish_shutdown_called = true;
 
-  /* Release the ref and set pollset->polling_island to NULL */
+  /* Release the ref and set pollset->po.pi to NULL */
   pollset_release_polling_island(exec_ctx, pollset, "ps_shutdown");
-  grpc_exec_ctx_sched(exec_ctx, pollset->shutdown_done, GRPC_ERROR_NONE, NULL);
+  grpc_closure_sched(exec_ctx, pollset->shutdown_done, GRPC_ERROR_NONE);
 }
 
-/* pollset->mu lock must be held by the caller before calling this */
+/* pollset->po.mu lock must be held by the caller before calling this */
 static void pollset_shutdown(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                              grpc_closure *closure) {
   GPR_TIMER_BEGIN("pollset_shutdown", 0);
@@ -1376,7 +1397,7 @@ static void pollset_shutdown(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
  * here */
 static void pollset_destroy(grpc_pollset *pollset) {
   GPR_ASSERT(!pollset_has_workers(pollset));
-  gpr_mu_destroy(&pollset->mu);
+  gpr_mu_destroy(&pollset->po.mu);
 }
 
 static void pollset_reset(grpc_pollset *pollset) {
@@ -1386,7 +1407,7 @@ static void pollset_reset(grpc_pollset *pollset) {
   pollset->finish_shutdown_called = false;
   pollset->kicked_without_pollers = false;
   pollset->shutdown_done = NULL;
-  GPR_ASSERT(pollset->polling_island == NULL);
+  GPR_ASSERT(pollset->po.pi == NULL);
 }
 
 static bool maybe_do_workqueue_work(grpc_exec_ctx *exec_ctx,
@@ -1399,7 +1420,9 @@ static bool maybe_do_workqueue_work(grpc_exec_ctx *exec_ctx,
         workqueue_maybe_wakeup(pi);
       }
       grpc_closure *c = (grpc_closure *)n;
-      grpc_closure_run(exec_ctx, c, c->error_data.error);
+      grpc_error *error = c->error_data.error;
+      c->cb(exec_ctx, c->cb_arg, error);
+      GRPC_ERROR_UNREF(error);
       return true;
     } else if (gpr_atm_no_barrier_load(&pi->workqueue_item_count) > 0) {
       /* n == NULL might mean there's work but it's not available to be popped
@@ -1426,7 +1449,7 @@ static void pollset_work_and_unlock(grpc_exec_ctx *exec_ctx,
   GPR_TIMER_BEGIN("pollset_work_and_unlock", 0);
 
   /* We need to get the epoll_fd to wait on. The epoll_fd is in inside the
-     latest polling island pointed by pollset->polling_island.
+     latest polling island pointed by pollset->po.pi
 
      Since epoll_fd is immutable, we can read it without obtaining the polling
      island lock. There is however a possibility that the polling island (from
@@ -1435,36 +1458,36 @@ static void pollset_work_and_unlock(grpc_exec_ctx *exec_ctx,
      right-away from epoll_wait() and pick up the latest polling_island the next
      this function (i.e pollset_work_and_unlock()) is called */
 
-  if (pollset->polling_island == NULL) {
-    pollset->polling_island = polling_island_create(exec_ctx, NULL, error);
-    if (pollset->polling_island == NULL) {
+  if (pollset->po.pi == NULL) {
+    pollset->po.pi = polling_island_create(exec_ctx, NULL, error);
+    if (pollset->po.pi == NULL) {
       GPR_TIMER_END("pollset_work_and_unlock", 0);
       return; /* Fatal error. We cannot continue */
     }
 
-    PI_ADD_REF(pollset->polling_island, "ps");
+    PI_ADD_REF(pollset->po.pi, "ps");
     GRPC_POLLING_TRACE("pollset_work: pollset: %p created new pi: %p",
-                       (void *)pollset, (void *)pollset->polling_island);
+                       (void *)pollset, (void *)pollset->po.pi);
   }
 
-  pi = polling_island_maybe_get_latest(pollset->polling_island);
+  pi = polling_island_maybe_get_latest(pollset->po.pi);
   epoll_fd = pi->epoll_fd;
 
-  /* Update the pollset->polling_island since the island being pointed by
-     pollset->polling_island maybe older than the one pointed by pi) */
-  if (pollset->polling_island != pi) {
+  /* Update the pollset->po.pi since the island being pointed by
+     pollset->po.pi maybe older than the one pointed by pi) */
+  if (pollset->po.pi != pi) {
     /* Always do PI_ADD_REF before PI_UNREF because PI_UNREF may cause the
        polling island to be deleted */
     PI_ADD_REF(pi, "ps");
-    PI_UNREF(exec_ctx, pollset->polling_island, "ps");
-    pollset->polling_island = pi;
+    PI_UNREF(exec_ctx, pollset->po.pi, "ps");
+    pollset->po.pi = pi;
   }
 
   /* Add an extra ref so that the island does not get destroyed (which means
      the epoll_fd won't be closed) while we are are doing an epoll_wait() on the
      epoll_fd */
   PI_ADD_REF(pi, "ps_work");
-  gpr_mu_unlock(&pollset->mu);
+  gpr_mu_unlock(&pollset->po.mu);
 
   /* If we get some workqueue work to do, it might end up completing an item on
      the completion queue, so there's no need to poll... so we skip that and
@@ -1537,17 +1560,17 @@ static void pollset_work_and_unlock(grpc_exec_ctx *exec_ctx,
   GPR_ASSERT(pi != NULL);
 
   /* Before leaving, release the extra ref we added to the polling island. It
-     is important to use "pi" here (i.e our old copy of pollset->polling_island
+     is important to use "pi" here (i.e our old copy of pollset->po.pi
      that we got before releasing the polling island lock). This is because
-     pollset->polling_island pointer might get udpated in other parts of the
+     pollset->po.pi pointer might get udpated in other parts of the
      code when there is an island merge while we are doing epoll_wait() above */
   PI_UNREF(exec_ctx, pi, "ps_work");
 
   GPR_TIMER_END("pollset_work_and_unlock", 0);
 }
 
-/* pollset->mu lock must be held by the caller before calling this.
-   The function pollset_work() may temporarily release the lock (pollset->mu)
+/* pollset->po.mu lock must be held by the caller before calling this.
+   The function pollset_work() may temporarily release the lock (pollset->po.mu)
    during the course of its execution but it will always re-acquire the lock and
    ensure that it is held by the time the function returns */
 static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
@@ -1617,7 +1640,7 @@ static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                             &g_orig_sigmask, &error);
     grpc_exec_ctx_flush(exec_ctx);
 
-    gpr_mu_lock(&pollset->mu);
+    gpr_mu_lock(&pollset->po.mu);
 
     /* Note: There is no need to reset worker.is_kicked to 0 since we are no
        longer going to use this worker */
@@ -1637,9 +1660,9 @@ static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
     GPR_TIMER_MARK("pollset_work.finish_shutdown_locked", 0);
     finish_shutdown_locked(exec_ctx, pollset);
 
-    gpr_mu_unlock(&pollset->mu);
+    gpr_mu_unlock(&pollset->po.mu);
     grpc_exec_ctx_flush(exec_ctx);
-    gpr_mu_lock(&pollset->mu);
+    gpr_mu_lock(&pollset->po.mu);
   }
 
   *worker_hdl = NULL;
@@ -1653,130 +1676,160 @@ static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
   return error;
 }
 
-static void pollset_add_fd(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
-                           grpc_fd *fd) {
-  GPR_TIMER_BEGIN("pollset_add_fd", 0);
-
-  grpc_error *error = GRPC_ERROR_NONE;
+static void add_poll_object(grpc_exec_ctx *exec_ctx, poll_obj *bag,
+                            poll_obj_type bag_type, poll_obj *item,
+                            poll_obj_type item_type) {
+  GPR_TIMER_BEGIN("add_poll_object", 0);
 
-  gpr_mu_lock(&pollset->mu);
-  gpr_mu_lock(&fd->mu);
+#ifdef PO_DEBUG
+  GPR_ASSERT(item->obj_type == item_type);
+  GPR_ASSERT(bag->obj_type == bag_type);
+#endif
 
+  grpc_error *error = GRPC_ERROR_NONE;
   polling_island *pi_new = NULL;
 
+  gpr_mu_lock(&bag->mu);
+  gpr_mu_lock(&item->mu);
+
 retry:
-  /* 1) If fd->polling_island and pollset->polling_island are both non-NULL and
-   *    equal, do nothing.
-   * 2) If fd->polling_island and pollset->polling_island are both NULL, create
-   *    a new polling island (with a refcount of 2) and make the polling_island
-   *    fields in both fd and pollset to point to the new island
-   * 3) If one of fd->polling_island or pollset->polling_island is NULL, update
-   *    the NULL polling_island field to point to the non-NULL polling_island
-   *    field (ensure that the refcount on the polling island is incremented by
-   *    1 to account for the newly added reference)
-   * 4) Finally, if fd->polling_island and pollset->polling_island are non-NULL
-   *    and different, merge both the polling islands and update the
-   *    polling_island fields in both fd and pollset to point to the merged
-   *    polling island.
+  /*
+   * 1) If item->pi and bag->pi are both non-NULL and equal, do nothing
+   * 2) If item->pi and bag->pi are both NULL, create a new polling island (with
+   *    a refcount of 2) and point item->pi and bag->pi to the new island
+   * 3) If exactly one of item->pi or bag->pi is NULL, update it to point to
+   *    the other's non-NULL pi
+   * 4) Finally if item->pi and bag-pi are non-NULL and not-equal, merge the
+   *    polling islands and update item->pi and bag->pi to point to the new
+   *    island
    */
 
-  if (fd->orphaned) {
-    gpr_mu_unlock(&fd->mu);
-    gpr_mu_unlock(&pollset->mu);
-    /* early out */
+  /* Early out if we are trying to add an 'fd' to a 'bag' but the fd is already
+   * orphaned */
+  if (item_type == POLL_OBJ_FD && (FD_FROM_PO(item))->orphaned) {
+    gpr_mu_unlock(&item->mu);
+    gpr_mu_unlock(&bag->mu);
     return;
   }
 
-  if (fd->polling_island == pollset->polling_island) {
-    pi_new = fd->polling_island;
+  if (item->pi == bag->pi) {
+    pi_new = item->pi;
     if (pi_new == NULL) {
-      /* Unlock before creating a new polling island: the polling island will
-         create a workqueue which creates a file descriptor, and holding an fd
-         lock here can eventually cause a loop to appear to TSAN (making it
-         unhappy). We don't think it's a real loop (there's an epoch point where
-         that loop possibility disappears), but the advantages of keeping TSAN
-         happy outweigh any performance advantage we might have by keeping the
-         lock held. */
-      gpr_mu_unlock(&fd->mu);
-      pi_new = polling_island_create(exec_ctx, fd, &error);
-      gpr_mu_lock(&fd->mu);
-      /* Need to reverify any assumptions made between the initial lock and
-         getting to this branch: if they've changed, we need to throw away our
-         work and figure things out again. */
-      if (fd->polling_island != NULL) {
-        GRPC_POLLING_TRACE(
-            "pollset_add_fd: Raced creating new polling island. pi_new: %p "
-            "(fd: %d, pollset: %p)",
-            (void *)pi_new, fd->fd, (void *)pollset);
-
-        /* No need to lock 'pi_new' here since this is a new polling island and
-         * no one has a reference to it yet */
-        polling_island_remove_all_fds_locked(pi_new, true, &error);
-
-        /* Ref and unref so that the polling island gets deleted during unref */
-        PI_ADD_REF(pi_new, "dance_of_destruction");
-        PI_UNREF(exec_ctx, pi_new, "dance_of_destruction");
-        goto retry;
+      /* GPR_ASSERT(item->pi == bag->pi == NULL) */
+
+      /* If we are adding an fd to a bag (i.e pollset or pollset_set), then
+       * we need to do some extra work to make TSAN happy */
+      if (item_type == POLL_OBJ_FD) {
+        /* Unlock before creating a new polling island: the polling island will
+           create a workqueue which creates a file descriptor, and holding an fd
+           lock here can eventually cause a loop to appear to TSAN (making it
+           unhappy). We don't think it's a real loop (there's an epoch point
+           where that loop possibility disappears), but the advantages of
+           keeping TSAN happy outweigh any performance advantage we might have
+           by keeping the lock held. */
+        gpr_mu_unlock(&item->mu);
+        pi_new = polling_island_create(exec_ctx, FD_FROM_PO(item), &error);
+        gpr_mu_lock(&item->mu);
+
+        /* Need to reverify any assumptions made between the initial lock and
+           getting to this branch: if they've changed, we need to throw away our
+           work and figure things out again. */
+        if (item->pi != NULL) {
+          GRPC_POLLING_TRACE(
+              "add_poll_object: Raced creating new polling island. pi_new: %p "
+              "(fd: %d, %s: %p)",
+              (void *)pi_new, FD_FROM_PO(item)->fd, poll_obj_string(bag_type),
+              (void *)bag);
+          /* No need to lock 'pi_new' here since this is a new polling island
+            * and no one has a reference to it yet */
+          polling_island_remove_all_fds_locked(pi_new, true, &error);
+
+          /* Ref and unref so that the polling island gets deleted during unref
+           */
+          PI_ADD_REF(pi_new, "dance_of_destruction");
+          PI_UNREF(exec_ctx, pi_new, "dance_of_destruction");
+          goto retry;
+        }
       } else {
-        GRPC_POLLING_TRACE(
-            "pollset_add_fd: Created new polling island. pi_new: %p (fd: %d, "
-            "pollset: %p)",
-            (void *)pi_new, fd->fd, (void *)pollset);
+        pi_new = polling_island_create(exec_ctx, NULL, &error);
       }
+
+      GRPC_POLLING_TRACE(
+          "add_poll_object: Created new polling island. pi_new: %p (%s: %p, "
+          "%s: %p)",
+          (void *)pi_new, poll_obj_string(item_type), (void *)item,
+          poll_obj_string(bag_type), (void *)bag);
+    } else {
+      GRPC_POLLING_TRACE(
+          "add_poll_object: Same polling island. pi: %p (%s, %s)",
+          (void *)pi_new, poll_obj_string(item_type),
+          poll_obj_string(bag_type));
+    }
+  } else if (item->pi == NULL) {
+    /* GPR_ASSERT(bag->pi != NULL) */
+    /* Make pi_new point to latest pi*/
+    pi_new = polling_island_lock(bag->pi);
+
+    if (item_type == POLL_OBJ_FD) {
+      grpc_fd *fd = FD_FROM_PO(item);
+      polling_island_add_fds_locked(pi_new, &fd, 1, true, &error);
     }
-  } else if (fd->polling_island == NULL) {
-    pi_new = polling_island_lock(pollset->polling_island);
-    polling_island_add_fds_locked(pi_new, &fd, 1, true, &error);
-    gpr_mu_unlock(&pi_new->mu);
 
+    gpr_mu_unlock(&pi_new->mu);
     GRPC_POLLING_TRACE(
-        "pollset_add_fd: fd->pi was NULL. pi_new: %p (fd: %d, pollset: %p, "
-        "pollset->pi: %p)",
-        (void *)pi_new, fd->fd, (void *)pollset,
-        (void *)pollset->polling_island);
-  } else if (pollset->polling_island == NULL) {
-    pi_new = polling_island_lock(fd->polling_island);
+        "add_poll_obj: item->pi was NULL. pi_new: %p (item(%s): %p, "
+        "bag(%s): %p)",
+        (void *)pi_new, poll_obj_string(item_type), (void *)item,
+        poll_obj_string(bag_type), (void *)bag);
+  } else if (bag->pi == NULL) {
+    /* GPR_ASSERT(item->pi != NULL) */
+    /* Make pi_new to point to latest pi */
+    pi_new = polling_island_lock(item->pi);
     gpr_mu_unlock(&pi_new->mu);
-
     GRPC_POLLING_TRACE(
-        "pollset_add_fd: pollset->pi was NULL. pi_new: %p (fd: %d, pollset: "
-        "%p, fd->pi: %p",
-        (void *)pi_new, fd->fd, (void *)pollset, (void *)fd->polling_island);
+        "add_poll_obj: bag->pi was NULL. pi_new: %p (item(%s): %p, "
+        "bag(%s): %p)",
+        (void *)pi_new, poll_obj_string(item_type), (void *)item,
+        poll_obj_string(bag_type), (void *)bag);
   } else {
-    pi_new = polling_island_merge(fd->polling_island, pollset->polling_island,
-                                  &error);
+    pi_new = polling_island_merge(item->pi, bag->pi, &error);
     GRPC_POLLING_TRACE(
-        "pollset_add_fd: polling islands merged. pi_new: %p (fd: %d, pollset: "
-        "%p, fd->pi: %p, pollset->pi: %p)",
-        (void *)pi_new, fd->fd, (void *)pollset, (void *)fd->polling_island,
-        (void *)pollset->polling_island);
+        "add_poll_obj: polling islands merged. pi_new: %p (item(%s): %p, "
+        "bag(%s): %p)",
+        (void *)pi_new, poll_obj_string(item_type), (void *)item,
+        poll_obj_string(bag_type), (void *)bag);
   }
 
-  /* At this point, pi_new is the polling island that both fd->polling_island
-     and pollset->polling_island must be pointing to */
+  /* At this point, pi_new is the polling island that both item->pi and bag->pi
+     MUST be pointing to */
 
-  if (fd->polling_island != pi_new) {
-    PI_ADD_REF(pi_new, "fd");
-    if (fd->polling_island != NULL) {
-      PI_UNREF(exec_ctx, fd->polling_island, "fd");
+  if (item->pi != pi_new) {
+    PI_ADD_REF(pi_new, poll_obj_string(item_type));
+    if (item->pi != NULL) {
+      PI_UNREF(exec_ctx, item->pi, poll_obj_string(item_type));
     }
-    fd->polling_island = pi_new;
+    item->pi = pi_new;
   }
 
-  if (pollset->polling_island != pi_new) {
-    PI_ADD_REF(pi_new, "ps");
-    if (pollset->polling_island != NULL) {
-      PI_UNREF(exec_ctx, pollset->polling_island, "ps");
+  if (bag->pi != pi_new) {
+    PI_ADD_REF(pi_new, poll_obj_string(bag_type));
+    if (bag->pi != NULL) {
+      PI_UNREF(exec_ctx, bag->pi, poll_obj_string(bag_type));
     }
-    pollset->polling_island = pi_new;
+    bag->pi = pi_new;
   }
 
-  gpr_mu_unlock(&fd->mu);
-  gpr_mu_unlock(&pollset->mu);
+  gpr_mu_unlock(&item->mu);
+  gpr_mu_unlock(&bag->mu);
 
-  GRPC_LOG_IF_ERROR("pollset_add_fd", error);
+  GRPC_LOG_IF_ERROR("add_poll_object", error);
+  GPR_TIMER_END("add_poll_object", 0);
+}
 
-  GPR_TIMER_END("pollset_add_fd", 0);
+static void pollset_add_fd(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
+                           grpc_fd *fd) {
+  add_poll_object(exec_ctx, &pollset->po, POLL_OBJ_POLLSET, &fd->po,
+                  POLL_OBJ_FD);
 }
 
 /*******************************************************************************
@@ -1784,142 +1837,60 @@ retry:
  */
 
 static grpc_pollset_set *pollset_set_create(void) {
-  grpc_pollset_set *pollset_set = gpr_malloc(sizeof(*pollset_set));
-  memset(pollset_set, 0, sizeof(*pollset_set));
-  gpr_mu_init(&pollset_set->mu);
-  return pollset_set;
+  grpc_pollset_set *pss = gpr_malloc(sizeof(*pss));
+  gpr_mu_init(&pss->po.mu);
+  pss->po.pi = NULL;
+#ifdef PO_DEBUG
+  pss->po.obj_type = POLL_OBJ_POLLSET_SET;
+#endif
+  return pss;
 }
 
-static void pollset_set_destroy(grpc_pollset_set *pollset_set) {
-  size_t i;
-  gpr_mu_destroy(&pollset_set->mu);
-  for (i = 0; i < pollset_set->fd_count; i++) {
-    GRPC_FD_UNREF(pollset_set->fds[i], "pollset_set");
+static void pollset_set_destroy(grpc_pollset_set *pss) {
+  gpr_mu_destroy(&pss->po.mu);
+
+  if (pss->po.pi != NULL) {
+    grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+    PI_UNREF(&exec_ctx, pss->po.pi, "pss_destroy");
+    grpc_exec_ctx_finish(&exec_ctx);
   }
-  gpr_free(pollset_set->pollsets);
-  gpr_free(pollset_set->pollset_sets);
-  gpr_free(pollset_set->fds);
-  gpr_free(pollset_set);
+
+  gpr_free(pss);
 }
 
-static void pollset_set_add_fd(grpc_exec_ctx *exec_ctx,
-                               grpc_pollset_set *pollset_set, grpc_fd *fd) {
-  size_t i;
-  gpr_mu_lock(&pollset_set->mu);
-  if (pollset_set->fd_count == pollset_set->fd_capacity) {
-    pollset_set->fd_capacity = GPR_MAX(8, 2 * pollset_set->fd_capacity);
-    pollset_set->fds = gpr_realloc(
-        pollset_set->fds, pollset_set->fd_capacity * sizeof(*pollset_set->fds));
-  }
-  GRPC_FD_REF(fd, "pollset_set");
-  pollset_set->fds[pollset_set->fd_count++] = fd;
-  for (i = 0; i < pollset_set->pollset_count; i++) {
-    pollset_add_fd(exec_ctx, pollset_set->pollsets[i], fd);
-  }
-  for (i = 0; i < pollset_set->pollset_set_count; i++) {
-    pollset_set_add_fd(exec_ctx, pollset_set->pollset_sets[i], fd);
-  }
-  gpr_mu_unlock(&pollset_set->mu);
+static void pollset_set_add_fd(grpc_exec_ctx *exec_ctx, grpc_pollset_set *pss,
+                               grpc_fd *fd) {
+  add_poll_object(exec_ctx, &pss->po, POLL_OBJ_POLLSET_SET, &fd->po,
+                  POLL_OBJ_FD);
 }
 
-static void pollset_set_del_fd(grpc_exec_ctx *exec_ctx,
-                               grpc_pollset_set *pollset_set, grpc_fd *fd) {
-  size_t i;
-  gpr_mu_lock(&pollset_set->mu);
-  for (i = 0; i < pollset_set->fd_count; i++) {
-    if (pollset_set->fds[i] == fd) {
-      pollset_set->fd_count--;
-      GPR_SWAP(grpc_fd *, pollset_set->fds[i],
-               pollset_set->fds[pollset_set->fd_count]);
-      GRPC_FD_UNREF(fd, "pollset_set");
-      break;
-    }
-  }
-  for (i = 0; i < pollset_set->pollset_set_count; i++) {
-    pollset_set_del_fd(exec_ctx, pollset_set->pollset_sets[i], fd);
-  }
-  gpr_mu_unlock(&pollset_set->mu);
+static void pollset_set_del_fd(grpc_exec_ctx *exec_ctx, grpc_pollset_set *pss,
+                               grpc_fd *fd) {
+  /* Nothing to do */
 }
 
 static void pollset_set_add_pollset(grpc_exec_ctx *exec_ctx,
-                                    grpc_pollset_set *pollset_set,
-                                    grpc_pollset *pollset) {
-  size_t i, j;
-  gpr_mu_lock(&pollset_set->mu);
-  if (pollset_set->pollset_count == pollset_set->pollset_capacity) {
-    pollset_set->pollset_capacity =
-        GPR_MAX(8, 2 * pollset_set->pollset_capacity);
-    pollset_set->pollsets =
-        gpr_realloc(pollset_set->pollsets, pollset_set->pollset_capacity *
-                                               sizeof(*pollset_set->pollsets));
-  }
-  pollset_set->pollsets[pollset_set->pollset_count++] = pollset;
-  for (i = 0, j = 0; i < pollset_set->fd_count; i++) {
-    if (fd_is_orphaned(pollset_set->fds[i])) {
-      GRPC_FD_UNREF(pollset_set->fds[i], "pollset_set");
-    } else {
-      pollset_add_fd(exec_ctx, pollset, pollset_set->fds[i]);
-      pollset_set->fds[j++] = pollset_set->fds[i];
-    }
-  }
-  pollset_set->fd_count = j;
-  gpr_mu_unlock(&pollset_set->mu);
+                                    grpc_pollset_set *pss, grpc_pollset *ps) {
+  add_poll_object(exec_ctx, &pss->po, POLL_OBJ_POLLSET_SET, &ps->po,
+                  POLL_OBJ_POLLSET);
 }
 
 static void pollset_set_del_pollset(grpc_exec_ctx *exec_ctx,
-                                    grpc_pollset_set *pollset_set,
-                                    grpc_pollset *pollset) {
-  size_t i;
-  gpr_mu_lock(&pollset_set->mu);
-  for (i = 0; i < pollset_set->pollset_count; i++) {
-    if (pollset_set->pollsets[i] == pollset) {
-      pollset_set->pollset_count--;
-      GPR_SWAP(grpc_pollset *, pollset_set->pollsets[i],
-               pollset_set->pollsets[pollset_set->pollset_count]);
-      break;
-    }
-  }
-  gpr_mu_unlock(&pollset_set->mu);
+                                    grpc_pollset_set *pss, grpc_pollset *ps) {
+  /* Nothing to do */
 }
 
 static void pollset_set_add_pollset_set(grpc_exec_ctx *exec_ctx,
                                         grpc_pollset_set *bag,
                                         grpc_pollset_set *item) {
-  size_t i, j;
-  gpr_mu_lock(&bag->mu);
-  if (bag->pollset_set_count == bag->pollset_set_capacity) {
-    bag->pollset_set_capacity = GPR_MAX(8, 2 * bag->pollset_set_capacity);
-    bag->pollset_sets =
-        gpr_realloc(bag->pollset_sets,
-                    bag->pollset_set_capacity * sizeof(*bag->pollset_sets));
-  }
-  bag->pollset_sets[bag->pollset_set_count++] = item;
-  for (i = 0, j = 0; i < bag->fd_count; i++) {
-    if (fd_is_orphaned(bag->fds[i])) {
-      GRPC_FD_UNREF(bag->fds[i], "pollset_set");
-    } else {
-      pollset_set_add_fd(exec_ctx, item, bag->fds[i]);
-      bag->fds[j++] = bag->fds[i];
-    }
-  }
-  bag->fd_count = j;
-  gpr_mu_unlock(&bag->mu);
+  add_poll_object(exec_ctx, &bag->po, POLL_OBJ_POLLSET_SET, &item->po,
+                  POLL_OBJ_POLLSET_SET);
 }
 
 static void pollset_set_del_pollset_set(grpc_exec_ctx *exec_ctx,
                                         grpc_pollset_set *bag,
                                         grpc_pollset_set *item) {
-  size_t i;
-  gpr_mu_lock(&bag->mu);
-  for (i = 0; i < bag->pollset_set_count; i++) {
-    if (bag->pollset_sets[i] == item) {
-      bag->pollset_set_count--;
-      GPR_SWAP(grpc_pollset_set *, bag->pollset_sets[i],
-               bag->pollset_sets[bag->pollset_set_count]);
-      break;
-    }
-  }
-  gpr_mu_unlock(&bag->mu);
+  /* Nothing to do */
 }
 
 /* Test helper functions
@@ -1927,9 +1898,9 @@ static void pollset_set_del_pollset_set(grpc_exec_ctx *exec_ctx,
 void *grpc_fd_get_polling_island(grpc_fd *fd) {
   polling_island *pi;
 
-  gpr_mu_lock(&fd->mu);
-  pi = fd->polling_island;
-  gpr_mu_unlock(&fd->mu);
+  gpr_mu_lock(&fd->po.mu);
+  pi = fd->po.pi;
+  gpr_mu_unlock(&fd->po.mu);
 
   return pi;
 }
@@ -1937,9 +1908,9 @@ void *grpc_fd_get_polling_island(grpc_fd *fd) {
 void *grpc_pollset_get_polling_island(grpc_pollset *ps) {
   polling_island *pi;
 
-  gpr_mu_lock(&ps->mu);
-  pi = ps->polling_island;
-  gpr_mu_unlock(&ps->mu);
+  gpr_mu_lock(&ps->po.mu);
+  pi = ps->po.pi;
+  gpr_mu_unlock(&ps->po.mu);
 
   return pi;
 }
@@ -2000,7 +1971,7 @@ static const grpc_event_engine_vtable vtable = {
 
     .workqueue_ref = workqueue_ref,
     .workqueue_unref = workqueue_unref,
-    .workqueue_enqueue = workqueue_enqueue,
+    .workqueue_scheduler = workqueue_scheduler,
 
     .shutdown_engine = shutdown_engine,
 };
diff --git a/src/core/lib/iomgr/ev_poll_posix.c b/src/core/lib/iomgr/ev_poll_posix.c
index 21b28e5554..5bc5621443 100644
--- a/src/core/lib/iomgr/ev_poll_posix.c
+++ b/src/core/lib/iomgr/ev_poll_posix.c
@@ -397,7 +397,7 @@ static void close_fd_locked(grpc_exec_ctx *exec_ctx, grpc_fd *fd) {
   if (!fd->released) {
     close(fd->fd);
   }
-  grpc_exec_ctx_sched(exec_ctx, fd->on_done_closure, GRPC_ERROR_NONE, NULL);
+  grpc_closure_sched(exec_ctx, fd->on_done_closure, GRPC_ERROR_NONE);
 }
 
 static int fd_wrapped_fd(grpc_fd *fd) {
@@ -457,16 +457,14 @@ static grpc_error *fd_shutdown_error(bool shutdown) {
 static void notify_on_locked(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
                              grpc_closure **st, grpc_closure *closure) {
   if (fd->shutdown) {
-    grpc_exec_ctx_sched(exec_ctx, closure, GRPC_ERROR_CREATE("FD shutdown"),
-                        NULL);
+    grpc_closure_sched(exec_ctx, closure, GRPC_ERROR_CREATE("FD shutdown"));
   } else if (*st == CLOSURE_NOT_READY) {
     /* not ready ==> switch to a waiting state by setting the closure */
     *st = closure;
   } else if (*st == CLOSURE_READY) {
     /* already ready ==> queue the closure to run immediately */
     *st = CLOSURE_NOT_READY;
-    grpc_exec_ctx_sched(exec_ctx, closure, fd_shutdown_error(fd->shutdown),
-                        NULL);
+    grpc_closure_sched(exec_ctx, closure, fd_shutdown_error(fd->shutdown));
     maybe_wake_one_watcher_locked(fd);
   } else {
     /* upcallptr was set to a different closure.  This is an error! */
@@ -489,7 +487,7 @@ static int set_ready_locked(grpc_exec_ctx *exec_ctx, grpc_fd *fd,
     return 0;
   } else {
     /* waiting ==> queue closure */
-    grpc_exec_ctx_sched(exec_ctx, *st, fd_shutdown_error(fd->shutdown), NULL);
+    grpc_closure_sched(exec_ctx, *st, fd_shutdown_error(fd->shutdown));
     *st = CLOSURE_NOT_READY;
     return 1;
   }
@@ -852,7 +850,7 @@ static void finish_shutdown(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset) {
     GRPC_FD_UNREF(pollset->fds[i], "multipoller");
   }
   pollset->fd_count = 0;
-  grpc_exec_ctx_sched(exec_ctx, pollset->shutdown_done, GRPC_ERROR_NONE, NULL);
+  grpc_closure_sched(exec_ctx, pollset->shutdown_done, GRPC_ERROR_NONE);
 }
 
 static void work_combine_error(grpc_error **composite, grpc_error *error) {
@@ -901,7 +899,7 @@ static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
   if (!pollset_has_workers(pollset) &&
       !grpc_closure_list_empty(pollset->idle_jobs)) {
     GPR_TIMER_MARK("pollset_work.idle_jobs", 0);
-    grpc_exec_ctx_enqueue_list(exec_ctx, &pollset->idle_jobs, NULL);
+    grpc_closure_list_sched(exec_ctx, &pollset->idle_jobs);
     goto done;
   }
   /* If we're shutting down then we don't execute any extended work */
@@ -1081,7 +1079,7 @@ static grpc_error *pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
        * TODO(dklempner): Can we refactor the shutdown logic to avoid this? */
       gpr_mu_lock(&pollset->mu);
     } else if (!grpc_closure_list_empty(pollset->idle_jobs)) {
-      grpc_exec_ctx_enqueue_list(exec_ctx, &pollset->idle_jobs, NULL);
+      grpc_closure_list_sched(exec_ctx, &pollset->idle_jobs);
       gpr_mu_unlock(&pollset->mu);
       grpc_exec_ctx_flush(exec_ctx);
       gpr_mu_lock(&pollset->mu);
@@ -1100,7 +1098,7 @@ static void pollset_shutdown(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
   pollset->shutdown_done = closure;
   pollset_kick(pollset, GRPC_POLLSET_KICK_BROADCAST);
   if (!pollset_has_workers(pollset)) {
-    grpc_exec_ctx_enqueue_list(exec_ctx, &pollset->idle_jobs, NULL);
+    grpc_closure_list_sched(exec_ctx, &pollset->idle_jobs);
   }
   if (!pollset->called_shutdown && !pollset_has_workers(pollset)) {
     pollset->called_shutdown = 1;
@@ -1288,10 +1286,8 @@ static void workqueue_unref(grpc_exec_ctx *exec_ctx,
                             grpc_workqueue *workqueue) {}
 #endif
 
-static void workqueue_enqueue(grpc_exec_ctx *exec_ctx,
-                              grpc_workqueue *workqueue, grpc_closure *closure,
-                              grpc_error *error) {
-  grpc_exec_ctx_sched(exec_ctx, closure, error, NULL);
+static grpc_closure_scheduler *workqueue_scheduler(grpc_workqueue *workqueue) {
+  return grpc_schedule_on_exec_ctx;
 }
 
 /*******************************************************************************
@@ -1534,7 +1530,7 @@ static const grpc_event_engine_vtable vtable = {
 
     .workqueue_ref = workqueue_ref,
     .workqueue_unref = workqueue_unref,
-    .workqueue_enqueue = workqueue_enqueue,
+    .workqueue_scheduler = workqueue_scheduler,
 
     .shutdown_engine = shutdown_engine,
 };
diff --git a/src/core/lib/iomgr/ev_posix.c b/src/core/lib/iomgr/ev_posix.c
index ab139895fd..2975d619e1 100644
--- a/src/core/lib/iomgr/ev_posix.c
+++ b/src/core/lib/iomgr/ev_posix.c
@@ -275,9 +275,8 @@ void grpc_workqueue_unref(grpc_exec_ctx *exec_ctx, grpc_workqueue *workqueue) {
 }
 #endif
 
-void grpc_workqueue_enqueue(grpc_exec_ctx *exec_ctx, grpc_workqueue *workqueue,
-                            grpc_closure *closure, grpc_error *error) {
-  g_event_engine->workqueue_enqueue(exec_ctx, workqueue, closure, error);
+grpc_closure_scheduler *grpc_workqueue_scheduler(grpc_workqueue *workqueue) {
+  return g_event_engine->workqueue_scheduler(workqueue);
 }
 
 #endif  // GRPC_POSIX_SOCKET
diff --git a/src/core/lib/iomgr/ev_posix.h b/src/core/lib/iomgr/ev_posix.h
index cb5832539d..1068a4bad5 100644
--- a/src/core/lib/iomgr/ev_posix.h
+++ b/src/core/lib/iomgr/ev_posix.h
@@ -106,8 +106,7 @@ typedef struct grpc_event_engine_vtable {
   grpc_workqueue *(*workqueue_ref)(grpc_workqueue *workqueue);
   void (*workqueue_unref)(grpc_exec_ctx *exec_ctx, grpc_workqueue *workqueue);
 #endif
-  void (*workqueue_enqueue)(grpc_exec_ctx *exec_ctx, grpc_workqueue *workqueue,
-                            grpc_closure *closure, grpc_error *error);
+  grpc_closure_scheduler *(*workqueue_scheduler)(grpc_workqueue *workqueue);
 } grpc_event_engine_vtable;
 
 void grpc_event_engine_init(void);
diff --git a/src/core/lib/iomgr/exec_ctx.c b/src/core/lib/iomgr/exec_ctx.c
index 604713e578..6aa788f8e5 100644
--- a/src/core/lib/iomgr/exec_ctx.c
+++ b/src/core/lib/iomgr/exec_ctx.c
@@ -57,7 +57,6 @@ bool grpc_always_ready_to_finish(grpc_exec_ctx *exec_ctx, void *arg_ignored) {
   return true;
 }
 
-#ifndef GRPC_EXECUTION_CONTEXT_SANITIZER
 bool grpc_exec_ctx_flush(grpc_exec_ctx *exec_ctx) {
   bool did_something = 0;
   GPR_TIMER_BEGIN("grpc_exec_ctx_flush", 0);
@@ -67,8 +66,10 @@ bool grpc_exec_ctx_flush(grpc_exec_ctx *exec_ctx) {
       exec_ctx->closure_list.head = exec_ctx->closure_list.tail = NULL;
       while (c != NULL) {
         grpc_closure *next = c->next_data.next;
+        grpc_error *error = c->error_data.error;
         did_something = true;
-        grpc_closure_run(exec_ctx, c, c->error_data.error);
+        c->cb(exec_ctx, c->cb_arg, error);
+        GRPC_ERROR_UNREF(error);
         c = next;
       }
     } else if (!grpc_combiner_continue_exec_ctx(exec_ctx)) {
@@ -76,30 +77,6 @@ bool grpc_exec_ctx_flush(grpc_exec_ctx *exec_ctx) {
     }
   }
   GPR_ASSERT(exec_ctx->active_combiner == NULL);
-  if (exec_ctx->stealing_from_workqueue != NULL) {
-    if (grpc_exec_ctx_ready_to_finish(exec_ctx)) {
-      grpc_workqueue_enqueue(exec_ctx, exec_ctx->stealing_from_workqueue,
-                             exec_ctx->stolen_closure,
-                             exec_ctx->stolen_closure->error_data.error);
-      GRPC_WORKQUEUE_UNREF(exec_ctx, exec_ctx->stealing_from_workqueue,
-                           "exec_ctx_sched");
-      exec_ctx->stealing_from_workqueue = NULL;
-      exec_ctx->stolen_closure = NULL;
-    } else {
-      grpc_closure *c = exec_ctx->stolen_closure;
-      GRPC_WORKQUEUE_UNREF(exec_ctx, exec_ctx->stealing_from_workqueue,
-                           "exec_ctx_sched");
-      exec_ctx->stealing_from_workqueue = NULL;
-      exec_ctx->stolen_closure = NULL;
-      grpc_error *error = c->error_data.error;
-      GPR_TIMER_BEGIN("grpc_exec_ctx_flush.stolen_cb", 0);
-      c->cb(exec_ctx, c->cb_arg, error);
-      GRPC_ERROR_UNREF(error);
-      GPR_TIMER_END("grpc_exec_ctx_flush.stolen_cb", 0);
-      grpc_exec_ctx_flush(exec_ctx);
-      did_something = true;
-    }
-  }
   GPR_TIMER_END("grpc_exec_ctx_flush", 0);
   return did_something;
 }
@@ -109,104 +86,21 @@ void grpc_exec_ctx_finish(grpc_exec_ctx *exec_ctx) {
   grpc_exec_ctx_flush(exec_ctx);
 }
 
-void grpc_exec_ctx_sched(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
-                         grpc_error *error,
-                         grpc_workqueue *offload_target_or_null) {
-  GPR_TIMER_BEGIN("grpc_exec_ctx_sched", 0);
-  if (offload_target_or_null == NULL) {
-    grpc_closure_list_append(&exec_ctx->closure_list, closure, error);
-  } else if (exec_ctx->stealing_from_workqueue == NULL) {
-    exec_ctx->stealing_from_workqueue = offload_target_or_null;
-    closure->error_data.error = error;
-    exec_ctx->stolen_closure = closure;
-  } else if (exec_ctx->stealing_from_workqueue != offload_target_or_null) {
-    grpc_workqueue_enqueue(exec_ctx, offload_target_or_null, closure, error);
-    GRPC_WORKQUEUE_UNREF(exec_ctx, offload_target_or_null, "exec_ctx_sched");
-  } else { /* stealing_from_workqueue == offload_target_or_null */
-    grpc_workqueue_enqueue(exec_ctx, offload_target_or_null,
-                           exec_ctx->stolen_closure,
-                           exec_ctx->stolen_closure->error_data.error);
-    closure->error_data.error = error;
-    exec_ctx->stolen_closure = closure;
-    GRPC_WORKQUEUE_UNREF(exec_ctx, offload_target_or_null, "exec_ctx_sched");
-  }
-  GPR_TIMER_END("grpc_exec_ctx_sched", 0);
+static void exec_ctx_run(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
+                         grpc_error *error) {
+  closure->cb(exec_ctx, closure->cb_arg, error);
+  GRPC_ERROR_UNREF(error);
 }
 
-void grpc_exec_ctx_enqueue_list(grpc_exec_ctx *exec_ctx,
-                                grpc_closure_list *list,
-                                grpc_workqueue *offload_target_or_null) {
-  grpc_closure_list_move(list, &exec_ctx->closure_list);
+static void exec_ctx_sched(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
+                           grpc_error *error) {
+  grpc_closure_list_append(&exec_ctx->closure_list, closure, error);
 }
 
 void grpc_exec_ctx_global_init(void) {}
 void grpc_exec_ctx_global_shutdown(void) {}
-#else
-static gpr_mu g_mu;
-static gpr_cv g_cv;
-static int g_threads = 0;
-
-static void run_closure(void *arg) {
-  grpc_closure *closure = arg;
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  closure->cb(&exec_ctx, closure->cb_arg, (closure->final_data & 1) != 0);
-  grpc_exec_ctx_finish(&exec_ctx);
-  gpr_mu_lock(&g_mu);
-  if (--g_threads == 0) {
-    gpr_cv_signal(&g_cv);
-  }
-  gpr_mu_unlock(&g_mu);
-}
-
-static void start_closure(grpc_closure *closure) {
-  gpr_thd_id id;
-  gpr_mu_lock(&g_mu);
-  g_threads++;
-  gpr_mu_unlock(&g_mu);
-  gpr_thd_new(&id, run_closure, closure, NULL);
-}
-
-bool grpc_exec_ctx_flush(grpc_exec_ctx *exec_ctx) { return false; }
-
-void grpc_exec_ctx_finish(grpc_exec_ctx *exec_ctx) {}
 
-void grpc_exec_ctx_enqueue(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
-                           bool success,
-                           grpc_workqueue *offload_target_or_null) {
-  GPR_ASSERT(offload_target_or_null == NULL);
-  if (closure == NULL) return;
-  closure->final_data = success;
-  start_closure(closure);
-}
-
-void grpc_exec_ctx_enqueue_list(grpc_exec_ctx *exec_ctx,
-                                grpc_closure_list *list,
-                                grpc_workqueue *offload_target_or_null) {
-  GPR_ASSERT(offload_target_or_null == NULL);
-  if (list == NULL) return;
-  grpc_closure *p = list->head;
-  while (p) {
-    grpc_closure *start = p;
-    p = grpc_closure_next(start);
-    start_closure(start);
-  }
-  grpc_closure_list r = GRPC_CLOSURE_LIST_INIT;
-  *list = r;
-}
-
-void grpc_exec_ctx_global_init(void) {
-  gpr_mu_init(&g_mu);
-  gpr_cv_init(&g_cv);
-}
-
-void grpc_exec_ctx_global_shutdown(void) {
-  gpr_mu_lock(&g_mu);
-  while (g_threads != 0) {
-    gpr_cv_wait(&g_cv, &g_mu, gpr_inf_future(GPR_CLOCK_REALTIME));
-  }
-  gpr_mu_unlock(&g_mu);
-
-  gpr_mu_destroy(&g_mu);
-  gpr_cv_destroy(&g_cv);
-}
-#endif
+static const grpc_closure_scheduler_vtable exec_ctx_scheduler_vtable = {
+    exec_ctx_run, exec_ctx_sched};
+static grpc_closure_scheduler exec_ctx_scheduler = {&exec_ctx_scheduler_vtable};
+grpc_closure_scheduler *grpc_schedule_on_exec_ctx = &exec_ctx_scheduler;
diff --git a/src/core/lib/iomgr/exec_ctx.h b/src/core/lib/iomgr/exec_ctx.h
index 7e50cb9825..e566f1b3e8 100644
--- a/src/core/lib/iomgr/exec_ctx.h
+++ b/src/core/lib/iomgr/exec_ctx.h
@@ -66,17 +66,6 @@ typedef struct grpc_combiner grpc_combiner;
 #ifndef GRPC_EXECUTION_CONTEXT_SANITIZER
 struct grpc_exec_ctx {
   grpc_closure_list closure_list;
-  /** The workqueue we're stealing work from.
-      As items are queued to the execution context, we try to steal one
-      workqueue item and execute it inline (assuming the exec_ctx is not
-      finished) - doing so does not invalidate the workqueue's contract, and
-      provides a small latency win in cases where we get a hit */
-  grpc_workqueue *stealing_from_workqueue;
-  /** The workqueue item that was stolen from the workqueue above. When new
-      items are scheduled to be offloaded to that workqueue, we need to update
-      this like a 1-deep fifo to maintain the invariant that workqueue items
-      queued by one thread are started in order */
-  grpc_closure *stolen_closure;
   /** currently active combiner: updated only via combiner.c */
   grpc_combiner *active_combiner;
   /** last active combiner in the active combiner list */
@@ -89,10 +78,7 @@ struct grpc_exec_ctx {
 /* initializer for grpc_exec_ctx:
    prefer to use GRPC_EXEC_CTX_INIT whenever possible */
 #define GRPC_EXEC_CTX_INIT_WITH_FINISH_CHECK(finish_check, finish_check_arg) \
-  {                                                                          \
-    GRPC_CLOSURE_LIST_INIT, NULL, NULL, NULL, NULL, false, finish_check_arg, \
-        finish_check                                                         \
-  }
+  { GRPC_CLOSURE_LIST_INIT, NULL, NULL, false, finish_check_arg, finish_check }
 #else
 struct grpc_exec_ctx {
   bool cached_ready_to_finish;
@@ -108,6 +94,8 @@ struct grpc_exec_ctx {
 #define GRPC_EXEC_CTX_INIT \
   GRPC_EXEC_CTX_INIT_WITH_FINISH_CHECK(grpc_always_ready_to_finish, NULL)
 
+extern grpc_closure_scheduler *grpc_schedule_on_exec_ctx;
+
 /** Flush any work that has been enqueued onto this grpc_exec_ctx.
  *  Caller must guarantee that no interfering locks are held.
  *  Returns true if work was performed, false otherwise. */
@@ -115,14 +103,6 @@ bool grpc_exec_ctx_flush(grpc_exec_ctx *exec_ctx);
 /** Finish any pending work for a grpc_exec_ctx. Must be called before
  *  the instance is destroyed, or work may be lost. */
 void grpc_exec_ctx_finish(grpc_exec_ctx *exec_ctx);
-/** Add a closure to be executed in the future.
-    If \a offload_target_or_null is NULL, the closure will be executed at the
-    next exec_ctx.{finish,flush} point.
-    If \a offload_target_or_null is non-NULL, the closure will be scheduled
-    against the workqueue, and a reference to the workqueue will be consumed. */
-void grpc_exec_ctx_sched(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
-                         grpc_error *error,
-                         grpc_workqueue *offload_target_or_null);
 /** Returns true if we'd like to leave this execution context as soon as
     possible: useful for deciding whether to do something more or not depending
     on outside context */
@@ -131,11 +111,6 @@ bool grpc_exec_ctx_ready_to_finish(grpc_exec_ctx *exec_ctx);
 bool grpc_never_ready_to_finish(grpc_exec_ctx *exec_ctx, void *arg_ignored);
 /** A finish check that is always ready to finish */
 bool grpc_always_ready_to_finish(grpc_exec_ctx *exec_ctx, void *arg_ignored);
-/** Add a list of closures to be executed at the next flush/finish point.
- *  Leaves \a list empty. */
-void grpc_exec_ctx_enqueue_list(grpc_exec_ctx *exec_ctx,
-                                grpc_closure_list *list,
-                                grpc_workqueue *offload_target_or_null);
 
 void grpc_exec_ctx_global_init(void);
 
diff --git a/src/core/lib/iomgr/executor.c b/src/core/lib/iomgr/executor.c
index 8d7535d6fe..852775564f 100644
--- a/src/core/lib/iomgr/executor.c
+++ b/src/core/lib/iomgr/executor.c
@@ -77,10 +77,18 @@ static void closure_exec_thread_func(void *ignored) {
       gpr_mu_unlock(&g_executor.mu);
       break;
     } else {
-      grpc_exec_ctx_enqueue_list(&exec_ctx, &g_executor.closures, NULL);
+      grpc_closure *c = g_executor.closures.head;
+      grpc_closure_list_init(&g_executor.closures);
+      gpr_mu_unlock(&g_executor.mu);
+      while (c != NULL) {
+        grpc_closure *next = c->next_data.next;
+        grpc_error *error = c->error_data.error;
+        c->cb(&exec_ctx, c->cb_arg, error);
+        GRPC_ERROR_UNREF(error);
+        c = next;
+      }
+      grpc_exec_ctx_flush(&exec_ctx);
     }
-    gpr_mu_unlock(&g_executor.mu);
-    grpc_exec_ctx_flush(&exec_ctx);
   }
   grpc_exec_ctx_finish(&exec_ctx);
 }
@@ -112,7 +120,8 @@ static void maybe_spawn_locked() {
   g_executor.pending_join = 1;
 }
 
-void grpc_executor_push(grpc_closure *closure, grpc_error *error) {
+static void executor_push(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
+                          grpc_error *error) {
   gpr_mu_lock(&g_executor.mu);
   if (g_executor.shutting_down == 0) {
     grpc_closure_list_append(&g_executor.closures, closure, error);
@@ -121,9 +130,8 @@ void grpc_executor_push(grpc_closure *closure, grpc_error *error) {
   gpr_mu_unlock(&g_executor.mu);
 }
 
-void grpc_executor_shutdown() {
+void grpc_executor_shutdown(grpc_exec_ctx *exec_ctx) {
   int pending_join;
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
 
   gpr_mu_lock(&g_executor.mu);
   pending_join = g_executor.pending_join;
@@ -133,11 +141,24 @@ void grpc_executor_shutdown() {
    * list below because we aren't accepting new work */
 
   /* Execute pending callbacks, some may be performing cleanups */
-  grpc_exec_ctx_enqueue_list(&exec_ctx, &g_executor.closures, NULL);
-  grpc_exec_ctx_finish(&exec_ctx);
+  grpc_closure *c = g_executor.closures.head;
+  grpc_closure_list_init(&g_executor.closures);
+  while (c != NULL) {
+    grpc_closure *next = c->next_data.next;
+    grpc_error *error = c->error_data.error;
+    c->cb(exec_ctx, c->cb_arg, error);
+    GRPC_ERROR_UNREF(error);
+    c = next;
+  }
+  grpc_exec_ctx_flush(exec_ctx);
   GPR_ASSERT(grpc_closure_list_empty(g_executor.closures));
   if (pending_join) {
     gpr_thd_join(g_executor.tid);
   }
   gpr_mu_destroy(&g_executor.mu);
 }
+
+static const grpc_closure_scheduler_vtable executor_vtable = {executor_push,
+                                                              executor_push};
+static grpc_closure_scheduler executor_scheduler = {&executor_vtable};
+grpc_closure_scheduler *grpc_executor_scheduler = &executor_scheduler;
diff --git a/src/core/lib/iomgr/executor.h b/src/core/lib/iomgr/executor.h
index da9dcd07d0..1213016383 100644
--- a/src/core/lib/iomgr/executor.h
+++ b/src/core/lib/iomgr/executor.h
@@ -43,11 +43,9 @@
  * non-blocking solution available. */
 void grpc_executor_init();
 
-/** Enqueue \a closure for its eventual execution of \a f(arg) on a separate
- * thread */
-void grpc_executor_push(grpc_closure *closure, grpc_error *error);
+extern grpc_closure_scheduler *grpc_executor_scheduler;
 
 /** Shutdown the executor, running all pending work as part of the call */
-void grpc_executor_shutdown();
+void grpc_executor_shutdown(grpc_exec_ctx *exec_ctx);
 
 #endif /* GRPC_CORE_LIB_IOMGR_EXECUTOR_H */
diff --git a/src/core/lib/iomgr/iocp_windows.c b/src/core/lib/iomgr/iocp_windows.c
index 60ebe43676..f0f4a6ff39 100644
--- a/src/core/lib/iomgr/iocp_windows.c
+++ b/src/core/lib/iomgr/iocp_windows.c
@@ -80,7 +80,6 @@ grpc_iocp_work_status grpc_iocp_work(grpc_exec_ctx *exec_ctx,
   LPOVERLAPPED overlapped;
   grpc_winsocket *socket;
   grpc_winsocket_callback_info *info;
-  grpc_closure *closure = NULL;
   success = GetQueuedCompletionStatus(
       g_iocp, &bytes, &completion_key, &overlapped,
       deadline_to_millis_timeout(deadline, gpr_now(deadline.clock_type)));
diff --git a/src/core/lib/iomgr/iomgr.c b/src/core/lib/iomgr/iomgr.c
index 3470b5ac81..001e528409 100644
--- a/src/core/lib/iomgr/iomgr.c
+++ b/src/core/lib/iomgr/iomgr.c
@@ -83,11 +83,10 @@ static void dump_objects(const char *kind) {
   }
 }
 
-void grpc_iomgr_shutdown(void) {
+void grpc_iomgr_shutdown(grpc_exec_ctx *exec_ctx) {
   gpr_timespec shutdown_deadline = gpr_time_add(
       gpr_now(GPR_CLOCK_REALTIME), gpr_time_from_seconds(10, GPR_TIMESPAN));
   gpr_timespec last_warning_time = gpr_now(GPR_CLOCK_REALTIME);
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
 
   grpc_iomgr_platform_flush();
 
@@ -104,10 +103,9 @@ void grpc_iomgr_shutdown(void) {
       }
       last_warning_time = gpr_now(GPR_CLOCK_REALTIME);
     }
-    if (grpc_timer_check(&exec_ctx, gpr_inf_future(GPR_CLOCK_MONOTONIC),
-                         NULL)) {
+    if (grpc_timer_check(exec_ctx, gpr_inf_future(GPR_CLOCK_MONOTONIC), NULL)) {
       gpr_mu_unlock(&g_mu);
-      grpc_exec_ctx_flush(&exec_ctx);
+      grpc_exec_ctx_flush(exec_ctx);
       grpc_iomgr_platform_flush();
       gpr_mu_lock(&g_mu);
       continue;
@@ -139,8 +137,8 @@ void grpc_iomgr_shutdown(void) {
   }
   gpr_mu_unlock(&g_mu);
 
-  grpc_timer_list_shutdown(&exec_ctx);
-  grpc_exec_ctx_finish(&exec_ctx);
+  grpc_timer_list_shutdown(exec_ctx);
+  grpc_exec_ctx_flush(exec_ctx);
 
   /* ensure all threads have left g_mu */
   gpr_mu_lock(&g_mu);
diff --git a/src/core/lib/iomgr/iomgr.h b/src/core/lib/iomgr/iomgr.h
index c1cfaf302e..245a1e08aa 100644
--- a/src/core/lib/iomgr/iomgr.h
+++ b/src/core/lib/iomgr/iomgr.h
@@ -34,12 +34,14 @@
 #ifndef GRPC_CORE_LIB_IOMGR_IOMGR_H
 #define GRPC_CORE_LIB_IOMGR_IOMGR_H
 
+#include <grpc/impl/codegen/exec_ctx_fwd.h>
 #include "src/core/lib/iomgr/port.h"
 
 /** Initializes the iomgr. */
 void grpc_iomgr_init(void);
 
-/** Signals the intention to shutdown the iomgr. */
-void grpc_iomgr_shutdown(void);
+/** Signals the intention to shutdown the iomgr. Expects to be able to flush
+ * exec_ctx. */
+void grpc_iomgr_shutdown(grpc_exec_ctx *exec_ctx);
 
 #endif /* GRPC_CORE_LIB_IOMGR_IOMGR_H */
diff --git a/src/core/lib/iomgr/pollset_uv.c b/src/core/lib/iomgr/pollset_uv.c
index 3a74b842b6..ed3edeee94 100644
--- a/src/core/lib/iomgr/pollset_uv.c
+++ b/src/core/lib/iomgr/pollset_uv.c
@@ -83,7 +83,7 @@ void grpc_pollset_shutdown(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
     // Drain any pending UV callbacks without blocking
     uv_run(uv_default_loop(), UV_RUN_NOWAIT);
   }
-  grpc_exec_ctx_sched(exec_ctx, closure, GRPC_ERROR_NONE, NULL);
+  grpc_closure_sched(exec_ctx, closure, GRPC_ERROR_NONE);
 }
 
 void grpc_pollset_destroy(grpc_pollset *pollset) {
diff --git a/src/core/lib/iomgr/pollset_windows.c b/src/core/lib/iomgr/pollset_windows.c
index 5540303e49..2a45e708df 100644
--- a/src/core/lib/iomgr/pollset_windows.c
+++ b/src/core/lib/iomgr/pollset_windows.c
@@ -109,7 +109,7 @@ void grpc_pollset_shutdown(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
   pollset->shutting_down = 1;
   grpc_pollset_kick(pollset, GRPC_POLLSET_KICK_BROADCAST);
   if (!pollset->is_iocp_worker) {
-    grpc_exec_ctx_sched(exec_ctx, closure, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, closure, GRPC_ERROR_NONE);
   } else {
     pollset->on_shutdown = closure;
   }
@@ -167,8 +167,7 @@ grpc_error *grpc_pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
       }
 
       if (pollset->shutting_down && pollset->on_shutdown != NULL) {
-        grpc_exec_ctx_sched(exec_ctx, pollset->on_shutdown, GRPC_ERROR_NONE,
-                            NULL);
+        grpc_closure_sched(exec_ctx, pollset->on_shutdown, GRPC_ERROR_NONE);
         pollset->on_shutdown = NULL;
       }
       goto done;
diff --git a/src/core/lib/iomgr/resolve_address.h b/src/core/lib/iomgr/resolve_address.h
index 275924448a..e03d16fa4e 100644
--- a/src/core/lib/iomgr/resolve_address.h
+++ b/src/core/lib/iomgr/resolve_address.h
@@ -36,6 +36,7 @@
 
 #include <stddef.h>
 #include "src/core/lib/iomgr/exec_ctx.h"
+#include "src/core/lib/iomgr/pollset_set.h"
 
 #define GRPC_MAX_SOCKADDR_SIZE 128
 
@@ -54,6 +55,7 @@ typedef struct {
 /* TODO(ctiller): add a timeout here */
 extern void (*grpc_resolve_address)(grpc_exec_ctx *exec_ctx, const char *addr,
                                     const char *default_port,
+                                    grpc_pollset_set *interested_parties,
                                     grpc_closure *on_done,
                                     grpc_resolved_addresses **addresses);
 /* Destroy resolved addresses */
diff --git a/src/core/lib/iomgr/resolve_address_posix.c b/src/core/lib/iomgr/resolve_address_posix.c
index de791b2b67..50e470d149 100644
--- a/src/core/lib/iomgr/resolve_address_posix.c
+++ b/src/core/lib/iomgr/resolve_address_posix.c
@@ -163,10 +163,9 @@ typedef struct {
 static void do_request_thread(grpc_exec_ctx *exec_ctx, void *rp,
                               grpc_error *error) {
   request *r = rp;
-  grpc_exec_ctx_sched(
+  grpc_closure_sched(
       exec_ctx, r->on_done,
-      grpc_blocking_resolve_address(r->name, r->default_port, r->addrs_out),
-      NULL);
+      grpc_blocking_resolve_address(r->name, r->default_port, r->addrs_out));
   gpr_free(r->name);
   gpr_free(r->default_port);
   gpr_free(r);
@@ -181,20 +180,22 @@ void grpc_resolved_addresses_destroy(grpc_resolved_addresses *addrs) {
 
 static void resolve_address_impl(grpc_exec_ctx *exec_ctx, const char *name,
                                  const char *default_port,
+                                 grpc_pollset_set *interested_parties,
                                  grpc_closure *on_done,
                                  grpc_resolved_addresses **addrs) {
   request *r = gpr_malloc(sizeof(request));
-  grpc_closure_init(&r->request_closure, do_request_thread, r);
+  grpc_closure_init(&r->request_closure, do_request_thread, r,
+                    grpc_executor_scheduler);
   r->name = gpr_strdup(name);
   r->default_port = gpr_strdup(default_port);
   r->on_done = on_done;
   r->addrs_out = addrs;
-  grpc_executor_push(&r->request_closure, GRPC_ERROR_NONE);
+  grpc_closure_sched(exec_ctx, &r->request_closure, GRPC_ERROR_NONE);
 }
 
-void (*grpc_resolve_address)(grpc_exec_ctx *exec_ctx, const char *name,
-                             const char *default_port, grpc_closure *on_done,
-                             grpc_resolved_addresses **addrs) =
-    resolve_address_impl;
+void (*grpc_resolve_address)(
+    grpc_exec_ctx *exec_ctx, const char *name, const char *default_port,
+    grpc_pollset_set *interested_parties, grpc_closure *on_done,
+    grpc_resolved_addresses **addrs) = resolve_address_impl;
 
 #endif
diff --git a/src/core/lib/iomgr/resolve_address_uv.c b/src/core/lib/iomgr/resolve_address_uv.c
index b8295acfa1..9b5f3209f0 100644
--- a/src/core/lib/iomgr/resolve_address_uv.c
+++ b/src/core/lib/iomgr/resolve_address_uv.c
@@ -98,7 +98,7 @@ static void getaddrinfo_callback(uv_getaddrinfo_t *req, int status,
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_error *error;
   error = handle_addrinfo_result(status, res, r->addresses);
-  grpc_exec_ctx_sched(&exec_ctx, r->on_done, error, NULL);
+  grpc_closure_sched(&exec_ctx, r->on_done, error);
   grpc_exec_ctx_finish(&exec_ctx);
 
   gpr_free(r->hints);
@@ -181,6 +181,7 @@ void grpc_resolved_addresses_destroy(grpc_resolved_addresses *addrs) {
 
 static void resolve_address_impl(grpc_exec_ctx *exec_ctx, const char *name,
                                  const char *default_port,
+                                 grpc_pollset_set *interested_parties,
                                  grpc_closure *on_done,
                                  grpc_resolved_addresses **addrs) {
   uv_getaddrinfo_t *req;
@@ -192,7 +193,7 @@ static void resolve_address_impl(grpc_exec_ctx *exec_ctx, const char *name,
   int s;
   err = try_split_host_port(name, default_port, &host, &port);
   if (err != GRPC_ERROR_NONE) {
-    grpc_exec_ctx_sched(exec_ctx, on_done, err, NULL);
+    grpc_closure_sched(exec_ctx, on_done, err);
     return;
   }
   r = gpr_malloc(sizeof(request));
@@ -216,16 +217,16 @@ static void resolve_address_impl(grpc_exec_ctx *exec_ctx, const char *name,
     *addrs = NULL;
     err = GRPC_ERROR_CREATE("getaddrinfo failed");
     err = grpc_error_set_str(err, GRPC_ERROR_STR_OS_ERROR, uv_strerror(s));
-    grpc_exec_ctx_sched(exec_ctx, on_done, err, NULL);
+    grpc_closure_sched(exec_ctx, on_done, err);
     gpr_free(r);
     gpr_free(req);
     gpr_free(hints);
   }
 }
 
-void (*grpc_resolve_address)(grpc_exec_ctx *exec_ctx, const char *name,
-                             const char *default_port, grpc_closure *on_done,
-                             grpc_resolved_addresses **addrs) =
-    resolve_address_impl;
+void (*grpc_resolve_address)(
+    grpc_exec_ctx *exec_ctx, const char *name, const char *default_port,
+    grpc_pollset_set *interested_parties, grpc_closure *on_done,
+    grpc_resolved_addresses **addrs) = resolve_address_impl;
 
 #endif /* GRPC_UV */
diff --git a/src/core/lib/iomgr/resolve_address_windows.c b/src/core/lib/iomgr/resolve_address_windows.c
index e139293c03..2439ce3cb7 100644
--- a/src/core/lib/iomgr/resolve_address_windows.c
+++ b/src/core/lib/iomgr/resolve_address_windows.c
@@ -154,7 +154,7 @@ static void do_request_thread(grpc_exec_ctx *exec_ctx, void *rp,
   } else {
     GRPC_ERROR_REF(error);
   }
-  grpc_exec_ctx_sched(exec_ctx, r->on_done, error, NULL);
+  grpc_closure_sched(exec_ctx, r->on_done, error);
   gpr_free(r->name);
   gpr_free(r->default_port);
   gpr_free(r);
@@ -169,20 +169,22 @@ void grpc_resolved_addresses_destroy(grpc_resolved_addresses *addrs) {
 
 static void resolve_address_impl(grpc_exec_ctx *exec_ctx, const char *name,
                                  const char *default_port,
+                                 grpc_pollset_set *interested_parties,
                                  grpc_closure *on_done,
                                  grpc_resolved_addresses **addresses) {
   request *r = gpr_malloc(sizeof(request));
-  grpc_closure_init(&r->request_closure, do_request_thread, r);
+  grpc_closure_init(&r->request_closure, do_request_thread, r,
+                    grpc_executor_scheduler);
   r->name = gpr_strdup(name);
   r->default_port = gpr_strdup(default_port);
   r->on_done = on_done;
   r->addresses = addresses;
-  grpc_executor_push(&r->request_closure, GRPC_ERROR_NONE);
+  grpc_closure_sched(exec_ctx, &r->request_closure, GRPC_ERROR_NONE);
 }
 
-void (*grpc_resolve_address)(grpc_exec_ctx *exec_ctx, const char *name,
-                             const char *default_port, grpc_closure *on_done,
-                             grpc_resolved_addresses **addresses) =
-    resolve_address_impl;
+void (*grpc_resolve_address)(
+    grpc_exec_ctx *exec_ctx, const char *name, const char *default_port,
+    grpc_pollset_set *interested_parties, grpc_closure *on_done,
+    grpc_resolved_addresses **addresses) = resolve_address_impl;
 
 #endif
diff --git a/src/core/lib/iomgr/resource_quota.c b/src/core/lib/iomgr/resource_quota.c
index 379bf9bd23..42a044df77 100644
--- a/src/core/lib/iomgr/resource_quota.c
+++ b/src/core/lib/iomgr/resource_quota.c
@@ -144,6 +144,12 @@ struct grpc_resource_quota {
   /* Closure around rq_reclamation_done */
   grpc_closure rq_reclamation_done_closure;
 
+  /* This is only really usable for debugging: it's always a stale pointer, but
+     a stale pointer that might just be fresh enough to guide us to where the
+     reclamation system is stuck */
+  grpc_closure *debug_only_last_initiated_reclaimer;
+  grpc_resource_user *debug_only_last_reclaimer_resource_user;
+
   /* Roots of all resource user lists */
   grpc_resource_user *roots[GRPC_RULIST_COUNT];
 
@@ -225,6 +231,7 @@ static void rulist_remove(grpc_resource_user *resource_user, grpc_rulist list) {
       resource_user->links[list].prev;
   resource_user->links[list].prev->links[list].next =
       resource_user->links[list].next;
+  resource_user->links[list].next = resource_user->links[list].prev = NULL;
 }
 
 /*******************************************************************************
@@ -250,17 +257,16 @@ static void rq_step(grpc_exec_ctx *exec_ctx, void *rq, grpc_error *error) {
   }
 
 done:
-  grpc_resource_quota_internal_unref(exec_ctx, resource_quota);
+  grpc_resource_quota_unref_internal(exec_ctx, resource_quota);
 }
 
 static void rq_step_sched(grpc_exec_ctx *exec_ctx,
                           grpc_resource_quota *resource_quota) {
   if (resource_quota->step_scheduled) return;
   resource_quota->step_scheduled = true;
-  grpc_resource_quota_internal_ref(resource_quota);
-  grpc_combiner_execute_finally(exec_ctx, resource_quota->combiner,
-                                &resource_quota->rq_step_closure,
-                                GRPC_ERROR_NONE, false);
+  grpc_resource_quota_ref_internal(resource_quota);
+  grpc_closure_sched(exec_ctx, &resource_quota->rq_step_closure,
+                     GRPC_ERROR_NONE);
 }
 
 /* returns true if all allocations are completed */
@@ -287,7 +293,7 @@ static bool rq_alloc(grpc_exec_ctx *exec_ctx,
     }
     if (resource_user->free_pool >= 0) {
       resource_user->allocating = false;
-      grpc_exec_ctx_enqueue_list(exec_ctx, &resource_user->on_allocated, NULL);
+      grpc_closure_list_sched(exec_ctx, &resource_user->on_allocated);
       gpr_mu_unlock(&resource_user->mu);
     } else {
       rulist_add_head(resource_user, GRPC_RULIST_AWAITING_ALLOCATION);
@@ -338,8 +344,11 @@ static bool rq_reclaim(grpc_exec_ctx *exec_ctx,
             destructive ? "destructive" : "benign");
   }
   resource_quota->reclaiming = true;
-  grpc_resource_quota_internal_ref(resource_quota);
+  grpc_resource_quota_ref_internal(resource_quota);
   grpc_closure *c = resource_user->reclaimers[destructive];
+  GPR_ASSERT(c);
+  resource_quota->debug_only_last_reclaimer_resource_user = resource_user;
+  resource_quota->debug_only_last_initiated_reclaimer = c;
   resource_user->reclaimers[destructive] = NULL;
   grpc_closure_run(exec_ctx, c, GRPC_ERROR_NONE);
   return true;
@@ -361,21 +370,10 @@ static void ru_slice_ref(void *p) {
   gpr_ref(&rc->refs);
 }
 
-static void ru_slice_unref(void *p) {
+static void ru_slice_unref(grpc_exec_ctx *exec_ctx, void *p) {
   ru_slice_refcount *rc = p;
   if (gpr_unref(&rc->refs)) {
-    /* TODO(ctiller): this is dangerous, but I think safe for now:
-       we have no guarantee here that we're at a safe point for creating an
-       execution context, but we have no way of writing this code otherwise.
-       In the future: consider lifting grpc_slice to grpc, and offering an
-       internal_{ref,unref} pair that is execution context aware.
-       Alternatively,
-       make exec_ctx be thread local and 'do the right thing' (whatever that
-       is)
-       if NULL */
-    grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-    grpc_resource_user_free(&exec_ctx, rc->resource_user, rc->size);
-    grpc_exec_ctx_finish(&exec_ctx);
+    grpc_resource_user_free(exec_ctx, rc->resource_user, rc->size);
     gpr_free(rc);
   }
 }
@@ -429,7 +427,7 @@ static bool ru_post_reclaimer(grpc_exec_ctx *exec_ctx,
   resource_user->new_reclaimers[destructive] = NULL;
   GPR_ASSERT(resource_user->reclaimers[destructive] == NULL);
   if (gpr_atm_acq_load(&resource_user->shutdown) > 0) {
-    grpc_exec_ctx_sched(exec_ctx, closure, GRPC_ERROR_CANCELLED, NULL);
+    grpc_closure_sched(exec_ctx, closure, GRPC_ERROR_CANCELLED);
     return false;
   }
   resource_user->reclaimers[destructive] = closure;
@@ -470,12 +468,14 @@ static void ru_post_destructive_reclaimer(grpc_exec_ctx *exec_ctx, void *ru,
 
 static void ru_shutdown(grpc_exec_ctx *exec_ctx, void *ru, grpc_error *error) {
   grpc_resource_user *resource_user = ru;
-  grpc_exec_ctx_sched(exec_ctx, resource_user->reclaimers[0],
-                      GRPC_ERROR_CANCELLED, NULL);
-  grpc_exec_ctx_sched(exec_ctx, resource_user->reclaimers[1],
-                      GRPC_ERROR_CANCELLED, NULL);
+  grpc_closure_sched(exec_ctx, resource_user->reclaimers[0],
+                     GRPC_ERROR_CANCELLED);
+  grpc_closure_sched(exec_ctx, resource_user->reclaimers[1],
+                     GRPC_ERROR_CANCELLED);
   resource_user->reclaimers[0] = NULL;
   resource_user->reclaimers[1] = NULL;
+  rulist_remove(resource_user, GRPC_RULIST_RECLAIMER_BENIGN);
+  rulist_remove(resource_user, GRPC_RULIST_RECLAIMER_DESTRUCTIVE);
 }
 
 static void ru_destroy(grpc_exec_ctx *exec_ctx, void *ru, grpc_error *error) {
@@ -484,15 +484,15 @@ static void ru_destroy(grpc_exec_ctx *exec_ctx, void *ru, grpc_error *error) {
   for (int i = 0; i < GRPC_RULIST_COUNT; i++) {
     rulist_remove(resource_user, (grpc_rulist)i);
   }
-  grpc_exec_ctx_sched(exec_ctx, resource_user->reclaimers[0],
-                      GRPC_ERROR_CANCELLED, NULL);
-  grpc_exec_ctx_sched(exec_ctx, resource_user->reclaimers[1],
-                      GRPC_ERROR_CANCELLED, NULL);
+  grpc_closure_sched(exec_ctx, resource_user->reclaimers[0],
+                     GRPC_ERROR_CANCELLED);
+  grpc_closure_sched(exec_ctx, resource_user->reclaimers[1],
+                     GRPC_ERROR_CANCELLED);
   if (resource_user->free_pool != 0) {
     resource_user->resource_quota->free_pool += resource_user->free_pool;
     rq_step_sched(exec_ctx, resource_user->resource_quota);
   }
-  grpc_resource_quota_internal_unref(exec_ctx, resource_user->resource_quota);
+  grpc_resource_quota_unref_internal(exec_ctx, resource_user->resource_quota);
   gpr_mu_destroy(&resource_user->mu);
   gpr_free(resource_user->name);
   gpr_free(resource_user);
@@ -528,7 +528,7 @@ static void rq_resize(grpc_exec_ctx *exec_ctx, void *args, grpc_error *error) {
   a->resource_quota->size += delta;
   a->resource_quota->free_pool += delta;
   rq_step_sched(exec_ctx, a->resource_quota);
-  grpc_resource_quota_internal_unref(exec_ctx, a->resource_quota);
+  grpc_resource_quota_unref_internal(exec_ctx, a->resource_quota);
   gpr_free(a);
 }
 
@@ -537,7 +537,7 @@ static void rq_reclamation_done(grpc_exec_ctx *exec_ctx, void *rq,
   grpc_resource_quota *resource_quota = rq;
   resource_quota->reclaiming = false;
   rq_step_sched(exec_ctx, resource_quota);
-  grpc_resource_quota_internal_unref(exec_ctx, resource_quota);
+  grpc_resource_quota_unref_internal(exec_ctx, resource_quota);
 }
 
 /*******************************************************************************
@@ -559,16 +559,19 @@ grpc_resource_quota *grpc_resource_quota_create(const char *name) {
     gpr_asprintf(&resource_quota->name, "anonymous_pool_%" PRIxPTR,
                  (intptr_t)resource_quota);
   }
-  grpc_closure_init(&resource_quota->rq_step_closure, rq_step, resource_quota);
+  grpc_closure_init(
+      &resource_quota->rq_step_closure, rq_step, resource_quota,
+      grpc_combiner_finally_scheduler(resource_quota->combiner, true));
   grpc_closure_init(&resource_quota->rq_reclamation_done_closure,
-                    rq_reclamation_done, resource_quota);
+                    rq_reclamation_done, resource_quota,
+                    grpc_combiner_scheduler(resource_quota->combiner, false));
   for (int i = 0; i < GRPC_RULIST_COUNT; i++) {
     resource_quota->roots[i] = NULL;
   }
   return resource_quota;
 }
 
-void grpc_resource_quota_internal_unref(grpc_exec_ctx *exec_ctx,
+void grpc_resource_quota_unref_internal(grpc_exec_ctx *exec_ctx,
                                         grpc_resource_quota *resource_quota) {
   if (gpr_unref(&resource_quota->refs)) {
     grpc_combiner_destroy(exec_ctx, resource_quota->combiner);
@@ -580,11 +583,11 @@ void grpc_resource_quota_internal_unref(grpc_exec_ctx *exec_ctx,
 /* Public API */
 void grpc_resource_quota_unref(grpc_resource_quota *resource_quota) {
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  grpc_resource_quota_internal_unref(&exec_ctx, resource_quota);
+  grpc_resource_quota_unref_internal(&exec_ctx, resource_quota);
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
-grpc_resource_quota *grpc_resource_quota_internal_ref(
+grpc_resource_quota *grpc_resource_quota_ref_internal(
     grpc_resource_quota *resource_quota) {
   gpr_ref(&resource_quota->refs);
   return resource_quota;
@@ -592,7 +595,7 @@ grpc_resource_quota *grpc_resource_quota_internal_ref(
 
 /* Public API */
 void grpc_resource_quota_ref(grpc_resource_quota *resource_quota) {
-  grpc_resource_quota_internal_ref(resource_quota);
+  grpc_resource_quota_ref_internal(resource_quota);
 }
 
 /* Public API */
@@ -600,11 +603,10 @@ void grpc_resource_quota_resize(grpc_resource_quota *resource_quota,
                                 size_t size) {
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   rq_resize_args *a = gpr_malloc(sizeof(*a));
-  a->resource_quota = grpc_resource_quota_internal_ref(resource_quota);
+  a->resource_quota = grpc_resource_quota_ref_internal(resource_quota);
   a->size = (int64_t)size;
-  grpc_closure_init(&a->closure, rq_resize, a);
-  grpc_combiner_execute(&exec_ctx, resource_quota->combiner, &a->closure,
-                        GRPC_ERROR_NONE, false);
+  grpc_closure_init(&a->closure, rq_resize, a, grpc_schedule_on_exec_ctx);
+  grpc_closure_sched(&exec_ctx, &a->closure, GRPC_ERROR_NONE);
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
@@ -617,7 +619,7 @@ grpc_resource_quota *grpc_resource_quota_from_channel_args(
   for (size_t i = 0; i < channel_args->num_args; i++) {
     if (0 == strcmp(channel_args->args[i].key, GRPC_ARG_RESOURCE_QUOTA)) {
       if (channel_args->args[i].type == GRPC_ARG_POINTER) {
-        return grpc_resource_quota_internal_ref(
+        return grpc_resource_quota_ref_internal(
             channel_args->args[i].value.pointer.p);
       } else {
         gpr_log(GPR_DEBUG, GRPC_ARG_RESOURCE_QUOTA " should be a pointer");
@@ -632,7 +634,9 @@ static void *rq_copy(void *rq) {
   return rq;
 }
 
-static void rq_destroy(void *rq) { grpc_resource_quota_unref(rq); }
+static void rq_destroy(grpc_exec_ctx *exec_ctx, void *rq) {
+  grpc_resource_quota_unref_internal(exec_ctx, rq);
+}
 
 static int rq_cmp(void *a, void *b) { return GPR_ICMP(a, b); }
 
@@ -649,17 +653,21 @@ grpc_resource_user *grpc_resource_user_create(
     grpc_resource_quota *resource_quota, const char *name) {
   grpc_resource_user *resource_user = gpr_malloc(sizeof(*resource_user));
   resource_user->resource_quota =
-      grpc_resource_quota_internal_ref(resource_quota);
+      grpc_resource_quota_ref_internal(resource_quota);
   grpc_closure_init(&resource_user->allocate_closure, &ru_allocate,
-                    resource_user);
+                    resource_user,
+                    grpc_combiner_scheduler(resource_quota->combiner, false));
   grpc_closure_init(&resource_user->add_to_free_pool_closure,
-                    &ru_add_to_free_pool, resource_user);
+                    &ru_add_to_free_pool, resource_user,
+                    grpc_combiner_scheduler(resource_quota->combiner, false));
   grpc_closure_init(&resource_user->post_reclaimer_closure[0],
-                    &ru_post_benign_reclaimer, resource_user);
+                    &ru_post_benign_reclaimer, resource_user,
+                    grpc_combiner_scheduler(resource_quota->combiner, false));
   grpc_closure_init(&resource_user->post_reclaimer_closure[1],
-                    &ru_post_destructive_reclaimer, resource_user);
-  grpc_closure_init(&resource_user->destroy_closure, &ru_destroy,
-                    resource_user);
+                    &ru_post_destructive_reclaimer, resource_user,
+                    grpc_combiner_scheduler(resource_quota->combiner, false));
+  grpc_closure_init(&resource_user->destroy_closure, &ru_destroy, resource_user,
+                    grpc_combiner_scheduler(resource_quota->combiner, false));
   gpr_mu_init(&resource_user->mu);
   gpr_atm_rel_store(&resource_user->refs, 1);
   gpr_atm_rel_store(&resource_user->shutdown, 0);
@@ -694,9 +702,8 @@ static void ru_unref_by(grpc_exec_ctx *exec_ctx,
   gpr_atm old = gpr_atm_full_fetch_add(&resource_user->refs, -amount);
   GPR_ASSERT(old >= amount);
   if (old == amount) {
-    grpc_combiner_execute(exec_ctx, resource_user->resource_quota->combiner,
-                          &resource_user->destroy_closure, GRPC_ERROR_NONE,
-                          false);
+    grpc_closure_sched(exec_ctx, &resource_user->destroy_closure,
+                       GRPC_ERROR_NONE);
   }
 }
 
@@ -712,9 +719,12 @@ void grpc_resource_user_unref(grpc_exec_ctx *exec_ctx,
 void grpc_resource_user_shutdown(grpc_exec_ctx *exec_ctx,
                                  grpc_resource_user *resource_user) {
   if (gpr_atm_full_fetch_add(&resource_user->shutdown, 1) == 0) {
-    grpc_combiner_execute(exec_ctx, resource_user->resource_quota->combiner,
-                          grpc_closure_create(ru_shutdown, resource_user),
-                          GRPC_ERROR_NONE, false);
+    grpc_closure_sched(exec_ctx,
+                       grpc_closure_create(
+                           ru_shutdown, resource_user,
+                           grpc_combiner_scheduler(
+                               resource_user->resource_quota->combiner, false)),
+                       GRPC_ERROR_NONE);
   }
 }
 
@@ -734,12 +744,11 @@ void grpc_resource_user_alloc(grpc_exec_ctx *exec_ctx,
                              GRPC_ERROR_NONE);
     if (!resource_user->allocating) {
       resource_user->allocating = true;
-      grpc_combiner_execute(exec_ctx, resource_user->resource_quota->combiner,
-                            &resource_user->allocate_closure, GRPC_ERROR_NONE,
-                            false);
+      grpc_closure_sched(exec_ctx, &resource_user->allocate_closure,
+                         GRPC_ERROR_NONE);
     }
   } else {
-    grpc_exec_ctx_sched(exec_ctx, optional_on_done, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, optional_on_done, GRPC_ERROR_NONE);
   }
   gpr_mu_unlock(&resource_user->mu);
 }
@@ -758,9 +767,8 @@ void grpc_resource_user_free(grpc_exec_ctx *exec_ctx,
   if (is_bigger_than_zero && was_zero_or_negative &&
       !resource_user->added_to_free_pool) {
     resource_user->added_to_free_pool = true;
-    grpc_combiner_execute(exec_ctx, resource_user->resource_quota->combiner,
-                          &resource_user->add_to_free_pool_closure,
-                          GRPC_ERROR_NONE, false);
+    grpc_closure_sched(exec_ctx, &resource_user->add_to_free_pool_closure,
+                       GRPC_ERROR_NONE);
   }
   gpr_mu_unlock(&resource_user->mu);
   ru_unref_by(exec_ctx, resource_user, (gpr_atm)size);
@@ -772,9 +780,9 @@ void grpc_resource_user_post_reclaimer(grpc_exec_ctx *exec_ctx,
                                        grpc_closure *closure) {
   GPR_ASSERT(resource_user->new_reclaimers[destructive] == NULL);
   resource_user->new_reclaimers[destructive] = closure;
-  grpc_combiner_execute(exec_ctx, resource_user->resource_quota->combiner,
-                        &resource_user->post_reclaimer_closure[destructive],
-                        GRPC_ERROR_NONE, false);
+  grpc_closure_sched(exec_ctx,
+                     &resource_user->post_reclaimer_closure[destructive],
+                     GRPC_ERROR_NONE);
 }
 
 void grpc_resource_user_finish_reclamation(grpc_exec_ctx *exec_ctx,
@@ -783,18 +791,20 @@ void grpc_resource_user_finish_reclamation(grpc_exec_ctx *exec_ctx,
     gpr_log(GPR_DEBUG, "RQ %s %s: reclamation complete",
             resource_user->resource_quota->name, resource_user->name);
   }
-  grpc_combiner_execute(
-      exec_ctx, resource_user->resource_quota->combiner,
-      &resource_user->resource_quota->rq_reclamation_done_closure,
-      GRPC_ERROR_NONE, false);
+  grpc_closure_sched(
+      exec_ctx, &resource_user->resource_quota->rq_reclamation_done_closure,
+      GRPC_ERROR_NONE);
 }
 
 void grpc_resource_user_slice_allocator_init(
     grpc_resource_user_slice_allocator *slice_allocator,
     grpc_resource_user *resource_user, grpc_iomgr_cb_func cb, void *p) {
-  grpc_closure_init(&slice_allocator->on_allocated, ru_allocated_slices,
-                    slice_allocator);
-  grpc_closure_init(&slice_allocator->on_done, cb, p);
+  grpc_closure_init(
+      &slice_allocator->on_allocated, ru_allocated_slices, slice_allocator,
+      grpc_combiner_scheduler(resource_user->resource_quota->combiner, false));
+  grpc_closure_init(
+      &slice_allocator->on_done, cb, p,
+      grpc_combiner_scheduler(resource_user->resource_quota->combiner, false));
   slice_allocator->resource_user = resource_user;
 }
 
diff --git a/src/core/lib/iomgr/resource_quota.h b/src/core/lib/iomgr/resource_quota.h
index 0181fd978b..ef286c2fce 100644
--- a/src/core/lib/iomgr/resource_quota.h
+++ b/src/core/lib/iomgr/resource_quota.h
@@ -77,9 +77,9 @@
 
 extern int grpc_resource_quota_trace;
 
-grpc_resource_quota *grpc_resource_quota_internal_ref(
+grpc_resource_quota *grpc_resource_quota_ref_internal(
     grpc_resource_quota *resource_quota);
-void grpc_resource_quota_internal_unref(grpc_exec_ctx *exec_ctx,
+void grpc_resource_quota_unref_internal(grpc_exec_ctx *exec_ctx,
                                         grpc_resource_quota *resource_quota);
 grpc_resource_quota *grpc_resource_quota_from_channel_args(
     const grpc_channel_args *channel_args);
diff --git a/src/core/lib/iomgr/socket_mutator.c b/src/core/lib/iomgr/socket_mutator.c
index 8b1efb6bab..34b61dcfe5 100644
--- a/src/core/lib/iomgr/socket_mutator.c
+++ b/src/core/lib/iomgr/socket_mutator.c
@@ -76,7 +76,7 @@ static void *socket_mutator_arg_copy(void *p) {
   return grpc_socket_mutator_ref(p);
 }
 
-static void socket_mutator_arg_destroy(void *p) {
+static void socket_mutator_arg_destroy(grpc_exec_ctx *exec_ctx, void *p) {
   grpc_socket_mutator_unref(p);
 }
 
diff --git a/src/core/lib/iomgr/socket_windows.c b/src/core/lib/iomgr/socket_windows.c
index 54911e0e31..2f2e02f715 100644
--- a/src/core/lib/iomgr/socket_windows.c
+++ b/src/core/lib/iomgr/socket_windows.c
@@ -131,7 +131,7 @@ static void socket_notify_on_iocp(grpc_exec_ctx *exec_ctx,
   gpr_mu_lock(&socket->state_mu);
   if (info->has_pending_iocp) {
     info->has_pending_iocp = 0;
-    grpc_exec_ctx_sched(exec_ctx, closure, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, closure, GRPC_ERROR_NONE);
   } else {
     info->closure = closure;
   }
@@ -154,7 +154,7 @@ void grpc_socket_become_ready(grpc_exec_ctx *exec_ctx, grpc_winsocket *socket,
   GPR_ASSERT(!info->has_pending_iocp);
   gpr_mu_lock(&socket->state_mu);
   if (info->closure) {
-    grpc_exec_ctx_sched(exec_ctx, info->closure, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, info->closure, GRPC_ERROR_NONE);
     info->closure = NULL;
   } else {
     info->has_pending_iocp = 1;
diff --git a/src/core/lib/iomgr/tcp_client_posix.c b/src/core/lib/iomgr/tcp_client_posix.c
index a3a70a8ed7..9a77c92016 100644
--- a/src/core/lib/iomgr/tcp_client_posix.c
+++ b/src/core/lib/iomgr/tcp_client_posix.c
@@ -65,6 +65,7 @@ typedef struct {
   grpc_fd *fd;
   gpr_timespec deadline;
   grpc_timer alarm;
+  grpc_closure on_alarm;
   int refs;
   grpc_closure write_closure;
   grpc_pollset_set *interested_parties;
@@ -128,7 +129,7 @@ static void tc_on_alarm(grpc_exec_ctx *exec_ctx, void *acp, grpc_error *error) {
   if (done) {
     gpr_mu_destroy(&ac->mu);
     gpr_free(ac->addr_str);
-    grpc_channel_args_destroy(ac->channel_args);
+    grpc_channel_args_destroy(exec_ctx, ac->channel_args);
     gpr_free(ac);
   }
 }
@@ -148,8 +149,8 @@ grpc_endpoint *grpc_tcp_client_create_from_fd(
             &channel_args->args[i], options);
       } else if (0 ==
                  strcmp(channel_args->args[i].key, GRPC_ARG_RESOURCE_QUOTA)) {
-        grpc_resource_quota_internal_unref(exec_ctx, resource_quota);
-        resource_quota = grpc_resource_quota_internal_ref(
+        grpc_resource_quota_unref_internal(exec_ctx, resource_quota);
+        resource_quota = grpc_resource_quota_ref_internal(
             channel_args->args[i].value.pointer.p);
       }
     }
@@ -157,7 +158,7 @@ grpc_endpoint *grpc_tcp_client_create_from_fd(
 
   grpc_endpoint *ep =
       grpc_tcp_create(fd, resource_quota, tcp_read_chunk_size, addr_str);
-  grpc_resource_quota_internal_unref(exec_ctx, resource_quota);
+  grpc_resource_quota_unref_internal(exec_ctx, resource_quota);
   return ep;
 }
 
@@ -262,10 +263,10 @@ finish:
   if (done) {
     gpr_mu_destroy(&ac->mu);
     gpr_free(ac->addr_str);
-    grpc_channel_args_destroy(ac->channel_args);
+    grpc_channel_args_destroy(exec_ctx, ac->channel_args);
     gpr_free(ac);
   }
-  grpc_exec_ctx_sched(exec_ctx, closure, error, NULL);
+  grpc_closure_sched(exec_ctx, closure, error);
 }
 
 static void tcp_client_connect_impl(grpc_exec_ctx *exec_ctx,
@@ -294,7 +295,7 @@ static void tcp_client_connect_impl(grpc_exec_ctx *exec_ctx,
 
   error = grpc_create_dualstack_socket(addr, SOCK_STREAM, 0, &dsmode, &fd);
   if (error != GRPC_ERROR_NONE) {
-    grpc_exec_ctx_sched(exec_ctx, closure, error, NULL);
+    grpc_closure_sched(exec_ctx, closure, error);
     return;
   }
   if (dsmode == GRPC_DSMODE_IPV4) {
@@ -303,7 +304,7 @@ static void tcp_client_connect_impl(grpc_exec_ctx *exec_ctx,
     addr = &addr4_copy;
   }
   if ((error = prepare_socket(addr, fd, channel_args)) != GRPC_ERROR_NONE) {
-    grpc_exec_ctx_sched(exec_ctx, closure, error, NULL);
+    grpc_closure_sched(exec_ctx, closure, error);
     return;
   }
 
@@ -321,14 +322,13 @@ static void tcp_client_connect_impl(grpc_exec_ctx *exec_ctx,
   if (err >= 0) {
     *ep =
         grpc_tcp_client_create_from_fd(exec_ctx, fdobj, channel_args, addr_str);
-    grpc_exec_ctx_sched(exec_ctx, closure, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, closure, GRPC_ERROR_NONE);
     goto done;
   }
 
   if (errno != EWOULDBLOCK && errno != EINPROGRESS) {
     grpc_fd_orphan(exec_ctx, fdobj, NULL, NULL, "tcp_client_connect_error");
-    grpc_exec_ctx_sched(exec_ctx, closure, GRPC_OS_ERROR(errno, "connect"),
-                        NULL);
+    grpc_closure_sched(exec_ctx, closure, GRPC_OS_ERROR(errno, "connect"));
     goto done;
   }
 
@@ -343,8 +343,8 @@ static void tcp_client_connect_impl(grpc_exec_ctx *exec_ctx,
   addr_str = NULL;
   gpr_mu_init(&ac->mu);
   ac->refs = 2;
-  ac->write_closure.cb = on_writable;
-  ac->write_closure.cb_arg = ac;
+  grpc_closure_init(&ac->write_closure, on_writable, ac,
+                    grpc_schedule_on_exec_ctx);
   ac->channel_args = grpc_channel_args_copy(channel_args);
 
   if (grpc_tcp_trace) {
@@ -353,9 +353,10 @@ static void tcp_client_connect_impl(grpc_exec_ctx *exec_ctx,
   }
 
   gpr_mu_lock(&ac->mu);
+  grpc_closure_init(&ac->on_alarm, tc_on_alarm, ac, grpc_schedule_on_exec_ctx);
   grpc_timer_init(exec_ctx, &ac->alarm,
                   gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC),
-                  tc_on_alarm, ac, gpr_now(GPR_CLOCK_MONOTONIC));
+                  &ac->on_alarm, gpr_now(GPR_CLOCK_MONOTONIC));
   grpc_fd_notify_on_write(exec_ctx, ac->fd, &ac->write_closure);
   gpr_mu_unlock(&ac->mu);
 
diff --git a/src/core/lib/iomgr/tcp_client_uv.c b/src/core/lib/iomgr/tcp_client_uv.c
index b07f9ceffa..5225a5402b 100644
--- a/src/core/lib/iomgr/tcp_client_uv.c
+++ b/src/core/lib/iomgr/tcp_client_uv.c
@@ -49,6 +49,7 @@
 typedef struct grpc_uv_tcp_connect {
   uv_connect_t connect_req;
   grpc_timer alarm;
+  grpc_closure on_alarm;
   uv_tcp_t *tcp_handle;
   grpc_closure *closure;
   grpc_endpoint **endpoint;
@@ -59,7 +60,7 @@ typedef struct grpc_uv_tcp_connect {
 
 static void uv_tcp_connect_cleanup(grpc_exec_ctx *exec_ctx,
                                    grpc_uv_tcp_connect *connect) {
-  grpc_resource_quota_internal_unref(exec_ctx, connect->resource_quota);
+  grpc_resource_quota_unref_internal(exec_ctx, connect->resource_quota);
   gpr_free(connect);
 }
 
@@ -110,7 +111,7 @@ static void uv_tc_on_connect(uv_connect_t *req, int status) {
   if (done) {
     uv_tcp_connect_cleanup(&exec_ctx, connect);
   }
-  grpc_exec_ctx_sched(&exec_ctx, closure, error, NULL);
+  grpc_closure_sched(&exec_ctx, closure, error);
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
@@ -128,8 +129,8 @@ static void tcp_client_connect_impl(grpc_exec_ctx *exec_ctx,
   if (channel_args != NULL) {
     for (size_t i = 0; i < channel_args->num_args; i++) {
       if (0 == strcmp(channel_args->args[i].key, GRPC_ARG_RESOURCE_QUOTA)) {
-        grpc_resource_quota_internal_unref(exec_ctx, resource_quota);
-        resource_quota = grpc_resource_quota_internal_ref(
+        grpc_resource_quota_unref_internal(exec_ctx, resource_quota);
+        resource_quota = grpc_resource_quota_ref_internal(
             channel_args->args[i].value.pointer.p);
       }
     }
@@ -148,9 +149,11 @@ static void tcp_client_connect_impl(grpc_exec_ctx *exec_ctx,
   uv_tcp_connect(&connect->connect_req, connect->tcp_handle,
                  (const struct sockaddr *)resolved_addr->addr,
                  uv_tc_on_connect);
+  grpc_closure_init(&connect->on_alarm, uv_tc_on_alarm, connect,
+                    grpc_schedule_on_exec_ctx);
   grpc_timer_init(exec_ctx, &connect->alarm,
                   gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC),
-                  uv_tc_on_alarm, connect, gpr_now(GPR_CLOCK_MONOTONIC));
+                  &connect->on_alarm, gpr_now(GPR_CLOCK_MONOTONIC));
 }
 
 // overridden by api_fuzzer.c
diff --git a/src/core/lib/iomgr/tcp_client_windows.c b/src/core/lib/iomgr/tcp_client_windows.c
index 1127588ebc..1e84ec3a1e 100644
--- a/src/core/lib/iomgr/tcp_client_windows.c
+++ b/src/core/lib/iomgr/tcp_client_windows.c
@@ -58,6 +58,7 @@ typedef struct {
   grpc_winsocket *socket;
   gpr_timespec deadline;
   grpc_timer alarm;
+  grpc_closure on_alarm;
   char *addr_name;
   int refs;
   grpc_closure on_connect;
@@ -71,7 +72,7 @@ static void async_connect_unlock_and_cleanup(grpc_exec_ctx *exec_ctx,
   int done = (--ac->refs == 0);
   gpr_mu_unlock(&ac->mu);
   if (done) {
-    grpc_resource_quota_internal_unref(exec_ctx, ac->resource_quota);
+    grpc_resource_quota_unref_internal(exec_ctx, ac->resource_quota);
     gpr_mu_destroy(&ac->mu);
     gpr_free(ac->addr_name);
     gpr_free(ac);
@@ -129,7 +130,7 @@ static void on_connect(grpc_exec_ctx *exec_ctx, void *acp, grpc_error *error) {
   async_connect_unlock_and_cleanup(exec_ctx, ac, socket);
   /* If the connection was aborted, the callback was already called when
      the deadline was met. */
-  grpc_exec_ctx_sched(exec_ctx, on_done, error, NULL);
+  grpc_closure_sched(exec_ctx, on_done, error);
 }
 
 /* Tries to issue one async connection, then schedules both an IOCP
@@ -157,8 +158,8 @@ void grpc_tcp_client_connect(grpc_exec_ctx *exec_ctx, grpc_closure *on_done,
   if (channel_args != NULL) {
     for (size_t i = 0; i < channel_args->num_args; i++) {
       if (0 == strcmp(channel_args->args[i].key, GRPC_ARG_RESOURCE_QUOTA)) {
-        grpc_resource_quota_internal_unref(exec_ctx, resource_quota);
-        resource_quota = grpc_resource_quota_internal_ref(
+        grpc_resource_quota_unref_internal(exec_ctx, resource_quota);
+        resource_quota = grpc_resource_quota_ref_internal(
             channel_args->args[i].value.pointer.p);
       }
     }
@@ -227,9 +228,10 @@ void grpc_tcp_client_connect(grpc_exec_ctx *exec_ctx, grpc_closure *on_done,
   ac->addr_name = grpc_sockaddr_to_uri(addr);
   ac->endpoint = endpoint;
   ac->resource_quota = resource_quota;
-  grpc_closure_init(&ac->on_connect, on_connect, ac);
+  grpc_closure_init(&ac->on_connect, on_connect, ac, grpc_schedule_on_exec_ctx);
 
-  grpc_timer_init(exec_ctx, &ac->alarm, deadline, on_alarm, ac,
+  grpc_closure_init(&ac->on_alarm, on_alarm, ac, grpc_schedule_on_exec_ctx);
+  grpc_timer_init(exec_ctx, &ac->alarm, deadline, &ac->on_alarm,
                   gpr_now(GPR_CLOCK_MONOTONIC));
   grpc_socket_notify_on_write(exec_ctx, socket, &ac->on_connect);
   return;
@@ -246,8 +248,8 @@ failure:
   } else if (sock != INVALID_SOCKET) {
     closesocket(sock);
   }
-  grpc_resource_quota_internal_unref(exec_ctx, resource_quota);
-  grpc_exec_ctx_sched(exec_ctx, on_done, final_error, NULL);
+  grpc_resource_quota_unref_internal(exec_ctx, resource_quota);
+  grpc_closure_sched(exec_ctx, on_done, final_error);
 }
 
 #endif /* GRPC_WINSOCK_SOCKET */
diff --git a/src/core/lib/iomgr/tcp_posix.c b/src/core/lib/iomgr/tcp_posix.c
index 12a4797e6f..ece44978b0 100644
--- a/src/core/lib/iomgr/tcp_posix.c
+++ b/src/core/lib/iomgr/tcp_posix.c
@@ -56,6 +56,7 @@
 #include "src/core/lib/debug/trace.h"
 #include "src/core/lib/iomgr/ev_posix.h"
 #include "src/core/lib/profiling/timers.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/string.h"
 
@@ -107,6 +108,12 @@ typedef struct {
   grpc_resource_user_slice_allocator slice_allocator;
 } grpc_tcp;
 
+static grpc_error *tcp_annotate_error(grpc_error *src_error, grpc_tcp *tcp) {
+  return grpc_error_set_str(
+      grpc_error_set_int(src_error, GRPC_ERROR_INT_FD, tcp->fd),
+      GRPC_ERROR_STR_TARGET_ADDRESS, tcp->peer_string);
+}
+
 static void tcp_handle_read(grpc_exec_ctx *exec_ctx, void *arg /* grpc_tcp */,
                             grpc_error *error);
 static void tcp_handle_write(grpc_exec_ctx *exec_ctx, void *arg /* grpc_tcp */,
@@ -121,7 +128,7 @@ static void tcp_shutdown(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep) {
 static void tcp_free(grpc_exec_ctx *exec_ctx, grpc_tcp *tcp) {
   grpc_fd_orphan(exec_ctx, tcp->em_fd, tcp->release_fd_cb, tcp->release_fd,
                  "tcp_unref_orphan");
-  grpc_slice_buffer_destroy(&tcp->last_read_buffer);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &tcp->last_read_buffer);
   grpc_resource_user_unref(exec_ctx, tcp->resource_user);
   gpr_free(tcp->peer_string);
   gpr_free(tcp);
@@ -162,7 +169,7 @@ static void tcp_ref(grpc_tcp *tcp) { gpr_ref(&tcp->refcount); }
 static void tcp_destroy(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep) {
   grpc_network_status_unregister_endpoint(ep);
   grpc_tcp *tcp = (grpc_tcp *)ep;
-  grpc_slice_buffer_reset_and_unref(&tcp->last_read_buffer);
+  grpc_slice_buffer_reset_and_unref_internal(exec_ctx, &tcp->last_read_buffer);
   TCP_UNREF(exec_ctx, tcp, "destroy");
 }
 
@@ -229,14 +236,17 @@ static void tcp_do_read(grpc_exec_ctx *exec_ctx, grpc_tcp *tcp) {
       /* We've consumed the edge, request a new one */
       grpc_fd_notify_on_read(exec_ctx, tcp->em_fd, &tcp->read_closure);
     } else {
-      grpc_slice_buffer_reset_and_unref(tcp->incoming_buffer);
-      call_read_cb(exec_ctx, tcp, GRPC_OS_ERROR(errno, "recvmsg"));
+      grpc_slice_buffer_reset_and_unref_internal(exec_ctx,
+                                                 tcp->incoming_buffer);
+      call_read_cb(exec_ctx, tcp,
+                   tcp_annotate_error(GRPC_OS_ERROR(errno, "recvmsg"), tcp));
       TCP_UNREF(exec_ctx, tcp, "read");
     }
   } else if (read_bytes == 0) {
     /* 0 read size ==> end of stream */
-    grpc_slice_buffer_reset_and_unref(tcp->incoming_buffer);
-    call_read_cb(exec_ctx, tcp, GRPC_ERROR_CREATE("Socket closed"));
+    grpc_slice_buffer_reset_and_unref_internal(exec_ctx, tcp->incoming_buffer);
+    call_read_cb(exec_ctx, tcp,
+                 tcp_annotate_error(GRPC_ERROR_CREATE("Socket closed"), tcp));
     TCP_UNREF(exec_ctx, tcp, "read");
   } else {
     GPR_ASSERT((size_t)read_bytes <= tcp->incoming_buffer->length);
@@ -260,8 +270,9 @@ static void tcp_read_allocation_done(grpc_exec_ctx *exec_ctx, void *tcpp,
                                      grpc_error *error) {
   grpc_tcp *tcp = tcpp;
   if (error != GRPC_ERROR_NONE) {
-    grpc_slice_buffer_reset_and_unref(tcp->incoming_buffer);
-    grpc_slice_buffer_reset_and_unref(&tcp->last_read_buffer);
+    grpc_slice_buffer_reset_and_unref_internal(exec_ctx, tcp->incoming_buffer);
+    grpc_slice_buffer_reset_and_unref_internal(exec_ctx,
+                                               &tcp->last_read_buffer);
     call_read_cb(exec_ctx, tcp, GRPC_ERROR_REF(error));
     TCP_UNREF(exec_ctx, tcp, "read");
   } else {
@@ -286,8 +297,9 @@ static void tcp_handle_read(grpc_exec_ctx *exec_ctx, void *arg /* grpc_tcp */,
   GPR_ASSERT(!tcp->finished_edge);
 
   if (error != GRPC_ERROR_NONE) {
-    grpc_slice_buffer_reset_and_unref(tcp->incoming_buffer);
-    grpc_slice_buffer_reset_and_unref(&tcp->last_read_buffer);
+    grpc_slice_buffer_reset_and_unref_internal(exec_ctx, tcp->incoming_buffer);
+    grpc_slice_buffer_reset_and_unref_internal(exec_ctx,
+                                               &tcp->last_read_buffer);
     call_read_cb(exec_ctx, tcp, GRPC_ERROR_REF(error));
     TCP_UNREF(exec_ctx, tcp, "read");
   } else {
@@ -301,14 +313,14 @@ static void tcp_read(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
   GPR_ASSERT(tcp->read_cb == NULL);
   tcp->read_cb = cb;
   tcp->incoming_buffer = incoming_buffer;
-  grpc_slice_buffer_reset_and_unref(incoming_buffer);
+  grpc_slice_buffer_reset_and_unref_internal(exec_ctx, incoming_buffer);
   grpc_slice_buffer_swap(incoming_buffer, &tcp->last_read_buffer);
   TCP_REF(tcp, "read");
   if (tcp->finished_edge) {
     tcp->finished_edge = false;
     grpc_fd_notify_on_read(exec_ctx, tcp->em_fd, &tcp->read_closure);
   } else {
-    grpc_exec_ctx_sched(exec_ctx, &tcp->read_closure, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, &tcp->read_closure, GRPC_ERROR_NONE);
   }
 }
 
@@ -365,8 +377,13 @@ static bool tcp_flush(grpc_tcp *tcp, grpc_error **error) {
         tcp->outgoing_slice_idx = unwind_slice_idx;
         tcp->outgoing_byte_idx = unwind_byte_idx;
         return false;
+      } else if (errno == EPIPE) {
+        *error = grpc_error_set_int(GRPC_OS_ERROR(errno, "sendmsg"),
+                                    GRPC_ERROR_INT_GRPC_STATUS,
+                                    GRPC_STATUS_UNAVAILABLE);
+        return true;
       } else {
-        *error = GRPC_OS_ERROR(errno, "sendmsg");
+        *error = tcp_annotate_error(GRPC_OS_ERROR(errno, "sendmsg"), tcp);
         return true;
       }
     }
@@ -447,10 +464,10 @@ static void tcp_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
 
   if (buf->length == 0) {
     GPR_TIMER_END("tcp_write", 0);
-    grpc_exec_ctx_sched(exec_ctx, cb, grpc_fd_is_shutdown(tcp->em_fd)
-                                          ? GRPC_ERROR_CREATE("EOF")
-                                          : GRPC_ERROR_NONE,
-                        NULL);
+    grpc_closure_sched(exec_ctx, cb,
+                       grpc_fd_is_shutdown(tcp->em_fd)
+                           ? tcp_annotate_error(GRPC_ERROR_CREATE("EOF"), tcp)
+                           : GRPC_ERROR_NONE);
     return;
   }
   tcp->outgoing_buffer = buf;
@@ -470,7 +487,7 @@ static void tcp_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
       gpr_log(GPR_DEBUG, "write: %s", str);
       grpc_error_free_string(str);
     }
-    grpc_exec_ctx_sched(exec_ctx, cb, error, NULL);
+    grpc_closure_sched(exec_ctx, cb, error);
   }
 
   GPR_TIMER_END("tcp_write", 0);
@@ -538,10 +555,10 @@ grpc_endpoint *grpc_tcp_create(grpc_fd *em_fd,
   gpr_ref_init(&tcp->refcount, 1);
   gpr_atm_no_barrier_store(&tcp->shutdown_count, 0);
   tcp->em_fd = em_fd;
-  tcp->read_closure.cb = tcp_handle_read;
-  tcp->read_closure.cb_arg = tcp;
-  tcp->write_closure.cb = tcp_handle_write;
-  tcp->write_closure.cb_arg = tcp;
+  grpc_closure_init(&tcp->read_closure, tcp_handle_read, tcp,
+                    grpc_schedule_on_exec_ctx);
+  grpc_closure_init(&tcp->write_closure, tcp_handle_write, tcp,
+                    grpc_schedule_on_exec_ctx);
   grpc_slice_buffer_init(&tcp->last_read_buffer);
   tcp->resource_user = grpc_resource_user_create(resource_quota, peer_string);
   grpc_resource_user_slice_allocator_init(
@@ -565,7 +582,7 @@ void grpc_tcp_destroy_and_release_fd(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
   GPR_ASSERT(ep->vtable == &vtable);
   tcp->release_fd = fd;
   tcp->release_fd_cb = done;
-  grpc_slice_buffer_reset_and_unref(&tcp->last_read_buffer);
+  grpc_slice_buffer_reset_and_unref_internal(exec_ctx, &tcp->last_read_buffer);
   TCP_UNREF(exec_ctx, tcp, "destroy");
 }
 
diff --git a/src/core/lib/iomgr/tcp_server.h b/src/core/lib/iomgr/tcp_server.h
index 6eba8c4057..437a94beff 100644
--- a/src/core/lib/iomgr/tcp_server.h
+++ b/src/core/lib/iomgr/tcp_server.h
@@ -52,7 +52,8 @@ typedef struct grpc_tcp_server_acceptor {
   unsigned fd_index;
 } grpc_tcp_server_acceptor;
 
-/* Called for newly connected TCP connections. */
+/* Called for newly connected TCP connections.
+   Takes ownership of acceptor. */
 typedef void (*grpc_tcp_server_cb)(grpc_exec_ctx *exec_ctx, void *arg,
                                    grpc_endpoint *ep,
                                    grpc_pollset *accepting_pollset,
diff --git a/src/core/lib/iomgr/tcp_server_posix.c b/src/core/lib/iomgr/tcp_server_posix.c
index 7e2fb0f1f9..20efb678b2 100644
--- a/src/core/lib/iomgr/tcp_server_posix.c
+++ b/src/core/lib/iomgr/tcp_server_posix.c
@@ -167,18 +167,18 @@ grpc_error *grpc_tcp_server_create(grpc_exec_ctx *exec_ctx,
         s->so_reuseport =
             has_so_reuseport && (args->args[i].value.integer != 0);
       } else {
-        grpc_resource_quota_internal_unref(exec_ctx, s->resource_quota);
+        grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
         gpr_free(s);
         return GRPC_ERROR_CREATE(GRPC_ARG_ALLOW_REUSEPORT
                                  " must be an integer");
       }
     } else if (0 == strcmp(GRPC_ARG_RESOURCE_QUOTA, args->args[i].key)) {
       if (args->args[i].type == GRPC_ARG_POINTER) {
-        grpc_resource_quota_internal_unref(exec_ctx, s->resource_quota);
+        grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
         s->resource_quota =
-            grpc_resource_quota_internal_ref(args->args[i].value.pointer.p);
+            grpc_resource_quota_ref_internal(args->args[i].value.pointer.p);
       } else {
-        grpc_resource_quota_internal_unref(exec_ctx, s->resource_quota);
+        grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
         gpr_free(s);
         return GRPC_ERROR_CREATE(GRPC_ARG_RESOURCE_QUOTA
                                  " must be a pointer to a buffer pool");
@@ -208,7 +208,7 @@ static void finish_shutdown(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s) {
   GPR_ASSERT(s->shutdown);
   gpr_mu_unlock(&s->mu);
   if (s->shutdown_complete != NULL) {
-    grpc_exec_ctx_sched(exec_ctx, s->shutdown_complete, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, s->shutdown_complete, GRPC_ERROR_NONE);
   }
 
   gpr_mu_destroy(&s->mu);
@@ -219,7 +219,7 @@ static void finish_shutdown(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s) {
     gpr_free(sp);
   }
 
-  grpc_resource_quota_internal_unref(exec_ctx, s->resource_quota);
+  grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
 
   gpr_free(s);
 }
@@ -254,8 +254,8 @@ static void deactivated_all_ports(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s) {
     grpc_tcp_listener *sp;
     for (sp = s->head; sp; sp = sp->next) {
       grpc_unlink_if_unix_domain_socket(&sp->addr);
-      sp->destroyed_closure.cb = destroyed_port;
-      sp->destroyed_closure.cb_arg = s;
+      grpc_closure_init(&sp->destroyed_closure, destroyed_port, s,
+                        grpc_schedule_on_exec_ctx);
       grpc_fd_orphan(exec_ctx, sp->emfd, &sp->destroyed_closure, NULL,
                      "tcp_listener_shutdown");
     }
@@ -381,16 +381,12 @@ error:
 /* event manager callback when reads are ready */
 static void on_read(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *err) {
   grpc_tcp_listener *sp = arg;
-  grpc_tcp_server_acceptor acceptor = {sp->server, sp->port_index,
-                                       sp->fd_index};
-  grpc_pollset *read_notifier_pollset = NULL;
-  grpc_fd *fdobj;
 
   if (err != GRPC_ERROR_NONE) {
     goto error;
   }
 
-  read_notifier_pollset =
+  grpc_pollset *read_notifier_pollset =
       sp->server->pollsets[(size_t)gpr_atm_no_barrier_fetch_add(
                                &sp->server->next_pollset_to_assign, 1) %
                            sp->server->pollset_count];
@@ -426,7 +422,7 @@ static void on_read(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *err) {
       gpr_log(GPR_DEBUG, "SERVER_CONNECT: incoming connection: %s", addr_str);
     }
 
-    fdobj = grpc_fd_create(fd, name);
+    grpc_fd *fdobj = grpc_fd_create(fd, name);
 
     if (read_notifier_pollset == NULL) {
       gpr_log(GPR_ERROR, "Read notifier pollset is not set on the fd");
@@ -435,11 +431,17 @@ static void on_read(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *err) {
 
     grpc_pollset_add_fd(exec_ctx, read_notifier_pollset, fdobj);
 
+    // Create acceptor.
+    grpc_tcp_server_acceptor *acceptor = gpr_malloc(sizeof(*acceptor));
+    acceptor->from_server = sp->server;
+    acceptor->port_index = sp->port_index;
+    acceptor->fd_index = sp->fd_index;
+
     sp->server->on_accept_cb(
         exec_ctx, sp->server->on_accept_cb_arg,
         grpc_tcp_create(fdobj, sp->server->resource_quota,
                         GRPC_TCP_DEFAULT_READ_SLICE_SIZE, addr_str),
-        read_notifier_pollset, &acceptor);
+        read_notifier_pollset, acceptor);
 
     gpr_free(name);
     gpr_free(addr_str);
@@ -721,8 +723,8 @@ void grpc_tcp_server_start(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s,
           "clone_port", clone_port(sp, (unsigned)(pollset_count - 1))));
       for (i = 0; i < pollset_count; i++) {
         grpc_pollset_add_fd(exec_ctx, pollsets[i], sp->emfd);
-        sp->read_closure.cb = on_read;
-        sp->read_closure.cb_arg = sp;
+        grpc_closure_init(&sp->read_closure, on_read, sp,
+                          grpc_schedule_on_exec_ctx);
         grpc_fd_notify_on_read(exec_ctx, sp->emfd, &sp->read_closure);
         s->active_ports++;
         sp = sp->next;
@@ -731,8 +733,8 @@ void grpc_tcp_server_start(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s,
       for (i = 0; i < pollset_count; i++) {
         grpc_pollset_add_fd(exec_ctx, pollsets[i], sp->emfd);
       }
-      sp->read_closure.cb = on_read;
-      sp->read_closure.cb_arg = sp;
+      grpc_closure_init(&sp->read_closure, on_read, sp,
+                        grpc_schedule_on_exec_ctx);
       grpc_fd_notify_on_read(exec_ctx, sp->emfd, &sp->read_closure);
       s->active_ports++;
       sp = sp->next;
@@ -758,7 +760,7 @@ void grpc_tcp_server_unref(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s) {
   if (gpr_unref(&s->refs)) {
     grpc_tcp_server_shutdown_listeners(exec_ctx, s);
     gpr_mu_lock(&s->mu);
-    grpc_exec_ctx_enqueue_list(exec_ctx, &s->shutdown_starting, NULL);
+    grpc_closure_list_sched(exec_ctx, &s->shutdown_starting);
     gpr_mu_unlock(&s->mu);
     tcp_server_destroy(exec_ctx, s);
   }
diff --git a/src/core/lib/iomgr/tcp_server_uv.c b/src/core/lib/iomgr/tcp_server_uv.c
index b5b9b92a20..eed2773f8a 100644
--- a/src/core/lib/iomgr/tcp_server_uv.c
+++ b/src/core/lib/iomgr/tcp_server_uv.c
@@ -89,11 +89,11 @@ grpc_error *grpc_tcp_server_create(grpc_exec_ctx *exec_ctx,
   for (size_t i = 0; i < (args == NULL ? 0 : args->num_args); i++) {
     if (0 == strcmp(GRPC_ARG_RESOURCE_QUOTA, args->args[i].key)) {
       if (args->args[i].type == GRPC_ARG_POINTER) {
-        grpc_resource_quota_internal_unref(exec_ctx, s->resource_quota);
+        grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
         s->resource_quota =
-            grpc_resource_quota_internal_ref(args->args[i].value.pointer.p);
+            grpc_resource_quota_ref_internal(args->args[i].value.pointer.p);
       } else {
-        grpc_resource_quota_internal_unref(exec_ctx, s->resource_quota);
+        grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
         gpr_free(s);
         return GRPC_ERROR_CREATE(GRPC_ARG_RESOURCE_QUOTA
                                  " must be a pointer to a buffer pool");
@@ -126,7 +126,7 @@ void grpc_tcp_server_shutdown_starting_add(grpc_tcp_server *s,
 
 static void finish_shutdown(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s) {
   if (s->shutdown_complete != NULL) {
-    grpc_exec_ctx_sched(exec_ctx, s->shutdown_complete, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, s->shutdown_complete, GRPC_ERROR_NONE);
   }
 
   while (s->head) {
@@ -136,7 +136,7 @@ static void finish_shutdown(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s) {
     gpr_free(sp->handle);
     gpr_free(sp);
   }
-  grpc_resource_quota_internal_unref(exec_ctx, s->resource_quota);
+  grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
   gpr_free(s);
 }
 
@@ -170,7 +170,7 @@ void grpc_tcp_server_unref(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s) {
   if (gpr_unref(&s->refs)) {
     /* Complete shutdown_starting work before destroying. */
     grpc_exec_ctx local_exec_ctx = GRPC_EXEC_CTX_INIT;
-    grpc_exec_ctx_enqueue_list(&local_exec_ctx, &s->shutdown_starting, NULL);
+    grpc_closure_list_sched(&local_exec_ctx, &s->shutdown_starting);
     if (exec_ctx == NULL) {
       grpc_exec_ctx_flush(&local_exec_ctx);
       tcp_server_destroy(&local_exec_ctx, s);
@@ -188,7 +188,6 @@ static void accepted_connection_close_cb(uv_handle_t *handle) {
 
 static void on_connect(uv_stream_t *server, int status) {
   grpc_tcp_listener *sp = (grpc_tcp_listener *)server->data;
-  grpc_tcp_server_acceptor acceptor = {sp->server, sp->port_index, 0};
   uv_tcp_t *client;
   grpc_endpoint *ep = NULL;
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
@@ -201,6 +200,7 @@ static void on_connect(uv_stream_t *server, int status) {
             uv_strerror(status));
     return;
   }
+
   client = gpr_malloc(sizeof(uv_tcp_t));
   uv_tcp_init(uv_default_loop(), client);
   // UV documentation says this is guaranteed to succeed
@@ -220,8 +220,13 @@ static void on_connect(uv_stream_t *server, int status) {
       gpr_log(GPR_INFO, "uv_tcp_getpeername error: %s", uv_strerror(status));
     }
     ep = grpc_tcp_create(client, sp->server->resource_quota, peer_name_string);
+    // Create acceptor.
+    grpc_tcp_server_acceptor *acceptor = gpr_malloc(sizeof(*acceptor));
+    acceptor->from_server = sp->server;
+    acceptor->port_index = sp->port_index;
+    acceptor->fd_index = 0;
     sp->server->on_accept_cb(&exec_ctx, sp->server->on_accept_cb_arg, ep, NULL,
-                             &acceptor);
+                             acceptor);
     grpc_exec_ctx_finish(&exec_ctx);
   }
 }
diff --git a/src/core/lib/iomgr/tcp_server_windows.c b/src/core/lib/iomgr/tcp_server_windows.c
index 40d1746730..dafe851ce8 100644
--- a/src/core/lib/iomgr/tcp_server_windows.c
+++ b/src/core/lib/iomgr/tcp_server_windows.c
@@ -116,11 +116,11 @@ grpc_error *grpc_tcp_server_create(grpc_exec_ctx *exec_ctx,
   for (size_t i = 0; i < (args == NULL ? 0 : args->num_args); i++) {
     if (0 == strcmp(GRPC_ARG_RESOURCE_QUOTA, args->args[i].key)) {
       if (args->args[i].type == GRPC_ARG_POINTER) {
-        grpc_resource_quota_internal_unref(exec_ctx, s->resource_quota);
+        grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
         s->resource_quota =
-            grpc_resource_quota_internal_ref(args->args[i].value.pointer.p);
+            grpc_resource_quota_ref_internal(args->args[i].value.pointer.p);
       } else {
-        grpc_resource_quota_internal_unref(exec_ctx, s->resource_quota);
+        grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
         gpr_free(s);
         return GRPC_ERROR_CREATE(GRPC_ARG_RESOURCE_QUOTA
                                  " must be a pointer to a buffer pool");
@@ -155,18 +155,19 @@ static void destroy_server(grpc_exec_ctx *exec_ctx, void *arg,
     grpc_winsocket_destroy(sp->socket);
     gpr_free(sp);
   }
-  grpc_resource_quota_internal_unref(exec_ctx, s->resource_quota);
+  grpc_resource_quota_unref_internal(exec_ctx, s->resource_quota);
   gpr_free(s);
 }
 
 static void finish_shutdown_locked(grpc_exec_ctx *exec_ctx,
                                    grpc_tcp_server *s) {
   if (s->shutdown_complete != NULL) {
-    grpc_exec_ctx_sched(exec_ctx, s->shutdown_complete, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, s->shutdown_complete, GRPC_ERROR_NONE);
   }
 
-  grpc_exec_ctx_sched(exec_ctx, grpc_closure_create(destroy_server, s),
-                      GRPC_ERROR_NONE, NULL);
+  grpc_closure_sched(exec_ctx, grpc_closure_create(destroy_server, s,
+                                                   grpc_schedule_on_exec_ctx),
+                     GRPC_ERROR_NONE);
 }
 
 grpc_tcp_server *grpc_tcp_server_ref(grpc_tcp_server *s) {
@@ -183,7 +184,6 @@ void grpc_tcp_server_shutdown_starting_add(grpc_tcp_server *s,
 }
 
 static void tcp_server_destroy(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s) {
-  int immediately_done = 0;
   grpc_tcp_listener *sp;
   gpr_mu_lock(&s->mu);
 
@@ -204,7 +204,7 @@ void grpc_tcp_server_unref(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s) {
   if (gpr_unref(&s->refs)) {
     grpc_tcp_server_shutdown_listeners(exec_ctx, s);
     gpr_mu_lock(&s->mu);
-    grpc_exec_ctx_enqueue_list(exec_ctx, &s->shutdown_starting, NULL);
+    grpc_closure_list_sched(exec_ctx, &s->shutdown_starting);
     gpr_mu_unlock(&s->mu);
     tcp_server_destroy(exec_ctx, s);
   }
@@ -247,7 +247,7 @@ static grpc_error *prepare_socket(SOCKET sock,
 failure:
   GPR_ASSERT(error != GRPC_ERROR_NONE);
   char *tgtaddr = grpc_sockaddr_to_uri(addr);
-  grpc_error *final_error = grpc_error_set_int(
+  grpc_error_set_int(
       grpc_error_set_str(GRPC_ERROR_CREATE_REFERENCING(
                              "Failed to prepare server socket", &error, 1),
                          GRPC_ERROR_STR_TARGET_ADDRESS, tgtaddr),
@@ -260,7 +260,6 @@ failure:
 
 static void decrement_active_ports_and_notify_locked(grpc_exec_ctx *exec_ctx,
                                                      grpc_tcp_listener *sp) {
-  int notify = 0;
   sp->shutting_down = 0;
   GPR_ASSERT(sp->server->active_ports > 0);
   if (0 == --sp->server->active_ports) {
@@ -323,7 +322,6 @@ failure:
 /* Event manager callback when reads are ready. */
 static void on_accept(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
   grpc_tcp_listener *sp = arg;
-  grpc_tcp_server_acceptor acceptor = {sp->server, sp->port_index, 0};
   SOCKET sock = sp->new_socket;
   grpc_winsocket_callback_info *info = &sp->socket->read_info;
   grpc_endpoint *ep = NULL;
@@ -396,8 +394,13 @@ static void on_accept(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
   /* The only time we should call our callback, is where we successfully
      managed to accept a connection, and created an endpoint. */
   if (ep) {
+    // Create acceptor.
+    grpc_tcp_server_acceptor *acceptor = gpr_malloc(sizeof(*acceptor));
+    acceptor->from_server = sp->server;
+    acceptor->port_index = sp->port_index;
+    acceptor->fd_index = 0;
     sp->server->on_accept_cb(exec_ctx, sp->server->on_accept_cb_arg, ep, NULL,
-                             &acceptor);
+                             acceptor);
   }
   /* As we were notified from the IOCP of one and exactly one accept,
      the former socked we created has now either been destroy or assigned
@@ -461,7 +464,7 @@ static grpc_error *add_socket_to_server(grpc_tcp_server *s, SOCKET sock,
   sp->new_socket = INVALID_SOCKET;
   sp->port = port;
   sp->port_index = port_index;
-  grpc_closure_init(&sp->on_accept, on_accept, sp);
+  grpc_closure_init(&sp->on_accept, on_accept, sp, grpc_schedule_on_exec_ctx);
   GPR_ASSERT(sp->socket);
   gpr_mu_unlock(&s->mu);
   *listener = sp;
diff --git a/src/core/lib/iomgr/tcp_uv.c b/src/core/lib/iomgr/tcp_uv.c
index 6e2ad1dbe9..3ddc79706b 100644
--- a/src/core/lib/iomgr/tcp_uv.c
+++ b/src/core/lib/iomgr/tcp_uv.c
@@ -169,7 +169,7 @@ static void read_callback(uv_stream_t *stream, ssize_t nread,
     // nread < 0: Error
     error = GRPC_ERROR_CREATE("TCP Read failed");
   }
-  grpc_exec_ctx_sched(&exec_ctx, cb, error, NULL);
+  grpc_closure_sched(&exec_ctx, cb, error);
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
@@ -181,7 +181,7 @@ static void uv_endpoint_read(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
   GPR_ASSERT(tcp->read_cb == NULL);
   tcp->read_cb = cb;
   tcp->read_slices = read_slices;
-  grpc_slice_buffer_reset_and_unref(read_slices);
+  grpc_slice_buffer_reset_and_unref_internal(exec_ctx, read_slices);
   TCP_REF(tcp, "read");
   // TODO(murgatroid99): figure out what the return value here means
   status =
@@ -190,7 +190,7 @@ static void uv_endpoint_read(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
     error = GRPC_ERROR_CREATE("TCP Read failed at start");
     error =
         grpc_error_set_str(error, GRPC_ERROR_STR_OS_ERROR, uv_strerror(status));
-    grpc_exec_ctx_sched(exec_ctx, cb, error, NULL);
+    grpc_closure_sched(exec_ctx, cb, error);
   }
   if (grpc_tcp_trace) {
     const char *str = grpc_error_string(error);
@@ -217,7 +217,7 @@ static void write_callback(uv_write_t *req, int status) {
   gpr_free(tcp->write_buffers);
   grpc_resource_user_free(&exec_ctx, tcp->resource_user,
                           sizeof(uv_buf_t) * tcp->write_slices->count);
-  grpc_exec_ctx_sched(&exec_ctx, cb, error, NULL);
+  grpc_closure_sched(&exec_ctx, cb, error);
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
@@ -243,8 +243,8 @@ static void uv_endpoint_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
   }
 
   if (tcp->shutting_down) {
-    grpc_exec_ctx_sched(exec_ctx, cb,
-                        GRPC_ERROR_CREATE("TCP socket is shutting down"), NULL);
+    grpc_closure_sched(exec_ctx, cb,
+                       GRPC_ERROR_CREATE("TCP socket is shutting down"));
     return;
   }
 
@@ -254,7 +254,7 @@ static void uv_endpoint_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
   if (tcp->write_slices->count == 0) {
     // No slices means we don't have to do anything,
     // and libuv doesn't like empty writes
-    grpc_exec_ctx_sched(exec_ctx, cb, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, cb, GRPC_ERROR_NONE);
     return;
   }
 
diff --git a/src/core/lib/iomgr/tcp_windows.c b/src/core/lib/iomgr/tcp_windows.c
index d4613b674e..84f791ba07 100644
--- a/src/core/lib/iomgr/tcp_windows.c
+++ b/src/core/lib/iomgr/tcp_windows.c
@@ -53,6 +53,7 @@
 #include "src/core/lib/iomgr/socket_windows.h"
 #include "src/core/lib/iomgr/tcp_client.h"
 #include "src/core/lib/iomgr/timer.h"
+#include "src/core/lib/slice/slice_internal.h"
 
 #if defined(__MSYS__) && defined(GPR_ARCH_64)
 /* Nasty workaround for nasty bug when using the 64 bits msys compiler
@@ -174,13 +175,13 @@ static void on_read(grpc_exec_ctx *exec_ctx, void *tcpp, grpc_error *error) {
       char *utf8_message = gpr_format_message(info->wsa_error);
       error = GRPC_ERROR_CREATE(utf8_message);
       gpr_free(utf8_message);
-      grpc_slice_unref(tcp->read_slice);
+      grpc_slice_unref_internal(exec_ctx, tcp->read_slice);
     } else {
       if (info->bytes_transfered != 0 && !tcp->shutting_down) {
         sub = grpc_slice_sub_no_ref(tcp->read_slice, 0, info->bytes_transfered);
         grpc_slice_buffer_add(tcp->read_slices, sub);
       } else {
-        grpc_slice_unref(tcp->read_slice);
+        grpc_slice_unref_internal(exec_ctx, tcp->read_slice);
         error = GRPC_ERROR_CREATE("End of TCP stream");
       }
     }
@@ -188,7 +189,7 @@ static void on_read(grpc_exec_ctx *exec_ctx, void *tcpp, grpc_error *error) {
 
   tcp->read_cb = NULL;
   TCP_UNREF(exec_ctx, tcp, "read");
-  grpc_exec_ctx_sched(exec_ctx, cb, error, NULL);
+  grpc_closure_sched(exec_ctx, cb, error);
 }
 
 static void win_read(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
@@ -202,14 +203,14 @@ static void win_read(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
   WSABUF buffer;
 
   if (tcp->shutting_down) {
-    grpc_exec_ctx_sched(exec_ctx, cb,
-                        GRPC_ERROR_CREATE("TCP socket is shutting down"), NULL);
+    grpc_closure_sched(exec_ctx, cb,
+                       GRPC_ERROR_CREATE("TCP socket is shutting down"));
     return;
   }
 
   tcp->read_cb = cb;
   tcp->read_slices = read_slices;
-  grpc_slice_buffer_reset_and_unref(read_slices);
+  grpc_slice_buffer_reset_and_unref_internal(exec_ctx, read_slices);
 
   tcp->read_slice = grpc_slice_malloc(8192);
 
@@ -227,7 +228,7 @@ static void win_read(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
   /* Did we get data immediately ? Yay. */
   if (info->wsa_error != WSAEWOULDBLOCK) {
     info->bytes_transfered = bytes_read;
-    grpc_exec_ctx_sched(exec_ctx, &tcp->on_read, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, &tcp->on_read, GRPC_ERROR_NONE);
     return;
   }
 
@@ -240,8 +241,8 @@ static void win_read(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
     int wsa_error = WSAGetLastError();
     if (wsa_error != WSA_IO_PENDING) {
       info->wsa_error = wsa_error;
-      grpc_exec_ctx_sched(exec_ctx, &tcp->on_read,
-                          GRPC_WSA_ERROR(info->wsa_error, "WSARecv"), NULL);
+      grpc_closure_sched(exec_ctx, &tcp->on_read,
+                         GRPC_WSA_ERROR(info->wsa_error, "WSARecv"));
       return;
     }
   }
@@ -272,7 +273,7 @@ static void on_write(grpc_exec_ctx *exec_ctx, void *tcpp, grpc_error *error) {
   }
 
   TCP_UNREF(exec_ctx, tcp, "write");
-  grpc_exec_ctx_sched(exec_ctx, cb, error, NULL);
+  grpc_closure_sched(exec_ctx, cb, error);
 }
 
 /* Initiates a write. */
@@ -290,8 +291,8 @@ static void win_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
   size_t len;
 
   if (tcp->shutting_down) {
-    grpc_exec_ctx_sched(exec_ctx, cb,
-                        GRPC_ERROR_CREATE("TCP socket is shutting down"), NULL);
+    grpc_closure_sched(exec_ctx, cb,
+                       GRPC_ERROR_CREATE("TCP socket is shutting down"));
     return;
   }
 
@@ -322,7 +323,7 @@ static void win_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
     grpc_error *error = status == 0
                             ? GRPC_ERROR_NONE
                             : GRPC_WSA_ERROR(info->wsa_error, "WSASend");
-    grpc_exec_ctx_sched(exec_ctx, cb, error, NULL);
+    grpc_closure_sched(exec_ctx, cb, error);
     if (allocated) gpr_free(allocated);
     return;
   }
@@ -340,8 +341,7 @@ static void win_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
     int wsa_error = WSAGetLastError();
     if (wsa_error != WSA_IO_PENDING) {
       TCP_UNREF(exec_ctx, tcp, "write");
-      grpc_exec_ctx_sched(exec_ctx, cb, GRPC_WSA_ERROR(wsa_error, "WSASend"),
-                          NULL);
+      grpc_closure_sched(exec_ctx, cb, GRPC_WSA_ERROR(wsa_error, "WSASend"));
       return;
     }
   }
@@ -424,8 +424,8 @@ grpc_endpoint *grpc_tcp_create(grpc_winsocket *socket,
   tcp->socket = socket;
   gpr_mu_init(&tcp->mu);
   gpr_ref_init(&tcp->refcount, 1);
-  grpc_closure_init(&tcp->on_read, on_read, tcp);
-  grpc_closure_init(&tcp->on_write, on_write, tcp);
+  grpc_closure_init(&tcp->on_read, on_read, tcp, grpc_schedule_on_exec_ctx);
+  grpc_closure_init(&tcp->on_write, on_write, tcp, grpc_schedule_on_exec_ctx);
   tcp->peer_string = gpr_strdup(peer_string);
   tcp->resource_user = grpc_resource_user_create(resource_quota, peer_string);
   /* Tell network status tracking code about the new endpoint */
diff --git a/src/core/lib/iomgr/timer.h b/src/core/lib/iomgr/timer.h
index 20fe98c4a7..d84a278b18 100644
--- a/src/core/lib/iomgr/timer.h
+++ b/src/core/lib/iomgr/timer.h
@@ -49,15 +49,15 @@
 
 typedef struct grpc_timer grpc_timer;
 
-/* Initialize *timer. When expired or canceled, timer_cb will be called with
-   *timer_cb_arg and error set to indicate if it expired (GRPC_ERROR_NONE) or
-   was canceled (GRPC_ERROR_CANCELLED). timer_cb is guaranteed to be called
-   exactly once, and application code should check the error to determine
-   how it was invoked. The application callback is also responsible for
-   maintaining information about when to free up any user-level state. */
+/* Initialize *timer. When expired or canceled, closure will be called with
+   error set to indicate if it expired (GRPC_ERROR_NONE) or was canceled
+   (GRPC_ERROR_CANCELLED). timer_cb is guaranteed to be called exactly once, and
+   application code should check the error to determine how it was invoked. The
+   application callback is also responsible for maintaining information about
+   when to free up any user-level state. */
 void grpc_timer_init(grpc_exec_ctx *exec_ctx, grpc_timer *timer,
-                     gpr_timespec deadline, grpc_iomgr_cb_func timer_cb,
-                     void *timer_cb_arg, gpr_timespec now);
+                     gpr_timespec deadline, grpc_closure *closure,
+                     gpr_timespec now);
 
 /* Note that there is no timer destroy function. This is because the
    timer is a one-time occurrence with a guarantee that the callback will
diff --git a/src/core/lib/iomgr/timer_generic.c b/src/core/lib/iomgr/timer_generic.c
index 00058f9d86..40c8351472 100644
--- a/src/core/lib/iomgr/timer_generic.c
+++ b/src/core/lib/iomgr/timer_generic.c
@@ -178,28 +178,27 @@ static void note_deadline_change(shard_type *shard) {
 }
 
 void grpc_timer_init(grpc_exec_ctx *exec_ctx, grpc_timer *timer,
-                     gpr_timespec deadline, grpc_iomgr_cb_func timer_cb,
-                     void *timer_cb_arg, gpr_timespec now) {
+                     gpr_timespec deadline, grpc_closure *closure,
+                     gpr_timespec now) {
   int is_first_timer = 0;
   shard_type *shard = &g_shards[shard_idx(timer)];
   GPR_ASSERT(deadline.clock_type == g_clock_type);
   GPR_ASSERT(now.clock_type == g_clock_type);
-  grpc_closure_init(&timer->closure, timer_cb, timer_cb_arg);
+  timer->closure = closure;
   timer->deadline = deadline;
   timer->triggered = 0;
 
   if (!g_initialized) {
     timer->triggered = 1;
-    grpc_exec_ctx_sched(
-        exec_ctx, &timer->closure,
-        GRPC_ERROR_CREATE("Attempt to create timer before initialization"),
-        NULL);
+    grpc_closure_sched(
+        exec_ctx, timer->closure,
+        GRPC_ERROR_CREATE("Attempt to create timer before initialization"));
     return;
   }
 
   if (gpr_time_cmp(deadline, now) <= 0) {
     timer->triggered = 1;
-    grpc_exec_ctx_sched(exec_ctx, &timer->closure, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, timer->closure, GRPC_ERROR_NONE);
     return;
   }
 
@@ -251,7 +250,7 @@ void grpc_timer_cancel(grpc_exec_ctx *exec_ctx, grpc_timer *timer) {
   shard_type *shard = &g_shards[shard_idx(timer)];
   gpr_mu_lock(&shard->mu);
   if (!timer->triggered) {
-    grpc_exec_ctx_sched(exec_ctx, &timer->closure, GRPC_ERROR_CANCELLED, NULL);
+    grpc_closure_sched(exec_ctx, timer->closure, GRPC_ERROR_CANCELLED);
     timer->triggered = 1;
     if (timer->heap_index == INVALID_HEAP_INDEX) {
       list_remove(timer);
@@ -317,7 +316,7 @@ static size_t pop_timers(grpc_exec_ctx *exec_ctx, shard_type *shard,
   grpc_timer *timer;
   gpr_mu_lock(&shard->mu);
   while ((timer = pop_one(shard, now))) {
-    grpc_exec_ctx_sched(exec_ctx, &timer->closure, GRPC_ERROR_REF(error), NULL);
+    grpc_closure_sched(exec_ctx, timer->closure, GRPC_ERROR_REF(error));
     n++;
   }
   *new_min_deadline = compute_min_deadline(shard);
diff --git a/src/core/lib/iomgr/timer_generic.h b/src/core/lib/iomgr/timer_generic.h
index e4494adb5f..9d901c7e68 100644
--- a/src/core/lib/iomgr/timer_generic.h
+++ b/src/core/lib/iomgr/timer_generic.h
@@ -43,7 +43,7 @@ struct grpc_timer {
   int triggered;
   struct grpc_timer *next;
   struct grpc_timer *prev;
-  grpc_closure closure;
+  grpc_closure *closure;
 };
 
 #endif /* GRPC_CORE_LIB_IOMGR_TIMER_GENERIC_H */
diff --git a/src/core/lib/iomgr/timer_uv.c b/src/core/lib/iomgr/timer_uv.c
index cfcb89268b..fa2cdee964 100644
--- a/src/core/lib/iomgr/timer_uv.c
+++ b/src/core/lib/iomgr/timer_uv.c
@@ -55,20 +55,20 @@ void run_expired_timer(uv_timer_t *handle) {
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   GPR_ASSERT(!timer->triggered);
   timer->triggered = 1;
-  grpc_exec_ctx_sched(&exec_ctx, &timer->closure, GRPC_ERROR_NONE, NULL);
+  grpc_closure_sched(&exec_ctx, timer->closure, GRPC_ERROR_NONE);
   stop_uv_timer(handle);
   grpc_exec_ctx_finish(&exec_ctx);
 }
 
 void grpc_timer_init(grpc_exec_ctx *exec_ctx, grpc_timer *timer,
-                     gpr_timespec deadline, grpc_iomgr_cb_func timer_cb,
-                     void *timer_cb_arg, gpr_timespec now) {
+                     gpr_timespec deadline, grpc_closure *closure,
+                     gpr_timespec now) {
   uint64_t timeout;
   uv_timer_t *uv_timer;
-  grpc_closure_init(&timer->closure, timer_cb, timer_cb_arg);
+  timer->closure = closure;
   if (gpr_time_cmp(deadline, now) <= 0) {
     timer->triggered = 1;
-    grpc_exec_ctx_sched(exec_ctx, &timer->closure, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, timer->closure, GRPC_ERROR_NONE);
     return;
   }
   timer->triggered = 0;
@@ -83,7 +83,7 @@ void grpc_timer_init(grpc_exec_ctx *exec_ctx, grpc_timer *timer,
 void grpc_timer_cancel(grpc_exec_ctx *exec_ctx, grpc_timer *timer) {
   if (!timer->triggered) {
     timer->triggered = 1;
-    grpc_exec_ctx_sched(exec_ctx, &timer->closure, GRPC_ERROR_CANCELLED, NULL);
+    grpc_closure_sched(exec_ctx, timer->closure, GRPC_ERROR_CANCELLED);
     stop_uv_timer((uv_timer_t *)timer->uv_timer);
   }
 }
diff --git a/src/core/lib/iomgr/timer_uv.h b/src/core/lib/iomgr/timer_uv.h
index 3de383ebd5..13cf8bd4fa 100644
--- a/src/core/lib/iomgr/timer_uv.h
+++ b/src/core/lib/iomgr/timer_uv.h
@@ -37,7 +37,7 @@
 #include "src/core/lib/iomgr/exec_ctx.h"
 
 struct grpc_timer {
-  grpc_closure closure;
+  grpc_closure *closure;
   /* This is actually a uv_timer_t*, but we want to keep platform-specific
      types out of headers */
   void *uv_timer;
diff --git a/src/core/lib/iomgr/udp_server.c b/src/core/lib/iomgr/udp_server.c
index 3c24ea9afa..dfbd295c91 100644
--- a/src/core/lib/iomgr/udp_server.c
+++ b/src/core/lib/iomgr/udp_server.c
@@ -126,7 +126,7 @@ grpc_udp_server *grpc_udp_server_create(void) {
 
 static void finish_shutdown(grpc_exec_ctx *exec_ctx, grpc_udp_server *s) {
   if (s->shutdown_complete != NULL) {
-    grpc_exec_ctx_sched(exec_ctx, s->shutdown_complete, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, s->shutdown_complete, GRPC_ERROR_NONE);
   }
 
   gpr_mu_destroy(&s->mu);
@@ -170,8 +170,8 @@ static void deactivated_all_ports(grpc_exec_ctx *exec_ctx, grpc_udp_server *s) {
     for (sp = s->head; sp; sp = sp->next) {
       grpc_unlink_if_unix_domain_socket(&sp->addr);
 
-      sp->destroyed_closure.cb = destroyed_port;
-      sp->destroyed_closure.cb_arg = s;
+      grpc_closure_init(&sp->destroyed_closure, destroyed_port, s,
+                        grpc_schedule_on_exec_ctx);
 
       /* Call the orphan_cb to signal that the FD is about to be closed and
        * should no longer be used. */
@@ -446,8 +446,8 @@ void grpc_udp_server_start(grpc_exec_ctx *exec_ctx, grpc_udp_server *s,
     for (i = 0; i < pollset_count; i++) {
       grpc_pollset_add_fd(exec_ctx, pollsets[i], sp->emfd);
     }
-    sp->read_closure.cb = on_read;
-    sp->read_closure.cb_arg = sp;
+    grpc_closure_init(&sp->read_closure, on_read, sp,
+                      grpc_schedule_on_exec_ctx);
     grpc_fd_notify_on_read(exec_ctx, sp->emfd, &sp->read_closure);
 
     s->active_ports++;
diff --git a/src/core/lib/iomgr/workqueue.h b/src/core/lib/iomgr/workqueue.h
index 73d9849843..371b0f55dc 100644
--- a/src/core/lib/iomgr/workqueue.h
+++ b/src/core/lib/iomgr/workqueue.h
@@ -72,17 +72,16 @@ grpc_workqueue *grpc_workqueue_ref(grpc_workqueue *workqueue);
 void grpc_workqueue_unref(grpc_exec_ctx *exec_ctx, grpc_workqueue *workqueue);
 #endif
 
-/** Add a work item to a workqueue. Items added to a work queue will be started
-    in approximately the order they were enqueued, on some thread that may or
-    may not be the current thread. Successive closures enqueued onto a workqueue
-    MAY be executed concurrently.
+/** Fetch the workqueue closure scheduler. Items added to a work queue will be
+    started in approximately the order they were enqueued, on some thread that
+    may or may not be the current thread. Successive closures enqueued onto a
+    workqueue MAY be executed concurrently.
 
     It is generally more expensive to add a closure to a workqueue than to the
     execution context, both in terms of CPU work and in execution latency.
 
     Use work queues when it's important that other threads be given a chance to
     tackle some workload. */
-void grpc_workqueue_enqueue(grpc_exec_ctx *exec_ctx, grpc_workqueue *workqueue,
-                            grpc_closure *closure, grpc_error *error);
+grpc_closure_scheduler *grpc_workqueue_scheduler(grpc_workqueue *workqueue);
 
 #endif /* GRPC_CORE_LIB_IOMGR_WORKQUEUE_H */
diff --git a/src/core/lib/iomgr/workqueue_uv.c b/src/core/lib/iomgr/workqueue_uv.c
index e58ca476cc..4d61b40912 100644
--- a/src/core/lib/iomgr/workqueue_uv.c
+++ b/src/core/lib/iomgr/workqueue_uv.c
@@ -58,9 +58,8 @@ grpc_workqueue *grpc_workqueue_ref(grpc_workqueue *workqueue) {
 void grpc_workqueue_unref(grpc_exec_ctx *exec_ctx, grpc_workqueue *workqueue) {}
 #endif
 
-void grpc_workqueue_enqueue(grpc_exec_ctx *exec_ctx, grpc_workqueue *workqueue,
-                            grpc_closure *closure, grpc_error *error) {
-  grpc_exec_ctx_sched(exec_ctx, closure, error, NULL);
+grpc_closure_scheduler *grpc_workqueue_scheduler(grpc_workqueue *workqueue) {
+  return grpc_schedule_on_exec_ctx;
 }
 
 #endif /* GPR_UV */
diff --git a/src/core/lib/iomgr/workqueue_windows.c b/src/core/lib/iomgr/workqueue_windows.c
index 5c93d3c59e..234b47cdf5 100644
--- a/src/core/lib/iomgr/workqueue_windows.c
+++ b/src/core/lib/iomgr/workqueue_windows.c
@@ -56,9 +56,8 @@ grpc_workqueue *grpc_workqueue_ref(grpc_workqueue *workqueue) {
 void grpc_workqueue_unref(grpc_exec_ctx *exec_ctx, grpc_workqueue *workqueue) {}
 #endif
 
-void grpc_workqueue_enqueue(grpc_exec_ctx *exec_ctx, grpc_workqueue *workqueue,
-                            grpc_closure *closure, grpc_error *error) {
-  grpc_exec_ctx_sched(exec_ctx, closure, error, NULL);
+grpc_closure_scheduler *grpc_workqueue_scheduler(grpc_workqueue *workqueue) {
+  return grpc_schedule_on_exec_ctx;
 }
 
 #endif /* GPR_WINDOWS */
diff --git a/src/core/lib/security/context/security_context.c b/src/core/lib/security/context/security_context.c
index 2204fadf54..fe82fabc31 100644
--- a/src/core/lib/security/context/security_context.c
+++ b/src/core/lib/security/context/security_context.c
@@ -47,6 +47,7 @@
 
 grpc_call_error grpc_call_set_credentials(grpc_call *call,
                                           grpc_call_credentials *creds) {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_client_security_context *ctx = NULL;
   GRPC_API_TRACE("grpc_call_set_credentials(call=%p, creds=%p)", 2,
                  (call, creds));
@@ -62,9 +63,10 @@ grpc_call_error grpc_call_set_credentials(grpc_call *call,
     grpc_call_context_set(call, GRPC_CONTEXT_SECURITY, ctx,
                           grpc_client_security_context_destroy);
   } else {
-    grpc_call_credentials_unref(ctx->creds);
+    grpc_call_credentials_unref(&exec_ctx, ctx->creds);
     ctx->creds = grpc_call_credentials_ref(creds);
   }
+  grpc_exec_ctx_finish(&exec_ctx);
   return GRPC_CALL_OK;
 }
 
@@ -96,13 +98,15 @@ grpc_client_security_context *grpc_client_security_context_create(void) {
 }
 
 void grpc_client_security_context_destroy(void *ctx) {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_client_security_context *c = (grpc_client_security_context *)ctx;
-  grpc_call_credentials_unref(c->creds);
+  grpc_call_credentials_unref(&exec_ctx, c->creds);
   GRPC_AUTH_CONTEXT_UNREF(c->auth_context, "client_security_context");
   if (c->extension.instance != NULL && c->extension.destroy != NULL) {
     c->extension.destroy(c->extension.instance);
   }
   gpr_free(ctx);
+  grpc_exec_ctx_finish(&exec_ctx);
 }
 
 /* --- grpc_server_security_context --- */
@@ -307,7 +311,7 @@ void grpc_auth_property_reset(grpc_auth_property *property) {
   memset(property, 0, sizeof(grpc_auth_property));
 }
 
-static void auth_context_pointer_arg_destroy(void *p) {
+static void auth_context_pointer_arg_destroy(grpc_exec_ctx *exec_ctx, void *p) {
   GRPC_AUTH_CONTEXT_UNREF(p, "auth_context_pointer_arg");
 }
 
diff --git a/src/core/lib/security/credentials/composite/composite_credentials.c b/src/core/lib/security/credentials/composite/composite_credentials.c
index d55d00b7b6..be1588dd8b 100644
--- a/src/core/lib/security/credentials/composite/composite_credentials.c
+++ b/src/core/lib/security/credentials/composite/composite_credentials.c
@@ -54,18 +54,20 @@ typedef struct {
   grpc_credentials_metadata_cb cb;
 } grpc_composite_call_credentials_metadata_context;
 
-static void composite_call_destruct(grpc_call_credentials *creds) {
+static void composite_call_destruct(grpc_exec_ctx *exec_ctx,
+                                    grpc_call_credentials *creds) {
   grpc_composite_call_credentials *c = (grpc_composite_call_credentials *)creds;
   size_t i;
   for (i = 0; i < c->inner.num_creds; i++) {
-    grpc_call_credentials_unref(c->inner.creds_array[i]);
+    grpc_call_credentials_unref(exec_ctx, c->inner.creds_array[i]);
   }
   gpr_free(c->inner.creds_array);
 }
 
 static void composite_call_md_context_destroy(
+    grpc_exec_ctx *exec_ctx,
     grpc_composite_call_credentials_metadata_context *ctx) {
-  grpc_credentials_md_store_unref(ctx->md_elems);
+  grpc_credentials_md_store_unref(exec_ctx, ctx->md_elems);
   gpr_free(ctx);
 }
 
@@ -103,7 +105,7 @@ static void composite_call_metadata_cb(grpc_exec_ctx *exec_ctx, void *user_data,
   /* We're done!. */
   ctx->cb(exec_ctx, ctx->user_data, ctx->md_elems->entries,
           ctx->md_elems->num_entries, GRPC_CREDENTIALS_OK, NULL);
-  composite_call_md_context_destroy(ctx);
+  composite_call_md_context_destroy(exec_ctx, ctx);
 }
 
 static void composite_call_get_request_metadata(
@@ -209,17 +211,19 @@ grpc_call_credentials *grpc_credentials_contains_type(
 
 /* -- Composite channel credentials. -- */
 
-static void composite_channel_destruct(grpc_channel_credentials *creds) {
+static void composite_channel_destruct(grpc_exec_ctx *exec_ctx,
+                                       grpc_channel_credentials *creds) {
   grpc_composite_channel_credentials *c =
       (grpc_composite_channel_credentials *)creds;
-  grpc_channel_credentials_unref(c->inner_creds);
-  grpc_call_credentials_unref(c->call_creds);
+  grpc_channel_credentials_unref(exec_ctx, c->inner_creds);
+  grpc_call_credentials_unref(exec_ctx, c->call_creds);
 }
 
 static grpc_security_status composite_channel_create_security_connector(
-    grpc_channel_credentials *creds, grpc_call_credentials *call_creds,
-    const char *target, const grpc_channel_args *args,
-    grpc_channel_security_connector **sc, grpc_channel_args **new_args) {
+    grpc_exec_ctx *exec_ctx, grpc_channel_credentials *creds,
+    grpc_call_credentials *call_creds, const char *target,
+    const grpc_channel_args *args, grpc_channel_security_connector **sc,
+    grpc_channel_args **new_args) {
   grpc_composite_channel_credentials *c =
       (grpc_composite_channel_credentials *)creds;
   grpc_security_status status = GRPC_SECURITY_ERROR;
@@ -233,11 +237,12 @@ static grpc_security_status composite_channel_create_security_connector(
     grpc_call_credentials *composite_call_creds =
         grpc_composite_call_credentials_create(c->call_creds, call_creds, NULL);
     status = c->inner_creds->vtable->create_security_connector(
-        c->inner_creds, composite_call_creds, target, args, sc, new_args);
-    grpc_call_credentials_unref(composite_call_creds);
+        exec_ctx, c->inner_creds, composite_call_creds, target, args, sc,
+        new_args);
+    grpc_call_credentials_unref(exec_ctx, composite_call_creds);
   } else {
     status = c->inner_creds->vtable->create_security_connector(
-        c->inner_creds, c->call_creds, target, args, sc, new_args);
+        exec_ctx, c->inner_creds, c->call_creds, target, args, sc, new_args);
   }
   return status;
 }
diff --git a/src/core/lib/security/credentials/credentials.c b/src/core/lib/security/credentials/credentials.c
index 1149e5c2ed..9781a22a86 100644
--- a/src/core/lib/security/credentials/credentials.c
+++ b/src/core/lib/security/credentials/credentials.c
@@ -66,8 +66,8 @@ grpc_credentials_metadata_request *grpc_credentials_metadata_request_create(
 }
 
 void grpc_credentials_metadata_request_destroy(
-    grpc_credentials_metadata_request *r) {
-  grpc_call_credentials_unref(r->creds);
+    grpc_exec_ctx *exec_ctx, grpc_credentials_metadata_request *r) {
+  grpc_call_credentials_unref(exec_ctx, r->creds);
   grpc_http_response_destroy(&r->response);
   gpr_free(r);
 }
@@ -79,17 +79,22 @@ grpc_channel_credentials *grpc_channel_credentials_ref(
   return creds;
 }
 
-void grpc_channel_credentials_unref(grpc_channel_credentials *creds) {
+void grpc_channel_credentials_unref(grpc_exec_ctx *exec_ctx,
+                                    grpc_channel_credentials *creds) {
   if (creds == NULL) return;
   if (gpr_unref(&creds->refcount)) {
-    if (creds->vtable->destruct != NULL) creds->vtable->destruct(creds);
+    if (creds->vtable->destruct != NULL) {
+      creds->vtable->destruct(exec_ctx, creds);
+    }
     gpr_free(creds);
   }
 }
 
 void grpc_channel_credentials_release(grpc_channel_credentials *creds) {
   GRPC_API_TRACE("grpc_channel_credentials_release(creds=%p)", 1, (creds));
-  grpc_channel_credentials_unref(creds);
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_channel_credentials_unref(&exec_ctx, creds);
+  grpc_exec_ctx_finish(&exec_ctx);
 }
 
 grpc_call_credentials *grpc_call_credentials_ref(grpc_call_credentials *creds) {
@@ -98,17 +103,22 @@ grpc_call_credentials *grpc_call_credentials_ref(grpc_call_credentials *creds) {
   return creds;
 }
 
-void grpc_call_credentials_unref(grpc_call_credentials *creds) {
+void grpc_call_credentials_unref(grpc_exec_ctx *exec_ctx,
+                                 grpc_call_credentials *creds) {
   if (creds == NULL) return;
   if (gpr_unref(&creds->refcount)) {
-    if (creds->vtable->destruct != NULL) creds->vtable->destruct(creds);
+    if (creds->vtable->destruct != NULL) {
+      creds->vtable->destruct(exec_ctx, creds);
+    }
     gpr_free(creds);
   }
 }
 
 void grpc_call_credentials_release(grpc_call_credentials *creds) {
   GRPC_API_TRACE("grpc_call_credentials_release(creds=%p)", 1, (creds));
-  grpc_call_credentials_unref(creds);
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_call_credentials_unref(&exec_ctx, creds);
+  grpc_exec_ctx_finish(&exec_ctx);
 }
 
 void grpc_call_credentials_get_request_metadata(
@@ -126,16 +136,16 @@ void grpc_call_credentials_get_request_metadata(
 }
 
 grpc_security_status grpc_channel_credentials_create_security_connector(
-    grpc_channel_credentials *channel_creds, const char *target,
-    const grpc_channel_args *args, grpc_channel_security_connector **sc,
-    grpc_channel_args **new_args) {
+    grpc_exec_ctx *exec_ctx, grpc_channel_credentials *channel_creds,
+    const char *target, const grpc_channel_args *args,
+    grpc_channel_security_connector **sc, grpc_channel_args **new_args) {
   *new_args = NULL;
   if (channel_creds == NULL) {
     return GRPC_SECURITY_ERROR;
   }
   GPR_ASSERT(channel_creds->vtable->create_security_connector != NULL);
   return channel_creds->vtable->create_security_connector(
-      channel_creds, NULL, target, args, sc, new_args);
+      exec_ctx, channel_creds, NULL, target, args, sc, new_args);
 }
 
 grpc_channel_credentials *
@@ -157,10 +167,13 @@ grpc_server_credentials *grpc_server_credentials_ref(
   return creds;
 }
 
-void grpc_server_credentials_unref(grpc_server_credentials *creds) {
+void grpc_server_credentials_unref(grpc_exec_ctx *exec_ctx,
+                                   grpc_server_credentials *creds) {
   if (creds == NULL) return;
   if (gpr_unref(&creds->refcount)) {
-    if (creds->vtable->destruct != NULL) creds->vtable->destruct(creds);
+    if (creds->vtable->destruct != NULL) {
+      creds->vtable->destruct(exec_ctx, creds);
+    }
     if (creds->processor.destroy != NULL && creds->processor.state != NULL) {
       creds->processor.destroy(creds->processor.state);
     }
@@ -170,16 +183,19 @@ void grpc_server_credentials_unref(grpc_server_credentials *creds) {
 
 void grpc_server_credentials_release(grpc_server_credentials *creds) {
   GRPC_API_TRACE("grpc_server_credentials_release(creds=%p)", 1, (creds));
-  grpc_server_credentials_unref(creds);
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_server_credentials_unref(&exec_ctx, creds);
+  grpc_exec_ctx_finish(&exec_ctx);
 }
 
 grpc_security_status grpc_server_credentials_create_security_connector(
-    grpc_server_credentials *creds, grpc_server_security_connector **sc) {
+    grpc_exec_ctx *exec_ctx, grpc_server_credentials *creds,
+    grpc_server_security_connector **sc) {
   if (creds == NULL || creds->vtable->create_security_connector == NULL) {
     gpr_log(GPR_ERROR, "Server credentials cannot create security context.");
     return GRPC_SECURITY_ERROR;
   }
-  return creds->vtable->create_security_connector(creds, sc);
+  return creds->vtable->create_security_connector(exec_ctx, creds, sc);
 }
 
 void grpc_server_credentials_set_auth_metadata_processor(
@@ -196,8 +212,9 @@ void grpc_server_credentials_set_auth_metadata_processor(
   creds->processor = processor;
 }
 
-static void server_credentials_pointer_arg_destroy(void *p) {
-  grpc_server_credentials_unref(p);
+static void server_credentials_pointer_arg_destroy(grpc_exec_ctx *exec_ctx,
+                                                   void *p) {
+  grpc_server_credentials_unref(exec_ctx, p);
 }
 
 static void *server_credentials_pointer_arg_copy(void *p) {
diff --git a/src/core/lib/security/credentials/credentials.h b/src/core/lib/security/credentials/credentials.h
index 85b3bc5350..3011df6b8a 100644
--- a/src/core/lib/security/credentials/credentials.h
+++ b/src/core/lib/security/credentials/credentials.h
@@ -101,12 +101,13 @@ void grpc_override_well_known_credentials_path_getter(
 /* --- grpc_channel_credentials. --- */
 
 typedef struct {
-  void (*destruct)(grpc_channel_credentials *c);
+  void (*destruct)(grpc_exec_ctx *exec_ctx, grpc_channel_credentials *c);
 
   grpc_security_status (*create_security_connector)(
-      grpc_channel_credentials *c, grpc_call_credentials *call_creds,
-      const char *target, const grpc_channel_args *args,
-      grpc_channel_security_connector **sc, grpc_channel_args **new_args);
+      grpc_exec_ctx *exec_ctx, grpc_channel_credentials *c,
+      grpc_call_credentials *call_creds, const char *target,
+      const grpc_channel_args *args, grpc_channel_security_connector **sc,
+      grpc_channel_args **new_args);
 
   grpc_channel_credentials *(*duplicate_without_call_credentials)(
       grpc_channel_credentials *c);
@@ -120,16 +121,17 @@ struct grpc_channel_credentials {
 
 grpc_channel_credentials *grpc_channel_credentials_ref(
     grpc_channel_credentials *creds);
-void grpc_channel_credentials_unref(grpc_channel_credentials *creds);
+void grpc_channel_credentials_unref(grpc_exec_ctx *exec_ctx,
+                                    grpc_channel_credentials *creds);
 
 /* Creates a security connector for the channel. May also create new channel
    args for the channel to be used in place of the passed in const args if
    returned non NULL. In that case the caller is responsible for destroying
    new_args after channel creation. */
 grpc_security_status grpc_channel_credentials_create_security_connector(
-    grpc_channel_credentials *creds, const char *target,
-    const grpc_channel_args *args, grpc_channel_security_connector **sc,
-    grpc_channel_args **new_args);
+    grpc_exec_ctx *exec_ctx, grpc_channel_credentials *creds,
+    const char *target, const grpc_channel_args *args,
+    grpc_channel_security_connector **sc, grpc_channel_args **new_args);
 
 /* Creates a version of the channel credentials without any attached call
    credentials. This can be used in order to open a channel to a non-trusted
@@ -162,7 +164,8 @@ void grpc_credentials_md_store_add_cstrings(grpc_credentials_md_store *store,
                                             const char *key, const char *value);
 grpc_credentials_md_store *grpc_credentials_md_store_ref(
     grpc_credentials_md_store *store);
-void grpc_credentials_md_store_unref(grpc_credentials_md_store *store);
+void grpc_credentials_md_store_unref(grpc_exec_ctx *exec_ctx,
+                                     grpc_credentials_md_store *store);
 
 /* --- grpc_call_credentials. --- */
 
@@ -172,7 +175,7 @@ typedef void (*grpc_credentials_metadata_cb)(
     size_t num_md, grpc_credentials_status status, const char *error_details);
 
 typedef struct {
-  void (*destruct)(grpc_call_credentials *c);
+  void (*destruct)(grpc_exec_ctx *exec_ctx, grpc_call_credentials *c);
   void (*get_request_metadata)(grpc_exec_ctx *exec_ctx,
                                grpc_call_credentials *c,
                                grpc_polling_entity *pollent,
@@ -188,7 +191,8 @@ struct grpc_call_credentials {
 };
 
 grpc_call_credentials *grpc_call_credentials_ref(grpc_call_credentials *creds);
-void grpc_call_credentials_unref(grpc_call_credentials *creds);
+void grpc_call_credentials_unref(grpc_exec_ctx *exec_ctx,
+                                 grpc_call_credentials *creds);
 void grpc_call_credentials_get_request_metadata(
     grpc_exec_ctx *exec_ctx, grpc_call_credentials *creds,
     grpc_polling_entity *pollent, grpc_auth_metadata_context context,
@@ -202,9 +206,10 @@ grpc_call_credentials *grpc_md_only_test_credentials_create(
 /* --- grpc_server_credentials. --- */
 
 typedef struct {
-  void (*destruct)(grpc_server_credentials *c);
+  void (*destruct)(grpc_exec_ctx *exec_ctx, grpc_server_credentials *c);
   grpc_security_status (*create_security_connector)(
-      grpc_server_credentials *c, grpc_server_security_connector **sc);
+      grpc_exec_ctx *exec_ctx, grpc_server_credentials *c,
+      grpc_server_security_connector **sc);
 } grpc_server_credentials_vtable;
 
 struct grpc_server_credentials {
@@ -215,12 +220,14 @@ struct grpc_server_credentials {
 };
 
 grpc_security_status grpc_server_credentials_create_security_connector(
-    grpc_server_credentials *creds, grpc_server_security_connector **sc);
+    grpc_exec_ctx *exec_ctx, grpc_server_credentials *creds,
+    grpc_server_security_connector **sc);
 
 grpc_server_credentials *grpc_server_credentials_ref(
     grpc_server_credentials *creds);
 
-void grpc_server_credentials_unref(grpc_server_credentials *creds);
+void grpc_server_credentials_unref(grpc_exec_ctx *exec_ctx,
+                                   grpc_server_credentials *creds);
 
 #define GRPC_SERVER_CREDENTIALS_ARG "grpc.server_credentials"
 
@@ -243,6 +250,6 @@ grpc_credentials_metadata_request *grpc_credentials_metadata_request_create(
     void *user_data);
 
 void grpc_credentials_metadata_request_destroy(
-    grpc_credentials_metadata_request *r);
+    grpc_exec_ctx *exec_ctx, grpc_credentials_metadata_request *r);
 
 #endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_CREDENTIALS_H */
diff --git a/src/core/lib/security/credentials/credentials_metadata.c b/src/core/lib/security/credentials/credentials_metadata.c
index e6cb567734..68da5fb4a8 100644
--- a/src/core/lib/security/credentials/credentials_metadata.c
+++ b/src/core/lib/security/credentials/credentials_metadata.c
@@ -37,6 +37,8 @@
 
 #include <string.h>
 
+#include "src/core/lib/slice/slice_internal.h"
+
 static void store_ensure_capacity(grpc_credentials_md_store *store) {
   if (store->num_entries == store->allocated) {
     store->allocated = (store->allocated == 0) ? 1 : store->allocated * 2;
@@ -62,8 +64,8 @@ void grpc_credentials_md_store_add(grpc_credentials_md_store *store,
                                    grpc_slice key, grpc_slice value) {
   if (store == NULL) return;
   store_ensure_capacity(store);
-  store->entries[store->num_entries].key = grpc_slice_ref(key);
-  store->entries[store->num_entries].value = grpc_slice_ref(value);
+  store->entries[store->num_entries].key = grpc_slice_ref_internal(key);
+  store->entries[store->num_entries].value = grpc_slice_ref_internal(value);
   store->num_entries++;
 }
 
@@ -85,14 +87,15 @@ grpc_credentials_md_store *grpc_credentials_md_store_ref(
   return store;
 }
 
-void grpc_credentials_md_store_unref(grpc_credentials_md_store *store) {
+void grpc_credentials_md_store_unref(grpc_exec_ctx *exec_ctx,
+                                     grpc_credentials_md_store *store) {
   if (store == NULL) return;
   if (gpr_unref(&store->refcount)) {
     if (store->entries != NULL) {
       size_t i;
       for (i = 0; i < store->num_entries; i++) {
-        grpc_slice_unref(store->entries[i].key);
-        grpc_slice_unref(store->entries[i].value);
+        grpc_slice_unref_internal(exec_ctx, store->entries[i].key);
+        grpc_slice_unref_internal(exec_ctx, store->entries[i].value);
       }
       gpr_free(store->entries);
     }
diff --git a/src/core/lib/security/credentials/fake/fake_credentials.c b/src/core/lib/security/credentials/fake/fake_credentials.c
index ea4cb76fb9..a8679d097d 100644
--- a/src/core/lib/security/credentials/fake/fake_credentials.c
+++ b/src/core/lib/security/credentials/fake/fake_credentials.c
@@ -45,16 +45,18 @@
 /* -- Fake transport security credentials. -- */
 
 static grpc_security_status fake_transport_security_create_security_connector(
-    grpc_channel_credentials *c, grpc_call_credentials *call_creds,
-    const char *target, const grpc_channel_args *args,
-    grpc_channel_security_connector **sc, grpc_channel_args **new_args) {
+    grpc_exec_ctx *exec_ctx, grpc_channel_credentials *c,
+    grpc_call_credentials *call_creds, const char *target,
+    const grpc_channel_args *args, grpc_channel_security_connector **sc,
+    grpc_channel_args **new_args) {
   *sc = grpc_fake_channel_security_connector_create(call_creds);
   return GRPC_SECURITY_OK;
 }
 
 static grpc_security_status
 fake_transport_security_server_create_security_connector(
-    grpc_server_credentials *c, grpc_server_security_connector **sc) {
+    grpc_exec_ctx *exec_ctx, grpc_server_credentials *c,
+    grpc_server_security_connector **sc) {
   *sc = grpc_fake_server_security_connector_create();
   return GRPC_SECURITY_OK;
 }
@@ -89,9 +91,10 @@ grpc_server_credentials *grpc_fake_transport_security_server_credentials_create(
 
 /* -- Metadata-only test credentials. -- */
 
-static void md_only_test_destruct(grpc_call_credentials *creds) {
+static void md_only_test_destruct(grpc_exec_ctx *exec_ctx,
+                                  grpc_call_credentials *creds) {
   grpc_md_only_test_credentials *c = (grpc_md_only_test_credentials *)creds;
-  grpc_credentials_md_store_unref(c->md_store);
+  grpc_credentials_md_store_unref(exec_ctx, c->md_store);
 }
 
 static void on_simulated_token_fetch_done(grpc_exec_ctx *exec_ctx,
@@ -101,7 +104,7 @@ static void on_simulated_token_fetch_done(grpc_exec_ctx *exec_ctx,
   grpc_md_only_test_credentials *c = (grpc_md_only_test_credentials *)r->creds;
   r->cb(exec_ctx, r->user_data, c->md_store->entries, c->md_store->num_entries,
         GRPC_CREDENTIALS_OK, NULL);
-  grpc_credentials_metadata_request_destroy(r);
+  grpc_credentials_metadata_request_destroy(exec_ctx, r);
 }
 
 static void md_only_test_get_request_metadata(
@@ -113,9 +116,10 @@ static void md_only_test_get_request_metadata(
   if (c->is_async) {
     grpc_credentials_metadata_request *cb_arg =
         grpc_credentials_metadata_request_create(creds, cb, user_data);
-    grpc_executor_push(
-        grpc_closure_create(on_simulated_token_fetch_done, cb_arg),
-        GRPC_ERROR_NONE);
+    grpc_closure_sched(exec_ctx,
+                       grpc_closure_create(on_simulated_token_fetch_done,
+                                           cb_arg, grpc_executor_scheduler),
+                       GRPC_ERROR_NONE);
   } else {
     cb(exec_ctx, user_data, c->md_store->entries, 1, GRPC_CREDENTIALS_OK, NULL);
   }
diff --git a/src/core/lib/security/credentials/google_default/google_default_credentials.c b/src/core/lib/security/credentials/google_default/google_default_credentials.c
index afe0e3d357..d6e1fe3dcf 100644
--- a/src/core/lib/security/credentials/google_default/google_default_credentials.c
+++ b/src/core/lib/security/credentials/google_default/google_default_credentials.c
@@ -45,6 +45,7 @@
 #include "src/core/lib/iomgr/polling_entity.h"
 #include "src/core/lib/security/credentials/jwt/jwt_credentials.h"
 #include "src/core/lib/security/credentials/oauth2/oauth2_credentials.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/env.h"
 #include "src/core/lib/support/string.h"
@@ -101,11 +102,10 @@ static void destroy_pollset(grpc_exec_ctx *exec_ctx, void *p, grpc_error *e) {
   grpc_pollset_destroy(p);
 }
 
-static int is_stack_running_on_compute_engine(void) {
+static int is_stack_running_on_compute_engine(grpc_exec_ctx *exec_ctx) {
   compute_engine_detector detector;
   grpc_httpcli_request request;
   grpc_httpcli_context context;
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_closure destroy_closure;
 
   /* The http call is local. If it takes more than one sec, it is for sure not
@@ -128,13 +128,14 @@ static int is_stack_running_on_compute_engine(void) {
   grpc_resource_quota *resource_quota =
       grpc_resource_quota_create("google_default_credentials");
   grpc_httpcli_get(
-      &exec_ctx, &context, &detector.pollent, resource_quota, &request,
+      exec_ctx, &context, &detector.pollent, resource_quota, &request,
       gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), max_detection_delay),
-      grpc_closure_create(on_compute_engine_detection_http_response, &detector),
+      grpc_closure_create(on_compute_engine_detection_http_response, &detector,
+                          grpc_schedule_on_exec_ctx),
       &detector.response);
-  grpc_resource_quota_internal_unref(&exec_ctx, resource_quota);
+  grpc_resource_quota_unref_internal(exec_ctx, resource_quota);
 
-  grpc_exec_ctx_flush(&exec_ctx);
+  grpc_exec_ctx_flush(exec_ctx);
 
   /* Block until we get the response. This is not ideal but this should only be
      called once for the lifetime of the process by the default credentials. */
@@ -143,7 +144,7 @@ static int is_stack_running_on_compute_engine(void) {
     grpc_pollset_worker *worker = NULL;
     if (!GRPC_LOG_IF_ERROR(
             "pollset_work",
-            grpc_pollset_work(&exec_ctx,
+            grpc_pollset_work(exec_ctx,
                               grpc_polling_entity_pollset(&detector.pollent),
                               &worker, gpr_now(GPR_CLOCK_MONOTONIC),
                               gpr_inf_future(GPR_CLOCK_MONOTONIC)))) {
@@ -155,12 +156,13 @@ static int is_stack_running_on_compute_engine(void) {
 
   grpc_httpcli_context_destroy(&context);
   grpc_closure_init(&destroy_closure, destroy_pollset,
-                    grpc_polling_entity_pollset(&detector.pollent));
-  grpc_pollset_shutdown(&exec_ctx,
+                    grpc_polling_entity_pollset(&detector.pollent),
+                    grpc_schedule_on_exec_ctx);
+  grpc_pollset_shutdown(exec_ctx,
                         grpc_polling_entity_pollset(&detector.pollent),
                         &destroy_closure);
-  grpc_exec_ctx_finish(&exec_ctx);
   g_polling_mu = NULL;
+  grpc_exec_ctx_flush(exec_ctx);
 
   gpr_free(grpc_polling_entity_pollset(&detector.pollent));
   grpc_http_response_destroy(&detector.response);
@@ -170,7 +172,7 @@ static int is_stack_running_on_compute_engine(void) {
 
 /* Takes ownership of creds_path if not NULL. */
 static grpc_error *create_default_creds_from_path(
-    char *creds_path, grpc_call_credentials **creds) {
+    grpc_exec_ctx *exec_ctx, char *creds_path, grpc_call_credentials **creds) {
   grpc_json *json = NULL;
   grpc_auth_json_key key;
   grpc_auth_refresh_token token;
@@ -200,7 +202,7 @@ static grpc_error *create_default_creds_from_path(
   if (grpc_auth_json_key_is_valid(&key)) {
     result =
         grpc_service_account_jwt_access_credentials_create_from_auth_json_key(
-            key, grpc_max_auth_token_lifetime());
+            exec_ctx, key, grpc_max_auth_token_lifetime());
     if (result == NULL) {
       error = GRPC_ERROR_CREATE(
           "grpc_service_account_jwt_access_credentials_create_from_auth_json_"
@@ -225,7 +227,7 @@ static grpc_error *create_default_creds_from_path(
 end:
   GPR_ASSERT((result == NULL) + (error == GRPC_ERROR_NONE) == 1);
   if (creds_path != NULL) gpr_free(creds_path);
-  grpc_slice_unref(creds_data);
+  grpc_slice_unref_internal(exec_ctx, creds_data);
   if (json != NULL) grpc_json_destroy(json);
   *creds = result;
   return error;
@@ -236,6 +238,7 @@ grpc_channel_credentials *grpc_google_default_credentials_create(void) {
   grpc_call_credentials *call_creds = NULL;
   grpc_error *error = GRPC_ERROR_CREATE("Failed to create Google credentials");
   grpc_error *err;
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
 
   GRPC_API_TRACE("grpc_google_default_credentials_create(void)", 0, ());
 
@@ -250,20 +253,22 @@ grpc_channel_credentials *grpc_google_default_credentials_create(void) {
 
   /* First, try the environment variable. */
   err = create_default_creds_from_path(
-      gpr_getenv(GRPC_GOOGLE_CREDENTIALS_ENV_VAR), &call_creds);
+      &exec_ctx, gpr_getenv(GRPC_GOOGLE_CREDENTIALS_ENV_VAR), &call_creds);
   if (err == GRPC_ERROR_NONE) goto end;
   error = grpc_error_add_child(error, err);
 
   /* Then the well-known file. */
   err = create_default_creds_from_path(
-      grpc_get_well_known_google_credentials_file_path(), &call_creds);
+      &exec_ctx, grpc_get_well_known_google_credentials_file_path(),
+      &call_creds);
   if (err == GRPC_ERROR_NONE) goto end;
   error = grpc_error_add_child(error, err);
 
   /* At last try to see if we're on compute engine (do the detection only once
      since it requires a network test). */
   if (!compute_engine_detection_done) {
-    int need_compute_engine_creds = is_stack_running_on_compute_engine();
+    int need_compute_engine_creds =
+        is_stack_running_on_compute_engine(&exec_ctx);
     compute_engine_detection_done = 1;
     if (need_compute_engine_creds) {
       call_creds = grpc_google_compute_engine_credentials_create(NULL);
@@ -286,8 +291,8 @@ end:
           grpc_composite_channel_credentials_create(ssl_creds, call_creds,
                                                     NULL));
       GPR_ASSERT(default_credentials != NULL);
-      grpc_channel_credentials_unref(ssl_creds);
-      grpc_call_credentials_unref(call_creds);
+      grpc_channel_credentials_unref(&exec_ctx, ssl_creds);
+      grpc_call_credentials_unref(&exec_ctx, call_creds);
       result = default_credentials;
     } else {
       gpr_log(GPR_ERROR, "Could not create google default credentials.");
@@ -299,18 +304,21 @@ end:
   } else {
     GRPC_ERROR_UNREF(error);
   }
+  grpc_exec_ctx_finish(&exec_ctx);
   return result;
 }
 
 void grpc_flush_cached_google_default_credentials(void) {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   gpr_once_init(&g_once, init_default_credentials);
   gpr_mu_lock(&g_state_mu);
   if (default_credentials != NULL) {
-    grpc_channel_credentials_unref(default_credentials);
+    grpc_channel_credentials_unref(&exec_ctx, default_credentials);
     default_credentials = NULL;
   }
   compute_engine_detection_done = 0;
   gpr_mu_unlock(&g_state_mu);
+  grpc_exec_ctx_finish(&exec_ctx);
 }
 
 /* -- Well known credentials path. -- */
diff --git a/src/core/lib/security/credentials/iam/iam_credentials.c b/src/core/lib/security/credentials/iam/iam_credentials.c
index 370a384d0e..abd69a9670 100644
--- a/src/core/lib/security/credentials/iam/iam_credentials.c
+++ b/src/core/lib/security/credentials/iam/iam_credentials.c
@@ -42,9 +42,10 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/sync.h>
 
-static void iam_destruct(grpc_call_credentials *creds) {
+static void iam_destruct(grpc_exec_ctx *exec_ctx,
+                         grpc_call_credentials *creds) {
   grpc_google_iam_credentials *c = (grpc_google_iam_credentials *)creds;
-  grpc_credentials_md_store_unref(c->iam_md);
+  grpc_credentials_md_store_unref(exec_ctx, c->iam_md);
 }
 
 static void iam_get_request_metadata(grpc_exec_ctx *exec_ctx,
diff --git a/src/core/lib/security/credentials/jwt/jwt_credentials.c b/src/core/lib/security/credentials/jwt/jwt_credentials.c
index 3daf0f4ef7..616be64a54 100644
--- a/src/core/lib/security/credentials/jwt/jwt_credentials.c
+++ b/src/core/lib/security/credentials/jwt/jwt_credentials.c
@@ -42,9 +42,10 @@
 #include <grpc/support/string_util.h>
 #include <grpc/support/sync.h>
 
-static void jwt_reset_cache(grpc_service_account_jwt_access_credentials *c) {
+static void jwt_reset_cache(grpc_exec_ctx *exec_ctx,
+                            grpc_service_account_jwt_access_credentials *c) {
   if (c->cached.jwt_md != NULL) {
-    grpc_credentials_md_store_unref(c->cached.jwt_md);
+    grpc_credentials_md_store_unref(exec_ctx, c->cached.jwt_md);
     c->cached.jwt_md = NULL;
   }
   if (c->cached.service_url != NULL) {
@@ -54,11 +55,12 @@ static void jwt_reset_cache(grpc_service_account_jwt_access_credentials *c) {
   c->cached.jwt_expiration = gpr_inf_past(GPR_CLOCK_REALTIME);
 }
 
-static void jwt_destruct(grpc_call_credentials *creds) {
+static void jwt_destruct(grpc_exec_ctx *exec_ctx,
+                         grpc_call_credentials *creds) {
   grpc_service_account_jwt_access_credentials *c =
       (grpc_service_account_jwt_access_credentials *)creds;
   grpc_auth_json_key_destruct(&c->key);
-  jwt_reset_cache(c);
+  jwt_reset_cache(exec_ctx, c);
   gpr_mu_destroy(&c->cache_mu);
 }
 
@@ -92,7 +94,7 @@ static void jwt_get_request_metadata(grpc_exec_ctx *exec_ctx,
     char *jwt = NULL;
     /* Generate a new jwt. */
     gpr_mu_lock(&c->cache_mu);
-    jwt_reset_cache(c);
+    jwt_reset_cache(exec_ctx, c);
     jwt = grpc_jwt_encode_and_sign(&c->key, context.service_url,
                                    c->jwt_lifetime, NULL);
     if (jwt != NULL) {
@@ -114,7 +116,7 @@ static void jwt_get_request_metadata(grpc_exec_ctx *exec_ctx,
   if (jwt_md != NULL) {
     cb(exec_ctx, user_data, jwt_md->entries, jwt_md->num_entries,
        GRPC_CREDENTIALS_OK, NULL);
-    grpc_credentials_md_store_unref(jwt_md);
+    grpc_credentials_md_store_unref(exec_ctx, jwt_md);
   } else {
     cb(exec_ctx, user_data, NULL, 0, GRPC_CREDENTIALS_ERROR,
        "Could not generate JWT.");
@@ -126,7 +128,8 @@ static grpc_call_credentials_vtable jwt_vtable = {jwt_destruct,
 
 grpc_call_credentials *
 grpc_service_account_jwt_access_credentials_create_from_auth_json_key(
-    grpc_auth_json_key key, gpr_timespec token_lifetime) {
+    grpc_exec_ctx *exec_ctx, grpc_auth_json_key key,
+    gpr_timespec token_lifetime) {
   grpc_service_account_jwt_access_credentials *c;
   if (!grpc_auth_json_key_is_valid(&key)) {
     gpr_log(GPR_ERROR, "Invalid input for jwt credentials creation");
@@ -140,7 +143,7 @@ grpc_service_account_jwt_access_credentials_create_from_auth_json_key(
   c->key = key;
   c->jwt_lifetime = token_lifetime;
   gpr_mu_init(&c->cache_mu);
-  jwt_reset_cache(c);
+  jwt_reset_cache(exec_ctx, c);
   return &c->base;
 }
 
@@ -183,6 +186,11 @@ grpc_call_credentials *grpc_service_account_jwt_access_credentials_create(
     gpr_free(clean_json);
   }
   GPR_ASSERT(reserved == NULL);
-  return grpc_service_account_jwt_access_credentials_create_from_auth_json_key(
-      grpc_auth_json_key_create_from_string(json_key), token_lifetime);
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_call_credentials *creds =
+      grpc_service_account_jwt_access_credentials_create_from_auth_json_key(
+          &exec_ctx, grpc_auth_json_key_create_from_string(json_key),
+          token_lifetime);
+  grpc_exec_ctx_finish(&exec_ctx);
+  return creds;
 }
diff --git a/src/core/lib/security/credentials/jwt/jwt_credentials.h b/src/core/lib/security/credentials/jwt/jwt_credentials.h
index d572606179..39b7aeafe8 100644
--- a/src/core/lib/security/credentials/jwt/jwt_credentials.h
+++ b/src/core/lib/security/credentials/jwt/jwt_credentials.h
@@ -57,6 +57,7 @@ typedef struct {
 // Takes ownership of the key.
 grpc_call_credentials *
 grpc_service_account_jwt_access_credentials_create_from_auth_json_key(
-    grpc_auth_json_key key, gpr_timespec token_lifetime);
+    grpc_exec_ctx *exec_ctx, grpc_auth_json_key key,
+    gpr_timespec token_lifetime);
 
 #endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_JWT_JWT_CREDENTIALS_H */
diff --git a/src/core/lib/security/credentials/jwt/jwt_verifier.c b/src/core/lib/security/credentials/jwt/jwt_verifier.c
index 42bd89dd0a..2270be8f44 100644
--- a/src/core/lib/security/credentials/jwt/jwt_verifier.c
+++ b/src/core/lib/security/credentials/jwt/jwt_verifier.c
@@ -36,11 +36,6 @@
 #include <limits.h>
 #include <string.h>
 
-#include "src/core/lib/http/httpcli.h"
-#include "src/core/lib/iomgr/polling_entity.h"
-#include "src/core/lib/security/util/b64.h"
-#include "src/core/lib/tsi/ssl_types.h"
-
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
@@ -48,6 +43,13 @@
 #include <grpc/support/useful.h>
 #include <openssl/pem.h>
 
+#include "src/core/lib/http/httpcli.h"
+#include "src/core/lib/iomgr/polling_entity.h"
+#include "src/core/lib/security/util/b64.h"
+#include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/support/string.h"
+#include "src/core/lib/tsi/ssl_types.h"
+
 /* --- Utils. --- */
 
 const char *grpc_jwt_verifier_status_to_string(
@@ -84,11 +86,12 @@ static const EVP_MD *evp_md_from_alg(const char *alg) {
   }
 }
 
-static grpc_json *parse_json_part_from_jwt(const char *str, size_t len,
+static grpc_json *parse_json_part_from_jwt(grpc_exec_ctx *exec_ctx,
+                                           const char *str, size_t len,
                                            grpc_slice *buffer) {
   grpc_json *json;
 
-  *buffer = grpc_base64_decode_with_len(str, len, 1);
+  *buffer = grpc_base64_decode_with_len(exec_ctx, str, len, 1);
   if (GRPC_SLICE_IS_EMPTY(*buffer)) {
     gpr_log(GPR_ERROR, "Invalid base64.");
     return NULL;
@@ -96,7 +99,7 @@ static grpc_json *parse_json_part_from_jwt(const char *str, size_t len,
   json = grpc_json_parse_string_with_len((char *)GRPC_SLICE_START_PTR(*buffer),
                                          GRPC_SLICE_LENGTH(*buffer));
   if (json == NULL) {
-    grpc_slice_unref(*buffer);
+    grpc_slice_unref_internal(exec_ctx, *buffer);
     gpr_log(GPR_ERROR, "JSON parsing error.");
   }
   return json;
@@ -132,13 +135,14 @@ typedef struct {
   grpc_slice buffer;
 } jose_header;
 
-static void jose_header_destroy(jose_header *h) {
-  grpc_slice_unref(h->buffer);
+static void jose_header_destroy(grpc_exec_ctx *exec_ctx, jose_header *h) {
+  grpc_slice_unref_internal(exec_ctx, h->buffer);
   gpr_free(h);
 }
 
 /* Takes ownership of json and buffer. */
-static jose_header *jose_header_from_json(grpc_json *json, grpc_slice buffer) {
+static jose_header *jose_header_from_json(grpc_exec_ctx *exec_ctx,
+                                          grpc_json *json, grpc_slice buffer) {
   grpc_json *cur;
   jose_header *h = gpr_malloc(sizeof(jose_header));
   memset(h, 0, sizeof(jose_header));
@@ -173,7 +177,7 @@ static jose_header *jose_header_from_json(grpc_json *json, grpc_slice buffer) {
 
 error:
   grpc_json_destroy(json);
-  jose_header_destroy(h);
+  jose_header_destroy(exec_ctx, h);
   return NULL;
 }
 
@@ -193,9 +197,9 @@ struct grpc_jwt_claims {
   grpc_slice buffer;
 };
 
-void grpc_jwt_claims_destroy(grpc_jwt_claims *claims) {
+void grpc_jwt_claims_destroy(grpc_exec_ctx *exec_ctx, grpc_jwt_claims *claims) {
   grpc_json_destroy(claims->json);
-  grpc_slice_unref(claims->buffer);
+  grpc_slice_unref_internal(exec_ctx, claims->buffer);
   gpr_free(claims);
 }
 
@@ -240,7 +244,8 @@ gpr_timespec grpc_jwt_claims_not_before(const grpc_jwt_claims *claims) {
 }
 
 /* Takes ownership of json and buffer even in case of failure. */
-grpc_jwt_claims *grpc_jwt_claims_from_json(grpc_json *json, grpc_slice buffer) {
+grpc_jwt_claims *grpc_jwt_claims_from_json(grpc_exec_ctx *exec_ctx,
+                                           grpc_json *json, grpc_slice buffer) {
   grpc_json *cur;
   grpc_jwt_claims *claims = gpr_malloc(sizeof(grpc_jwt_claims));
   memset(claims, 0, sizeof(grpc_jwt_claims));
@@ -281,7 +286,7 @@ grpc_jwt_claims *grpc_jwt_claims_from_json(grpc_json *json, grpc_slice buffer) {
   return claims;
 
 error:
-  grpc_jwt_claims_destroy(claims);
+  grpc_jwt_claims_destroy(exec_ctx, claims);
   return NULL;
 }
 
@@ -305,6 +310,17 @@ grpc_jwt_verifier_status grpc_jwt_claims_check(const grpc_jwt_claims *claims,
     return GRPC_JWT_VERIFIER_TIME_CONSTRAINT_FAILURE;
   }
 
+  /* This should be probably up to the upper layer to decide but let's harcode
+     the 99% use case here for email issuers, where the JWT must be self
+     issued. */
+  if (grpc_jwt_issuer_email_domain(claims->iss) != NULL &&
+      claims->sub != NULL && strcmp(claims->iss, claims->sub) != 0) {
+    gpr_log(GPR_ERROR,
+            "Email issuer (%s) cannot assert another subject (%s) than itself.",
+            claims->iss, claims->sub);
+    return GRPC_JWT_VERIFIER_BAD_SUBJECT;
+  }
+
   if (audience == NULL) {
     audience_ok = claims->aud == NULL;
   } else {
@@ -362,12 +378,12 @@ static verifier_cb_ctx *verifier_cb_ctx_create(
   return ctx;
 }
 
-void verifier_cb_ctx_destroy(verifier_cb_ctx *ctx) {
+void verifier_cb_ctx_destroy(grpc_exec_ctx *exec_ctx, verifier_cb_ctx *ctx) {
   if (ctx->audience != NULL) gpr_free(ctx->audience);
-  if (ctx->claims != NULL) grpc_jwt_claims_destroy(ctx->claims);
-  grpc_slice_unref(ctx->signature);
-  grpc_slice_unref(ctx->signed_data);
-  jose_header_destroy(ctx->header);
+  if (ctx->claims != NULL) grpc_jwt_claims_destroy(exec_ctx, ctx->claims);
+  grpc_slice_unref_internal(exec_ctx, ctx->signature);
+  grpc_slice_unref_internal(exec_ctx, ctx->signed_data);
+  jose_header_destroy(exec_ctx, ctx->header);
   for (size_t i = 0; i < HTTP_RESPONSE_COUNT; i++) {
     grpc_http_response_destroy(&ctx->responses[i]);
   }
@@ -447,23 +463,24 @@ end:
   return result;
 }
 
-static BIGNUM *bignum_from_base64(const char *b64) {
+static BIGNUM *bignum_from_base64(grpc_exec_ctx *exec_ctx, const char *b64) {
   BIGNUM *result = NULL;
   grpc_slice bin;
 
   if (b64 == NULL) return NULL;
-  bin = grpc_base64_decode(b64, 1);
+  bin = grpc_base64_decode(exec_ctx, b64, 1);
   if (GRPC_SLICE_IS_EMPTY(bin)) {
     gpr_log(GPR_ERROR, "Invalid base64 for big num.");
     return NULL;
   }
   result = BN_bin2bn(GRPC_SLICE_START_PTR(bin),
                      TSI_SIZE_AS_SIZE(GRPC_SLICE_LENGTH(bin)), NULL);
-  grpc_slice_unref(bin);
+  grpc_slice_unref_internal(exec_ctx, bin);
   return result;
 }
 
-static EVP_PKEY *pkey_from_jwk(const grpc_json *json, const char *kty) {
+static EVP_PKEY *pkey_from_jwk(grpc_exec_ctx *exec_ctx, const grpc_json *json,
+                               const char *kty) {
   const grpc_json *key_prop;
   RSA *rsa = NULL;
   EVP_PKEY *result = NULL;
@@ -480,10 +497,12 @@ static EVP_PKEY *pkey_from_jwk(const grpc_json *json, const char *kty) {
   }
   for (key_prop = json->child; key_prop != NULL; key_prop = key_prop->next) {
     if (strcmp(key_prop->key, "n") == 0) {
-      rsa->n = bignum_from_base64(validate_string_field(key_prop, "n"));
+      rsa->n =
+          bignum_from_base64(exec_ctx, validate_string_field(key_prop, "n"));
       if (rsa->n == NULL) goto end;
     } else if (strcmp(key_prop->key, "e") == 0) {
-      rsa->e = bignum_from_base64(validate_string_field(key_prop, "e"));
+      rsa->e =
+          bignum_from_base64(exec_ctx, validate_string_field(key_prop, "e"));
       if (rsa->e == NULL) goto end;
     }
   }
@@ -499,7 +518,8 @@ end:
   return result;
 }
 
-static EVP_PKEY *find_verification_key(const grpc_json *json,
+static EVP_PKEY *find_verification_key(grpc_exec_ctx *exec_ctx,
+                                       const grpc_json *json,
                                        const char *header_alg,
                                        const char *header_kid) {
   const grpc_json *jkey;
@@ -543,7 +563,7 @@ static EVP_PKEY *find_verification_key(const grpc_json *json,
     }
     if (alg != NULL && kid != NULL && kty != NULL &&
         strcmp(kid, header_kid) == 0 && strcmp(alg, header_alg) == 0) {
-      return pkey_from_jwk(jkey, kty);
+      return pkey_from_jwk(exec_ctx, jkey, kty);
     }
   }
   gpr_log(GPR_ERROR,
@@ -597,7 +617,7 @@ static void on_keys_retrieved(grpc_exec_ctx *exec_ctx, void *user_data,
     goto end;
   }
   verification_key =
-      find_verification_key(json, ctx->header->alg, ctx->header->kid);
+      find_verification_key(exec_ctx, json, ctx->header->alg, ctx->header->kid);
   if (verification_key == NULL) {
     gpr_log(GPR_ERROR, "Could not find verification key with kid %s.",
             ctx->header->kid);
@@ -621,8 +641,8 @@ static void on_keys_retrieved(grpc_exec_ctx *exec_ctx, void *user_data,
 end:
   if (json != NULL) grpc_json_destroy(json);
   if (verification_key != NULL) EVP_PKEY_free(verification_key);
-  ctx->user_cb(ctx->user_data, status, claims);
-  verifier_cb_ctx_destroy(ctx);
+  ctx->user_cb(exec_ctx, ctx->user_data, status, claims);
+  verifier_cb_ctx_destroy(exec_ctx, ctx);
 }
 
 static void on_openid_config_retrieved(grpc_exec_ctx *exec_ctx, void *user_data,
@@ -665,17 +685,18 @@ static void on_openid_config_retrieved(grpc_exec_ctx *exec_ctx, void *user_data,
   grpc_httpcli_get(
       exec_ctx, &ctx->verifier->http_ctx, &ctx->pollent, resource_quota, &req,
       gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), grpc_jwt_verifier_max_delay),
-      grpc_closure_create(on_keys_retrieved, ctx),
+      grpc_closure_create(on_keys_retrieved, ctx, grpc_schedule_on_exec_ctx),
       &ctx->responses[HTTP_RESPONSE_KEYS]);
-  grpc_resource_quota_internal_unref(exec_ctx, resource_quota);
+  grpc_resource_quota_unref_internal(exec_ctx, resource_quota);
   grpc_json_destroy(json);
   gpr_free(req.host);
   return;
 
 error:
   if (json != NULL) grpc_json_destroy(json);
-  ctx->user_cb(ctx->user_data, GRPC_JWT_VERIFIER_KEY_RETRIEVAL_ERROR, NULL);
-  verifier_cb_ctx_destroy(ctx);
+  ctx->user_cb(exec_ctx, ctx->user_data, GRPC_JWT_VERIFIER_KEY_RETRIEVAL_ERROR,
+               NULL);
+  verifier_cb_ctx_destroy(exec_ctx, ctx);
 }
 
 static email_key_mapping *verifier_get_mapping(grpc_jwt_verifier *v,
@@ -705,10 +726,26 @@ static void verifier_put_mapping(grpc_jwt_verifier *v, const char *email_domain,
   GPR_ASSERT(v->num_mappings <= v->allocated_mappings);
 }
 
+/* Very non-sophisticated way to detect an email address. Should be good
+   enough for now... */
+const char *grpc_jwt_issuer_email_domain(const char *issuer) {
+  const char *at_sign = strchr(issuer, '@');
+  if (at_sign == NULL) return NULL;
+  const char *email_domain = at_sign + 1;
+  if (*email_domain == '\0') return NULL;
+  const char *dot = strrchr(email_domain, '.');
+  if (dot == NULL || dot == email_domain) return email_domain;
+  GPR_ASSERT(dot > email_domain);
+  /* There may be a subdomain, we just want the domain. */
+  dot = gpr_memrchr(email_domain, '.', (size_t)(dot - email_domain));
+  if (dot == NULL) return email_domain;
+  return dot + 1;
+}
+
 /* Takes ownership of ctx. */
 static void retrieve_key_and_verify(grpc_exec_ctx *exec_ctx,
                                     verifier_cb_ctx *ctx) {
-  const char *at_sign;
+  const char *email_domain;
   grpc_closure *http_cb;
   char *path_prefix = NULL;
   const char *iss;
@@ -733,13 +770,9 @@ static void retrieve_key_and_verify(grpc_exec_ctx *exec_ctx,
      Nobody seems to implement the account/email/webfinger part 2. of the spec
      so we will rely instead on email/url mappings if we detect such an issuer.
      Part 4, on the other hand is implemented by both google and salesforce. */
-
-  /* Very non-sophisticated way to detect an email address. Should be good
-     enough for now... */
-  at_sign = strchr(iss, '@');
-  if (at_sign != NULL) {
+  email_domain = grpc_jwt_issuer_email_domain(iss);
+  if (email_domain != NULL) {
     email_key_mapping *mapping;
-    const char *email_domain = at_sign + 1;
     GPR_ASSERT(ctx->verifier != NULL);
     mapping = verifier_get_mapping(ctx->verifier, email_domain);
     if (mapping == NULL) {
@@ -754,7 +787,8 @@ static void retrieve_key_and_verify(grpc_exec_ctx *exec_ctx,
       *(path_prefix++) = '\0';
       gpr_asprintf(&req.http.path, "/%s/%s", path_prefix, iss);
     }
-    http_cb = grpc_closure_create(on_keys_retrieved, ctx);
+    http_cb =
+        grpc_closure_create(on_keys_retrieved, ctx, grpc_schedule_on_exec_ctx);
     rsp_idx = HTTP_RESPONSE_KEYS;
   } else {
     req.host = gpr_strdup(strstr(iss, "https://") == iss ? iss + 8 : iss);
@@ -766,7 +800,8 @@ static void retrieve_key_and_verify(grpc_exec_ctx *exec_ctx,
       gpr_asprintf(&req.http.path, "/%s%s", path_prefix,
                    GRPC_OPENID_CONFIG_URL_SUFFIX);
     }
-    http_cb = grpc_closure_create(on_openid_config_retrieved, ctx);
+    http_cb = grpc_closure_create(on_openid_config_retrieved, ctx,
+                                  grpc_schedule_on_exec_ctx);
     rsp_idx = HTTP_RESPONSE_OPENID;
   }
 
@@ -779,14 +814,15 @@ static void retrieve_key_and_verify(grpc_exec_ctx *exec_ctx,
       exec_ctx, &ctx->verifier->http_ctx, &ctx->pollent, resource_quota, &req,
       gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), grpc_jwt_verifier_max_delay),
       http_cb, &ctx->responses[rsp_idx]);
-  grpc_resource_quota_internal_unref(exec_ctx, resource_quota);
+  grpc_resource_quota_unref_internal(exec_ctx, resource_quota);
   gpr_free(req.host);
   gpr_free(req.http.path);
   return;
 
 error:
-  ctx->user_cb(ctx->user_data, GRPC_JWT_VERIFIER_KEY_RETRIEVAL_ERROR, NULL);
-  verifier_cb_ctx_destroy(ctx);
+  ctx->user_cb(exec_ctx, ctx->user_data, GRPC_JWT_VERIFIER_KEY_RETRIEVAL_ERROR,
+               NULL);
+  verifier_cb_ctx_destroy(exec_ctx, ctx);
 }
 
 void grpc_jwt_verifier_verify(grpc_exec_ctx *exec_ctx,
@@ -808,22 +844,24 @@ void grpc_jwt_verifier_verify(grpc_exec_ctx *exec_ctx,
   GPR_ASSERT(verifier != NULL && jwt != NULL && audience != NULL && cb != NULL);
   dot = strchr(cur, '.');
   if (dot == NULL) goto error;
-  json = parse_json_part_from_jwt(cur, (size_t)(dot - cur), &header_buffer);
+  json = parse_json_part_from_jwt(exec_ctx, cur, (size_t)(dot - cur),
+                                  &header_buffer);
   if (json == NULL) goto error;
-  header = jose_header_from_json(json, header_buffer);
+  header = jose_header_from_json(exec_ctx, json, header_buffer);
   if (header == NULL) goto error;
 
   cur = dot + 1;
   dot = strchr(cur, '.');
   if (dot == NULL) goto error;
-  json = parse_json_part_from_jwt(cur, (size_t)(dot - cur), &claims_buffer);
+  json = parse_json_part_from_jwt(exec_ctx, cur, (size_t)(dot - cur),
+                                  &claims_buffer);
   if (json == NULL) goto error;
-  claims = grpc_jwt_claims_from_json(json, claims_buffer);
+  claims = grpc_jwt_claims_from_json(exec_ctx, json, claims_buffer);
   if (claims == NULL) goto error;
 
   signed_jwt_len = (size_t)(dot - jwt);
   cur = dot + 1;
-  signature = grpc_base64_decode(cur, 1);
+  signature = grpc_base64_decode(exec_ctx, cur, 1);
   if (GRPC_SLICE_IS_EMPTY(signature)) goto error;
   retrieve_key_and_verify(
       exec_ctx,
@@ -832,9 +870,9 @@ void grpc_jwt_verifier_verify(grpc_exec_ctx *exec_ctx,
   return;
 
 error:
-  if (header != NULL) jose_header_destroy(header);
-  if (claims != NULL) grpc_jwt_claims_destroy(claims);
-  cb(user_data, GRPC_JWT_VERIFIER_BAD_FORMAT, NULL);
+  if (header != NULL) jose_header_destroy(exec_ctx, header);
+  if (claims != NULL) grpc_jwt_claims_destroy(exec_ctx, claims);
+  cb(exec_ctx, user_data, GRPC_JWT_VERIFIER_BAD_FORMAT, NULL);
 }
 
 grpc_jwt_verifier *grpc_jwt_verifier_create(
diff --git a/src/core/lib/security/credentials/jwt/jwt_verifier.h b/src/core/lib/security/credentials/jwt/jwt_verifier.h
index f09f9d5d47..4fa320a415 100644
--- a/src/core/lib/security/credentials/jwt/jwt_verifier.h
+++ b/src/core/lib/security/credentials/jwt/jwt_verifier.h
@@ -43,8 +43,7 @@
 /* --- Constants. --- */
 
 #define GRPC_OPENID_CONFIG_URL_SUFFIX "/.well-known/openid-configuration"
-#define GRPC_GOOGLE_SERVICE_ACCOUNTS_EMAIL_DOMAIN \
-  "developer.gserviceaccount.com"
+#define GRPC_GOOGLE_SERVICE_ACCOUNTS_EMAIL_DOMAIN "gserviceaccount.com"
 #define GRPC_GOOGLE_SERVICE_ACCOUNTS_KEY_URL_PREFIX \
   "www.googleapis.com/robot/v1/metadata/x509"
 
@@ -57,6 +56,7 @@ typedef enum {
   GRPC_JWT_VERIFIER_BAD_AUDIENCE,
   GRPC_JWT_VERIFIER_KEY_RETRIEVAL_ERROR,
   GRPC_JWT_VERIFIER_TIME_CONSTRAINT_FAILURE,
+  GRPC_JWT_VERIFIER_BAD_SUBJECT,
   GRPC_JWT_VERIFIER_GENERIC_ERROR
 } grpc_jwt_verifier_status;
 
@@ -66,7 +66,7 @@ const char *grpc_jwt_verifier_status_to_string(grpc_jwt_verifier_status status);
 
 typedef struct grpc_jwt_claims grpc_jwt_claims;
 
-void grpc_jwt_claims_destroy(grpc_jwt_claims *claims);
+void grpc_jwt_claims_destroy(grpc_exec_ctx *exec_ctx, grpc_jwt_claims *claims);
 
 /* Returns the whole JSON tree of the claims. */
 const grpc_json *grpc_jwt_claims_json(const grpc_jwt_claims *claims);
@@ -115,7 +115,8 @@ void grpc_jwt_verifier_destroy(grpc_jwt_verifier *verifier);
    is done (maybe in another thread).
    It is the responsibility of the callee to call grpc_jwt_claims_destroy on
    the claims. */
-typedef void (*grpc_jwt_verification_done_cb)(void *user_data,
+typedef void (*grpc_jwt_verification_done_cb)(grpc_exec_ctx *exec_ctx,
+                                              void *user_data,
                                               grpc_jwt_verifier_status status,
                                               grpc_jwt_claims *claims);
 
@@ -129,8 +130,10 @@ void grpc_jwt_verifier_verify(grpc_exec_ctx *exec_ctx,
 
 /* --- TESTING ONLY exposed functions. --- */
 
-grpc_jwt_claims *grpc_jwt_claims_from_json(grpc_json *json, grpc_slice buffer);
+grpc_jwt_claims *grpc_jwt_claims_from_json(grpc_exec_ctx *exec_ctx,
+                                           grpc_json *json, grpc_slice buffer);
 grpc_jwt_verifier_status grpc_jwt_claims_check(const grpc_jwt_claims *claims,
                                                const char *audience);
+const char *grpc_jwt_issuer_email_domain(const char *issuer);
 
 #endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_JWT_JWT_VERIFIER_H */
diff --git a/src/core/lib/security/credentials/oauth2/oauth2_credentials.c b/src/core/lib/security/credentials/oauth2/oauth2_credentials.c
index b3625b22c0..1b0e43a1e4 100644
--- a/src/core/lib/security/credentials/oauth2/oauth2_credentials.c
+++ b/src/core/lib/security/credentials/oauth2/oauth2_credentials.c
@@ -118,18 +118,19 @@ void grpc_auth_refresh_token_destruct(grpc_auth_refresh_token *refresh_token) {
 // Oauth2 Token Fetcher credentials.
 //
 
-static void oauth2_token_fetcher_destruct(grpc_call_credentials *creds) {
+static void oauth2_token_fetcher_destruct(grpc_exec_ctx *exec_ctx,
+                                          grpc_call_credentials *creds) {
   grpc_oauth2_token_fetcher_credentials *c =
       (grpc_oauth2_token_fetcher_credentials *)creds;
-  grpc_credentials_md_store_unref(c->access_token_md);
+  grpc_credentials_md_store_unref(exec_ctx, c->access_token_md);
   gpr_mu_destroy(&c->mu);
   grpc_httpcli_context_destroy(&c->httpcli_context);
 }
 
 grpc_credentials_status
 grpc_oauth2_token_fetcher_credentials_parse_server_response(
-    const grpc_http_response *response, grpc_credentials_md_store **token_md,
-    gpr_timespec *token_lifetime) {
+    grpc_exec_ctx *exec_ctx, const grpc_http_response *response,
+    grpc_credentials_md_store **token_md, gpr_timespec *token_lifetime) {
   char *null_terminated_body = NULL;
   char *new_access_token = NULL;
   grpc_credentials_status status = GRPC_CREDENTIALS_OK;
@@ -198,7 +199,7 @@ grpc_oauth2_token_fetcher_credentials_parse_server_response(
     token_lifetime->tv_sec = strtol(expires_in->value, NULL, 10);
     token_lifetime->tv_nsec = 0;
     token_lifetime->clock_type = GPR_TIMESPAN;
-    if (*token_md != NULL) grpc_credentials_md_store_unref(*token_md);
+    if (*token_md != NULL) grpc_credentials_md_store_unref(exec_ctx, *token_md);
     *token_md = grpc_credentials_md_store_create(1);
     grpc_credentials_md_store_add_cstrings(
         *token_md, GRPC_AUTHORIZATION_METADATA_KEY, new_access_token);
@@ -207,7 +208,7 @@ grpc_oauth2_token_fetcher_credentials_parse_server_response(
 
 end:
   if (status != GRPC_CREDENTIALS_OK && (*token_md != NULL)) {
-    grpc_credentials_md_store_unref(*token_md);
+    grpc_credentials_md_store_unref(exec_ctx, *token_md);
     *token_md = NULL;
   }
   if (null_terminated_body != NULL) gpr_free(null_terminated_body);
@@ -230,7 +231,7 @@ static void on_oauth2_token_fetcher_http_response(grpc_exec_ctx *exec_ctx,
 
   gpr_mu_lock(&c->mu);
   status = grpc_oauth2_token_fetcher_credentials_parse_server_response(
-      &r->response, &c->access_token_md, &token_lifetime);
+      exec_ctx, &r->response, &c->access_token_md, &token_lifetime);
   if (status == GRPC_CREDENTIALS_OK) {
     c->token_expiration =
         gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), token_lifetime);
@@ -242,7 +243,7 @@ static void on_oauth2_token_fetcher_http_response(grpc_exec_ctx *exec_ctx,
           "Error occured when fetching oauth2 token.");
   }
   gpr_mu_unlock(&c->mu);
-  grpc_credentials_metadata_request_destroy(r);
+  grpc_credentials_metadata_request_destroy(exec_ctx, r);
 }
 
 static void oauth2_token_fetcher_get_request_metadata(
@@ -268,7 +269,7 @@ static void oauth2_token_fetcher_get_request_metadata(
   if (cached_access_token_md != NULL) {
     cb(exec_ctx, user_data, cached_access_token_md->entries,
        cached_access_token_md->num_entries, GRPC_CREDENTIALS_OK, NULL);
-    grpc_credentials_md_store_unref(cached_access_token_md);
+    grpc_credentials_md_store_unref(exec_ctx, cached_access_token_md);
   } else {
     c->fetch_func(
         exec_ctx,
@@ -312,10 +313,12 @@ static void compute_engine_fetch_oauth2(
      extreme memory pressure. */
   grpc_resource_quota *resource_quota =
       grpc_resource_quota_create("oauth2_credentials");
-  grpc_httpcli_get(exec_ctx, httpcli_context, pollent, resource_quota, &request,
-                   deadline, grpc_closure_create(response_cb, metadata_req),
-                   &metadata_req->response);
-  grpc_resource_quota_internal_unref(exec_ctx, resource_quota);
+  grpc_httpcli_get(
+      exec_ctx, httpcli_context, pollent, resource_quota, &request, deadline,
+      grpc_closure_create(response_cb, metadata_req, grpc_schedule_on_exec_ctx),
+
+      &metadata_req->response);
+  grpc_resource_quota_unref_internal(exec_ctx, resource_quota);
 }
 
 grpc_call_credentials *grpc_google_compute_engine_credentials_create(
@@ -334,11 +337,12 @@ grpc_call_credentials *grpc_google_compute_engine_credentials_create(
 // Google Refresh Token credentials.
 //
 
-static void refresh_token_destruct(grpc_call_credentials *creds) {
+static void refresh_token_destruct(grpc_exec_ctx *exec_ctx,
+                                   grpc_call_credentials *creds) {
   grpc_google_refresh_token_credentials *c =
       (grpc_google_refresh_token_credentials *)creds;
   grpc_auth_refresh_token_destruct(&c->refresh_token);
-  oauth2_token_fetcher_destruct(&c->base.base);
+  oauth2_token_fetcher_destruct(exec_ctx, &c->base.base);
 }
 
 static grpc_call_credentials_vtable refresh_token_vtable = {
@@ -368,11 +372,12 @@ static void refresh_token_fetch_oauth2(
      extreme memory pressure. */
   grpc_resource_quota *resource_quota =
       grpc_resource_quota_create("oauth2_credentials_refresh");
-  grpc_httpcli_post(exec_ctx, httpcli_context, pollent, resource_quota,
-                    &request, body, strlen(body), deadline,
-                    grpc_closure_create(response_cb, metadata_req),
-                    &metadata_req->response);
-  grpc_resource_quota_internal_unref(exec_ctx, resource_quota);
+  grpc_httpcli_post(
+      exec_ctx, httpcli_context, pollent, resource_quota, &request, body,
+      strlen(body), deadline,
+      grpc_closure_create(response_cb, metadata_req, grpc_schedule_on_exec_ctx),
+      &metadata_req->response);
+  grpc_resource_quota_unref_internal(exec_ctx, resource_quota);
   gpr_free(body);
 }
 
@@ -424,9 +429,10 @@ grpc_call_credentials *grpc_google_refresh_token_credentials_create(
 // Oauth2 Access Token credentials.
 //
 
-static void access_token_destruct(grpc_call_credentials *creds) {
+static void access_token_destruct(grpc_exec_ctx *exec_ctx,
+                                  grpc_call_credentials *creds) {
   grpc_access_token_credentials *c = (grpc_access_token_credentials *)creds;
-  grpc_credentials_md_store_unref(c->access_token_md);
+  grpc_credentials_md_store_unref(exec_ctx, c->access_token_md);
 }
 
 static void access_token_get_request_metadata(
diff --git a/src/core/lib/security/credentials/oauth2/oauth2_credentials.h b/src/core/lib/security/credentials/oauth2/oauth2_credentials.h
index 7f6f205c22..2d7c02ccf5 100644
--- a/src/core/lib/security/credentials/oauth2/oauth2_credentials.h
+++ b/src/core/lib/security/credentials/oauth2/oauth2_credentials.h
@@ -103,7 +103,7 @@ grpc_refresh_token_credentials_create_from_auth_refresh_token(
 // Exposed for testing only.
 grpc_credentials_status
 grpc_oauth2_token_fetcher_credentials_parse_server_response(
-    const struct grpc_http_response *response,
+    grpc_exec_ctx *exec_ctx, const struct grpc_http_response *response,
     grpc_credentials_md_store **token_md, gpr_timespec *token_lifetime);
 
 #endif /* GRPC_CORE_LIB_SECURITY_CREDENTIALS_OAUTH2_OAUTH2_CREDENTIALS_H */
diff --git a/src/core/lib/security/credentials/plugin/plugin_credentials.c b/src/core/lib/security/credentials/plugin/plugin_credentials.c
index 5d950098a0..f90d7dce83 100644
--- a/src/core/lib/security/credentials/plugin/plugin_credentials.c
+++ b/src/core/lib/security/credentials/plugin/plugin_credentials.c
@@ -35,20 +35,22 @@
 
 #include <string.h>
 
-#include "src/core/lib/surface/api_trace.h"
-
 #include <grpc/grpc.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
 #include <grpc/support/sync.h>
 
+#include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/surface/api_trace.h"
+
 typedef struct {
   void *user_data;
   grpc_credentials_metadata_cb cb;
 } grpc_metadata_plugin_request;
 
-static void plugin_destruct(grpc_call_credentials *creds) {
+static void plugin_destruct(grpc_exec_ctx *exec_ctx,
+                            grpc_call_credentials *creds) {
   grpc_plugin_credentials *c = (grpc_plugin_credentials *)creds;
   if (c->plugin.state != NULL && c->plugin.destroy != NULL) {
     c->plugin.destroy(c->plugin.state);
@@ -100,8 +102,8 @@ static void plugin_md_request_metadata_ready(void *request,
       r->cb(&exec_ctx, r->user_data, md_array, num_md, GRPC_CREDENTIALS_OK,
             NULL);
       for (i = 0; i < num_md; i++) {
-        grpc_slice_unref(md_array[i].key);
-        grpc_slice_unref(md_array[i].value);
+        grpc_slice_unref_internal(&exec_ctx, md_array[i].key);
+        grpc_slice_unref_internal(&exec_ctx, md_array[i].value);
       }
       gpr_free(md_array);
     } else if (num_md == 0) {
diff --git a/src/core/lib/security/credentials/ssl/ssl_credentials.c b/src/core/lib/security/credentials/ssl/ssl_credentials.c
index 0dc1fccec4..4eebb7d613 100644
--- a/src/core/lib/security/credentials/ssl/ssl_credentials.c
+++ b/src/core/lib/security/credentials/ssl/ssl_credentials.c
@@ -57,7 +57,8 @@ static void ssl_copy_key_material(const char *input, unsigned char **output,
 // SSL Channel Credentials.
 //
 
-static void ssl_destruct(grpc_channel_credentials *creds) {
+static void ssl_destruct(grpc_exec_ctx *exec_ctx,
+                         grpc_channel_credentials *creds) {
   grpc_ssl_credentials *c = (grpc_ssl_credentials *)creds;
   if (c->config.pem_root_certs != NULL) gpr_free(c->config.pem_root_certs);
   if (c->config.pem_private_key != NULL) gpr_free(c->config.pem_private_key);
@@ -65,9 +66,10 @@ static void ssl_destruct(grpc_channel_credentials *creds) {
 }
 
 static grpc_security_status ssl_create_security_connector(
-    grpc_channel_credentials *creds, grpc_call_credentials *call_creds,
-    const char *target, const grpc_channel_args *args,
-    grpc_channel_security_connector **sc, grpc_channel_args **new_args) {
+    grpc_exec_ctx *exec_ctx, grpc_channel_credentials *creds,
+    grpc_call_credentials *call_creds, const char *target,
+    const grpc_channel_args *args, grpc_channel_security_connector **sc,
+    grpc_channel_args **new_args) {
   grpc_ssl_credentials *c = (grpc_ssl_credentials *)creds;
   grpc_security_status status = GRPC_SECURITY_OK;
   size_t i = 0;
@@ -83,7 +85,7 @@ static grpc_security_status ssl_create_security_connector(
     }
   }
   status = grpc_ssl_channel_security_connector_create(
-      call_creds, &c->config, target, overridden_target_name, sc);
+      exec_ctx, call_creds, &c->config, target, overridden_target_name, sc);
   if (status != GRPC_SECURITY_OK) {
     return status;
   }
@@ -138,7 +140,8 @@ grpc_channel_credentials *grpc_ssl_credentials_create(
 // SSL Server Credentials.
 //
 
-static void ssl_server_destruct(grpc_server_credentials *creds) {
+static void ssl_server_destruct(grpc_exec_ctx *exec_ctx,
+                                grpc_server_credentials *creds) {
   grpc_ssl_server_credentials *c = (grpc_ssl_server_credentials *)creds;
   size_t i;
   for (i = 0; i < c->config.num_key_cert_pairs; i++) {
@@ -161,9 +164,10 @@ static void ssl_server_destruct(grpc_server_credentials *creds) {
 }
 
 static grpc_security_status ssl_server_create_security_connector(
-    grpc_server_credentials *creds, grpc_server_security_connector **sc) {
+    grpc_exec_ctx *exec_ctx, grpc_server_credentials *creds,
+    grpc_server_security_connector **sc) {
   grpc_ssl_server_credentials *c = (grpc_ssl_server_credentials *)creds;
-  return grpc_ssl_server_security_connector_create(&c->config, sc);
+  return grpc_ssl_server_security_connector_create(exec_ctx, &c->config, sc);
 }
 
 static grpc_server_credentials_vtable ssl_server_vtable = {
diff --git a/src/core/lib/security/transport/client_auth_filter.c b/src/core/lib/security/transport/client_auth_filter.c
index 053bf5972c..b7f6fd23e3 100644
--- a/src/core/lib/security/transport/client_auth_filter.c
+++ b/src/core/lib/security/transport/client_auth_filter.c
@@ -44,6 +44,7 @@
 #include "src/core/lib/security/context/security_context.h"
 #include "src/core/lib/security/credentials/credentials.h"
 #include "src/core/lib/security/transport/security_connector.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/surface/call.h"
 #include "src/core/lib/transport/static_metadata.h"
@@ -93,7 +94,8 @@ static void bubble_up_error(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
   call_data *calld = elem->call_data;
   gpr_log(GPR_ERROR, "Client side authentication failure: %s", error_msg);
   grpc_slice error_slice = grpc_slice_from_copied_string(error_msg);
-  grpc_transport_stream_op_add_close(&calld->op, status, &error_slice);
+  grpc_transport_stream_op_add_close(exec_ctx, &calld->op, status,
+                                     &error_slice);
   grpc_call_next_op(exec_ctx, elem, &calld->op);
 }
 
@@ -121,8 +123,9 @@ static void on_credentials_metadata(grpc_exec_ctx *exec_ctx, void *user_data,
   for (i = 0; i < num_md; i++) {
     grpc_metadata_batch_add_tail(
         mdb, &calld->md_links[i],
-        grpc_mdelem_from_slices(grpc_slice_ref(md_elems[i].key),
-                                grpc_slice_ref(md_elems[i].value)));
+        grpc_mdelem_from_slices(exec_ctx,
+                                grpc_slice_ref_internal(md_elems[i].key),
+                                grpc_slice_ref_internal(md_elems[i].value)));
   }
   grpc_call_next_op(exec_ctx, elem, op);
 }
@@ -248,10 +251,10 @@ static void auth_start_transport_op(grpc_exec_ctx *exec_ctx,
       /* Pointer comparison is OK for md_elems created from the same context.
        */
       if (md->key == GRPC_MDSTR_AUTHORITY) {
-        if (calld->host != NULL) GRPC_MDSTR_UNREF(calld->host);
+        if (calld->host != NULL) GRPC_MDSTR_UNREF(exec_ctx, calld->host);
         calld->host = GRPC_MDSTR_REF(md->value);
       } else if (md->key == GRPC_MDSTR_PATH) {
-        if (calld->method != NULL) GRPC_MDSTR_UNREF(calld->method);
+        if (calld->method != NULL) GRPC_MDSTR_UNREF(exec_ctx, calld->method);
         calld->method = GRPC_MDSTR_REF(md->value);
       }
     }
@@ -292,20 +295,20 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
                               const grpc_call_final_info *final_info,
                               void *ignored) {
   call_data *calld = elem->call_data;
-  grpc_call_credentials_unref(calld->creds);
+  grpc_call_credentials_unref(exec_ctx, calld->creds);
   if (calld->host != NULL) {
-    GRPC_MDSTR_UNREF(calld->host);
+    GRPC_MDSTR_UNREF(exec_ctx, calld->host);
   }
   if (calld->method != NULL) {
-    GRPC_MDSTR_UNREF(calld->method);
+    GRPC_MDSTR_UNREF(exec_ctx, calld->method);
   }
   reset_auth_metadata_context(&calld->auth_md_context);
 }
 
 /* Constructor for channel_data */
-static void init_channel_elem(grpc_exec_ctx *exec_ctx,
-                              grpc_channel_element *elem,
-                              grpc_channel_element_args *args) {
+static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
+                                     grpc_channel_element *elem,
+                                     grpc_channel_element_args *args) {
   grpc_security_connector *sc =
       grpc_find_security_connector_in_args(args->channel_args);
   grpc_auth_context *auth_context =
@@ -327,6 +330,7 @@ static void init_channel_elem(grpc_exec_ctx *exec_ctx,
           sc, "client_auth_filter");
   chand->auth_context =
       GRPC_AUTH_CONTEXT_REF(auth_context, "client_auth_filter");
+  return GRPC_ERROR_NONE;
 }
 
 /* Destructor for channel data */
@@ -336,7 +340,7 @@ static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
   channel_data *chand = elem->channel_data;
   grpc_channel_security_connector *sc = chand->security_connector;
   if (sc != NULL) {
-    GRPC_SECURITY_CONNECTOR_UNREF(&sc->base, "client_auth_filter");
+    GRPC_SECURITY_CONNECTOR_UNREF(exec_ctx, &sc->base, "client_auth_filter");
   }
   GRPC_AUTH_CONTEXT_UNREF(chand->auth_context, "client_auth_filter");
 }
diff --git a/src/core/lib/security/transport/handshake.c b/src/core/lib/security/transport/handshake.c
deleted file mode 100644
index 9623797610..0000000000
--- a/src/core/lib/security/transport/handshake.c
+++ /dev/null
@@ -1,374 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include "src/core/lib/security/transport/handshake.h"
-
-#include <stdbool.h>
-#include <string.h>
-
-#include <grpc/slice_buffer.h>
-#include <grpc/support/alloc.h>
-#include <grpc/support/log.h>
-#include "src/core/lib/iomgr/timer.h"
-#include "src/core/lib/security/context/security_context.h"
-#include "src/core/lib/security/transport/secure_endpoint.h"
-#include "src/core/lib/security/transport/tsi_error.h"
-
-#define GRPC_INITIAL_HANDSHAKE_BUFFER_SIZE 256
-
-typedef struct {
-  grpc_security_connector *connector;
-  tsi_handshaker *handshaker;
-  bool is_client_side;
-  unsigned char *handshake_buffer;
-  size_t handshake_buffer_size;
-  grpc_endpoint *wrapped_endpoint;
-  grpc_endpoint *secure_endpoint;
-  grpc_slice_buffer left_overs;
-  grpc_slice_buffer incoming;
-  grpc_slice_buffer outgoing;
-  grpc_security_handshake_done_cb cb;
-  void *user_data;
-  grpc_closure on_handshake_data_sent_to_peer;
-  grpc_closure on_handshake_data_received_from_peer;
-  grpc_auth_context *auth_context;
-  grpc_timer timer;
-  gpr_refcount refs;
-} grpc_security_handshake;
-
-static void on_handshake_data_received_from_peer(grpc_exec_ctx *exec_ctx,
-                                                 void *setup,
-                                                 grpc_error *error);
-
-static void on_handshake_data_sent_to_peer(grpc_exec_ctx *exec_ctx, void *setup,
-                                           grpc_error *error);
-
-static void security_connector_remove_handshake(grpc_security_handshake *h) {
-  GPR_ASSERT(!h->is_client_side);
-  grpc_security_connector_handshake_list *node;
-  grpc_security_connector_handshake_list *tmp;
-  grpc_server_security_connector *sc =
-      (grpc_server_security_connector *)h->connector;
-  gpr_mu_lock(&sc->mu);
-  node = sc->handshaking_handshakes;
-  if (node && node->handshake == h) {
-    sc->handshaking_handshakes = node->next;
-    gpr_free(node);
-    gpr_mu_unlock(&sc->mu);
-    return;
-  }
-  while (node) {
-    if (node->next->handshake == h) {
-      tmp = node->next;
-      node->next = node->next->next;
-      gpr_free(tmp);
-      gpr_mu_unlock(&sc->mu);
-      return;
-    }
-    node = node->next;
-  }
-  gpr_mu_unlock(&sc->mu);
-}
-
-static void unref_handshake(grpc_security_handshake *h) {
-  if (gpr_unref(&h->refs)) {
-    if (h->handshaker != NULL) tsi_handshaker_destroy(h->handshaker);
-    if (h->handshake_buffer != NULL) gpr_free(h->handshake_buffer);
-    grpc_slice_buffer_destroy(&h->left_overs);
-    grpc_slice_buffer_destroy(&h->outgoing);
-    grpc_slice_buffer_destroy(&h->incoming);
-    GRPC_AUTH_CONTEXT_UNREF(h->auth_context, "handshake");
-    GRPC_SECURITY_CONNECTOR_UNREF(h->connector, "handshake");
-    gpr_free(h);
-  }
-}
-
-static void security_handshake_done(grpc_exec_ctx *exec_ctx,
-                                    grpc_security_handshake *h,
-                                    grpc_error *error) {
-  grpc_timer_cancel(exec_ctx, &h->timer);
-  if (!h->is_client_side) {
-    security_connector_remove_handshake(h);
-  }
-  if (error == GRPC_ERROR_NONE) {
-    h->cb(exec_ctx, h->user_data, GRPC_SECURITY_OK, h->secure_endpoint,
-          h->auth_context);
-  } else {
-    const char *msg = grpc_error_string(error);
-    gpr_log(GPR_DEBUG, "Security handshake failed: %s", msg);
-    grpc_error_free_string(msg);
-
-    if (h->secure_endpoint != NULL) {
-      grpc_endpoint_shutdown(exec_ctx, h->secure_endpoint);
-      grpc_endpoint_destroy(exec_ctx, h->secure_endpoint);
-    } else {
-      grpc_endpoint_destroy(exec_ctx, h->wrapped_endpoint);
-    }
-    h->cb(exec_ctx, h->user_data, GRPC_SECURITY_ERROR, NULL, NULL);
-  }
-  unref_handshake(h);
-  GRPC_ERROR_UNREF(error);
-}
-
-static void on_peer_checked(grpc_exec_ctx *exec_ctx, void *user_data,
-                            grpc_security_status status,
-                            grpc_auth_context *auth_context) {
-  grpc_security_handshake *h = user_data;
-  tsi_frame_protector *protector;
-  tsi_result result;
-  if (status != GRPC_SECURITY_OK) {
-    security_handshake_done(
-        exec_ctx, h,
-        grpc_error_set_int(GRPC_ERROR_CREATE("Error checking peer."),
-                           GRPC_ERROR_INT_SECURITY_STATUS, status));
-    return;
-  }
-  h->auth_context = GRPC_AUTH_CONTEXT_REF(auth_context, "handshake");
-  result =
-      tsi_handshaker_create_frame_protector(h->handshaker, NULL, &protector);
-  if (result != TSI_OK) {
-    security_handshake_done(
-        exec_ctx, h,
-        grpc_set_tsi_error_result(
-            GRPC_ERROR_CREATE("Frame protector creation failed"), result));
-    return;
-  }
-  h->secure_endpoint =
-      grpc_secure_endpoint_create(protector, h->wrapped_endpoint,
-                                  h->left_overs.slices, h->left_overs.count);
-  h->left_overs.count = 0;
-  h->left_overs.length = 0;
-  security_handshake_done(exec_ctx, h, GRPC_ERROR_NONE);
-  return;
-}
-
-static void check_peer(grpc_exec_ctx *exec_ctx, grpc_security_handshake *h) {
-  tsi_peer peer;
-  tsi_result result = tsi_handshaker_extract_peer(h->handshaker, &peer);
-
-  if (result != TSI_OK) {
-    security_handshake_done(
-        exec_ctx, h, grpc_set_tsi_error_result(
-                         GRPC_ERROR_CREATE("Peer extraction failed"), result));
-    return;
-  }
-  grpc_security_connector_check_peer(exec_ctx, h->connector, peer,
-                                     on_peer_checked, h);
-}
-
-static void send_handshake_bytes_to_peer(grpc_exec_ctx *exec_ctx,
-                                         grpc_security_handshake *h) {
-  size_t offset = 0;
-  tsi_result result = TSI_OK;
-  grpc_slice to_send;
-
-  do {
-    size_t to_send_size = h->handshake_buffer_size - offset;
-    result = tsi_handshaker_get_bytes_to_send_to_peer(
-        h->handshaker, h->handshake_buffer + offset, &to_send_size);
-    offset += to_send_size;
-    if (result == TSI_INCOMPLETE_DATA) {
-      h->handshake_buffer_size *= 2;
-      h->handshake_buffer =
-          gpr_realloc(h->handshake_buffer, h->handshake_buffer_size);
-    }
-  } while (result == TSI_INCOMPLETE_DATA);
-
-  if (result != TSI_OK) {
-    security_handshake_done(exec_ctx, h,
-                            grpc_set_tsi_error_result(
-                                GRPC_ERROR_CREATE("Handshake failed"), result));
-    return;
-  }
-
-  to_send =
-      grpc_slice_from_copied_buffer((const char *)h->handshake_buffer, offset);
-  grpc_slice_buffer_reset_and_unref(&h->outgoing);
-  grpc_slice_buffer_add(&h->outgoing, to_send);
-  /* TODO(klempner,jboeuf): This should probably use the client setup
-     deadline */
-  grpc_endpoint_write(exec_ctx, h->wrapped_endpoint, &h->outgoing,
-                      &h->on_handshake_data_sent_to_peer);
-}
-
-static void on_handshake_data_received_from_peer(grpc_exec_ctx *exec_ctx,
-                                                 void *handshake,
-                                                 grpc_error *error) {
-  grpc_security_handshake *h = handshake;
-  size_t consumed_slice_size = 0;
-  tsi_result result = TSI_OK;
-  size_t i;
-  size_t num_left_overs;
-  int has_left_overs_in_current_slice = 0;
-
-  if (error != GRPC_ERROR_NONE) {
-    security_handshake_done(
-        exec_ctx, h,
-        GRPC_ERROR_CREATE_REFERENCING("Handshake read failed", &error, 1));
-    return;
-  }
-
-  for (i = 0; i < h->incoming.count; i++) {
-    consumed_slice_size = GRPC_SLICE_LENGTH(h->incoming.slices[i]);
-    result = tsi_handshaker_process_bytes_from_peer(
-        h->handshaker, GRPC_SLICE_START_PTR(h->incoming.slices[i]),
-        &consumed_slice_size);
-    if (!tsi_handshaker_is_in_progress(h->handshaker)) break;
-  }
-
-  if (tsi_handshaker_is_in_progress(h->handshaker)) {
-    /* We may need more data. */
-    if (result == TSI_INCOMPLETE_DATA) {
-      grpc_endpoint_read(exec_ctx, h->wrapped_endpoint, &h->incoming,
-                         &h->on_handshake_data_received_from_peer);
-      return;
-    } else {
-      send_handshake_bytes_to_peer(exec_ctx, h);
-      return;
-    }
-  }
-
-  if (result != TSI_OK) {
-    security_handshake_done(exec_ctx, h,
-                            grpc_set_tsi_error_result(
-                                GRPC_ERROR_CREATE("Handshake failed"), result));
-    return;
-  }
-
-  /* Handshake is done and successful this point. */
-  has_left_overs_in_current_slice =
-      (consumed_slice_size < GRPC_SLICE_LENGTH(h->incoming.slices[i]));
-  num_left_overs =
-      (has_left_overs_in_current_slice ? 1 : 0) + h->incoming.count - i - 1;
-  if (num_left_overs == 0) {
-    check_peer(exec_ctx, h);
-    return;
-  }
-
-  /* Put the leftovers in our buffer (ownership transfered). */
-  if (has_left_overs_in_current_slice) {
-    grpc_slice_buffer_add(
-        &h->left_overs,
-        grpc_slice_split_tail(&h->incoming.slices[i], consumed_slice_size));
-    grpc_slice_unref(
-        h->incoming.slices[i]); /* split_tail above increments refcount. */
-  }
-  grpc_slice_buffer_addn(
-      &h->left_overs, &h->incoming.slices[i + 1],
-      num_left_overs - (size_t)has_left_overs_in_current_slice);
-  check_peer(exec_ctx, h);
-}
-
-/* If handshake is NULL, the handshake is done. */
-static void on_handshake_data_sent_to_peer(grpc_exec_ctx *exec_ctx,
-                                           void *handshake, grpc_error *error) {
-  grpc_security_handshake *h = handshake;
-
-  /* Make sure that write is OK. */
-  if (error != GRPC_ERROR_NONE) {
-    if (handshake != NULL)
-      security_handshake_done(
-          exec_ctx, h,
-          GRPC_ERROR_CREATE_REFERENCING("Handshake write failed", &error, 1));
-    return;
-  }
-
-  /* We may be done. */
-  if (tsi_handshaker_is_in_progress(h->handshaker)) {
-    /* TODO(klempner,jboeuf): This should probably use the client setup
-       deadline */
-    grpc_endpoint_read(exec_ctx, h->wrapped_endpoint, &h->incoming,
-                       &h->on_handshake_data_received_from_peer);
-  } else {
-    check_peer(exec_ctx, h);
-  }
-}
-
-static void on_timeout(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {
-  grpc_security_handshake *h = arg;
-  if (error == GRPC_ERROR_NONE) {
-    grpc_endpoint_shutdown(exec_ctx, h->wrapped_endpoint);
-  }
-  unref_handshake(h);
-}
-
-void grpc_do_security_handshake(
-    grpc_exec_ctx *exec_ctx, tsi_handshaker *handshaker,
-    grpc_security_connector *connector, bool is_client_side,
-    grpc_endpoint *nonsecure_endpoint, grpc_slice_buffer *read_buffer,
-    gpr_timespec deadline, grpc_security_handshake_done_cb cb,
-    void *user_data) {
-  grpc_security_connector_handshake_list *handshake_node;
-  grpc_security_handshake *h = gpr_malloc(sizeof(grpc_security_handshake));
-  memset(h, 0, sizeof(grpc_security_handshake));
-  h->handshaker = handshaker;
-  h->connector = GRPC_SECURITY_CONNECTOR_REF(connector, "handshake");
-  h->is_client_side = is_client_side;
-  h->handshake_buffer_size = GRPC_INITIAL_HANDSHAKE_BUFFER_SIZE;
-  h->handshake_buffer = gpr_malloc(h->handshake_buffer_size);
-  h->wrapped_endpoint = nonsecure_endpoint;
-  h->user_data = user_data;
-  h->cb = cb;
-  gpr_ref_init(&h->refs, 2); /* timer and handshake proper each get a ref */
-  grpc_closure_init(&h->on_handshake_data_sent_to_peer,
-                    on_handshake_data_sent_to_peer, h);
-  grpc_closure_init(&h->on_handshake_data_received_from_peer,
-                    on_handshake_data_received_from_peer, h);
-  grpc_slice_buffer_init(&h->left_overs);
-  grpc_slice_buffer_init(&h->outgoing);
-  grpc_slice_buffer_init(&h->incoming);
-  if (read_buffer != NULL) {
-    grpc_slice_buffer_move_into(read_buffer, &h->incoming);
-    gpr_free(read_buffer);
-  }
-  if (!is_client_side) {
-    grpc_server_security_connector *server_connector =
-        (grpc_server_security_connector *)connector;
-    handshake_node = gpr_malloc(sizeof(grpc_security_connector_handshake_list));
-    handshake_node->handshake = h;
-    gpr_mu_lock(&server_connector->mu);
-    handshake_node->next = server_connector->handshaking_handshakes;
-    server_connector->handshaking_handshakes = handshake_node;
-    gpr_mu_unlock(&server_connector->mu);
-  }
-  send_handshake_bytes_to_peer(exec_ctx, h);
-  grpc_timer_init(exec_ctx, &h->timer,
-                  gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC),
-                  on_timeout, h, gpr_now(GPR_CLOCK_MONOTONIC));
-}
-
-void grpc_security_handshake_shutdown(grpc_exec_ctx *exec_ctx,
-                                      void *handshake) {
-  grpc_security_handshake *h = handshake;
-  grpc_endpoint_shutdown(exec_ctx, h->wrapped_endpoint);
-}
diff --git a/src/core/lib/security/transport/secure_endpoint.c b/src/core/lib/security/transport/secure_endpoint.c
index 1b278410e8..18a7a6f7e7 100644
--- a/src/core/lib/security/transport/secure_endpoint.c
+++ b/src/core/lib/security/transport/secure_endpoint.c
@@ -46,6 +46,7 @@
 #include "src/core/lib/profiling/timers.h"
 #include "src/core/lib/security/transport/secure_endpoint.h"
 #include "src/core/lib/security/transport/tsi_error.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/tsi/transport_security_interface.h"
@@ -80,11 +81,11 @@ static void destroy(grpc_exec_ctx *exec_ctx, secure_endpoint *secure_ep) {
   secure_endpoint *ep = secure_ep;
   grpc_endpoint_destroy(exec_ctx, ep->wrapped_ep);
   tsi_frame_protector_destroy(ep->protector);
-  grpc_slice_buffer_destroy(&ep->leftover_bytes);
-  grpc_slice_unref(ep->read_staging_buffer);
-  grpc_slice_unref(ep->write_staging_buffer);
-  grpc_slice_buffer_destroy(&ep->output_buffer);
-  grpc_slice_buffer_destroy(&ep->source_buffer);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &ep->leftover_bytes);
+  grpc_slice_unref_internal(exec_ctx, ep->read_staging_buffer);
+  grpc_slice_unref_internal(exec_ctx, ep->write_staging_buffer);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &ep->output_buffer);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &ep->source_buffer);
   gpr_mu_destroy(&ep->protector_mu);
   gpr_free(ep);
 }
@@ -146,7 +147,7 @@ static void call_read_cb(grpc_exec_ctx *exec_ctx, secure_endpoint *ep,
     }
   }
   ep->read_buffer = NULL;
-  grpc_exec_ctx_sched(exec_ctx, ep->read_cb, error, NULL);
+  grpc_closure_sched(exec_ctx, ep->read_cb, error);
   SECURE_ENDPOINT_UNREF(exec_ctx, ep, "read");
 }
 
@@ -160,7 +161,7 @@ static void on_read(grpc_exec_ctx *exec_ctx, void *user_data,
   uint8_t *end = GRPC_SLICE_END_PTR(ep->read_staging_buffer);
 
   if (error != GRPC_ERROR_NONE) {
-    grpc_slice_buffer_reset_and_unref(ep->read_buffer);
+    grpc_slice_buffer_reset_and_unref_internal(exec_ctx, ep->read_buffer);
     call_read_cb(exec_ctx, ep, GRPC_ERROR_CREATE_REFERENCING(
                                    "Secure read failed", &error, 1));
     return;
@@ -215,10 +216,10 @@ static void on_read(grpc_exec_ctx *exec_ctx, void *user_data,
 
   /* TODO(yangg) experiment with moving this block after read_cb to see if it
      helps latency */
-  grpc_slice_buffer_reset_and_unref(&ep->source_buffer);
+  grpc_slice_buffer_reset_and_unref_internal(exec_ctx, &ep->source_buffer);
 
   if (result != TSI_OK) {
-    grpc_slice_buffer_reset_and_unref(ep->read_buffer);
+    grpc_slice_buffer_reset_and_unref_internal(exec_ctx, ep->read_buffer);
     call_read_cb(exec_ctx, ep, grpc_set_tsi_error_result(
                                    GRPC_ERROR_CREATE("Unwrap failed"), result));
     return;
@@ -232,7 +233,7 @@ static void endpoint_read(grpc_exec_ctx *exec_ctx, grpc_endpoint *secure_ep,
   secure_endpoint *ep = (secure_endpoint *)secure_ep;
   ep->read_cb = cb;
   ep->read_buffer = slices;
-  grpc_slice_buffer_reset_and_unref(ep->read_buffer);
+  grpc_slice_buffer_reset_and_unref_internal(exec_ctx, ep->read_buffer);
 
   SECURE_ENDPOINT_REF(ep, "read");
   if (ep->leftover_bytes.count) {
@@ -264,7 +265,7 @@ static void endpoint_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *secure_ep,
   uint8_t *cur = GRPC_SLICE_START_PTR(ep->write_staging_buffer);
   uint8_t *end = GRPC_SLICE_END_PTR(ep->write_staging_buffer);
 
-  grpc_slice_buffer_reset_and_unref(&ep->output_buffer);
+  grpc_slice_buffer_reset_and_unref_internal(exec_ctx, &ep->output_buffer);
 
   if (grpc_trace_secure_endpoint) {
     for (i = 0; i < slices->count; i++) {
@@ -328,11 +329,10 @@ static void endpoint_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *secure_ep,
 
   if (result != TSI_OK) {
     /* TODO(yangg) do different things according to the error type? */
-    grpc_slice_buffer_reset_and_unref(&ep->output_buffer);
-    grpc_exec_ctx_sched(
+    grpc_slice_buffer_reset_and_unref_internal(exec_ctx, &ep->output_buffer);
+    grpc_closure_sched(
         exec_ctx, cb,
-        grpc_set_tsi_error_result(GRPC_ERROR_CREATE("Wrap failed"), result),
-        NULL);
+        grpc_set_tsi_error_result(GRPC_ERROR_CREATE("Wrap failed"), result));
     GPR_TIMER_END("secure_endpoint.endpoint_write", 0);
     return;
   }
@@ -372,7 +372,10 @@ static char *endpoint_get_peer(grpc_endpoint *secure_ep) {
   return grpc_endpoint_get_peer(ep->wrapped_ep);
 }
 
-static int endpoint_get_fd(grpc_endpoint *secure_ep) { return -1; }
+static int endpoint_get_fd(grpc_endpoint *secure_ep) {
+  secure_endpoint *ep = (secure_endpoint *)secure_ep;
+  return grpc_endpoint_get_fd(ep->wrapped_ep);
+}
 
 static grpc_workqueue *endpoint_get_workqueue(grpc_endpoint *secure_ep) {
   secure_endpoint *ep = (secure_endpoint *)secure_ep;
@@ -407,14 +410,14 @@ grpc_endpoint *grpc_secure_endpoint_create(
   grpc_slice_buffer_init(&ep->leftover_bytes);
   for (i = 0; i < leftover_nslices; i++) {
     grpc_slice_buffer_add(&ep->leftover_bytes,
-                          grpc_slice_ref(leftover_slices[i]));
+                          grpc_slice_ref_internal(leftover_slices[i]));
   }
   ep->write_staging_buffer = grpc_slice_malloc(STAGING_BUFFER_SIZE);
   ep->read_staging_buffer = grpc_slice_malloc(STAGING_BUFFER_SIZE);
   grpc_slice_buffer_init(&ep->output_buffer);
   grpc_slice_buffer_init(&ep->source_buffer);
   ep->read_buffer = NULL;
-  grpc_closure_init(&ep->on_read, on_read, ep);
+  grpc_closure_init(&ep->on_read, on_read, ep, grpc_schedule_on_exec_ctx);
   gpr_mu_init(&ep->protector_mu);
   gpr_ref_init(&ep->ref, 1);
   return &ep->base;
diff --git a/src/core/lib/security/transport/security_connector.c b/src/core/lib/security/transport/security_connector.c
index 0fbd63a7e1..5aa26e0577 100644
--- a/src/core/lib/security/transport/security_connector.c
+++ b/src/core/lib/security/transport/security_connector.c
@@ -43,11 +43,12 @@
 #include <grpc/support/string_util.h>
 
 #include "src/core/ext/transport/chttp2/alpn/alpn.h"
+#include "src/core/lib/channel/handshaker.h"
 #include "src/core/lib/iomgr/load_file.h"
 #include "src/core/lib/security/context/security_context.h"
 #include "src/core/lib/security/credentials/credentials.h"
-#include "src/core/lib/security/transport/handshake.h"
 #include "src/core/lib/security/transport/secure_endpoint.h"
+#include "src/core/lib/security/transport/security_handshaker.h"
 #include "src/core/lib/support/env.h"
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/tsi/fake_transport_security.h"
@@ -111,58 +112,34 @@ const tsi_peer_property *tsi_peer_get_property_by_name(const tsi_peer *peer,
   return NULL;
 }
 
-void grpc_server_security_connector_shutdown(
-    grpc_exec_ctx *exec_ctx, grpc_server_security_connector *connector) {
-  grpc_security_connector_handshake_list *tmp;
-  gpr_mu_lock(&connector->mu);
-  while (connector->handshaking_handshakes) {
-    tmp = connector->handshaking_handshakes;
-    grpc_security_handshake_shutdown(
-        exec_ctx, connector->handshaking_handshakes->handshake);
-    connector->handshaking_handshakes = tmp->next;
-    gpr_free(tmp);
+void grpc_channel_security_connector_add_handshakers(
+    grpc_exec_ctx *exec_ctx, grpc_channel_security_connector *connector,
+    grpc_handshake_manager *handshake_mgr) {
+  if (connector != NULL) {
+    connector->add_handshakers(exec_ctx, connector, handshake_mgr);
   }
-  gpr_mu_unlock(&connector->mu);
 }
 
-void grpc_channel_security_connector_do_handshake(
-    grpc_exec_ctx *exec_ctx, grpc_channel_security_connector *sc,
-    grpc_endpoint *nonsecure_endpoint, grpc_slice_buffer *read_buffer,
-    gpr_timespec deadline, grpc_security_handshake_done_cb cb,
-    void *user_data) {
-  if (sc == NULL || nonsecure_endpoint == NULL) {
-    gpr_free(read_buffer);
-    cb(exec_ctx, user_data, GRPC_SECURITY_ERROR, NULL, NULL);
-  } else {
-    sc->do_handshake(exec_ctx, sc, nonsecure_endpoint, read_buffer, deadline,
-                     cb, user_data);
-  }
-}
-
-void grpc_server_security_connector_do_handshake(
-    grpc_exec_ctx *exec_ctx, grpc_server_security_connector *sc,
-    grpc_tcp_server_acceptor *acceptor, grpc_endpoint *nonsecure_endpoint,
-    grpc_slice_buffer *read_buffer, gpr_timespec deadline,
-    grpc_security_handshake_done_cb cb, void *user_data) {
-  if (sc == NULL || nonsecure_endpoint == NULL) {
-    gpr_free(read_buffer);
-    cb(exec_ctx, user_data, GRPC_SECURITY_ERROR, NULL, NULL);
-  } else {
-    sc->do_handshake(exec_ctx, sc, acceptor, nonsecure_endpoint, read_buffer,
-                     deadline, cb, user_data);
+void grpc_server_security_connector_add_handshakers(
+    grpc_exec_ctx *exec_ctx, grpc_server_security_connector *connector,
+    grpc_handshake_manager *handshake_mgr) {
+  if (connector != NULL) {
+    connector->add_handshakers(exec_ctx, connector, handshake_mgr);
   }
 }
 
 void grpc_security_connector_check_peer(grpc_exec_ctx *exec_ctx,
                                         grpc_security_connector *sc,
                                         tsi_peer peer,
-                                        grpc_security_peer_check_cb cb,
-                                        void *user_data) {
+                                        grpc_auth_context **auth_context,
+                                        grpc_closure *on_peer_checked) {
   if (sc == NULL) {
-    cb(exec_ctx, user_data, GRPC_SECURITY_ERROR, NULL);
+    grpc_closure_sched(
+        exec_ctx, on_peer_checked,
+        GRPC_ERROR_CREATE("cannot check peer -- no security connector"));
     tsi_peer_destruct(&peer);
   } else {
-    sc->vtable->check_peer(exec_ctx, sc, peer, cb, user_data);
+    sc->vtable->check_peer(exec_ctx, sc, peer, auth_context, on_peer_checked);
   }
 }
 
@@ -195,7 +172,8 @@ grpc_security_connector *grpc_security_connector_ref(
 }
 
 #ifdef GRPC_SECURITY_CONNECTOR_REFCOUNT_DEBUG
-void grpc_security_connector_unref(grpc_security_connector *sc,
+void grpc_security_connector_unref(grpc_exec_ctx *exec_ctx,
+                                   grpc_security_connector *sc,
                                    const char *file, int line,
                                    const char *reason) {
   if (sc == NULL) return;
@@ -203,14 +181,15 @@ void grpc_security_connector_unref(grpc_security_connector *sc,
           "SECURITY_CONNECTOR:%p unref %d -> %d %s", sc,
           (int)sc->refcount.count, (int)sc->refcount.count - 1, reason);
 #else
-void grpc_security_connector_unref(grpc_security_connector *sc) {
+void grpc_security_connector_unref(grpc_exec_ctx *exec_ctx,
+                                   grpc_security_connector *sc) {
   if (sc == NULL) return;
 #endif
-  if (gpr_unref(&sc->refcount)) sc->vtable->destroy(sc);
+  if (gpr_unref(&sc->refcount)) sc->vtable->destroy(exec_ctx, sc);
 }
 
-static void connector_pointer_arg_destroy(void *p) {
-  GRPC_SECURITY_CONNECTOR_UNREF(p, "connector_pointer_arg_destroy");
+static void connector_pointer_arg_destroy(grpc_exec_ctx *exec_ctx, void *p) {
+  GRPC_SECURITY_CONNECTOR_UNREF(exec_ctx, p, "connector_pointer_arg_destroy");
 }
 
 static void *connector_pointer_arg_copy(void *p) {
@@ -256,51 +235,51 @@ grpc_security_connector *grpc_find_security_connector_in_args(
 
 /* -- Fake implementation. -- */
 
-static void fake_channel_destroy(grpc_security_connector *sc) {
+static void fake_channel_destroy(grpc_exec_ctx *exec_ctx,
+                                 grpc_security_connector *sc) {
   grpc_channel_security_connector *c = (grpc_channel_security_connector *)sc;
-  grpc_call_credentials_unref(c->request_metadata_creds);
+  grpc_call_credentials_unref(exec_ctx, c->request_metadata_creds);
   gpr_free(sc);
 }
 
-static void fake_server_destroy(grpc_security_connector *sc) {
-  grpc_server_security_connector *c = (grpc_server_security_connector *)sc;
-  gpr_mu_destroy(&c->mu);
+static void fake_server_destroy(grpc_exec_ctx *exec_ctx,
+                                grpc_security_connector *sc) {
   gpr_free(sc);
 }
 
 static void fake_check_peer(grpc_exec_ctx *exec_ctx,
                             grpc_security_connector *sc, tsi_peer peer,
-                            grpc_security_peer_check_cb cb, void *user_data) {
+                            grpc_auth_context **auth_context,
+                            grpc_closure *on_peer_checked) {
   const char *prop_name;
-  grpc_security_status status = GRPC_SECURITY_OK;
-  grpc_auth_context *auth_context = NULL;
+  grpc_error *error = GRPC_ERROR_NONE;
+  *auth_context = NULL;
   if (peer.property_count != 1) {
-    gpr_log(GPR_ERROR, "Fake peers should only have 1 property.");
-    status = GRPC_SECURITY_ERROR;
+    error = GRPC_ERROR_CREATE("Fake peers should only have 1 property.");
     goto end;
   }
   prop_name = peer.properties[0].name;
   if (prop_name == NULL ||
       strcmp(prop_name, TSI_CERTIFICATE_TYPE_PEER_PROPERTY)) {
-    gpr_log(GPR_ERROR, "Unexpected property in fake peer: %s.",
-            prop_name == NULL ? "<EMPTY>" : prop_name);
-    status = GRPC_SECURITY_ERROR;
+    char *msg;
+    gpr_asprintf(&msg, "Unexpected property in fake peer: %s.",
+                 prop_name == NULL ? "<EMPTY>" : prop_name);
+    error = GRPC_ERROR_CREATE(msg);
+    gpr_free(msg);
     goto end;
   }
   if (strncmp(peer.properties[0].value.data, TSI_FAKE_CERTIFICATE_TYPE,
               peer.properties[0].value.length)) {
-    gpr_log(GPR_ERROR, "Invalid value for cert type property.");
-    status = GRPC_SECURITY_ERROR;
+    error = GRPC_ERROR_CREATE("Invalid value for cert type property.");
     goto end;
   }
-  auth_context = grpc_auth_context_create(NULL);
+  *auth_context = grpc_auth_context_create(NULL);
   grpc_auth_context_add_cstring_property(
-      auth_context, GRPC_TRANSPORT_SECURITY_TYPE_PROPERTY_NAME,
+      *auth_context, GRPC_TRANSPORT_SECURITY_TYPE_PROPERTY_NAME,
       GRPC_FAKE_TRANSPORT_SECURITY_TYPE);
 
 end:
-  cb(exec_ctx, user_data, status, auth_context);
-  grpc_auth_context_unref(auth_context);
+  grpc_closure_sched(exec_ctx, on_peer_checked, error);
   tsi_peer_destruct(&peer);
 }
 
@@ -313,26 +292,24 @@ static void fake_channel_check_call_host(grpc_exec_ctx *exec_ctx,
   cb(exec_ctx, user_data, GRPC_SECURITY_OK);
 }
 
-static void fake_channel_do_handshake(grpc_exec_ctx *exec_ctx,
-                                      grpc_channel_security_connector *sc,
-                                      grpc_endpoint *nonsecure_endpoint,
-                                      grpc_slice_buffer *read_buffer,
-                                      gpr_timespec deadline,
-                                      grpc_security_handshake_done_cb cb,
-                                      void *user_data) {
-  grpc_do_security_handshake(exec_ctx, tsi_create_fake_handshaker(1), &sc->base,
-                             true, nonsecure_endpoint, read_buffer, deadline,
-                             cb, user_data);
+static void fake_channel_add_handshakers(
+    grpc_exec_ctx *exec_ctx, grpc_channel_security_connector *sc,
+    grpc_handshake_manager *handshake_mgr) {
+  grpc_handshake_manager_add(
+      handshake_mgr,
+      grpc_security_handshaker_create(
+          exec_ctx, tsi_create_fake_handshaker(true /* is_client */),
+          &sc->base));
 }
 
-static void fake_server_do_handshake(
-    grpc_exec_ctx *exec_ctx, grpc_server_security_connector *sc,
-    grpc_tcp_server_acceptor *acceptor, grpc_endpoint *nonsecure_endpoint,
-    grpc_slice_buffer *read_buffer, gpr_timespec deadline,
-    grpc_security_handshake_done_cb cb, void *user_data) {
-  grpc_do_security_handshake(exec_ctx, tsi_create_fake_handshaker(0), &sc->base,
-                             false, nonsecure_endpoint, read_buffer, deadline,
-                             cb, user_data);
+static void fake_server_add_handshakers(grpc_exec_ctx *exec_ctx,
+                                        grpc_server_security_connector *sc,
+                                        grpc_handshake_manager *handshake_mgr) {
+  grpc_handshake_manager_add(
+      handshake_mgr,
+      grpc_security_handshaker_create(
+          exec_ctx, tsi_create_fake_handshaker(false /* is_client */),
+          &sc->base));
 }
 
 static grpc_security_connector_vtable fake_channel_vtable = {
@@ -350,7 +327,7 @@ grpc_channel_security_connector *grpc_fake_channel_security_connector_create(
   c->base.vtable = &fake_channel_vtable;
   c->request_metadata_creds = grpc_call_credentials_ref(request_metadata_creds);
   c->check_call_host = fake_channel_check_call_host;
-  c->do_handshake = fake_channel_do_handshake;
+  c->add_handshakers = fake_channel_add_handshakers;
   return c;
 }
 
@@ -362,8 +339,7 @@ grpc_server_security_connector *grpc_fake_server_security_connector_create(
   gpr_ref_init(&c->base.refcount, 1);
   c->base.vtable = &fake_server_vtable;
   c->base.url_scheme = GRPC_FAKE_SECURITY_URL_SCHEME;
-  c->do_handshake = fake_server_do_handshake;
-  gpr_mu_init(&c->mu);
+  c->add_handshakers = fake_server_add_handshakers;
   return c;
 }
 
@@ -381,10 +357,11 @@ typedef struct {
   tsi_ssl_handshaker_factory *handshaker_factory;
 } grpc_ssl_server_security_connector;
 
-static void ssl_channel_destroy(grpc_security_connector *sc) {
+static void ssl_channel_destroy(grpc_exec_ctx *exec_ctx,
+                                grpc_security_connector *sc) {
   grpc_ssl_channel_security_connector *c =
       (grpc_ssl_channel_security_connector *)sc;
-  grpc_call_credentials_unref(c->base.request_metadata_creds);
+  grpc_call_credentials_unref(exec_ctx, c->base.request_metadata_creds);
   if (c->handshaker_factory != NULL) {
     tsi_ssl_handshaker_factory_destroy(c->handshaker_factory);
   }
@@ -393,14 +370,13 @@ static void ssl_channel_destroy(grpc_security_connector *sc) {
   gpr_free(sc);
 }
 
-static void ssl_server_destroy(grpc_security_connector *sc) {
+static void ssl_server_destroy(grpc_exec_ctx *exec_ctx,
+                               grpc_security_connector *sc) {
   grpc_ssl_server_security_connector *c =
       (grpc_ssl_server_security_connector *)sc;
-
   if (c->handshaker_factory != NULL) {
     tsi_ssl_handshaker_factory_destroy(c->handshaker_factory);
   }
-  gpr_mu_destroy(&c->base.mu);
   gpr_free(sc);
 }
 
@@ -419,49 +395,35 @@ static grpc_security_status ssl_create_handshaker(
   return GRPC_SECURITY_OK;
 }
 
-static void ssl_channel_do_handshake(grpc_exec_ctx *exec_ctx,
-                                     grpc_channel_security_connector *sc,
-                                     grpc_endpoint *nonsecure_endpoint,
-                                     grpc_slice_buffer *read_buffer,
-                                     gpr_timespec deadline,
-                                     grpc_security_handshake_done_cb cb,
-                                     void *user_data) {
+static void ssl_channel_add_handshakers(grpc_exec_ctx *exec_ctx,
+                                        grpc_channel_security_connector *sc,
+                                        grpc_handshake_manager *handshake_mgr) {
   grpc_ssl_channel_security_connector *c =
       (grpc_ssl_channel_security_connector *)sc;
-  tsi_handshaker *handshaker;
-  grpc_security_status status = ssl_create_handshaker(
-      c->handshaker_factory, true,
-      c->overridden_target_name != NULL ? c->overridden_target_name
-                                        : c->target_name,
-      &handshaker);
-  if (status != GRPC_SECURITY_OK) {
-    gpr_free(read_buffer);
-    cb(exec_ctx, user_data, status, NULL, NULL);
-  } else {
-    grpc_do_security_handshake(exec_ctx, handshaker, &sc->base, true,
-                               nonsecure_endpoint, read_buffer, deadline, cb,
-                               user_data);
-  }
-}
-
-static void ssl_server_do_handshake(
-    grpc_exec_ctx *exec_ctx, grpc_server_security_connector *sc,
-    grpc_tcp_server_acceptor *acceptor, grpc_endpoint *nonsecure_endpoint,
-    grpc_slice_buffer *read_buffer, gpr_timespec deadline,
-    grpc_security_handshake_done_cb cb, void *user_data) {
+  // Instantiate TSI handshaker.
+  tsi_handshaker *tsi_hs = NULL;
+  ssl_create_handshaker(c->handshaker_factory, true /* is_client */,
+                        c->overridden_target_name != NULL
+                            ? c->overridden_target_name
+                            : c->target_name,
+                        &tsi_hs);
+  // Create handshakers.
+  grpc_handshake_manager_add(handshake_mgr, grpc_security_handshaker_create(
+                                                exec_ctx, tsi_hs, &sc->base));
+}
+
+static void ssl_server_add_handshakers(grpc_exec_ctx *exec_ctx,
+                                       grpc_server_security_connector *sc,
+                                       grpc_handshake_manager *handshake_mgr) {
   grpc_ssl_server_security_connector *c =
       (grpc_ssl_server_security_connector *)sc;
-  tsi_handshaker *handshaker;
-  grpc_security_status status =
-      ssl_create_handshaker(c->handshaker_factory, false, NULL, &handshaker);
-  if (status != GRPC_SECURITY_OK) {
-    gpr_free(read_buffer);
-    cb(exec_ctx, user_data, status, NULL, NULL);
-  } else {
-    grpc_do_security_handshake(exec_ctx, handshaker, &sc->base, false,
-                               nonsecure_endpoint, read_buffer, deadline, cb,
-                               user_data);
-  }
+  // Instantiate TSI handshaker.
+  tsi_handshaker *tsi_hs = NULL;
+  ssl_create_handshaker(c->handshaker_factory, false /* is_client */,
+                        NULL /* peer_name */, &tsi_hs);
+  // Create handshakers.
+  grpc_handshake_manager_add(handshake_mgr, grpc_security_handshaker_create(
+                                                exec_ctx, tsi_hs, &sc->base));
 }
 
 static int ssl_host_matches_name(const tsi_peer *peer, const char *peer_name) {
@@ -518,57 +480,53 @@ grpc_auth_context *tsi_ssl_peer_to_auth_context(const tsi_peer *peer) {
   return ctx;
 }
 
-static grpc_security_status ssl_check_peer(grpc_security_connector *sc,
-                                           const char *peer_name,
-                                           const tsi_peer *peer,
-                                           grpc_auth_context **auth_context) {
+static grpc_error *ssl_check_peer(grpc_security_connector *sc,
+                                  const char *peer_name, const tsi_peer *peer,
+                                  grpc_auth_context **auth_context) {
   /* Check the ALPN. */
   const tsi_peer_property *p =
       tsi_peer_get_property_by_name(peer, TSI_SSL_ALPN_SELECTED_PROTOCOL);
   if (p == NULL) {
-    gpr_log(GPR_ERROR, "Missing selected ALPN property.");
-    return GRPC_SECURITY_ERROR;
+    return GRPC_ERROR_CREATE(
+        "Cannot check peer: missing selected ALPN property.");
   }
   if (!grpc_chttp2_is_alpn_version_supported(p->value.data, p->value.length)) {
-    gpr_log(GPR_ERROR, "Invalid ALPN value.");
-    return GRPC_SECURITY_ERROR;
+    return GRPC_ERROR_CREATE("Cannot check peer: invalid ALPN value.");
   }
 
   /* Check the peer name if specified. */
   if (peer_name != NULL && !ssl_host_matches_name(peer, peer_name)) {
-    gpr_log(GPR_ERROR, "Peer name %s is not in peer certificate", peer_name);
-    return GRPC_SECURITY_ERROR;
+    char *msg;
+    gpr_asprintf(&msg, "Peer name %s is not in peer certificate", peer_name);
+    grpc_error *error = GRPC_ERROR_CREATE(msg);
+    gpr_free(msg);
+    return error;
   }
   *auth_context = tsi_ssl_peer_to_auth_context(peer);
-  return GRPC_SECURITY_OK;
+  return GRPC_ERROR_NONE;
 }
 
 static void ssl_channel_check_peer(grpc_exec_ctx *exec_ctx,
                                    grpc_security_connector *sc, tsi_peer peer,
-                                   grpc_security_peer_check_cb cb,
-                                   void *user_data) {
+                                   grpc_auth_context **auth_context,
+                                   grpc_closure *on_peer_checked) {
   grpc_ssl_channel_security_connector *c =
       (grpc_ssl_channel_security_connector *)sc;
-  grpc_security_status status;
-  grpc_auth_context *auth_context = NULL;
-  status = ssl_check_peer(sc, c->overridden_target_name != NULL
-                                  ? c->overridden_target_name
-                                  : c->target_name,
-                          &peer, &auth_context);
-  cb(exec_ctx, user_data, status, auth_context);
-  grpc_auth_context_unref(auth_context);
+  grpc_error *error = ssl_check_peer(sc, c->overridden_target_name != NULL
+                                             ? c->overridden_target_name
+                                             : c->target_name,
+                                     &peer, auth_context);
+  grpc_closure_sched(exec_ctx, on_peer_checked, error);
   tsi_peer_destruct(&peer);
 }
 
 static void ssl_server_check_peer(grpc_exec_ctx *exec_ctx,
                                   grpc_security_connector *sc, tsi_peer peer,
-                                  grpc_security_peer_check_cb cb,
-                                  void *user_data) {
-  grpc_auth_context *auth_context = NULL;
-  grpc_security_status status = ssl_check_peer(sc, NULL, &peer, &auth_context);
+                                  grpc_auth_context **auth_context,
+                                  grpc_closure *on_peer_checked) {
+  grpc_error *error = ssl_check_peer(sc, NULL, &peer, auth_context);
   tsi_peer_destruct(&peer);
-  cb(exec_ctx, user_data, status, auth_context);
-  grpc_auth_context_unref(auth_context);
+  grpc_closure_sched(exec_ctx, on_peer_checked, error);
 }
 
 static void add_shallow_auth_property_to_peer(tsi_peer *peer,
@@ -719,7 +677,7 @@ size_t grpc_get_default_ssl_roots(const unsigned char **pem_root_certs) {
 }
 
 grpc_security_status grpc_ssl_channel_security_connector_create(
-    grpc_call_credentials *request_metadata_creds,
+    grpc_exec_ctx *exec_ctx, grpc_call_credentials *request_metadata_creds,
     const grpc_ssl_config *config, const char *target_name,
     const char *overridden_target_name, grpc_channel_security_connector **sc) {
   size_t num_alpn_protocols = grpc_chttp2_num_alpn_versions();
@@ -765,7 +723,7 @@ grpc_security_status grpc_ssl_channel_security_connector_create(
   c->base.request_metadata_creds =
       grpc_call_credentials_ref(request_metadata_creds);
   c->base.check_call_host = ssl_channel_check_call_host;
-  c->base.do_handshake = ssl_channel_do_handshake;
+  c->base.add_handshakers = ssl_channel_add_handshakers;
   gpr_split_host_port(target_name, &c->target_name, &port);
   gpr_free(port);
   if (overridden_target_name != NULL) {
@@ -780,7 +738,7 @@ grpc_security_status grpc_ssl_channel_security_connector_create(
   if (result != TSI_OK) {
     gpr_log(GPR_ERROR, "Handshaker factory creation failed with %s.",
             tsi_result_to_string(result));
-    ssl_channel_destroy(&c->base.base);
+    ssl_channel_destroy(exec_ctx, &c->base.base);
     *sc = NULL;
     goto error;
   }
@@ -796,7 +754,8 @@ error:
 }
 
 grpc_security_status grpc_ssl_server_security_connector_create(
-    const grpc_ssl_server_config *config, grpc_server_security_connector **sc) {
+    grpc_exec_ctx *exec_ctx, const grpc_ssl_server_config *config,
+    grpc_server_security_connector **sc) {
   size_t num_alpn_protocols = grpc_chttp2_num_alpn_versions();
   const unsigned char **alpn_protocol_strings =
       gpr_malloc(sizeof(const char *) * num_alpn_protocols);
@@ -836,12 +795,11 @@ grpc_security_status grpc_ssl_server_security_connector_create(
   if (result != TSI_OK) {
     gpr_log(GPR_ERROR, "Handshaker factory creation failed with %s.",
             tsi_result_to_string(result));
-    ssl_server_destroy(&c->base.base);
+    ssl_server_destroy(exec_ctx, &c->base.base);
     *sc = NULL;
     goto error;
   }
-  gpr_mu_init(&c->base.mu);
-  c->base.do_handshake = ssl_server_do_handshake;
+  c->base.add_handshakers = ssl_server_add_handshakers;
   *sc = &c->base;
   gpr_free((void *)alpn_protocol_strings);
   gpr_free(alpn_protocol_string_lengths);
diff --git a/src/core/lib/security/transport/security_connector.h b/src/core/lib/security/transport/security_connector.h
index dc02692b01..eba4e6d1d7 100644
--- a/src/core/lib/security/transport/security_connector.h
+++ b/src/core/lib/security/transport/security_connector.h
@@ -35,6 +35,8 @@
 #define GRPC_CORE_LIB_SECURITY_TRANSPORT_SECURITY_CONNECTOR_H
 
 #include <grpc/grpc_security.h>
+
+#include "src/core/lib/channel/handshaker.h"
 #include "src/core/lib/iomgr/endpoint.h"
 #include "src/core/lib/iomgr/tcp_server.h"
 #include "src/core/lib/tsi/transport_security_interface.h"
@@ -57,21 +59,11 @@ typedef struct grpc_security_connector grpc_security_connector;
 
 #define GRPC_SECURITY_CONNECTOR_ARG "grpc.security_connector"
 
-typedef void (*grpc_security_peer_check_cb)(grpc_exec_ctx *exec_ctx,
-                                            void *user_data,
-                                            grpc_security_status status,
-                                            grpc_auth_context *auth_context);
-
-/* Ownership of the secure_endpoint is transfered. */
-typedef void (*grpc_security_handshake_done_cb)(
-    grpc_exec_ctx *exec_ctx, void *user_data, grpc_security_status status,
-    grpc_endpoint *secure_endpoint, grpc_auth_context *auth_context);
-
 typedef struct {
-  void (*destroy)(grpc_security_connector *sc);
+  void (*destroy)(grpc_exec_ctx *exec_ctx, grpc_security_connector *sc);
   void (*check_peer)(grpc_exec_ctx *exec_ctx, grpc_security_connector *sc,
-                     tsi_peer peer, grpc_security_peer_check_cb cb,
-                     void *user_data);
+                     tsi_peer peer, grpc_auth_context **auth_context,
+                     grpc_closure *on_peer_checked);
 } grpc_security_connector_vtable;
 
 typedef struct grpc_security_connector_handshake_list {
@@ -89,29 +81,32 @@ struct grpc_security_connector {
 #ifdef GRPC_SECURITY_CONNECTOR_REFCOUNT_DEBUG
 #define GRPC_SECURITY_CONNECTOR_REF(p, r) \
   grpc_security_connector_ref((p), __FILE__, __LINE__, (r))
-#define GRPC_SECURITY_CONNECTOR_UNREF(p, r) \
-  grpc_security_connector_unref((p), __FILE__, __LINE__, (r))
+#define GRPC_SECURITY_CONNECTOR_UNREF(exec_ctx, p, r) \
+  grpc_security_connector_unref((exec_ctx), (p), __FILE__, __LINE__, (r))
 grpc_security_connector *grpc_security_connector_ref(
     grpc_security_connector *policy, const char *file, int line,
     const char *reason);
-void grpc_security_connector_unref(grpc_security_connector *policy,
+void grpc_security_connector_unref(grpc_exec_ctx *exec_ctx,
+                                   grpc_security_connector *policy,
                                    const char *file, int line,
                                    const char *reason);
 #else
 #define GRPC_SECURITY_CONNECTOR_REF(p, r) grpc_security_connector_ref((p))
-#define GRPC_SECURITY_CONNECTOR_UNREF(p, r) grpc_security_connector_unref((p))
+#define GRPC_SECURITY_CONNECTOR_UNREF(exec_ctx, p, r) \
+  grpc_security_connector_unref((exec_ctx), (p))
 grpc_security_connector *grpc_security_connector_ref(
     grpc_security_connector *policy);
-void grpc_security_connector_unref(grpc_security_connector *policy);
+void grpc_security_connector_unref(grpc_exec_ctx *exec_ctx,
+                                   grpc_security_connector *policy);
 #endif
 
 /* Check the peer. Callee takes ownership of the peer object.
-   The callback will include the resulting auth_context. */
+   When done, sets *auth_context and invokes on_peer_checked. */
 void grpc_security_connector_check_peer(grpc_exec_ctx *exec_ctx,
                                         grpc_security_connector *sc,
                                         tsi_peer peer,
-                                        grpc_security_peer_check_cb cb,
-                                        void *user_data);
+                                        grpc_auth_context **auth_context,
+                                        grpc_closure *on_peer_checked);
 
 /* Util to encapsulate the connector in a channel arg. */
 grpc_arg grpc_security_connector_to_arg(grpc_security_connector *sc);
@@ -141,11 +136,9 @@ struct grpc_channel_security_connector {
                           grpc_channel_security_connector *sc, const char *host,
                           grpc_auth_context *auth_context,
                           grpc_security_call_host_check_cb cb, void *user_data);
-  void (*do_handshake)(grpc_exec_ctx *exec_ctx,
-                       grpc_channel_security_connector *sc,
-                       grpc_endpoint *nonsecure_endpoint,
-                       grpc_slice_buffer *read_buffer, gpr_timespec deadline,
-                       grpc_security_handshake_done_cb cb, void *user_data);
+  void (*add_handshakers)(grpc_exec_ctx *exec_ctx,
+                          grpc_channel_security_connector *sc,
+                          grpc_handshake_manager *handshake_mgr);
 };
 
 /* Checks that the host that will be set for a call is acceptable. */
@@ -154,11 +147,10 @@ void grpc_channel_security_connector_check_call_host(
     const char *host, grpc_auth_context *auth_context,
     grpc_security_call_host_check_cb cb, void *user_data);
 
-/* Handshake. */
-void grpc_channel_security_connector_do_handshake(
+/* Registers handshakers with \a handshake_mgr. */
+void grpc_channel_security_connector_add_handshakers(
     grpc_exec_ctx *exec_ctx, grpc_channel_security_connector *connector,
-    grpc_endpoint *nonsecure_endpoint, grpc_slice_buffer *read_buffer,
-    gpr_timespec deadline, grpc_security_handshake_done_cb cb, void *user_data);
+    grpc_handshake_manager *handshake_mgr);
 
 /* --- server_security_connector object. ---
 
@@ -169,25 +161,14 @@ typedef struct grpc_server_security_connector grpc_server_security_connector;
 
 struct grpc_server_security_connector {
   grpc_security_connector base;
-  gpr_mu mu;
-  grpc_security_connector_handshake_list *handshaking_handshakes;
-  const grpc_channel_args *channel_args;
-  void (*do_handshake)(grpc_exec_ctx *exec_ctx,
-                       grpc_server_security_connector *sc,
-                       grpc_tcp_server_acceptor *acceptor,
-                       grpc_endpoint *nonsecure_endpoint,
-                       grpc_slice_buffer *read_buffer, gpr_timespec deadline,
-                       grpc_security_handshake_done_cb cb, void *user_data);
+  void (*add_handshakers)(grpc_exec_ctx *exec_ctx,
+                          grpc_server_security_connector *sc,
+                          grpc_handshake_manager *handshake_mgr);
 };
 
-void grpc_server_security_connector_do_handshake(
+void grpc_server_security_connector_add_handshakers(
     grpc_exec_ctx *exec_ctx, grpc_server_security_connector *sc,
-    grpc_tcp_server_acceptor *acceptor, grpc_endpoint *nonsecure_endpoint,
-    grpc_slice_buffer *read_buffer, gpr_timespec deadline,
-    grpc_security_handshake_done_cb cb, void *user_data);
-
-void grpc_server_security_connector_shutdown(
-    grpc_exec_ctx *exec_ctx, grpc_server_security_connector *connector);
+    grpc_handshake_manager *handshake_mgr);
 
 /* --- Creation security connectors. --- */
 
@@ -225,7 +206,7 @@ typedef struct {
   specific error code otherwise.
 */
 grpc_security_status grpc_ssl_channel_security_connector_create(
-    grpc_call_credentials *request_metadata_creds,
+    grpc_exec_ctx *exec_ctx, grpc_call_credentials *request_metadata_creds,
     const grpc_ssl_config *config, const char *target_name,
     const char *overridden_target_name, grpc_channel_security_connector **sc);
 
@@ -254,7 +235,8 @@ typedef struct {
   specific error code otherwise.
 */
 grpc_security_status grpc_ssl_server_security_connector_create(
-    const grpc_ssl_server_config *config, grpc_server_security_connector **sc);
+    grpc_exec_ctx *exec_ctx, const grpc_ssl_server_config *config,
+    grpc_server_security_connector **sc);
 
 /* Util. */
 const tsi_peer_property *tsi_peer_get_property_by_name(const tsi_peer *peer,
diff --git a/src/core/lib/security/transport/security_handshaker.c b/src/core/lib/security/transport/security_handshaker.c
new file mode 100644
index 0000000000..5e75856c7a
--- /dev/null
+++ b/src/core/lib/security/transport/security_handshaker.c
@@ -0,0 +1,501 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "src/core/lib/security/transport/security_handshaker.h"
+
+#include <stdbool.h>
+#include <string.h>
+
+#include <grpc/slice_buffer.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/channel/handshaker.h"
+#include "src/core/lib/channel/handshaker_registry.h"
+#include "src/core/lib/security/context/security_context.h"
+#include "src/core/lib/security/transport/secure_endpoint.h"
+#include "src/core/lib/security/transport/tsi_error.h"
+#include "src/core/lib/slice/slice_internal.h"
+
+#define GRPC_INITIAL_HANDSHAKE_BUFFER_SIZE 256
+
+typedef struct {
+  grpc_handshaker base;
+
+  // State set at creation time.
+  tsi_handshaker *handshaker;
+  grpc_security_connector *connector;
+
+  gpr_mu mu;
+  gpr_refcount refs;
+
+  bool shutdown;
+  // Endpoint and read buffer to destroy after a shutdown.
+  grpc_endpoint *endpoint_to_destroy;
+  grpc_slice_buffer *read_buffer_to_destroy;
+
+  // State saved while performing the handshake.
+  grpc_handshaker_args *args;
+  grpc_closure *on_handshake_done;
+
+  unsigned char *handshake_buffer;
+  size_t handshake_buffer_size;
+  grpc_slice_buffer left_overs;
+  grpc_slice_buffer outgoing;
+  grpc_closure on_handshake_data_sent_to_peer;
+  grpc_closure on_handshake_data_received_from_peer;
+  grpc_closure on_peer_checked;
+  grpc_auth_context *auth_context;
+} security_handshaker;
+
+static void security_handshaker_unref(grpc_exec_ctx *exec_ctx,
+                                      security_handshaker *h) {
+  if (gpr_unref(&h->refs)) {
+    gpr_mu_destroy(&h->mu);
+    tsi_handshaker_destroy(h->handshaker);
+    if (h->endpoint_to_destroy != NULL) {
+      grpc_endpoint_destroy(exec_ctx, h->endpoint_to_destroy);
+    }
+    if (h->read_buffer_to_destroy != NULL) {
+      grpc_slice_buffer_destroy_internal(exec_ctx, h->read_buffer_to_destroy);
+      gpr_free(h->read_buffer_to_destroy);
+    }
+    gpr_free(h->handshake_buffer);
+    grpc_slice_buffer_destroy_internal(exec_ctx, &h->left_overs);
+    grpc_slice_buffer_destroy_internal(exec_ctx, &h->outgoing);
+    GRPC_AUTH_CONTEXT_UNREF(h->auth_context, "handshake");
+    GRPC_SECURITY_CONNECTOR_UNREF(exec_ctx, h->connector, "handshake");
+    gpr_free(h);
+  }
+}
+
+// Set args fields to NULL, saving the endpoint and read buffer for
+// later destruction.
+static void cleanup_args_for_failure_locked(grpc_exec_ctx *exec_ctx,
+                                            security_handshaker *h) {
+  h->endpoint_to_destroy = h->args->endpoint;
+  h->args->endpoint = NULL;
+  h->read_buffer_to_destroy = h->args->read_buffer;
+  h->args->read_buffer = NULL;
+  grpc_channel_args_destroy(exec_ctx, h->args->args);
+  h->args->args = NULL;
+}
+
+// If the handshake failed or we're shutting down, clean up and invoke the
+// callback with the error.
+static void security_handshake_failed_locked(grpc_exec_ctx *exec_ctx,
+                                             security_handshaker *h,
+                                             grpc_error *error) {
+  if (error == GRPC_ERROR_NONE) {
+    // If we were shut down after the handshake succeeded but before an
+    // endpoint callback was invoked, we need to generate our own error.
+    error = GRPC_ERROR_CREATE("Handshaker shutdown");
+  }
+  const char *msg = grpc_error_string(error);
+  gpr_log(GPR_DEBUG, "Security handshake failed: %s", msg);
+  grpc_error_free_string(msg);
+  if (!h->shutdown) {
+    // TODO(ctiller): It is currently necessary to shutdown endpoints
+    // before destroying them, even if we know that there are no
+    // pending read/write callbacks.  This should be fixed, at which
+    // point this can be removed.
+    grpc_endpoint_shutdown(exec_ctx, h->args->endpoint);
+    // Not shutting down, so the write failed.  Clean up before
+    // invoking the callback.
+    cleanup_args_for_failure_locked(exec_ctx, h);
+    // Set shutdown to true so that subsequent calls to
+    // security_handshaker_shutdown() do nothing.
+    h->shutdown = true;
+  }
+  // Invoke callback.
+  grpc_closure_sched(exec_ctx, h->on_handshake_done, error);
+}
+
+static void on_peer_checked(grpc_exec_ctx *exec_ctx, void *arg,
+                            grpc_error *error) {
+  security_handshaker *h = arg;
+  gpr_mu_lock(&h->mu);
+  if (error != GRPC_ERROR_NONE || h->shutdown) {
+    security_handshake_failed_locked(exec_ctx, h, GRPC_ERROR_REF(error));
+    goto done;
+  }
+  // Get frame protector.
+  tsi_frame_protector *protector;
+  tsi_result result =
+      tsi_handshaker_create_frame_protector(h->handshaker, NULL, &protector);
+  if (result != TSI_OK) {
+    error = grpc_set_tsi_error_result(
+        GRPC_ERROR_CREATE("Frame protector creation failed"), result);
+    security_handshake_failed_locked(exec_ctx, h, error);
+    goto done;
+  }
+  // Success.
+  // Create secure endpoint.
+  h->args->endpoint = grpc_secure_endpoint_create(
+      protector, h->args->endpoint, h->left_overs.slices, h->left_overs.count);
+  h->left_overs.count = 0;
+  h->left_overs.length = 0;
+  // Clear out the read buffer before it gets passed to the transport,
+  // since any excess bytes were already copied to h->left_overs.
+  grpc_slice_buffer_reset_and_unref_internal(exec_ctx, h->args->read_buffer);
+  // Add auth context to channel args.
+  grpc_arg auth_context_arg = grpc_auth_context_to_arg(h->auth_context);
+  grpc_channel_args *tmp_args = h->args->args;
+  h->args->args =
+      grpc_channel_args_copy_and_add(tmp_args, &auth_context_arg, 1);
+  grpc_channel_args_destroy(exec_ctx, tmp_args);
+  // Invoke callback.
+  grpc_closure_sched(exec_ctx, h->on_handshake_done, GRPC_ERROR_NONE);
+  // Set shutdown to true so that subsequent calls to
+  // security_handshaker_shutdown() do nothing.
+  h->shutdown = true;
+done:
+  gpr_mu_unlock(&h->mu);
+  security_handshaker_unref(exec_ctx, h);
+}
+
+static grpc_error *check_peer_locked(grpc_exec_ctx *exec_ctx,
+                                     security_handshaker *h) {
+  tsi_peer peer;
+  tsi_result result = tsi_handshaker_extract_peer(h->handshaker, &peer);
+  if (result != TSI_OK) {
+    return grpc_set_tsi_error_result(
+        GRPC_ERROR_CREATE("Peer extraction failed"), result);
+  }
+  grpc_security_connector_check_peer(exec_ctx, h->connector, peer,
+                                     &h->auth_context, &h->on_peer_checked);
+  return GRPC_ERROR_NONE;
+}
+
+static grpc_error *send_handshake_bytes_to_peer_locked(grpc_exec_ctx *exec_ctx,
+                                                       security_handshaker *h) {
+  // Get data to send.
+  tsi_result result = TSI_OK;
+  size_t offset = 0;
+  do {
+    size_t to_send_size = h->handshake_buffer_size - offset;
+    result = tsi_handshaker_get_bytes_to_send_to_peer(
+        h->handshaker, h->handshake_buffer + offset, &to_send_size);
+    offset += to_send_size;
+    if (result == TSI_INCOMPLETE_DATA) {
+      h->handshake_buffer_size *= 2;
+      h->handshake_buffer =
+          gpr_realloc(h->handshake_buffer, h->handshake_buffer_size);
+    }
+  } while (result == TSI_INCOMPLETE_DATA);
+  if (result != TSI_OK) {
+    return grpc_set_tsi_error_result(GRPC_ERROR_CREATE("Handshake failed"),
+                                     result);
+  }
+  // Send data.
+  grpc_slice to_send =
+      grpc_slice_from_copied_buffer((const char *)h->handshake_buffer, offset);
+  grpc_slice_buffer_reset_and_unref_internal(exec_ctx, &h->outgoing);
+  grpc_slice_buffer_add(&h->outgoing, to_send);
+  grpc_endpoint_write(exec_ctx, h->args->endpoint, &h->outgoing,
+                      &h->on_handshake_data_sent_to_peer);
+  return GRPC_ERROR_NONE;
+}
+
+static void on_handshake_data_received_from_peer(grpc_exec_ctx *exec_ctx,
+                                                 void *arg, grpc_error *error) {
+  security_handshaker *h = arg;
+  gpr_mu_lock(&h->mu);
+  if (error != GRPC_ERROR_NONE || h->shutdown) {
+    security_handshake_failed_locked(
+        exec_ctx, h,
+        GRPC_ERROR_CREATE_REFERENCING("Handshake read failed", &error, 1));
+    gpr_mu_unlock(&h->mu);
+    security_handshaker_unref(exec_ctx, h);
+    return;
+  }
+  // Process received data.
+  tsi_result result = TSI_OK;
+  size_t consumed_slice_size = 0;
+  size_t i;
+  for (i = 0; i < h->args->read_buffer->count; i++) {
+    consumed_slice_size = GRPC_SLICE_LENGTH(h->args->read_buffer->slices[i]);
+    result = tsi_handshaker_process_bytes_from_peer(
+        h->handshaker, GRPC_SLICE_START_PTR(h->args->read_buffer->slices[i]),
+        &consumed_slice_size);
+    if (!tsi_handshaker_is_in_progress(h->handshaker)) break;
+  }
+  if (tsi_handshaker_is_in_progress(h->handshaker)) {
+    /* We may need more data. */
+    if (result == TSI_INCOMPLETE_DATA) {
+      grpc_endpoint_read(exec_ctx, h->args->endpoint, h->args->read_buffer,
+                         &h->on_handshake_data_received_from_peer);
+      goto done;
+    } else {
+      error = send_handshake_bytes_to_peer_locked(exec_ctx, h);
+      if (error != GRPC_ERROR_NONE) {
+        security_handshake_failed_locked(exec_ctx, h, error);
+        gpr_mu_unlock(&h->mu);
+        security_handshaker_unref(exec_ctx, h);
+        return;
+      }
+      goto done;
+    }
+  }
+  if (result != TSI_OK) {
+    security_handshake_failed_locked(
+        exec_ctx, h, grpc_set_tsi_error_result(
+                         GRPC_ERROR_CREATE("Handshake failed"), result));
+    gpr_mu_unlock(&h->mu);
+    security_handshaker_unref(exec_ctx, h);
+    return;
+  }
+  /* Handshake is done and successful this point. */
+  bool has_left_overs_in_current_slice =
+      (consumed_slice_size <
+       GRPC_SLICE_LENGTH(h->args->read_buffer->slices[i]));
+  size_t num_left_overs = (has_left_overs_in_current_slice ? 1 : 0) +
+                          h->args->read_buffer->count - i - 1;
+  if (num_left_overs > 0) {
+    /* Put the leftovers in our buffer (ownership transfered). */
+    if (has_left_overs_in_current_slice) {
+      grpc_slice_buffer_add(
+          &h->left_overs,
+          grpc_slice_split_tail(&h->args->read_buffer->slices[i],
+                                consumed_slice_size));
+      /* split_tail above increments refcount. */
+      grpc_slice_unref_internal(exec_ctx, h->args->read_buffer->slices[i]);
+    }
+    grpc_slice_buffer_addn(
+        &h->left_overs, &h->args->read_buffer->slices[i + 1],
+        num_left_overs - (size_t)has_left_overs_in_current_slice);
+  }
+  // Check peer.
+  error = check_peer_locked(exec_ctx, h);
+  if (error != GRPC_ERROR_NONE) {
+    security_handshake_failed_locked(exec_ctx, h, error);
+    gpr_mu_unlock(&h->mu);
+    security_handshaker_unref(exec_ctx, h);
+    return;
+  }
+done:
+  gpr_mu_unlock(&h->mu);
+}
+
+static void on_handshake_data_sent_to_peer(grpc_exec_ctx *exec_ctx, void *arg,
+                                           grpc_error *error) {
+  security_handshaker *h = arg;
+  gpr_mu_lock(&h->mu);
+  if (error != GRPC_ERROR_NONE || h->shutdown) {
+    security_handshake_failed_locked(
+        exec_ctx, h,
+        GRPC_ERROR_CREATE_REFERENCING("Handshake write failed", &error, 1));
+    gpr_mu_unlock(&h->mu);
+    security_handshaker_unref(exec_ctx, h);
+    return;
+  }
+  /* We may be done. */
+  if (tsi_handshaker_is_in_progress(h->handshaker)) {
+    grpc_endpoint_read(exec_ctx, h->args->endpoint, h->args->read_buffer,
+                       &h->on_handshake_data_received_from_peer);
+  } else {
+    error = check_peer_locked(exec_ctx, h);
+    if (error != GRPC_ERROR_NONE) {
+      security_handshake_failed_locked(exec_ctx, h, error);
+      gpr_mu_unlock(&h->mu);
+      security_handshaker_unref(exec_ctx, h);
+      return;
+    }
+  }
+  gpr_mu_unlock(&h->mu);
+}
+
+//
+// public handshaker API
+//
+
+static void security_handshaker_destroy(grpc_exec_ctx *exec_ctx,
+                                        grpc_handshaker *handshaker) {
+  security_handshaker *h = (security_handshaker *)handshaker;
+  security_handshaker_unref(exec_ctx, h);
+}
+
+static void security_handshaker_shutdown(grpc_exec_ctx *exec_ctx,
+                                         grpc_handshaker *handshaker) {
+  security_handshaker *h = (security_handshaker *)handshaker;
+  gpr_mu_lock(&h->mu);
+  if (!h->shutdown) {
+    h->shutdown = true;
+    grpc_endpoint_shutdown(exec_ctx, h->args->endpoint);
+    cleanup_args_for_failure_locked(exec_ctx, h);
+  }
+  gpr_mu_unlock(&h->mu);
+}
+
+static void security_handshaker_do_handshake(grpc_exec_ctx *exec_ctx,
+                                             grpc_handshaker *handshaker,
+                                             grpc_tcp_server_acceptor *acceptor,
+                                             grpc_closure *on_handshake_done,
+                                             grpc_handshaker_args *args) {
+  security_handshaker *h = (security_handshaker *)handshaker;
+  gpr_mu_lock(&h->mu);
+  h->args = args;
+  h->on_handshake_done = on_handshake_done;
+  gpr_ref(&h->refs);
+  grpc_error *error = send_handshake_bytes_to_peer_locked(exec_ctx, h);
+  if (error != GRPC_ERROR_NONE) {
+    security_handshake_failed_locked(exec_ctx, h, error);
+    gpr_mu_unlock(&h->mu);
+    security_handshaker_unref(exec_ctx, h);
+    return;
+  }
+  gpr_mu_unlock(&h->mu);
+}
+
+static const grpc_handshaker_vtable security_handshaker_vtable = {
+    security_handshaker_destroy, security_handshaker_shutdown,
+    security_handshaker_do_handshake};
+
+static grpc_handshaker *security_handshaker_create(
+    grpc_exec_ctx *exec_ctx, tsi_handshaker *handshaker,
+    grpc_security_connector *connector) {
+  security_handshaker *h = gpr_malloc(sizeof(security_handshaker));
+  memset(h, 0, sizeof(security_handshaker));
+  grpc_handshaker_init(&security_handshaker_vtable, &h->base);
+  h->handshaker = handshaker;
+  h->connector = GRPC_SECURITY_CONNECTOR_REF(connector, "handshake");
+  gpr_mu_init(&h->mu);
+  gpr_ref_init(&h->refs, 1);
+  h->handshake_buffer_size = GRPC_INITIAL_HANDSHAKE_BUFFER_SIZE;
+  h->handshake_buffer = gpr_malloc(h->handshake_buffer_size);
+  grpc_closure_init(&h->on_handshake_data_sent_to_peer,
+                    on_handshake_data_sent_to_peer, h,
+                    grpc_schedule_on_exec_ctx);
+  grpc_closure_init(&h->on_handshake_data_received_from_peer,
+                    on_handshake_data_received_from_peer, h,
+                    grpc_schedule_on_exec_ctx);
+  grpc_closure_init(&h->on_peer_checked, on_peer_checked, h,
+                    grpc_schedule_on_exec_ctx);
+  grpc_slice_buffer_init(&h->left_overs);
+  grpc_slice_buffer_init(&h->outgoing);
+  return &h->base;
+}
+
+//
+// fail_handshaker
+//
+
+static void fail_handshaker_destroy(grpc_exec_ctx *exec_ctx,
+                                    grpc_handshaker *handshaker) {
+  gpr_free(handshaker);
+}
+
+static void fail_handshaker_shutdown(grpc_exec_ctx *exec_ctx,
+                                     grpc_handshaker *handshaker) {}
+
+static void fail_handshaker_do_handshake(grpc_exec_ctx *exec_ctx,
+                                         grpc_handshaker *handshaker,
+                                         grpc_tcp_server_acceptor *acceptor,
+                                         grpc_closure *on_handshake_done,
+                                         grpc_handshaker_args *args) {
+  grpc_closure_sched(exec_ctx, on_handshake_done,
+                     GRPC_ERROR_CREATE("Failed to create security handshaker"));
+}
+
+static const grpc_handshaker_vtable fail_handshaker_vtable = {
+    fail_handshaker_destroy, fail_handshaker_shutdown,
+    fail_handshaker_do_handshake};
+
+static grpc_handshaker *fail_handshaker_create() {
+  grpc_handshaker *h = gpr_malloc(sizeof(*h));
+  grpc_handshaker_init(&fail_handshaker_vtable, h);
+  return h;
+}
+
+//
+// handshaker factories
+//
+
+static void client_handshaker_factory_add_handshakers(
+    grpc_exec_ctx *exec_ctx, grpc_handshaker_factory *handshaker_factory,
+    const grpc_channel_args *args, grpc_handshake_manager *handshake_mgr) {
+  grpc_channel_security_connector *security_connector =
+      (grpc_channel_security_connector *)grpc_find_security_connector_in_args(
+          args);
+  grpc_channel_security_connector_add_handshakers(exec_ctx, security_connector,
+                                                  handshake_mgr);
+}
+
+static void server_handshaker_factory_add_handshakers(
+    grpc_exec_ctx *exec_ctx, grpc_handshaker_factory *hf,
+    const grpc_channel_args *args, grpc_handshake_manager *handshake_mgr) {
+  grpc_server_security_connector *security_connector =
+      (grpc_server_security_connector *)grpc_find_security_connector_in_args(
+          args);
+  grpc_server_security_connector_add_handshakers(exec_ctx, security_connector,
+                                                 handshake_mgr);
+}
+
+static void handshaker_factory_destroy(
+    grpc_exec_ctx *exec_ctx, grpc_handshaker_factory *handshaker_factory) {}
+
+static const grpc_handshaker_factory_vtable client_handshaker_factory_vtable = {
+    client_handshaker_factory_add_handshakers, handshaker_factory_destroy};
+
+static grpc_handshaker_factory client_handshaker_factory = {
+    &client_handshaker_factory_vtable};
+
+static const grpc_handshaker_factory_vtable server_handshaker_factory_vtable = {
+    server_handshaker_factory_add_handshakers, handshaker_factory_destroy};
+
+static grpc_handshaker_factory server_handshaker_factory = {
+    &server_handshaker_factory_vtable};
+
+//
+// exported functions
+//
+
+grpc_handshaker *grpc_security_handshaker_create(
+    grpc_exec_ctx *exec_ctx, tsi_handshaker *handshaker,
+    grpc_security_connector *connector) {
+  // If no TSI handshaker was created, return a handshaker that always fails.
+  // Otherwise, return a real security handshaker.
+  if (handshaker == NULL) {
+    return fail_handshaker_create();
+  } else {
+    return security_handshaker_create(exec_ctx, handshaker, connector);
+  }
+}
+
+void grpc_security_register_handshaker_factories() {
+  grpc_handshaker_factory_register(false /* at_start */, HANDSHAKER_CLIENT,
+                                   &client_handshaker_factory);
+  grpc_handshaker_factory_register(false /* at_start */, HANDSHAKER_SERVER,
+                                   &server_handshaker_factory);
+}
diff --git a/src/core/lib/security/transport/handshake.h b/src/core/lib/security/transport/security_handshaker.h
index f894540515..0b9eda178f 100644
--- a/src/core/lib/security/transport/handshake.h
+++ b/src/core/lib/security/transport/security_handshaker.h
@@ -31,20 +31,19 @@
  *
  */
 
-#ifndef GRPC_CORE_LIB_SECURITY_TRANSPORT_HANDSHAKE_H
-#define GRPC_CORE_LIB_SECURITY_TRANSPORT_HANDSHAKE_H
+#ifndef GRPC_CORE_LIB_SECURITY_TRANSPORT_SECURITY_HANDSHAKER_H
+#define GRPC_CORE_LIB_SECURITY_TRANSPORT_SECURITY_HANDSHAKER_H
 
-#include "src/core/lib/iomgr/endpoint.h"
+#include "src/core/lib/channel/handshaker.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/security/transport/security_connector.h"
 
-/* Calls the callback upon completion. Takes owership of handshaker and
- * read_buffer. */
-void grpc_do_security_handshake(
+/// Creates a security handshaker using \a handshaker.
+grpc_handshaker *grpc_security_handshaker_create(
     grpc_exec_ctx *exec_ctx, tsi_handshaker *handshaker,
-    grpc_security_connector *connector, bool is_client_side,
-    grpc_endpoint *nonsecure_endpoint, grpc_slice_buffer *read_buffer,
-    gpr_timespec deadline, grpc_security_handshake_done_cb cb, void *user_data);
+    grpc_security_connector *connector);
 
-void grpc_security_handshake_shutdown(grpc_exec_ctx *exec_ctx, void *handshake);
+/// Registers security handshaker factories.
+void grpc_security_register_handshaker_factories();
 
-#endif /* GRPC_CORE_LIB_SECURITY_TRANSPORT_HANDSHAKE_H */
+#endif /* GRPC_CORE_LIB_SECURITY_TRANSPORT_SECURITY_HANDSHAKER_H */
diff --git a/src/core/lib/security/transport/server_auth_filter.c b/src/core/lib/security/transport/server_auth_filter.c
index eaa1d0720b..5e98ba895d 100644
--- a/src/core/lib/security/transport/server_auth_filter.c
+++ b/src/core/lib/security/transport/server_auth_filter.c
@@ -83,7 +83,8 @@ static grpc_metadata_array metadata_batch_to_md_array(
   return result;
 }
 
-static grpc_mdelem *remove_consumed_md(void *user_data, grpc_mdelem *md) {
+static grpc_mdelem *remove_consumed_md(grpc_exec_ctx *exec_ctx, void *user_data,
+                                       grpc_mdelem *md) {
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
   size_t i;
@@ -129,10 +130,10 @@ static void on_md_processing_done(
   if (status == GRPC_STATUS_OK) {
     calld->consumed_md = consumed_md;
     calld->num_consumed_md = num_consumed_md;
-    grpc_metadata_batch_filter(calld->recv_initial_metadata, remove_consumed_md,
-                               elem);
+    grpc_metadata_batch_filter(&exec_ctx, calld->recv_initial_metadata,
+                               remove_consumed_md, elem);
     grpc_metadata_array_destroy(&calld->md);
-    grpc_exec_ctx_sched(&exec_ctx, calld->on_done_recv, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(&exec_ctx, calld->on_done_recv, GRPC_ERROR_NONE);
   } else {
     grpc_slice message;
     grpc_transport_stream_op *close_op = gpr_malloc(sizeof(*close_op));
@@ -148,13 +149,13 @@ static void on_md_processing_done(
       calld->transport_op->send_message = NULL;
     }
     calld->transport_op->send_trailing_metadata = NULL;
-    close_op->on_complete = grpc_closure_create(destroy_op, close_op);
-    grpc_transport_stream_op_add_close(close_op, status, &message);
+    close_op->on_complete =
+        grpc_closure_create(destroy_op, close_op, grpc_schedule_on_exec_ctx);
+    grpc_transport_stream_op_add_close(&exec_ctx, close_op, status, &message);
     grpc_call_next_op(&exec_ctx, elem, close_op);
-    grpc_exec_ctx_sched(&exec_ctx, calld->on_done_recv,
-                        grpc_error_set_int(GRPC_ERROR_CREATE(error_details),
-                                           GRPC_ERROR_INT_GRPC_STATUS, status),
-                        NULL);
+    grpc_closure_sched(&exec_ctx, calld->on_done_recv,
+                       grpc_error_set_int(GRPC_ERROR_CREATE(error_details),
+                                          GRPC_ERROR_INT_GRPC_STATUS, status));
   }
 
   grpc_exec_ctx_finish(&exec_ctx);
@@ -174,8 +175,7 @@ static void auth_on_recv(grpc_exec_ctx *exec_ctx, void *user_data,
       return;
     }
   }
-  grpc_exec_ctx_sched(exec_ctx, calld->on_done_recv, GRPC_ERROR_REF(error),
-                      NULL);
+  grpc_closure_sched(exec_ctx, calld->on_done_recv, GRPC_ERROR_REF(error));
 }
 
 static void set_recv_ops_md_callbacks(grpc_call_element *elem,
@@ -214,7 +214,8 @@ static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx,
 
   /* initialize members */
   memset(calld, 0, sizeof(*calld));
-  grpc_closure_init(&calld->auth_on_recv, auth_on_recv, elem);
+  grpc_closure_init(&calld->auth_on_recv, auth_on_recv, elem,
+                    grpc_schedule_on_exec_ctx);
 
   if (args->context[GRPC_CONTEXT_SECURITY].value != NULL) {
     args->context[GRPC_CONTEXT_SECURITY].destroy(
@@ -238,9 +239,9 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
                               void *ignored) {}
 
 /* Constructor for channel_data */
-static void init_channel_elem(grpc_exec_ctx *exec_ctx,
-                              grpc_channel_element *elem,
-                              grpc_channel_element_args *args) {
+static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
+                                     grpc_channel_element *elem,
+                                     grpc_channel_element_args *args) {
   grpc_auth_context *auth_context =
       grpc_find_auth_context_in_args(args->channel_args);
   grpc_server_credentials *creds =
@@ -256,6 +257,7 @@ static void init_channel_elem(grpc_exec_ctx *exec_ctx,
   chand->auth_context =
       GRPC_AUTH_CONTEXT_REF(auth_context, "server_auth_filter");
   chand->creds = grpc_server_credentials_ref(creds);
+  return GRPC_ERROR_NONE;
 }
 
 /* Destructor for channel data */
@@ -264,7 +266,7 @@ static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
   /* grab pointers to our data from the channel element */
   channel_data *chand = elem->channel_data;
   GRPC_AUTH_CONTEXT_UNREF(chand->auth_context, "server_auth_filter");
-  grpc_server_credentials_unref(chand->creds);
+  grpc_server_credentials_unref(exec_ctx, chand->creds);
 }
 
 const grpc_channel_filter grpc_server_auth_filter = {
diff --git a/src/core/lib/security/util/b64.c b/src/core/lib/security/util/b64.c
index 4892e8e621..bbd7e335a6 100644
--- a/src/core/lib/security/util/b64.c
+++ b/src/core/lib/security/util/b64.c
@@ -40,6 +40,8 @@
 #include <grpc/support/log.h>
 #include <grpc/support/useful.h>
 
+#include "src/core/lib/slice/slice_internal.h"
+
 /* --- Constants. --- */
 
 static const int8_t base64_bytes[] = {
@@ -120,8 +122,9 @@ char *grpc_base64_encode(const void *vdata, size_t data_size, int url_safe,
   return result;
 }
 
-grpc_slice grpc_base64_decode(const char *b64, int url_safe) {
-  return grpc_base64_decode_with_len(b64, strlen(b64), url_safe);
+grpc_slice grpc_base64_decode(grpc_exec_ctx *exec_ctx, const char *b64,
+                              int url_safe) {
+  return grpc_base64_decode_with_len(exec_ctx, b64, strlen(b64), url_safe);
 }
 
 static void decode_one_char(const unsigned char *codes, unsigned char *result,
@@ -182,8 +185,8 @@ static int decode_group(const unsigned char *codes, size_t num_codes,
   return 1;
 }
 
-grpc_slice grpc_base64_decode_with_len(const char *b64, size_t b64_len,
-                                       int url_safe) {
+grpc_slice grpc_base64_decode_with_len(grpc_exec_ctx *exec_ctx, const char *b64,
+                                       size_t b64_len, int url_safe) {
   grpc_slice result = grpc_slice_malloc(b64_len);
   unsigned char *current = GRPC_SLICE_START_PTR(result);
   size_t result_size = 0;
@@ -228,6 +231,6 @@ grpc_slice grpc_base64_decode_with_len(const char *b64, size_t b64_len,
   return result;
 
 fail:
-  grpc_slice_unref(result);
+  grpc_slice_unref_internal(exec_ctx, result);
   return gpr_empty_slice();
 }
diff --git a/src/core/lib/security/util/b64.h b/src/core/lib/security/util/b64.h
index 6ea0b5365b..d42a136f61 100644
--- a/src/core/lib/security/util/b64.h
+++ b/src/core/lib/security/util/b64.h
@@ -43,10 +43,11 @@ char *grpc_base64_encode(const void *data, size_t data_size, int url_safe,
 
 /* Decodes data according to the base64 specification. Returns an empty
    slice in case of failure. */
-grpc_slice grpc_base64_decode(const char *b64, int url_safe);
+grpc_slice grpc_base64_decode(grpc_exec_ctx *exec_ctx, const char *b64,
+                              int url_safe);
 
 /* Same as above except that the length is provided by the caller. */
-grpc_slice grpc_base64_decode_with_len(const char *b64, size_t b64_len,
-                                       int url_safe);
+grpc_slice grpc_base64_decode_with_len(grpc_exec_ctx *exec_ctx, const char *b64,
+                                       size_t b64_len, int url_safe);
 
 #endif /* GRPC_CORE_LIB_SECURITY_UTIL_B64_H */
diff --git a/src/core/lib/slice/percent_encoding.c b/src/core/lib/slice/percent_encoding.c
index b9e35f1c71..c76c58d371 100644
--- a/src/core/lib/slice/percent_encoding.c
+++ b/src/core/lib/slice/percent_encoding.c
@@ -35,6 +35,8 @@
 
 #include <grpc/support/log.h>
 
+#include "src/core/lib/slice/slice_internal.h"
+
 const uint8_t grpc_url_percent_encoding_unreserved_bytes[256 / 8] = {
     0x00, 0x00, 0x00, 0x00, 0x00, 0x60, 0xff, 0x03, 0xfe, 0xff, 0xff,
     0x87, 0xfe, 0xff, 0xff, 0x47, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
@@ -66,7 +68,7 @@ grpc_slice grpc_percent_encode_slice(grpc_slice slice,
   }
   // no unreserved bytes: return the string unmodified
   if (!any_reserved_bytes) {
-    return grpc_slice_ref(slice);
+    return grpc_slice_ref_internal(slice);
   }
   // second pass: actually encode
   grpc_slice out = grpc_slice_malloc(output_length);
@@ -119,7 +121,7 @@ bool grpc_strict_percent_decode_slice(grpc_slice slice_in,
     }
   }
   if (!any_percent_encoded_stuff) {
-    *slice_out = grpc_slice_ref(slice_in);
+    *slice_out = grpc_slice_ref_internal(slice_in);
     return true;
   }
   p = GRPC_SLICE_START_PTR(slice_in);
@@ -158,7 +160,7 @@ grpc_slice grpc_permissive_percent_decode_slice(grpc_slice slice_in) {
     }
   }
   if (!any_percent_encoded_stuff) {
-    return grpc_slice_ref(slice_in);
+    return grpc_slice_ref_internal(slice_in);
   }
   p = GRPC_SLICE_START_PTR(slice_in);
   grpc_slice out = grpc_slice_malloc(out_length);
diff --git a/src/core/lib/slice/slice.c b/src/core/lib/slice/slice.c
index 52977e6d9a..76118102ec 100644
--- a/src/core/lib/slice/slice.c
+++ b/src/core/lib/slice/slice.c
@@ -31,12 +31,16 @@
  *
  */
 
+#include "src/core/lib/slice/slice_internal.h"
+
 #include <grpc/slice.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 
 #include <string.h>
 
+#include "src/core/lib/iomgr/exec_ctx.h"
+
 grpc_slice gpr_empty_slice(void) {
   grpc_slice out;
   out.refcount = 0;
@@ -44,25 +48,37 @@ grpc_slice gpr_empty_slice(void) {
   return out;
 }
 
-grpc_slice grpc_slice_ref(grpc_slice slice) {
+grpc_slice grpc_slice_ref_internal(grpc_slice slice) {
   if (slice.refcount) {
     slice.refcount->ref(slice.refcount);
   }
   return slice;
 }
 
-void grpc_slice_unref(grpc_slice slice) {
+void grpc_slice_unref_internal(grpc_exec_ctx *exec_ctx, grpc_slice slice) {
   if (slice.refcount) {
-    slice.refcount->unref(slice.refcount);
+    slice.refcount->unref(exec_ctx, slice.refcount);
   }
 }
 
+/* Public API */
+grpc_slice grpc_slice_ref(grpc_slice slice) {
+  return grpc_slice_ref_internal(slice);
+}
+
+/* Public API */
+void grpc_slice_unref(grpc_slice slice) {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_slice_unref_internal(&exec_ctx, slice);
+  grpc_exec_ctx_finish(&exec_ctx);
+}
+
 /* grpc_slice_from_static_string support structure - a refcount that does
    nothing */
-static void noop_ref_or_unref(void *unused) {}
+static void noop_ref(void *unused) {}
+static void noop_unref(grpc_exec_ctx *exec_ctx, void *unused) {}
 
-static grpc_slice_refcount noop_refcount = {noop_ref_or_unref,
-                                            noop_ref_or_unref};
+static grpc_slice_refcount noop_refcount = {noop_ref, noop_unref};
 
 grpc_slice grpc_slice_from_static_string(const char *s) {
   grpc_slice slice;
@@ -86,7 +102,7 @@ static void new_slice_ref(void *p) {
   gpr_ref(&r->refs);
 }
 
-static void new_slice_unref(void *p) {
+static void new_slice_unref(grpc_exec_ctx *exec_ctx, void *p) {
   new_slice_refcount *r = p;
   if (gpr_unref(&r->refs)) {
     r->user_destroy(r->user_data);
@@ -131,7 +147,7 @@ static void new_with_len_ref(void *p) {
   gpr_ref(&r->refs);
 }
 
-static void new_with_len_unref(void *p) {
+static void new_with_len_unref(grpc_exec_ctx *exec_ctx, void *p) {
   new_with_len_slice_refcount *r = p;
   if (gpr_unref(&r->refs)) {
     r->user_destroy(r->user_data, r->user_length);
@@ -177,7 +193,7 @@ static void malloc_ref(void *p) {
   gpr_ref(&r->refs);
 }
 
-static void malloc_unref(void *p) {
+static void malloc_unref(grpc_exec_ctx *exec_ctx, void *p) {
   malloc_refcount *r = p;
   if (gpr_unref(&r->refs)) {
     gpr_free(r);
diff --git a/src/core/lib/slice/slice_buffer.c b/src/core/lib/slice/slice_buffer.c
index 990ef128bd..08eaf4963a 100644
--- a/src/core/lib/slice/slice_buffer.c
+++ b/src/core/lib/slice/slice_buffer.c
@@ -40,6 +40,8 @@
 #include <grpc/support/log.h>
 #include <grpc/support/useful.h>
 
+#include "src/core/lib/slice/slice_internal.h"
+
 /* grow a buffer; requires GRPC_SLICE_BUFFER_INLINE_ELEMENTS > 1 */
 #define GROW(x) (3 * (x) / 2)
 
@@ -63,13 +65,20 @@ void grpc_slice_buffer_init(grpc_slice_buffer *sb) {
   sb->slices = sb->inlined;
 }
 
-void grpc_slice_buffer_destroy(grpc_slice_buffer *sb) {
-  grpc_slice_buffer_reset_and_unref(sb);
+void grpc_slice_buffer_destroy_internal(grpc_exec_ctx *exec_ctx,
+                                        grpc_slice_buffer *sb) {
+  grpc_slice_buffer_reset_and_unref_internal(exec_ctx, sb);
   if (sb->slices != sb->inlined) {
     gpr_free(sb->slices);
   }
 }
 
+void grpc_slice_buffer_destroy(grpc_slice_buffer *sb) {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_slice_buffer_destroy_internal(&exec_ctx, sb);
+  grpc_exec_ctx_finish(&exec_ctx);
+}
+
 uint8_t *grpc_slice_buffer_tiny_add(grpc_slice_buffer *sb, size_t n) {
   grpc_slice *back;
   uint8_t *out;
@@ -154,17 +163,24 @@ void grpc_slice_buffer_pop(grpc_slice_buffer *sb) {
   }
 }
 
-void grpc_slice_buffer_reset_and_unref(grpc_slice_buffer *sb) {
+void grpc_slice_buffer_reset_and_unref_internal(grpc_exec_ctx *exec_ctx,
+                                                grpc_slice_buffer *sb) {
   size_t i;
 
   for (i = 0; i < sb->count; i++) {
-    grpc_slice_unref(sb->slices[i]);
+    grpc_slice_unref_internal(exec_ctx, sb->slices[i]);
   }
 
   sb->count = 0;
   sb->length = 0;
 }
 
+void grpc_slice_buffer_reset_and_unref(grpc_slice_buffer *sb) {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_slice_buffer_reset_and_unref_internal(&exec_ctx, sb);
+  grpc_exec_ctx_finish(&exec_ctx);
+}
+
 void grpc_slice_buffer_swap(grpc_slice_buffer *a, grpc_slice_buffer *b) {
   GPR_SWAP(size_t, a->count, b->count);
   GPR_SWAP(size_t, a->capacity, b->capacity);
diff --git a/src/core/lib/slice/slice_internal.h b/src/core/lib/slice/slice_internal.h
new file mode 100644
index 0000000000..6185333ca7
--- /dev/null
+++ b/src/core/lib/slice/slice_internal.h
@@ -0,0 +1,49 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_SLICE_SLICE_INTERNAL_H
+#define GRPC_CORE_LIB_SLICE_SLICE_INTERNAL_H
+
+#include <grpc/slice.h>
+#include <grpc/slice_buffer.h>
+
+#include "src/core/lib/iomgr/exec_ctx.h"
+
+grpc_slice grpc_slice_ref_internal(grpc_slice slice);
+void grpc_slice_unref_internal(grpc_exec_ctx *exec_ctx, grpc_slice slice);
+void grpc_slice_buffer_reset_and_unref_internal(grpc_exec_ctx *exec_ctx,
+                                                grpc_slice_buffer *sb);
+void grpc_slice_buffer_destroy_internal(grpc_exec_ctx *exec_ctx,
+                                        grpc_slice_buffer *sb);
+
+#endif /* GRPC_CORE_LIB_SLICE_SLICE_INTERNAL_H */
diff --git a/src/core/lib/slice/slice_string_helpers.c b/src/core/lib/slice/slice_string_helpers.c
index 4731762ece..839c366b32 100644
--- a/src/core/lib/slice/slice_string_helpers.c
+++ b/src/core/lib/slice/slice_string_helpers.c
@@ -37,6 +37,7 @@
 
 #include <grpc/support/log.h>
 
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/support/string.h"
 
 char *grpc_dump_slice(grpc_slice s, uint32_t flags) {
@@ -84,6 +85,6 @@ void grpc_slice_split(grpc_slice str, const char *sep, grpc_slice_buffer *dst) {
     grpc_slice_buffer_add_indexed(
         dst, grpc_slice_sub(str, end + sep_len, GRPC_SLICE_LENGTH(str)));
   } else { /* no sep found, add whole input */
-    grpc_slice_buffer_add_indexed(dst, grpc_slice_ref(str));
+    grpc_slice_buffer_add_indexed(dst, grpc_slice_ref_internal(str));
   }
 }
diff --git a/src/core/lib/support/backoff.c b/src/core/lib/support/backoff.c
index e89ef47220..0612472712 100644
--- a/src/core/lib/support/backoff.c
+++ b/src/core/lib/support/backoff.c
@@ -35,8 +35,10 @@
 
 #include <grpc/support/useful.h>
 
-void gpr_backoff_init(gpr_backoff *backoff, double multiplier, double jitter,
+void gpr_backoff_init(gpr_backoff *backoff, int64_t initial_connect_timeout,
+                      double multiplier, double jitter,
                       int64_t min_timeout_millis, int64_t max_timeout_millis) {
+  backoff->initial_connect_timeout = initial_connect_timeout;
   backoff->multiplier = multiplier;
   backoff->jitter = jitter;
   backoff->min_timeout_millis = min_timeout_millis;
@@ -45,9 +47,10 @@ void gpr_backoff_init(gpr_backoff *backoff, double multiplier, double jitter,
 }
 
 gpr_timespec gpr_backoff_begin(gpr_backoff *backoff, gpr_timespec now) {
-  backoff->current_timeout_millis = backoff->min_timeout_millis;
-  return gpr_time_add(
-      now, gpr_time_from_millis(backoff->current_timeout_millis, GPR_TIMESPAN));
+  backoff->current_timeout_millis = backoff->initial_connect_timeout;
+  const int64_t first_timeout =
+      GPR_MAX(backoff->current_timeout_millis, backoff->min_timeout_millis);
+  return gpr_time_add(now, gpr_time_from_millis(first_timeout, GPR_TIMESPAN));
 }
 
 /* Generate a random number between 0 and 1. */
@@ -57,20 +60,28 @@ static double generate_uniform_random_number(uint32_t *rng_state) {
 }
 
 gpr_timespec gpr_backoff_step(gpr_backoff *backoff, gpr_timespec now) {
-  double new_timeout_millis =
+  const double new_timeout_millis =
       backoff->multiplier * (double)backoff->current_timeout_millis;
-  double jitter_range = backoff->jitter * new_timeout_millis;
-  double jitter =
+  backoff->current_timeout_millis =
+      GPR_MIN((int64_t)new_timeout_millis, backoff->max_timeout_millis);
+
+  const double jitter_range_width = backoff->jitter * new_timeout_millis;
+  const double jitter =
       (2 * generate_uniform_random_number(&backoff->rng_state) - 1) *
-      jitter_range;
+      jitter_range_width;
+
   backoff->current_timeout_millis =
-      GPR_CLAMP((int64_t)(new_timeout_millis + jitter),
-                backoff->min_timeout_millis, backoff->max_timeout_millis);
-  return gpr_time_add(
+      (int64_t)((double)(backoff->current_timeout_millis) + jitter);
+
+  const gpr_timespec current_deadline = gpr_time_add(
       now, gpr_time_from_millis(backoff->current_timeout_millis, GPR_TIMESPAN));
+
+  const gpr_timespec min_deadline = gpr_time_add(
+      now, gpr_time_from_millis(backoff->min_timeout_millis, GPR_TIMESPAN));
+
+  return gpr_time_max(current_deadline, min_deadline);
 }
 
 void gpr_backoff_reset(gpr_backoff *backoff) {
-  // forces step() to return a timeout of min_timeout_millis
-  backoff->current_timeout_millis = 0;
+  backoff->current_timeout_millis = backoff->initial_connect_timeout;
 }
diff --git a/src/core/lib/support/backoff.h b/src/core/lib/support/backoff.h
index 6d40c15546..5e9b740824 100644
--- a/src/core/lib/support/backoff.h
+++ b/src/core/lib/support/backoff.h
@@ -37,7 +37,9 @@
 #include <grpc/support/time.h>
 
 typedef struct {
-  /// const: multiplier between retry attempts
+  /// const:  how long to wait after the first failure before retrying
+  int64_t initial_connect_timeout;
+  /// const: factor with which to multiply backoff after a failed retry
   double multiplier;
   /// const: amount to randomize backoffs
   double jitter;
@@ -54,7 +56,8 @@ typedef struct {
 } gpr_backoff;
 
 /// Initialize backoff machinery - does not need to be destroyed
-void gpr_backoff_init(gpr_backoff *backoff, double multiplier, double jitter,
+void gpr_backoff_init(gpr_backoff *backoff, int64_t initial_connect_timeout,
+                      double multiplier, double jitter,
                       int64_t min_timeout_millis, int64_t max_timeout_millis);
 
 /// Begin retry loop: returns a timespec for the NEXT retry
diff --git a/src/core/lib/support/string.c b/src/core/lib/support/string.c
index f10a30f0fd..d20b86f7cf 100644
--- a/src/core/lib/support/string.c
+++ b/src/core/lib/support/string.c
@@ -275,3 +275,41 @@ int gpr_stricmp(const char *a, const char *b) {
   } while (ca == cb && ca && cb);
   return ca - cb;
 }
+
+static void add_string_to_split(const char *beg, const char *end, char ***strs,
+                                size_t *nstrs, size_t *capstrs) {
+  char *out = gpr_malloc((size_t)(end - beg) + 1);
+  memcpy(out, beg, (size_t)(end - beg));
+  out[end - beg] = 0;
+  if (*nstrs == *capstrs) {
+    *capstrs = GPR_MAX(8, 2 * *capstrs);
+    *strs = gpr_realloc(*strs, sizeof(*strs) * *capstrs);
+  }
+  (*strs)[*nstrs] = out;
+  ++*nstrs;
+}
+
+void gpr_string_split(const char *input, const char *sep, char ***strs,
+                      size_t *nstrs) {
+  char *next;
+  *strs = NULL;
+  *nstrs = 0;
+  size_t capstrs = 0;
+  while ((next = strstr(input, sep))) {
+    add_string_to_split(input, next, strs, nstrs, &capstrs);
+    input = next + strlen(sep);
+  }
+  add_string_to_split(input, input + strlen(input), strs, nstrs, &capstrs);
+}
+
+void *gpr_memrchr(const void *s, int c, size_t n) {
+  if (s == NULL) return NULL;
+  char *b = (char *)s;
+  size_t i;
+  for (i = 0; i < n; i++) {
+    if (b[n - i - 1] == c) {
+      return &b[n - i - 1];
+    }
+  }
+  return NULL;
+}
diff --git a/src/core/lib/support/string.h b/src/core/lib/support/string.h
index e933e2eb46..d1c52faed4 100644
--- a/src/core/lib/support/string.h
+++ b/src/core/lib/support/string.h
@@ -36,8 +36,6 @@
 
 #include <stddef.h>
 
-#include <grpc/slice.h>
-#include <grpc/slice_buffer.h>
 #include <grpc/support/port_platform.h>
 
 #ifdef __cplusplus
@@ -98,6 +96,9 @@ char *gpr_strjoin(const char **strs, size_t nstrs, size_t *total_length);
 char *gpr_strjoin_sep(const char **strs, size_t nstrs, const char *sep,
                       size_t *total_length);
 
+void gpr_string_split(const char *input, const char *sep, char ***strs,
+                      size_t *nstrs);
+
 /* A vector of strings... for building up a final string one piece at a time */
 typedef struct {
   char **strs;
@@ -118,6 +119,8 @@ char *gpr_strvec_flatten(gpr_strvec *strs, size_t *total_length);
     lower(a)==lower(b), >0 if lower(a)>lower(b) */
 int gpr_stricmp(const char *a, const char *b);
 
+void *gpr_memrchr(const void *s, int c, size_t n);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/core/lib/support/tmpfile.h b/src/core/lib/support/tmpfile.h
index 8952e5ec3d..f613cf9bc8 100644
--- a/src/core/lib/support/tmpfile.h
+++ b/src/core/lib/support/tmpfile.h
@@ -36,8 +36,6 @@
 
 #include <stdio.h>
 
-#include <grpc/slice.h>
-
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/src/core/lib/surface/README.md b/src/core/lib/surface/README.md
new file mode 100644
index 0000000000..74cbd71131
--- /dev/null
+++ b/src/core/lib/surface/README.md
@@ -0,0 +1,4 @@
+# Surface
+
+Surface provides the bulk of the gRPC Core public API, and translates it into
+calls against core components.
diff --git a/src/core/lib/surface/alarm.c b/src/core/lib/surface/alarm.c
index aa9d60ee6a..e71c0ebfc5 100644
--- a/src/core/lib/surface/alarm.c
+++ b/src/core/lib/surface/alarm.c
@@ -38,6 +38,7 @@
 
 struct grpc_alarm {
   grpc_timer alarm;
+  grpc_closure on_alarm;
   grpc_cq_completion completion;
   /** completion queue where events about this alarm will be posted */
   grpc_completion_queue *cq;
@@ -64,9 +65,11 @@ grpc_alarm *grpc_alarm_create(grpc_completion_queue *cq, gpr_timespec deadline,
   alarm->tag = tag;
 
   grpc_cq_begin_op(cq, tag);
+  grpc_closure_init(&alarm->on_alarm, alarm_cb, alarm,
+                    grpc_schedule_on_exec_ctx);
   grpc_timer_init(&exec_ctx, &alarm->alarm,
                   gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC),
-                  alarm_cb, alarm, gpr_now(GPR_CLOCK_MONOTONIC));
+                  &alarm->on_alarm, gpr_now(GPR_CLOCK_MONOTONIC));
   grpc_exec_ctx_finish(&exec_ctx);
   return alarm;
 }
diff --git a/src/core/lib/surface/byte_buffer.c b/src/core/lib/surface/byte_buffer.c
index d646591a65..c8e2fdfdad 100644
--- a/src/core/lib/surface/byte_buffer.c
+++ b/src/core/lib/surface/byte_buffer.c
@@ -35,6 +35,8 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 
+#include "src/core/lib/slice/slice_internal.h"
+
 grpc_byte_buffer *grpc_raw_byte_buffer_create(grpc_slice *slices,
                                               size_t nslices) {
   return grpc_raw_compressed_byte_buffer_create(slices, nslices,
@@ -50,7 +52,7 @@ grpc_byte_buffer *grpc_raw_compressed_byte_buffer_create(
   bb->data.raw.compression = compression;
   grpc_slice_buffer_init(&bb->data.raw.slice_buffer);
   for (i = 0; i < nslices; i++) {
-    grpc_slice_ref(slices[i]);
+    grpc_slice_ref_internal(slices[i]);
     grpc_slice_buffer_add(&bb->data.raw.slice_buffer, slices[i]);
   }
   return bb;
@@ -82,12 +84,14 @@ grpc_byte_buffer *grpc_byte_buffer_copy(grpc_byte_buffer *bb) {
 
 void grpc_byte_buffer_destroy(grpc_byte_buffer *bb) {
   if (!bb) return;
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   switch (bb->type) {
     case GRPC_BB_RAW:
-      grpc_slice_buffer_destroy(&bb->data.raw.slice_buffer);
+      grpc_slice_buffer_destroy_internal(&exec_ctx, &bb->data.raw.slice_buffer);
       break;
   }
   gpr_free(bb);
+  grpc_exec_ctx_finish(&exec_ctx);
 }
 
 size_t grpc_byte_buffer_length(grpc_byte_buffer *bb) {
diff --git a/src/core/lib/surface/byte_buffer_reader.c b/src/core/lib/surface/byte_buffer_reader.c
index 0089959fbb..1a6ccdaddb 100644
--- a/src/core/lib/surface/byte_buffer_reader.c
+++ b/src/core/lib/surface/byte_buffer_reader.c
@@ -42,6 +42,7 @@
 #include <grpc/support/log.h>
 
 #include "src/core/lib/compression/message_compress.h"
+#include "src/core/lib/slice/slice_internal.h"
 
 static int is_compressed(grpc_byte_buffer *buffer) {
   switch (buffer->type) {
@@ -56,13 +57,15 @@ static int is_compressed(grpc_byte_buffer *buffer) {
 
 int grpc_byte_buffer_reader_init(grpc_byte_buffer_reader *reader,
                                  grpc_byte_buffer *buffer) {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_slice_buffer decompressed_slices_buffer;
   reader->buffer_in = buffer;
   switch (reader->buffer_in->type) {
     case GRPC_BB_RAW:
       grpc_slice_buffer_init(&decompressed_slices_buffer);
       if (is_compressed(reader->buffer_in)) {
-        if (grpc_msg_decompress(reader->buffer_in->data.raw.compression,
+        if (grpc_msg_decompress(&exec_ctx,
+                                reader->buffer_in->data.raw.compression,
                                 &reader->buffer_in->data.raw.slice_buffer,
                                 &decompressed_slices_buffer) == 0) {
           gpr_log(GPR_ERROR,
@@ -76,13 +79,15 @@ int grpc_byte_buffer_reader_init(grpc_byte_buffer_reader *reader,
               grpc_raw_byte_buffer_create(decompressed_slices_buffer.slices,
                                           decompressed_slices_buffer.count);
         }
-        grpc_slice_buffer_destroy(&decompressed_slices_buffer);
+        grpc_slice_buffer_destroy_internal(&exec_ctx,
+                                           &decompressed_slices_buffer);
       } else { /* not compressed, use the input buffer as output */
         reader->buffer_out = reader->buffer_in;
       }
       reader->current.index = 0;
       break;
   }
+  grpc_exec_ctx_finish(&exec_ctx);
   return 1;
 }
 
@@ -104,7 +109,8 @@ int grpc_byte_buffer_reader_next(grpc_byte_buffer_reader *reader,
       grpc_slice_buffer *slice_buffer;
       slice_buffer = &reader->buffer_out->data.raw.slice_buffer;
       if (reader->current.index < slice_buffer->count) {
-        *slice = grpc_slice_ref(slice_buffer->slices[reader->current.index]);
+        *slice = grpc_slice_ref_internal(
+            slice_buffer->slices[reader->current.index]);
         reader->current.index += 1;
         return 1;
       }
@@ -121,12 +127,14 @@ grpc_slice grpc_byte_buffer_reader_readall(grpc_byte_buffer_reader *reader) {
   grpc_slice out_slice = grpc_slice_malloc(input_size);
   uint8_t *const outbuf = GRPC_SLICE_START_PTR(out_slice); /* just an alias */
 
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   while (grpc_byte_buffer_reader_next(reader, &in_slice) != 0) {
     const size_t slice_length = GRPC_SLICE_LENGTH(in_slice);
     memcpy(&(outbuf[bytes_read]), GRPC_SLICE_START_PTR(in_slice), slice_length);
     bytes_read += slice_length;
-    grpc_slice_unref(in_slice);
+    grpc_slice_unref_internal(&exec_ctx, in_slice);
     GPR_ASSERT(bytes_read <= input_size);
   }
+  grpc_exec_ctx_finish(&exec_ctx);
   return out_slice;
 }
diff --git a/src/core/lib/surface/call.c b/src/core/lib/surface/call.c
index 1e0f3eeca5..899e8fab3f 100644
--- a/src/core/lib/surface/call.c
+++ b/src/core/lib/surface/call.c
@@ -49,6 +49,7 @@
 #include "src/core/lib/compression/algorithm_metadata.h"
 #include "src/core/lib/iomgr/timer.h"
 #include "src/core/lib/profiling/timers.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/surface/api_trace.h"
@@ -226,12 +227,12 @@ static void destroy_call(grpc_exec_ctx *exec_ctx, void *call_stack,
 static void receiving_slice_ready(grpc_exec_ctx *exec_ctx, void *bctlp,
                                   grpc_error *error);
 
-grpc_error *grpc_call_create(const grpc_call_create_args *args,
+grpc_error *grpc_call_create(grpc_exec_ctx *exec_ctx,
+                             const grpc_call_create_args *args,
                              grpc_call **out_call) {
   size_t i, j;
   grpc_channel_stack *channel_stack =
       grpc_channel_get_channel_stack(args->channel);
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_call *call;
   GPR_TIMER_BEGIN("grpc_call_create", 0);
   call = gpr_malloc(sizeof(grpc_call) + channel_stack->call_stack_size);
@@ -315,14 +316,14 @@ grpc_error *grpc_call_create(const grpc_call_create_args *args,
   GRPC_CHANNEL_INTERNAL_REF(args->channel, "call");
   /* initial refcount dropped by grpc_call_destroy */
   grpc_error *error = grpc_call_stack_init(
-      &exec_ctx, channel_stack, 1, destroy_call, call, call->context,
+      exec_ctx, channel_stack, 1, destroy_call, call, call->context,
       args->server_transport_data, path, call->start_time, send_deadline,
       CALL_STACK_FROM_CALL(call));
   if (error != GRPC_ERROR_NONE) {
     grpc_status_code status;
     const char *error_str;
     grpc_error_get_status(error, &status, &error_str);
-    close_with_status(&exec_ctx, call, status, error_str);
+    close_with_status(exec_ctx, call, status, error_str);
   }
   if (args->cq != NULL) {
     GPR_ASSERT(
@@ -338,12 +339,11 @@ grpc_error *grpc_call_create(const grpc_call_create_args *args,
   }
   if (!grpc_polling_entity_is_empty(&call->pollent)) {
     grpc_call_stack_set_pollset_or_pollset_set(
-        &exec_ctx, CALL_STACK_FROM_CALL(call), &call->pollent);
+        exec_ctx, CALL_STACK_FROM_CALL(call), &call->pollent);
   }
 
-  if (path != NULL) GRPC_MDSTR_UNREF(path);
+  if (path != NULL) GRPC_MDSTR_UNREF(exec_ctx, path);
 
-  grpc_exec_ctx_finish(&exec_ctx);
   GPR_TIMER_END("grpc_call_create", 0);
   return error;
 }
@@ -404,7 +404,7 @@ static void destroy_call(grpc_exec_ctx *exec_ctx, void *call,
   GPR_TIMER_BEGIN("destroy_call", 0);
   for (i = 0; i < 2; i++) {
     grpc_metadata_batch_destroy(
-        &c->metadata_batch[1 /* is_receiving */][i /* is_initial */]);
+        exec_ctx, &c->metadata_batch[1 /* is_receiving */][i /* is_initial */]);
   }
   if (c->receiving_stream != NULL) {
     grpc_byte_stream_destroy(exec_ctx, c->receiving_stream);
@@ -412,11 +412,11 @@ static void destroy_call(grpc_exec_ctx *exec_ctx, void *call,
   gpr_mu_destroy(&c->mu);
   for (i = 0; i < STATUS_SOURCE_COUNT; i++) {
     if (c->status[i].details) {
-      GRPC_MDSTR_UNREF(c->status[i].details);
+      GRPC_MDSTR_UNREF(exec_ctx, c->status[i].details);
     }
   }
   for (ii = 0; ii < c->send_extra_metadata_count; ii++) {
-    GRPC_MDELEM_UNREF(c->send_extra_metadata[ii].md);
+    GRPC_MDELEM_UNREF(exec_ctx, c->send_extra_metadata[ii].md);
   }
   for (i = 0; i < GRPC_CONTEXT_COUNT; i++) {
     if (c->context[i].destroy) {
@@ -446,22 +446,22 @@ static void set_status_code(grpc_call *call, status_source source,
   call->status[source].code = (grpc_status_code)status;
 }
 
-static void set_status_details(grpc_call *call, status_source source,
-                               grpc_mdstr *status) {
+static void set_status_details(grpc_exec_ctx *exec_ctx, grpc_call *call,
+                               status_source source, grpc_mdstr *status) {
   if (call->status[source].details != NULL) {
-    GRPC_MDSTR_UNREF(status);
+    GRPC_MDSTR_UNREF(exec_ctx, status);
   } else {
     call->status[source].details = status;
   }
 }
 
-static void set_status_from_error(grpc_call *call, status_source source,
-                                  grpc_error *error) {
+static void set_status_from_error(grpc_exec_ctx *exec_ctx, grpc_call *call,
+                                  status_source source, grpc_error *error) {
   grpc_status_code status;
   const char *msg;
   grpc_error_get_status(error, &status, &msg);
   set_status_code(call, source, (uint32_t)status);
-  set_status_details(call, source, grpc_mdstr_from_string(msg));
+  set_status_details(exec_ctx, call, source, grpc_mdstr_from_string(msg));
 }
 
 static void set_incoming_compression_algorithm(
@@ -495,7 +495,8 @@ uint32_t grpc_call_test_only_get_message_flags(grpc_call *call) {
 
 static void destroy_encodings_accepted_by_peer(void *p) { return; }
 
-static void set_encodings_accepted_by_peer(grpc_call *call, grpc_mdelem *mdel) {
+static void set_encodings_accepted_by_peer(grpc_exec_ctx *exec_ctx,
+                                           grpc_call *call, grpc_mdelem *mdel) {
   size_t i;
   grpc_compression_algorithm algorithm;
   grpc_slice_buffer accept_encoding_parts;
@@ -535,7 +536,7 @@ static void set_encodings_accepted_by_peer(grpc_call *call, grpc_mdelem *mdel) {
     }
   }
 
-  grpc_slice_buffer_destroy(&accept_encoding_parts);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &accept_encoding_parts);
 
   grpc_mdelem_set_user_data(
       mdel, destroy_encodings_accepted_by_peer,
@@ -593,12 +594,10 @@ static grpc_metadata *get_md_elem(grpc_metadata *metadata,
   return res;
 }
 
-static int prepare_application_metadata(grpc_call *call, int count,
-                                        grpc_metadata *metadata,
-                                        int is_trailing,
-                                        int prepend_extra_metadata,
-                                        grpc_metadata *additional_metadata,
-                                        int additional_metadata_count) {
+static int prepare_application_metadata(
+    grpc_exec_ctx *exec_ctx, grpc_call *call, int count,
+    grpc_metadata *metadata, int is_trailing, int prepend_extra_metadata,
+    grpc_metadata *additional_metadata, int additional_metadata_count) {
   int total_count = count + additional_metadata_count;
   int i;
   grpc_metadata_batch *batch =
@@ -609,7 +608,7 @@ static int prepare_application_metadata(grpc_call *call, int count,
     grpc_linked_mdelem *l = (grpc_linked_mdelem *)&md->internal_data;
     GPR_ASSERT(sizeof(grpc_linked_mdelem) == sizeof(md->internal_data));
     l->md = grpc_mdelem_from_string_and_buffer(
-        md->key, (const uint8_t *)md->value, md->value_length);
+        exec_ctx, md->key, (const uint8_t *)md->value, md->value_length);
     if (!grpc_header_key_is_legal(grpc_mdstr_as_c_string(l->md->key),
                                   GRPC_MDSTR_LENGTH(l->md->key))) {
       gpr_log(GPR_ERROR, "attempt to send invalid metadata key: %s",
@@ -629,7 +628,7 @@ static int prepare_application_metadata(grpc_call *call, int count,
       const grpc_metadata *md =
           get_md_elem(metadata, additional_metadata, j, count);
       grpc_linked_mdelem *l = (grpc_linked_mdelem *)&md->internal_data;
-      GRPC_MDELEM_UNREF(l->md);
+      GRPC_MDELEM_UNREF(exec_ctx, l->md);
     }
     return 0;
   }
@@ -794,7 +793,8 @@ static void send_cancel(grpc_exec_ctx *exec_ctx, void *tcp, grpc_error *error) {
   memset(&tc->op, 0, sizeof(tc->op));
   tc->op.cancel_error = tc->error;
   /* reuse closure to catch completion */
-  grpc_closure_init(&tc->closure, done_termination, tc);
+  grpc_closure_init(&tc->closure, done_termination, tc,
+                    grpc_schedule_on_exec_ctx);
   tc->op.on_complete = &tc->closure;
   execute_op(exec_ctx, tc->call, &tc->op);
 }
@@ -804,23 +804,25 @@ static void send_close(grpc_exec_ctx *exec_ctx, void *tcp, grpc_error *error) {
   memset(&tc->op, 0, sizeof(tc->op));
   tc->op.close_error = tc->error;
   /* reuse closure to catch completion */
-  grpc_closure_init(&tc->closure, done_termination, tc);
+  grpc_closure_init(&tc->closure, done_termination, tc,
+                    grpc_schedule_on_exec_ctx);
   tc->op.on_complete = &tc->closure;
   execute_op(exec_ctx, tc->call, &tc->op);
 }
 
 static grpc_call_error terminate_with_status(grpc_exec_ctx *exec_ctx,
                                              termination_closure *tc) {
-  set_status_from_error(tc->call, STATUS_FROM_API_OVERRIDE, tc->error);
+  set_status_from_error(exec_ctx, tc->call, STATUS_FROM_API_OVERRIDE,
+                        tc->error);
 
   if (tc->type == TC_CANCEL) {
-    grpc_closure_init(&tc->closure, send_cancel, tc);
+    grpc_closure_init(&tc->closure, send_cancel, tc, grpc_schedule_on_exec_ctx);
     GRPC_CALL_INTERNAL_REF(tc->call, "cancel");
   } else if (tc->type == TC_CLOSE) {
-    grpc_closure_init(&tc->closure, send_close, tc);
+    grpc_closure_init(&tc->closure, send_close, tc, grpc_schedule_on_exec_ctx);
     GRPC_CALL_INTERNAL_REF(tc->call, "close");
   }
-  grpc_exec_ctx_sched(exec_ctx, &tc->closure, GRPC_ERROR_NONE, NULL);
+  grpc_closure_sched(exec_ctx, &tc->closure, GRPC_ERROR_NONE);
   return GRPC_CALL_OK;
 }
 
@@ -928,7 +930,8 @@ static grpc_compression_algorithm decode_compression(grpc_mdelem *md) {
   return algorithm;
 }
 
-static grpc_mdelem *recv_common_filter(grpc_call *call, grpc_mdelem *elem) {
+static grpc_mdelem *recv_common_filter(grpc_exec_ctx *exec_ctx, grpc_call *call,
+                                       grpc_mdelem *elem) {
   if (elem->key == GRPC_MDSTR_GRPC_STATUS) {
     GPR_TIMER_BEGIN("status", 0);
     set_status_code(call, STATUS_FROM_WIRE, decode_status(elem));
@@ -936,7 +939,8 @@ static grpc_mdelem *recv_common_filter(grpc_call *call, grpc_mdelem *elem) {
     return NULL;
   } else if (elem->key == GRPC_MDSTR_GRPC_MESSAGE) {
     GPR_TIMER_BEGIN("status-details", 0);
-    set_status_details(call, STATUS_FROM_WIRE, GRPC_MDSTR_REF(elem->value));
+    set_status_details(exec_ctx, call, STATUS_FROM_WIRE,
+                       GRPC_MDSTR_REF(elem->value));
     GPR_TIMER_END("status-details", 0);
     return NULL;
   }
@@ -962,9 +966,10 @@ static grpc_mdelem *publish_app_metadata(grpc_call *call, grpc_mdelem *elem,
   return elem;
 }
 
-static grpc_mdelem *recv_initial_filter(void *callp, grpc_mdelem *elem) {
-  grpc_call *call = callp;
-  elem = recv_common_filter(call, elem);
+static grpc_mdelem *recv_initial_filter(grpc_exec_ctx *exec_ctx, void *args,
+                                        grpc_mdelem *elem) {
+  grpc_call *call = args;
+  elem = recv_common_filter(exec_ctx, call, elem);
   if (elem == NULL) {
     return NULL;
   } else if (elem->key == GRPC_MDSTR_GRPC_ENCODING) {
@@ -974,7 +979,7 @@ static grpc_mdelem *recv_initial_filter(void *callp, grpc_mdelem *elem) {
     return NULL;
   } else if (elem->key == GRPC_MDSTR_GRPC_ACCEPT_ENCODING) {
     GPR_TIMER_BEGIN("encodings_accepted_by_peer", 0);
-    set_encodings_accepted_by_peer(call, elem);
+    set_encodings_accepted_by_peer(exec_ctx, call, elem);
     GPR_TIMER_END("encodings_accepted_by_peer", 0);
     return NULL;
   } else {
@@ -982,9 +987,10 @@ static grpc_mdelem *recv_initial_filter(void *callp, grpc_mdelem *elem) {
   }
 }
 
-static grpc_mdelem *recv_trailing_filter(void *callp, grpc_mdelem *elem) {
-  grpc_call *call = callp;
-  elem = recv_common_filter(call, elem);
+static grpc_mdelem *recv_trailing_filter(grpc_exec_ctx *exec_ctx, void *args,
+                                         grpc_mdelem *elem) {
+  grpc_call *call = args;
+  elem = recv_common_filter(exec_ctx, call, elem);
   if (elem == NULL) {
     return NULL;
   } else {
@@ -1138,8 +1144,8 @@ static void process_data_after_md(grpc_exec_ctx *exec_ctx,
     } else {
       *call->receiving_buffer = grpc_raw_byte_buffer_create(NULL, 0);
     }
-    grpc_closure_init(&call->receiving_slice_ready, receiving_slice_ready,
-                      bctl);
+    grpc_closure_init(&call->receiving_slice_ready, receiving_slice_ready, bctl,
+                      grpc_schedule_on_exec_ctx);
     continue_receiving_slices(exec_ctx, bctl);
   }
 }
@@ -1234,7 +1240,7 @@ static void receiving_initial_metadata_ready(grpc_exec_ctx *exec_ctx,
   if (error == GRPC_ERROR_NONE) {
     grpc_metadata_batch *md =
         &call->metadata_batch[1 /* is_receiving */][0 /* is_trailing */];
-    grpc_metadata_batch_filter(md, recv_initial_filter, call);
+    grpc_metadata_batch_filter(exec_ctx, md, recv_initial_filter, call);
 
     GPR_TIMER_BEGIN("validate_filtered_metadata", 0);
     validate_filtered_metadata(exec_ctx, bctl);
@@ -1251,9 +1257,10 @@ static void receiving_initial_metadata_ready(grpc_exec_ctx *exec_ctx,
   call->has_initial_md_been_received = true;
   if (call->saved_receiving_stream_ready_bctlp != NULL) {
     grpc_closure *saved_rsr_closure = grpc_closure_create(
-        receiving_stream_ready, call->saved_receiving_stream_ready_bctlp);
+        receiving_stream_ready, call->saved_receiving_stream_ready_bctlp,
+        grpc_schedule_on_exec_ctx);
     call->saved_receiving_stream_ready_bctlp = NULL;
-    grpc_exec_ctx_sched(exec_ctx, saved_rsr_closure, error, NULL);
+    grpc_closure_sched(exec_ctx, saved_rsr_closure, error);
   }
 
   gpr_mu_unlock(&call->mu);
@@ -1278,14 +1285,15 @@ static void finish_batch(grpc_exec_ctx *exec_ctx, void *bctlp,
   intptr_t status;
   if (error != GRPC_ERROR_NONE &&
       grpc_error_get_int(error, GRPC_ERROR_INT_GRPC_STATUS, &status)) {
-    set_status_from_error(call, STATUS_FROM_CORE, error);
+    set_status_from_error(exec_ctx, call, STATUS_FROM_CORE, error);
   }
 
   if (bctl->send_initial_metadata) {
     if (error != GRPC_ERROR_NONE) {
-      set_status_from_error(call, STATUS_FROM_CORE, error);
+      set_status_from_error(exec_ctx, call, STATUS_FROM_CORE, error);
     }
     grpc_metadata_batch_destroy(
+        exec_ctx,
         &call->metadata_batch[0 /* is_receiving */][0 /* is_trailing */]);
   }
   if (bctl->send_message) {
@@ -1293,12 +1301,13 @@ static void finish_batch(grpc_exec_ctx *exec_ctx, void *bctlp,
   }
   if (bctl->send_final_op) {
     grpc_metadata_batch_destroy(
+        exec_ctx,
         &call->metadata_batch[0 /* is_receiving */][1 /* is_trailing */]);
   }
   if (bctl->recv_final_op) {
     grpc_metadata_batch *md =
         &call->metadata_batch[1 /* is_receiving */][1 /* is_trailing */];
-    grpc_metadata_batch_filter(md, recv_trailing_filter, call);
+    grpc_metadata_batch_filter(exec_ctx, md, recv_trailing_filter, call);
 
     call->received_final_op = true;
     /* propagate cancellation to any interested children */
@@ -1435,7 +1444,7 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
         bctl->send_initial_metadata = 1;
         call->sent_initial_metadata = 1;
         if (!prepare_application_metadata(
-                call, (int)op->data.send_initial_metadata.count,
+                exec_ctx, call, (int)op->data.send_initial_metadata.count,
                 op->data.send_initial_metadata.metadata, 0, call->is_client,
                 &compression_md, (int)additional_metadata_count)) {
           error = GRPC_CALL_ERROR_INVALID_METADATA;
@@ -1515,15 +1524,15 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
         call->sent_final_op = 1;
         call->send_extra_metadata_count = 1;
         call->send_extra_metadata[0].md = grpc_channel_get_reffed_status_elem(
-            call->channel, op->data.send_status_from_server.status);
+            exec_ctx, call->channel, op->data.send_status_from_server.status);
         if (op->data.send_status_from_server.status_details != NULL) {
           call->send_extra_metadata[1].md = grpc_mdelem_from_metadata_strings(
-              GRPC_MDSTR_GRPC_MESSAGE,
+              exec_ctx, GRPC_MDSTR_GRPC_MESSAGE,
               grpc_mdstr_from_string(
                   op->data.send_status_from_server.status_details));
           call->send_extra_metadata_count++;
           set_status_details(
-              call, STATUS_FROM_API_OVERRIDE,
+              exec_ctx, call, STATUS_FROM_API_OVERRIDE,
               GRPC_MDSTR_REF(call->send_extra_metadata[1].md->value));
         }
         if (op->data.send_status_from_server.status != GRPC_STATUS_OK) {
@@ -1531,7 +1540,7 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
                           (uint32_t)op->data.send_status_from_server.status);
         }
         if (!prepare_application_metadata(
-                call,
+                exec_ctx, call,
                 (int)op->data.send_status_from_server.trailing_metadata_count,
                 op->data.send_status_from_server.trailing_metadata, 1, 1, NULL,
                 0)) {
@@ -1551,10 +1560,15 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
           error = GRPC_CALL_ERROR_TOO_MANY_OPERATIONS;
           goto done_with_error;
         }
+        /* IF this is a server, then GRPC_OP_RECV_INITIAL_METADATA *must* come
+           from server.c. In that case, it's coming from accept_stream, and in
+           that case we're not necessarily covered by a poller. */
+        stream_op->covered_by_poller = call->is_client;
         call->received_initial_metadata = 1;
         call->buffered_metadata[0] = op->data.recv_initial_metadata;
         grpc_closure_init(&call->receiving_initial_metadata_ready,
-                          receiving_initial_metadata_ready, bctl);
+                          receiving_initial_metadata_ready, bctl,
+                          grpc_schedule_on_exec_ctx);
         bctl->recv_initial_metadata = 1;
         stream_op->recv_initial_metadata =
             &call->metadata_batch[1 /* is_receiving */][0 /* is_trailing */];
@@ -1577,7 +1591,7 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
         call->receiving_buffer = op->data.recv_message;
         stream_op->recv_message = &call->receiving_stream;
         grpc_closure_init(&call->receiving_stream_ready, receiving_stream_ready,
-                          bctl);
+                          bctl, grpc_schedule_on_exec_ctx);
         stream_op->recv_message_ready = &call->receiving_stream_ready;
         num_completion_callbacks_needed++;
         break;
@@ -1642,7 +1656,8 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
   gpr_ref_init(&bctl->steps_to_complete, num_completion_callbacks_needed);
 
   stream_op->context = call->context;
-  grpc_closure_init(&bctl->finish_batch, finish_batch, bctl);
+  grpc_closure_init(&bctl->finish_batch, finish_batch, bctl,
+                    grpc_schedule_on_exec_ctx);
   stream_op->on_complete = &bctl->finish_batch;
   gpr_mu_unlock(&call->mu);
 
@@ -1656,7 +1671,7 @@ done_with_error:
   /* reverse any mutations that occured */
   if (bctl->send_initial_metadata) {
     call->sent_initial_metadata = 0;
-    grpc_metadata_batch_clear(&call->metadata_batch[0][0]);
+    grpc_metadata_batch_clear(exec_ctx, &call->metadata_batch[0][0]);
   }
   if (bctl->send_message) {
     call->sending_message = 0;
@@ -1664,7 +1679,7 @@ done_with_error:
   }
   if (bctl->send_final_op) {
     call->sent_final_op = 0;
-    grpc_metadata_batch_clear(&call->metadata_batch[0][1]);
+    grpc_metadata_batch_clear(exec_ctx, &call->metadata_batch[0][1]);
   }
   if (bctl->recv_initial_metadata) {
     call->received_initial_metadata = 0;
diff --git a/src/core/lib/surface/call.h b/src/core/lib/surface/call.h
index 18af41b7fb..233340c329 100644
--- a/src/core/lib/surface/call.h
+++ b/src/core/lib/surface/call.h
@@ -70,7 +70,8 @@ typedef struct grpc_call_create_args {
 /* Create a new call based on \a args.
    Regardless of success or failure, always returns a valid new call into *call
    */
-grpc_error *grpc_call_create(const grpc_call_create_args *args,
+grpc_error *grpc_call_create(grpc_exec_ctx *exec_ctx,
+                             const grpc_call_create_args *args,
                              grpc_call **call);
 
 void grpc_call_set_completion_queue(grpc_exec_ctx *exec_ctx, grpc_call *call,
diff --git a/src/core/lib/surface/channel.c b/src/core/lib/surface/channel.c
index 1389df6886..b87295786e 100644
--- a/src/core/lib/surface/channel.c
+++ b/src/core/lib/surface/channel.c
@@ -86,87 +86,91 @@ grpc_channel *grpc_channel_create(grpc_exec_ctx *exec_ctx, const char *target,
                                   const grpc_channel_args *input_args,
                                   grpc_channel_stack_type channel_stack_type,
                                   grpc_transport *optional_transport) {
-  bool is_client = grpc_channel_stack_type_is_client(channel_stack_type);
-
   grpc_channel_stack_builder *builder = grpc_channel_stack_builder_create();
-  grpc_channel_stack_builder_set_channel_arguments(builder, input_args);
+  grpc_channel_stack_builder_set_channel_arguments(exec_ctx, builder,
+                                                   input_args);
   grpc_channel_stack_builder_set_target(builder, target);
   grpc_channel_stack_builder_set_transport(builder, optional_transport);
-  grpc_channel *channel;
-  grpc_channel_args *args;
   if (!grpc_channel_init_create_stack(exec_ctx, builder, channel_stack_type)) {
-    grpc_channel_stack_builder_destroy(builder);
+    grpc_channel_stack_builder_destroy(exec_ctx, builder);
     return NULL;
-  } else {
-    args = grpc_channel_args_copy(
-        grpc_channel_stack_builder_get_channel_arguments(builder));
-    channel = grpc_channel_stack_builder_finish(
-        exec_ctx, builder, sizeof(grpc_channel), 1, destroy_channel, NULL);
+  }
+  grpc_channel_args *args = grpc_channel_args_copy(
+      grpc_channel_stack_builder_get_channel_arguments(builder));
+  grpc_channel *channel;
+  grpc_error *error = grpc_channel_stack_builder_finish(
+      exec_ctx, builder, sizeof(grpc_channel), 1, destroy_channel, NULL,
+      (void **)&channel);
+  if (error != GRPC_ERROR_NONE) {
+    const char *msg = grpc_error_string(error);
+    gpr_log(GPR_ERROR, "channel stack builder failed: %s", msg);
+    grpc_error_free_string(msg);
+    GRPC_ERROR_UNREF(error);
+    goto done;
   }
 
   memset(channel, 0, sizeof(*channel));
   channel->target = gpr_strdup(target);
-  channel->is_client = is_client;
+  channel->is_client = grpc_channel_stack_type_is_client(channel_stack_type);
   gpr_mu_init(&channel->registered_call_mu);
   channel->registered_calls = NULL;
 
   grpc_compression_options_init(&channel->compression_options);
-  if (args) {
-    for (size_t i = 0; i < args->num_args; i++) {
-      if (0 == strcmp(args->args[i].key, GRPC_ARG_DEFAULT_AUTHORITY)) {
-        if (args->args[i].type != GRPC_ARG_STRING) {
-          gpr_log(GPR_ERROR, "%s ignored: it must be a string",
-                  GRPC_ARG_DEFAULT_AUTHORITY);
-        } else {
-          if (channel->default_authority) {
-            /* setting this takes precedence over anything else */
-            GRPC_MDELEM_UNREF(channel->default_authority);
-          }
-          channel->default_authority = grpc_mdelem_from_strings(
-              ":authority", args->args[i].value.string);
+
+  for (size_t i = 0; i < args->num_args; i++) {
+    if (0 == strcmp(args->args[i].key, GRPC_ARG_DEFAULT_AUTHORITY)) {
+      if (args->args[i].type != GRPC_ARG_STRING) {
+        gpr_log(GPR_ERROR, "%s ignored: it must be a string",
+                GRPC_ARG_DEFAULT_AUTHORITY);
+      } else {
+        if (channel->default_authority) {
+          /* setting this takes precedence over anything else */
+          GRPC_MDELEM_UNREF(exec_ctx, channel->default_authority);
         }
-      } else if (0 ==
-                 strcmp(args->args[i].key, GRPC_SSL_TARGET_NAME_OVERRIDE_ARG)) {
-        if (args->args[i].type != GRPC_ARG_STRING) {
-          gpr_log(GPR_ERROR, "%s ignored: it must be a string",
+        channel->default_authority = grpc_mdelem_from_strings(
+            exec_ctx, ":authority", args->args[i].value.string);
+      }
+    } else if (0 ==
+               strcmp(args->args[i].key, GRPC_SSL_TARGET_NAME_OVERRIDE_ARG)) {
+      if (args->args[i].type != GRPC_ARG_STRING) {
+        gpr_log(GPR_ERROR, "%s ignored: it must be a string",
+                GRPC_SSL_TARGET_NAME_OVERRIDE_ARG);
+      } else {
+        if (channel->default_authority) {
+          /* other ways of setting this (notably ssl) take precedence */
+          gpr_log(GPR_ERROR,
+                  "%s ignored: default host already set some other way",
                   GRPC_SSL_TARGET_NAME_OVERRIDE_ARG);
         } else {
-          if (channel->default_authority) {
-            /* other ways of setting this (notably ssl) take precedence */
-            gpr_log(GPR_ERROR,
-                    "%s ignored: default host already set some other way",
-                    GRPC_SSL_TARGET_NAME_OVERRIDE_ARG);
-          } else {
-            channel->default_authority = grpc_mdelem_from_strings(
-                ":authority", args->args[i].value.string);
-          }
+          channel->default_authority = grpc_mdelem_from_strings(
+              exec_ctx, ":authority", args->args[i].value.string);
         }
-      } else if (0 == strcmp(args->args[i].key,
-                             GRPC_COMPRESSION_CHANNEL_DEFAULT_LEVEL)) {
-        channel->compression_options.default_level.is_set = true;
-        GPR_ASSERT(args->args[i].value.integer >= 0 &&
-                   args->args[i].value.integer < GRPC_COMPRESS_LEVEL_COUNT);
-        channel->compression_options.default_level.level =
-            (grpc_compression_level)args->args[i].value.integer;
-      } else if (0 == strcmp(args->args[i].key,
-                             GRPC_COMPRESSION_CHANNEL_DEFAULT_ALGORITHM)) {
-        channel->compression_options.default_algorithm.is_set = true;
-        GPR_ASSERT(args->args[i].value.integer >= 0 &&
-                   args->args[i].value.integer <
-                       GRPC_COMPRESS_ALGORITHMS_COUNT);
-        channel->compression_options.default_algorithm.algorithm =
-            (grpc_compression_algorithm)args->args[i].value.integer;
-      } else if (0 ==
-                 strcmp(args->args[i].key,
-                        GRPC_COMPRESSION_CHANNEL_ENABLED_ALGORITHMS_BITSET)) {
-        channel->compression_options.enabled_algorithms_bitset =
-            (uint32_t)args->args[i].value.integer |
-            0x1; /* always support no compression */
       }
+    } else if (0 == strcmp(args->args[i].key,
+                           GRPC_COMPRESSION_CHANNEL_DEFAULT_LEVEL)) {
+      channel->compression_options.default_level.is_set = true;
+      GPR_ASSERT(args->args[i].value.integer >= 0 &&
+                 args->args[i].value.integer < GRPC_COMPRESS_LEVEL_COUNT);
+      channel->compression_options.default_level.level =
+          (grpc_compression_level)args->args[i].value.integer;
+    } else if (0 == strcmp(args->args[i].key,
+                           GRPC_COMPRESSION_CHANNEL_DEFAULT_ALGORITHM)) {
+      channel->compression_options.default_algorithm.is_set = true;
+      GPR_ASSERT(args->args[i].value.integer >= 0 &&
+                 args->args[i].value.integer < GRPC_COMPRESS_ALGORITHMS_COUNT);
+      channel->compression_options.default_algorithm.algorithm =
+          (grpc_compression_algorithm)args->args[i].value.integer;
+    } else if (0 ==
+               strcmp(args->args[i].key,
+                      GRPC_COMPRESSION_CHANNEL_ENABLED_ALGORITHMS_BITSET)) {
+      channel->compression_options.enabled_algorithms_bitset =
+          (uint32_t)args->args[i].value.integer |
+          0x1; /* always support no compression */
     }
-    grpc_channel_args_destroy(args);
   }
 
+done:
+  grpc_channel_args_destroy(exec_ctx, args);
   return channel;
 }
 
@@ -185,10 +189,10 @@ void grpc_channel_get_info(grpc_channel *channel,
 }
 
 static grpc_call *grpc_channel_create_call_internal(
-    grpc_channel *channel, grpc_call *parent_call, uint32_t propagation_mask,
-    grpc_completion_queue *cq, grpc_pollset_set *pollset_set_alternative,
-    grpc_mdelem *path_mdelem, grpc_mdelem *authority_mdelem,
-    gpr_timespec deadline) {
+    grpc_exec_ctx *exec_ctx, grpc_channel *channel, grpc_call *parent_call,
+    uint32_t propagation_mask, grpc_completion_queue *cq,
+    grpc_pollset_set *pollset_set_alternative, grpc_mdelem *path_mdelem,
+    grpc_mdelem *authority_mdelem, gpr_timespec deadline) {
   grpc_mdelem *send_metadata[2];
   size_t num_metadata = 0;
 
@@ -215,7 +219,7 @@ static grpc_call *grpc_channel_create_call_internal(
   args.send_deadline = deadline;
 
   grpc_call *call;
-  GRPC_LOG_IF_ERROR("call_create", grpc_call_create(&args, &call));
+  GRPC_LOG_IF_ERROR("call_create", grpc_call_create(exec_ctx, &args, &call));
   return call;
 }
 
@@ -236,26 +240,30 @@ grpc_call *grpc_channel_create_call(grpc_channel *channel,
       (channel, parent_call, (unsigned)propagation_mask, cq, method, host,
        deadline.tv_sec, deadline.tv_nsec, (int)deadline.clock_type, reserved));
   GPR_ASSERT(!reserved);
-  return grpc_channel_create_call_internal(
-      channel, parent_call, propagation_mask, cq, NULL,
-      grpc_mdelem_from_metadata_strings(GRPC_MDSTR_PATH,
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_call *call = grpc_channel_create_call_internal(
+      &exec_ctx, channel, parent_call, propagation_mask, cq, NULL,
+      grpc_mdelem_from_metadata_strings(&exec_ctx, GRPC_MDSTR_PATH,
                                         grpc_mdstr_from_string(method)),
-      host ? grpc_mdelem_from_metadata_strings(GRPC_MDSTR_AUTHORITY,
+      host ? grpc_mdelem_from_metadata_strings(&exec_ctx, GRPC_MDSTR_AUTHORITY,
                                                grpc_mdstr_from_string(host))
            : NULL,
       deadline);
+  grpc_exec_ctx_finish(&exec_ctx);
+  return call;
 }
 
 grpc_call *grpc_channel_create_pollset_set_call(
-    grpc_channel *channel, grpc_call *parent_call, uint32_t propagation_mask,
-    grpc_pollset_set *pollset_set, const char *method, const char *host,
-    gpr_timespec deadline, void *reserved) {
+    grpc_exec_ctx *exec_ctx, grpc_channel *channel, grpc_call *parent_call,
+    uint32_t propagation_mask, grpc_pollset_set *pollset_set,
+    const char *method, const char *host, gpr_timespec deadline,
+    void *reserved) {
   GPR_ASSERT(!reserved);
   return grpc_channel_create_call_internal(
-      channel, parent_call, propagation_mask, NULL, pollset_set,
-      grpc_mdelem_from_metadata_strings(GRPC_MDSTR_PATH,
+      exec_ctx, channel, parent_call, propagation_mask, NULL, pollset_set,
+      grpc_mdelem_from_metadata_strings(exec_ctx, GRPC_MDSTR_PATH,
                                         grpc_mdstr_from_string(method)),
-      host ? grpc_mdelem_from_metadata_strings(GRPC_MDSTR_AUTHORITY,
+      host ? grpc_mdelem_from_metadata_strings(exec_ctx, GRPC_MDSTR_AUTHORITY,
                                                grpc_mdstr_from_string(host))
            : NULL,
       deadline);
@@ -268,15 +276,18 @@ void *grpc_channel_register_call(grpc_channel *channel, const char *method,
       "grpc_channel_register_call(channel=%p, method=%s, host=%s, reserved=%p)",
       4, (channel, method, host, reserved));
   GPR_ASSERT(!reserved);
-  rc->path = grpc_mdelem_from_metadata_strings(GRPC_MDSTR_PATH,
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  rc->path = grpc_mdelem_from_metadata_strings(&exec_ctx, GRPC_MDSTR_PATH,
                                                grpc_mdstr_from_string(method));
-  rc->authority = host ? grpc_mdelem_from_metadata_strings(
-                             GRPC_MDSTR_AUTHORITY, grpc_mdstr_from_string(host))
-                       : NULL;
+  rc->authority =
+      host ? grpc_mdelem_from_metadata_strings(&exec_ctx, GRPC_MDSTR_AUTHORITY,
+                                               grpc_mdstr_from_string(host))
+           : NULL;
   gpr_mu_lock(&channel->registered_call_mu);
   rc->next = channel->registered_calls;
   channel->registered_calls = rc;
   gpr_mu_unlock(&channel->registered_call_mu);
+  grpc_exec_ctx_finish(&exec_ctx);
   return rc;
 }
 
@@ -296,10 +307,13 @@ grpc_call *grpc_channel_create_registered_call(
           registered_call_handle, deadline.tv_sec, deadline.tv_nsec,
           (int)deadline.clock_type, reserved));
   GPR_ASSERT(!reserved);
-  return grpc_channel_create_call_internal(
-      channel, parent_call, propagation_mask, completion_queue, NULL,
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_call *call = grpc_channel_create_call_internal(
+      &exec_ctx, channel, parent_call, propagation_mask, completion_queue, NULL,
       GRPC_MDELEM_REF(rc->path),
       rc->authority ? GRPC_MDELEM_REF(rc->authority) : NULL, deadline);
+  grpc_exec_ctx_finish(&exec_ctx);
+  return call;
 }
 
 #ifdef GRPC_STREAM_REFCOUNT_DEBUG
@@ -325,14 +339,14 @@ static void destroy_channel(grpc_exec_ctx *exec_ctx, void *arg,
   while (channel->registered_calls) {
     registered_call *rc = channel->registered_calls;
     channel->registered_calls = rc->next;
-    GRPC_MDELEM_UNREF(rc->path);
+    GRPC_MDELEM_UNREF(exec_ctx, rc->path);
     if (rc->authority) {
-      GRPC_MDELEM_UNREF(rc->authority);
+      GRPC_MDELEM_UNREF(exec_ctx, rc->authority);
     }
     gpr_free(rc);
   }
   if (channel->default_authority != NULL) {
-    GRPC_MDELEM_UNREF(channel->default_authority);
+    GRPC_MDELEM_UNREF(exec_ctx, channel->default_authority);
   }
   gpr_mu_destroy(&channel->registered_call_mu);
   gpr_free(channel->target);
@@ -362,7 +376,8 @@ grpc_compression_options grpc_channel_compression_options(
   return channel->compression_options;
 }
 
-grpc_mdelem *grpc_channel_get_reffed_status_elem(grpc_channel *channel, int i) {
+grpc_mdelem *grpc_channel_get_reffed_status_elem(grpc_exec_ctx *exec_ctx,
+                                                 grpc_channel *channel, int i) {
   char tmp[GPR_LTOA_MIN_BUFSIZE];
   switch (i) {
     case 0:
@@ -373,6 +388,6 @@ grpc_mdelem *grpc_channel_get_reffed_status_elem(grpc_channel *channel, int i) {
       return GRPC_MDELEM_GRPC_STATUS_2;
   }
   gpr_ltoa(i, tmp);
-  return grpc_mdelem_from_metadata_strings(GRPC_MDSTR_GRPC_STATUS,
+  return grpc_mdelem_from_metadata_strings(exec_ctx, GRPC_MDSTR_GRPC_STATUS,
                                            grpc_mdstr_from_string(tmp));
 }
diff --git a/src/core/lib/surface/channel.h b/src/core/lib/surface/channel.h
index 23cc8656ca..2ebadb7a15 100644
--- a/src/core/lib/surface/channel.h
+++ b/src/core/lib/surface/channel.h
@@ -51,9 +51,10 @@ grpc_channel *grpc_channel_create(grpc_exec_ctx *exec_ctx, const char *target,
     properties from the server call to this new client call, depending on the
     value of \a propagation_mask (see propagation_bits.h for possible values) */
 grpc_call *grpc_channel_create_pollset_set_call(
-    grpc_channel *channel, grpc_call *parent_call, uint32_t propagation_mask,
-    grpc_pollset_set *pollset_set, const char *method, const char *host,
-    gpr_timespec deadline, void *reserved);
+    grpc_exec_ctx *exec_ctx, grpc_channel *channel, grpc_call *parent_call,
+    uint32_t propagation_mask, grpc_pollset_set *pollset_set,
+    const char *method, const char *host, gpr_timespec deadline,
+    void *reserved);
 
 /** Get a (borrowed) pointer to this channels underlying channel stack */
 grpc_channel_stack *grpc_channel_get_channel_stack(grpc_channel *channel);
@@ -62,7 +63,8 @@ grpc_channel_stack *grpc_channel_get_channel_stack(grpc_channel *channel);
     status_code.
 
     The returned elem is owned by the caller. */
-grpc_mdelem *grpc_channel_get_reffed_status_elem(grpc_channel *channel,
+grpc_mdelem *grpc_channel_get_reffed_status_elem(grpc_exec_ctx *exec_ctx,
+                                                 grpc_channel *channel,
                                                  int status_code);
 
 #ifdef GRPC_STREAM_REFCOUNT_DEBUG
diff --git a/src/core/lib/surface/channel_init.c b/src/core/lib/surface/channel_init.c
index 0627b34479..7acb444d9b 100644
--- a/src/core/lib/surface/channel_init.c
+++ b/src/core/lib/surface/channel_init.c
@@ -131,7 +131,7 @@ bool grpc_channel_init_create_stack(grpc_exec_ctx *exec_ctx,
 
   for (size_t i = 0; i < g_slots[type].num_slots; i++) {
     const stage_slot *slot = &g_slots[type].slots[i];
-    if (!slot->fn(builder, slot->arg)) {
+    if (!slot->fn(exec_ctx, builder, slot->arg)) {
       return false;
     }
   }
diff --git a/src/core/lib/surface/channel_init.h b/src/core/lib/surface/channel_init.h
index b53f2aefb9..411f5eae18 100644
--- a/src/core/lib/surface/channel_init.h
+++ b/src/core/lib/surface/channel_init.h
@@ -51,7 +51,8 @@ extern "C" {
 
 /// One stage of mutation: call functions against \a builder to influence the
 /// finally constructed channel stack
-typedef bool (*grpc_channel_init_stage)(grpc_channel_stack_builder *builder,
+typedef bool (*grpc_channel_init_stage)(grpc_exec_ctx *exec_ctx,
+                                        grpc_channel_stack_builder *builder,
                                         void *arg);
 
 /// Global initialization of the system
diff --git a/src/core/lib/surface/channel_ping.c b/src/core/lib/surface/channel_ping.c
index 0d2f01a649..e68febdddf 100644
--- a/src/core/lib/surface/channel_ping.c
+++ b/src/core/lib/surface/channel_ping.c
@@ -71,7 +71,7 @@ void grpc_channel_ping(grpc_channel *channel, grpc_completion_queue *cq,
   GPR_ASSERT(reserved == NULL);
   pr->tag = tag;
   pr->cq = cq;
-  grpc_closure_init(&pr->closure, ping_done, pr);
+  grpc_closure_init(&pr->closure, ping_done, pr, grpc_schedule_on_exec_ctx);
   op->send_ping = &pr->closure;
   op->bind_pollset = grpc_cq_pollset(cq);
   grpc_cq_begin_op(cq, tag);
diff --git a/src/core/lib/surface/completion_queue.c b/src/core/lib/surface/completion_queue.c
index 4e0feb56ac..4613c9021e 100644
--- a/src/core/lib/surface/completion_queue.c
+++ b/src/core/lib/surface/completion_queue.c
@@ -168,7 +168,8 @@ grpc_completion_queue *grpc_completion_queue_create(void *reserved) {
 #ifndef NDEBUG
   cc->outstanding_tag_count = 0;
 #endif
-  grpc_closure_init(&cc->pollset_shutdown_done, on_pollset_shutdown_done, cc);
+  grpc_closure_init(&cc->pollset_shutdown_done, on_pollset_shutdown_done, cc,
+                    grpc_schedule_on_exec_ctx);
 
   GPR_TIMER_END("grpc_completion_queue_create", 0);
 
@@ -354,11 +355,13 @@ static void dump_pending_tags(grpc_completion_queue *cc) {
   gpr_strvec v;
   gpr_strvec_init(&v);
   gpr_strvec_add(&v, gpr_strdup("PENDING TAGS:"));
+  gpr_mu_lock(cc->mu);
   for (size_t i = 0; i < cc->outstanding_tag_count; i++) {
     char *s;
     gpr_asprintf(&s, " %p", cc->outstanding_tags[i]);
     gpr_strvec_add(&v, s);
   }
+  gpr_mu_unlock(cc->mu);
   char *out = gpr_strvec_flatten(&v, NULL);
   gpr_strvec_destroy(&v);
   gpr_log(GPR_DEBUG, "%s", out);
diff --git a/src/core/lib/surface/init.c b/src/core/lib/surface/init.c
index 7903f57a68..f61bf1582e 100644
--- a/src/core/lib/surface/init.c
+++ b/src/core/lib/surface/init.c
@@ -44,6 +44,7 @@
 #include "src/core/lib/channel/compress_filter.h"
 #include "src/core/lib/channel/connected_channel.h"
 #include "src/core/lib/channel/deadline_filter.h"
+#include "src/core/lib/channel/handshaker_registry.h"
 #include "src/core/lib/channel/http_client_filter.h"
 #include "src/core/lib/channel/http_server_filter.h"
 #include "src/core/lib/channel/message_size_filter.h"
@@ -80,17 +81,20 @@ static void do_basic_init(void) {
   g_initializations = 0;
 }
 
-static bool append_filter(grpc_channel_stack_builder *builder, void *arg) {
+static bool append_filter(grpc_exec_ctx *exec_ctx,
+                          grpc_channel_stack_builder *builder, void *arg) {
   return grpc_channel_stack_builder_append_filter(
       builder, (const grpc_channel_filter *)arg, NULL, NULL);
 }
 
-static bool prepend_filter(grpc_channel_stack_builder *builder, void *arg) {
+static bool prepend_filter(grpc_exec_ctx *exec_ctx,
+                           grpc_channel_stack_builder *builder, void *arg) {
   return grpc_channel_stack_builder_prepend_filter(
       builder, (const grpc_channel_filter *)arg, NULL, NULL);
 }
 
-static bool maybe_add_http_filter(grpc_channel_stack_builder *builder,
+static bool maybe_add_http_filter(grpc_exec_ctx *exec_ctx,
+                                  grpc_channel_stack_builder *builder,
                                   void *arg) {
   grpc_transport *t = grpc_channel_stack_builder_get_transport(builder);
   if (t && strstr(t->vtable->name, "http")) {
@@ -201,6 +205,8 @@ void grpc_init(void) {
     grpc_executor_init();
     gpr_timers_global_init();
     grpc_cq_global_init();
+    grpc_handshaker_factory_registry_init();
+    grpc_security_init();
     for (i = 0; i < g_number_of_plugins; i++) {
       if (g_all_of_the_plugins[i].init != NULL) {
         g_all_of_the_plugins[i].init();
@@ -221,11 +227,12 @@ void grpc_init(void) {
 void grpc_shutdown(void) {
   int i;
   GRPC_API_TRACE("grpc_shutdown(void)", 0, ());
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   gpr_mu_lock(&g_init_mu);
   if (--g_initializations == 0) {
-    grpc_executor_shutdown();
+    grpc_executor_shutdown(&exec_ctx);
     grpc_cq_global_shutdown();
-    grpc_iomgr_shutdown();
+    grpc_iomgr_shutdown(&exec_ctx);
     gpr_timers_global_destroy();
     grpc_tracer_shutdown();
     for (i = g_number_of_plugins; i >= 0; i--) {
@@ -233,9 +240,11 @@ void grpc_shutdown(void) {
         g_all_of_the_plugins[i].destroy();
       }
     }
-    grpc_mdctx_global_shutdown();
+    grpc_mdctx_global_shutdown(&exec_ctx);
+    grpc_handshaker_factory_registry_shutdown(&exec_ctx);
   }
   gpr_mu_unlock(&g_init_mu);
+  grpc_exec_ctx_finish(&exec_ctx);
 }
 
 int grpc_is_initialized(void) {
diff --git a/src/core/lib/surface/init.h b/src/core/lib/surface/init.h
index b1bf57c10d..3d1c528be0 100644
--- a/src/core/lib/surface/init.h
+++ b/src/core/lib/surface/init.h
@@ -36,6 +36,7 @@
 
 void grpc_register_security_filters(void);
 void grpc_security_pre_init(void);
+void grpc_security_init(void);
 int grpc_is_initialized(void);
 
 #endif /* GRPC_CORE_LIB_SURFACE_INIT_H */
diff --git a/src/core/lib/surface/init_secure.c b/src/core/lib/surface/init_secure.c
index 7ee7b51568..a44407d3bb 100644
--- a/src/core/lib/surface/init_secure.c
+++ b/src/core/lib/surface/init_secure.c
@@ -41,6 +41,7 @@
 #include "src/core/lib/security/transport/auth_filters.h"
 #include "src/core/lib/security/transport/secure_endpoint.h"
 #include "src/core/lib/security/transport/security_connector.h"
+#include "src/core/lib/security/transport/security_handshaker.h"
 #include "src/core/lib/surface/channel_init.h"
 #include "src/core/lib/tsi/transport_security_interface.h"
 
@@ -50,7 +51,7 @@ void grpc_security_pre_init(void) {
 }
 
 static bool maybe_prepend_client_auth_filter(
-    grpc_channel_stack_builder *builder, void *arg) {
+    grpc_exec_ctx *exec_ctx, grpc_channel_stack_builder *builder, void *arg) {
   const grpc_channel_args *args =
       grpc_channel_stack_builder_get_channel_arguments(builder);
   if (args) {
@@ -65,7 +66,7 @@ static bool maybe_prepend_client_auth_filter(
 }
 
 static bool maybe_prepend_server_auth_filter(
-    grpc_channel_stack_builder *builder, void *arg) {
+    grpc_exec_ctx *exec_ctx, grpc_channel_stack_builder *builder, void *arg) {
   const grpc_channel_args *args =
       grpc_channel_stack_builder_get_channel_arguments(builder);
   if (args) {
@@ -87,3 +88,5 @@ void grpc_register_security_filters(void) {
   grpc_channel_init_register_stage(GRPC_SERVER_CHANNEL, INT_MAX,
                                    maybe_prepend_server_auth_filter, NULL);
 }
+
+void grpc_security_init() { grpc_security_register_handshaker_factories(); }
diff --git a/src/core/lib/surface/init_unsecure.c b/src/core/lib/surface/init_unsecure.c
index f952739e0a..dbc9223ae0 100644
--- a/src/core/lib/surface/init_unsecure.c
+++ b/src/core/lib/surface/init_unsecure.c
@@ -36,3 +36,5 @@
 void grpc_security_pre_init(void) {}
 
 void grpc_register_security_filters(void) {}
+
+void grpc_security_init(void) {}
diff --git a/src/core/lib/surface/lame_client.c b/src/core/lib/surface/lame_client.c
index d0df8e7e17..ae1eac09a9 100644
--- a/src/core/lib/surface/lame_client.c
+++ b/src/core/lib/surface/lame_client.c
@@ -55,14 +55,15 @@ typedef struct {
   const char *error_message;
 } channel_data;
 
-static void fill_metadata(grpc_call_element *elem, grpc_metadata_batch *mdb) {
+static void fill_metadata(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
+                          grpc_metadata_batch *mdb) {
   call_data *calld = elem->call_data;
   channel_data *chand = elem->channel_data;
   char tmp[GPR_LTOA_MIN_BUFSIZE];
   gpr_ltoa(chand->error_code, tmp);
-  calld->status.md = grpc_mdelem_from_strings("grpc-status", tmp);
+  calld->status.md = grpc_mdelem_from_strings(exec_ctx, "grpc-status", tmp);
   calld->details.md =
-      grpc_mdelem_from_strings("grpc-message", chand->error_message);
+      grpc_mdelem_from_strings(exec_ctx, "grpc-message", chand->error_message);
   calld->status.prev = calld->details.next = NULL;
   calld->status.next = &calld->details;
   calld->details.prev = &calld->status;
@@ -76,9 +77,9 @@ static void lame_start_transport_stream_op(grpc_exec_ctx *exec_ctx,
                                            grpc_transport_stream_op *op) {
   GRPC_CALL_LOG_OP(GPR_INFO, elem, op);
   if (op->recv_initial_metadata != NULL) {
-    fill_metadata(elem, op->recv_initial_metadata);
+    fill_metadata(exec_ctx, elem, op->recv_initial_metadata);
   } else if (op->recv_trailing_metadata != NULL) {
-    fill_metadata(elem, op->recv_trailing_metadata);
+    fill_metadata(exec_ctx, elem, op->recv_trailing_metadata);
   }
   grpc_transport_stream_op_finish_with_failure(
       exec_ctx, op, GRPC_ERROR_CREATE("lame client channel"));
@@ -98,16 +99,16 @@ static void lame_start_transport_op(grpc_exec_ctx *exec_ctx,
   if (op->on_connectivity_state_change) {
     GPR_ASSERT(*op->connectivity_state != GRPC_CHANNEL_SHUTDOWN);
     *op->connectivity_state = GRPC_CHANNEL_SHUTDOWN;
-    grpc_exec_ctx_sched(exec_ctx, op->on_connectivity_state_change,
-                        GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, op->on_connectivity_state_change,
+                       GRPC_ERROR_NONE);
   }
   if (op->send_ping != NULL) {
-    grpc_exec_ctx_sched(exec_ctx, op->send_ping,
-                        GRPC_ERROR_CREATE("lame client channel"), NULL);
+    grpc_closure_sched(exec_ctx, op->send_ping,
+                       GRPC_ERROR_CREATE("lame client channel"));
   }
   GRPC_ERROR_UNREF(op->disconnect_with_error);
   if (op->on_consumed != NULL) {
-    grpc_exec_ctx_sched(exec_ctx, op->on_consumed, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, op->on_consumed, GRPC_ERROR_NONE);
   }
 }
 
@@ -123,11 +124,12 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
   gpr_free(and_free_memory);
 }
 
-static void init_channel_elem(grpc_exec_ctx *exec_ctx,
-                              grpc_channel_element *elem,
-                              grpc_channel_element_args *args) {
+static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
+                                     grpc_channel_element *elem,
+                                     grpc_channel_element_args *args) {
   GPR_ASSERT(args->is_first);
   GPR_ASSERT(args->is_last);
+  return GRPC_ERROR_NONE;
 }
 
 static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
diff --git a/src/core/lib/surface/server.c b/src/core/lib/surface/server.c
index fe73aa375c..addb7c4fbc 100644
--- a/src/core/lib/surface/server.c
+++ b/src/core/lib/surface/server.c
@@ -45,6 +45,7 @@
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/channel/connected_channel.h"
 #include "src/core/lib/iomgr/iomgr.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/support/stack_lockfree.h"
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/surface/api_trace.h"
@@ -271,14 +272,15 @@ struct shutdown_cleanup_args {
 static void shutdown_cleanup(grpc_exec_ctx *exec_ctx, void *arg,
                              grpc_error *error) {
   struct shutdown_cleanup_args *a = arg;
-  grpc_slice_unref(a->slice);
+  grpc_slice_unref_internal(exec_ctx, a->slice);
   gpr_free(a);
 }
 
 static void send_shutdown(grpc_exec_ctx *exec_ctx, grpc_channel *channel,
                           int send_goaway, grpc_error *send_disconnect) {
   struct shutdown_cleanup_args *sc = gpr_malloc(sizeof(*sc));
-  grpc_closure_init(&sc->closure, shutdown_cleanup, sc);
+  grpc_closure_init(&sc->closure, shutdown_cleanup, sc,
+                    grpc_schedule_on_exec_ctx);
   grpc_transport_op *op = grpc_make_transport_op(&sc->closure);
   grpc_channel_element *elem;
 
@@ -346,9 +348,9 @@ static void request_matcher_zombify_all_pending_calls(grpc_exec_ctx *exec_ctx,
     gpr_mu_unlock(&calld->mu_state);
     grpc_closure_init(
         &calld->kill_zombie_closure, kill_zombie,
-        grpc_call_stack_element(grpc_call_get_call_stack(calld->call), 0));
-    grpc_exec_ctx_sched(exec_ctx, &calld->kill_zombie_closure, GRPC_ERROR_NONE,
-                        NULL);
+        grpc_call_stack_element(grpc_call_get_call_stack(calld->call), 0),
+        grpc_schedule_on_exec_ctx);
+    grpc_closure_sched(exec_ctx, &calld->kill_zombie_closure, GRPC_ERROR_NONE);
   }
 }
 
@@ -379,7 +381,7 @@ static void server_ref(grpc_server *server) {
 static void server_delete(grpc_exec_ctx *exec_ctx, grpc_server *server) {
   registered_method *rm;
   size_t i;
-  grpc_channel_args_destroy(server->channel_args);
+  grpc_channel_args_destroy(exec_ctx, server->channel_args);
   gpr_mu_destroy(&server->mu_global);
   gpr_mu_destroy(&server->mu_call);
   while ((rm = server->registered_methods) != NULL) {
@@ -440,8 +442,8 @@ static void destroy_channel(grpc_exec_ctx *exec_ctx, channel_data *chand,
   orphan_channel(chand);
   server_ref(chand->server);
   maybe_finish_shutdown(exec_ctx, chand->server);
-  chand->finish_destroy_channel_closure.cb = finish_destroy_channel;
-  chand->finish_destroy_channel_closure.cb_arg = chand;
+  grpc_closure_init(&chand->finish_destroy_channel_closure,
+                    finish_destroy_channel, chand, grpc_schedule_on_exec_ctx);
 
   if (grpc_server_channel_trace && error != GRPC_ERROR_NONE) {
     const char *msg = grpc_error_string(error);
@@ -545,8 +547,9 @@ static void publish_new_rpc(grpc_exec_ctx *exec_ctx, void *arg,
     gpr_mu_unlock(&calld->mu_state);
     grpc_closure_init(
         &calld->kill_zombie_closure, kill_zombie,
-        grpc_call_stack_element(grpc_call_get_call_stack(calld->call), 0));
-    grpc_exec_ctx_sched(exec_ctx, &calld->kill_zombie_closure, error, NULL);
+        grpc_call_stack_element(grpc_call_get_call_stack(calld->call), 0),
+        grpc_schedule_on_exec_ctx);
+    grpc_closure_sched(exec_ctx, &calld->kill_zombie_closure, error);
     return;
   }
 
@@ -590,9 +593,9 @@ static void finish_start_new_rpc(
     gpr_mu_lock(&calld->mu_state);
     calld->state = ZOMBIED;
     gpr_mu_unlock(&calld->mu_state);
-    grpc_closure_init(&calld->kill_zombie_closure, kill_zombie, elem);
-    grpc_exec_ctx_sched(exec_ctx, &calld->kill_zombie_closure, GRPC_ERROR_NONE,
-                        NULL);
+    grpc_closure_init(&calld->kill_zombie_closure, kill_zombie, elem,
+                      grpc_schedule_on_exec_ctx);
+    grpc_closure_sched(exec_ctx, &calld->kill_zombie_closure, GRPC_ERROR_NONE);
     return;
   }
 
@@ -607,7 +610,8 @@ static void finish_start_new_rpc(
       memset(&op, 0, sizeof(op));
       op.op = GRPC_OP_RECV_MESSAGE;
       op.data.recv_message = &calld->payload;
-      grpc_closure_init(&calld->publish, publish_new_rpc, elem);
+      grpc_closure_init(&calld->publish, publish_new_rpc, elem,
+                        grpc_schedule_on_exec_ctx);
       grpc_call_start_batch_and_execute(exec_ctx, calld->call, &op, 1,
                                         &calld->publish);
       break;
@@ -740,7 +744,8 @@ static void maybe_finish_shutdown(grpc_exec_ctx *exec_ctx,
   }
 }
 
-static grpc_mdelem *server_filter(void *user_data, grpc_mdelem *md) {
+static grpc_mdelem *server_filter(grpc_exec_ctx *exec_ctx, void *user_data,
+                                  grpc_mdelem *md) {
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
   if (md->key == GRPC_MDSTR_PATH) {
@@ -764,7 +769,8 @@ static void server_on_recv_initial_metadata(grpc_exec_ctx *exec_ctx, void *ptr,
   gpr_timespec op_deadline;
 
   GRPC_ERROR_REF(error);
-  grpc_metadata_batch_filter(calld->recv_initial_metadata, server_filter, elem);
+  grpc_metadata_batch_filter(exec_ctx, calld->recv_initial_metadata,
+                             server_filter, elem);
   op_deadline = calld->recv_initial_metadata->deadline;
   if (0 != gpr_time_cmp(op_deadline, gpr_inf_future(op_deadline.clock_type))) {
     calld->deadline = op_deadline;
@@ -813,9 +819,10 @@ static void got_initial_metadata(grpc_exec_ctx *exec_ctx, void *ptr,
     if (calld->state == NOT_STARTED) {
       calld->state = ZOMBIED;
       gpr_mu_unlock(&calld->mu_state);
-      grpc_closure_init(&calld->kill_zombie_closure, kill_zombie, elem);
-      grpc_exec_ctx_sched(exec_ctx, &calld->kill_zombie_closure,
-                          GRPC_ERROR_NONE, NULL);
+      grpc_closure_init(&calld->kill_zombie_closure, kill_zombie, elem,
+                        grpc_schedule_on_exec_ctx);
+      grpc_closure_sched(exec_ctx, &calld->kill_zombie_closure,
+                         GRPC_ERROR_NONE);
     } else if (calld->state == PENDING) {
       calld->state = ZOMBIED;
       gpr_mu_unlock(&calld->mu_state);
@@ -838,7 +845,7 @@ static void accept_stream(grpc_exec_ctx *exec_ctx, void *cd,
   args.server_transport_data = transport_server_data;
   args.send_deadline = gpr_inf_future(GPR_CLOCK_MONOTONIC);
   grpc_call *call;
-  grpc_error *error = grpc_call_create(&args, &call);
+  grpc_error *error = grpc_call_create(exec_ctx, &args, &call);
   grpc_call_element *elem =
       grpc_call_stack_element(grpc_call_get_call_stack(call), 0);
   if (error != GRPC_ERROR_NONE) {
@@ -851,7 +858,8 @@ static void accept_stream(grpc_exec_ctx *exec_ctx, void *cd,
   memset(&op, 0, sizeof(op));
   op.op = GRPC_OP_RECV_INITIAL_METADATA;
   op.data.recv_initial_metadata = &calld->initial_metadata;
-  grpc_closure_init(&calld->got_initial_metadata, got_initial_metadata, elem);
+  grpc_closure_init(&calld->got_initial_metadata, got_initial_metadata, elem,
+                    grpc_schedule_on_exec_ctx);
   grpc_call_start_batch_and_execute(exec_ctx, call, &op, 1,
                                     &calld->got_initial_metadata);
 }
@@ -887,7 +895,8 @@ static grpc_error *init_call_elem(grpc_exec_ctx *exec_ctx,
   gpr_mu_init(&calld->mu_state);
 
   grpc_closure_init(&calld->server_on_recv_initial_metadata,
-                    server_on_recv_initial_metadata, elem);
+                    server_on_recv_initial_metadata, elem,
+                    grpc_schedule_on_exec_ctx);
 
   server_ref(chand->server);
   return GRPC_ERROR_NONE;
@@ -902,10 +911,10 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
   GPR_ASSERT(calld->state != PENDING);
 
   if (calld->host) {
-    GRPC_MDSTR_UNREF(calld->host);
+    GRPC_MDSTR_UNREF(exec_ctx, calld->host);
   }
   if (calld->path) {
-    GRPC_MDSTR_UNREF(calld->path);
+    GRPC_MDSTR_UNREF(exec_ctx, calld->path);
   }
   grpc_metadata_array_destroy(&calld->initial_metadata);
 
@@ -914,9 +923,9 @@ static void destroy_call_elem(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
   server_unref(exec_ctx, chand->server);
 }
 
-static void init_channel_elem(grpc_exec_ctx *exec_ctx,
-                              grpc_channel_element *elem,
-                              grpc_channel_element_args *args) {
+static grpc_error *init_channel_elem(grpc_exec_ctx *exec_ctx,
+                                     grpc_channel_element *elem,
+                                     grpc_channel_element_args *args) {
   channel_data *chand = elem->channel_data;
   GPR_ASSERT(args->is_first);
   GPR_ASSERT(!args->is_last);
@@ -926,7 +935,9 @@ static void init_channel_elem(grpc_exec_ctx *exec_ctx,
   chand->registered_methods = NULL;
   chand->connectivity_state = GRPC_CHANNEL_IDLE;
   grpc_closure_init(&chand->channel_connectivity_changed,
-                    channel_connectivity_changed, chand);
+                    channel_connectivity_changed, chand,
+                    grpc_schedule_on_exec_ctx);
+  return GRPC_ERROR_NONE;
 }
 
 static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
@@ -936,10 +947,10 @@ static void destroy_channel_elem(grpc_exec_ctx *exec_ctx,
   if (chand->registered_methods) {
     for (i = 0; i < chand->registered_method_slots; i++) {
       if (chand->registered_methods[i].method) {
-        GRPC_MDSTR_UNREF(chand->registered_methods[i].method);
+        GRPC_MDSTR_UNREF(exec_ctx, chand->registered_methods[i].method);
       }
       if (chand->registered_methods[i].host) {
-        GRPC_MDSTR_UNREF(chand->registered_methods[i].host);
+        GRPC_MDSTR_UNREF(exec_ctx, chand->registered_methods[i].host);
       }
     }
     gpr_free(chand->registered_methods);
@@ -1277,7 +1288,8 @@ void grpc_server_shutdown_and_notify(grpc_server *server,
 
   /* Shutdown listeners */
   for (l = server->listeners; l; l = l->next) {
-    grpc_closure_init(&l->destroy_done, listener_destroy_done, server);
+    grpc_closure_init(&l->destroy_done, listener_destroy_done, server,
+                      grpc_schedule_on_exec_ctx);
     l->destroy(&exec_ctx, server, l->arg, &l->destroy_done);
   }
 
@@ -1383,9 +1395,10 @@ static grpc_call_error queue_call_request(grpc_exec_ctx *exec_ctx,
         gpr_mu_unlock(&calld->mu_state);
         grpc_closure_init(
             &calld->kill_zombie_closure, kill_zombie,
-            grpc_call_stack_element(grpc_call_get_call_stack(calld->call), 0));
-        grpc_exec_ctx_sched(exec_ctx, &calld->kill_zombie_closure,
-                            GRPC_ERROR_NONE, NULL);
+            grpc_call_stack_element(grpc_call_get_call_stack(calld->call), 0),
+            grpc_schedule_on_exec_ctx);
+        grpc_closure_sched(exec_ctx, &calld->kill_zombie_closure,
+                           GRPC_ERROR_NONE);
       } else {
         GPR_ASSERT(calld->state == PENDING);
         calld->state = ACTIVATED;
diff --git a/src/core/lib/surface/validate_metadata.c b/src/core/lib/surface/validate_metadata.c
index 84f0a083bc..f49dd8584b 100644
--- a/src/core/lib/surface/validate_metadata.c
+++ b/src/core/lib/surface/validate_metadata.c
@@ -53,7 +53,7 @@ int grpc_header_key_is_legal(const char *key, size_t length) {
       0x00, 0x00, 0x00, 0x00, 0x00, 0x60, 0xff, 0x03, 0x00, 0x00, 0x00,
       0x80, 0xfe, 0xff, 0xff, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
       0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
-  if (length == 0) {
+  if (length == 0 || key[0] == ':') {
     return 0;
   }
   return conforms_to(key, length, legal_header_bits);
diff --git a/src/core/lib/transport/README.md b/src/core/lib/transport/README.md
new file mode 100644
index 0000000000..e7e135edeb
--- /dev/null
+++ b/src/core/lib/transport/README.md
@@ -0,0 +1,7 @@
+# Transport
+
+Common implementation details for gRPC Transports.
+
+Transports multiplex messages across some single connection. In ext/ there are
+implementations atop [a custom http2 implementation](/src/core/ext/transport/chttp2/README.md)
+and atop [cronet](/src/core/ext/transport/cronet/README.md).
diff --git a/src/core/lib/transport/byte_stream.c b/src/core/lib/transport/byte_stream.c
index 2f1d7b7c60..4d4206189e 100644
--- a/src/core/lib/transport/byte_stream.c
+++ b/src/core/lib/transport/byte_stream.c
@@ -37,6 +37,8 @@
 
 #include <grpc/support/log.h>
 
+#include "src/core/lib/slice/slice_internal.h"
+
 int grpc_byte_stream_next(grpc_exec_ctx *exec_ctx,
                           grpc_byte_stream *byte_stream, grpc_slice *slice,
                           size_t max_size_hint, grpc_closure *on_complete) {
@@ -57,7 +59,8 @@ static int slice_buffer_stream_next(grpc_exec_ctx *exec_ctx,
                                     grpc_closure *on_complete) {
   grpc_slice_buffer_stream *stream = (grpc_slice_buffer_stream *)byte_stream;
   GPR_ASSERT(stream->cursor < stream->backing_buffer->count);
-  *slice = grpc_slice_ref(stream->backing_buffer->slices[stream->cursor]);
+  *slice =
+      grpc_slice_ref_internal(stream->backing_buffer->slices[stream->cursor]);
   stream->cursor++;
   return 1;
 }
diff --git a/src/core/lib/transport/connectivity_state.c b/src/core/lib/transport/connectivity_state.c
index 4f49d7cf7d..c656d93740 100644
--- a/src/core/lib/transport/connectivity_state.c
+++ b/src/core/lib/transport/connectivity_state.c
@@ -81,7 +81,7 @@ void grpc_connectivity_state_destroy(grpc_exec_ctx *exec_ctx,
     } else {
       error = GRPC_ERROR_CREATE("Shutdown connectivity owner");
     }
-    grpc_exec_ctx_sched(exec_ctx, w->notify, error, NULL);
+    grpc_closure_sched(exec_ctx, w->notify, error);
     gpr_free(w);
   }
   GRPC_ERROR_UNREF(tracker->current_error);
@@ -121,7 +121,7 @@ bool grpc_connectivity_state_notify_on_state_change(
   if (current == NULL) {
     grpc_connectivity_state_watcher *w = tracker->watchers;
     if (w != NULL && w->notify == notify) {
-      grpc_exec_ctx_sched(exec_ctx, notify, GRPC_ERROR_CANCELLED, NULL);
+      grpc_closure_sched(exec_ctx, notify, GRPC_ERROR_CANCELLED);
       tracker->watchers = w->next;
       gpr_free(w);
       return false;
@@ -129,7 +129,7 @@ bool grpc_connectivity_state_notify_on_state_change(
     while (w != NULL) {
       grpc_connectivity_state_watcher *rm_candidate = w->next;
       if (rm_candidate != NULL && rm_candidate->notify == notify) {
-        grpc_exec_ctx_sched(exec_ctx, notify, GRPC_ERROR_CANCELLED, NULL);
+        grpc_closure_sched(exec_ctx, notify, GRPC_ERROR_CANCELLED);
         w->next = w->next->next;
         gpr_free(rm_candidate);
         return false;
@@ -140,8 +140,8 @@ bool grpc_connectivity_state_notify_on_state_change(
   } else {
     if (tracker->current_state != *current) {
       *current = tracker->current_state;
-      grpc_exec_ctx_sched(exec_ctx, notify,
-                          GRPC_ERROR_REF(tracker->current_error), NULL);
+      grpc_closure_sched(exec_ctx, notify,
+                         GRPC_ERROR_REF(tracker->current_error));
     } else {
       grpc_connectivity_state_watcher *w = gpr_malloc(sizeof(*w));
       w->current = current;
@@ -191,8 +191,8 @@ void grpc_connectivity_state_set(grpc_exec_ctx *exec_ctx,
       gpr_log(GPR_DEBUG, "NOTIFY: %p %s: %p", tracker, tracker->name,
               w->notify);
     }
-    grpc_exec_ctx_sched(exec_ctx, w->notify,
-                        GRPC_ERROR_REF(tracker->current_error), NULL);
+    grpc_closure_sched(exec_ctx, w->notify,
+                       GRPC_ERROR_REF(tracker->current_error));
     gpr_free(w);
   }
 }
diff --git a/src/core/lib/transport/mdstr_hash_table.c b/src/core/lib/transport/mdstr_hash_table.c
index 3d01e56df7..2791bf653b 100644
--- a/src/core/lib/transport/mdstr_hash_table.c
+++ b/src/core/lib/transport/mdstr_hash_table.c
@@ -94,13 +94,14 @@ grpc_mdstr_hash_table* grpc_mdstr_hash_table_ref(grpc_mdstr_hash_table* table) {
   return table;
 }
 
-void grpc_mdstr_hash_table_unref(grpc_mdstr_hash_table* table) {
+void grpc_mdstr_hash_table_unref(grpc_exec_ctx* exec_ctx,
+                                 grpc_mdstr_hash_table* table) {
   if (table != NULL && gpr_unref(&table->refs)) {
     for (size_t i = 0; i < table->size; ++i) {
       grpc_mdstr_hash_table_entry* entry = &table->entries[i];
       if (entry->key != NULL) {
-        GRPC_MDSTR_UNREF(entry->key);
-        entry->vtable->destroy_value(entry->value);
+        GRPC_MDSTR_UNREF(exec_ctx, entry->key);
+        entry->vtable->destroy_value(exec_ctx, entry->value);
       }
     }
     gpr_free(table->entries);
diff --git a/src/core/lib/transport/mdstr_hash_table.h b/src/core/lib/transport/mdstr_hash_table.h
index 8982ec3a8d..57f497ee27 100644
--- a/src/core/lib/transport/mdstr_hash_table.h
+++ b/src/core/lib/transport/mdstr_hash_table.h
@@ -49,7 +49,7 @@
 typedef struct grpc_mdstr_hash_table grpc_mdstr_hash_table;
 
 typedef struct grpc_mdstr_hash_table_vtable {
-  void (*destroy_value)(void* value);
+  void (*destroy_value)(grpc_exec_ctx* exec_ctx, void* value);
   void* (*copy_value)(void* value);
 } grpc_mdstr_hash_table_vtable;
 
@@ -66,7 +66,8 @@ grpc_mdstr_hash_table* grpc_mdstr_hash_table_create(
     size_t num_entries, grpc_mdstr_hash_table_entry* entries);
 
 grpc_mdstr_hash_table* grpc_mdstr_hash_table_ref(grpc_mdstr_hash_table* table);
-void grpc_mdstr_hash_table_unref(grpc_mdstr_hash_table* table);
+void grpc_mdstr_hash_table_unref(grpc_exec_ctx* exec_ctx,
+                                 grpc_mdstr_hash_table* table);
 
 /** Returns the value from \a table associated with \a key.
     Returns NULL if \a key is not found. */
diff --git a/src/core/lib/transport/metadata.c b/src/core/lib/transport/metadata.c
index fac19b91d9..54c39df6a7 100644
--- a/src/core/lib/transport/metadata.c
+++ b/src/core/lib/transport/metadata.c
@@ -47,6 +47,7 @@
 
 #include "src/core/lib/iomgr/iomgr_internal.h"
 #include "src/core/lib/profiling/timers.h"
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/support/murmur_hash.h"
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/transport/static_metadata.h"
@@ -153,7 +154,7 @@ static size_t g_static_mdtab_maxprobe;
 static strtab_shard g_strtab_shard[STRTAB_SHARD_COUNT];
 static mdtab_shard g_mdtab_shard[MDTAB_SHARD_COUNT];
 
-static void gc_mdtab(mdtab_shard *shard);
+static void gc_mdtab(grpc_exec_ctx *exec_ctx, mdtab_shard *shard);
 
 void grpc_test_only_set_metadata_hash_seed(uint32_t seed) {
   g_hash_seed = seed;
@@ -227,12 +228,12 @@ void grpc_mdctx_global_init(void) {
   }
 }
 
-void grpc_mdctx_global_shutdown(void) {
+void grpc_mdctx_global_shutdown(grpc_exec_ctx *exec_ctx) {
   size_t i;
   for (i = 0; i < MDTAB_SHARD_COUNT; i++) {
     mdtab_shard *shard = &g_mdtab_shard[i];
     gpr_mu_destroy(&shard->mu);
-    gc_mdtab(shard);
+    gc_mdtab(exec_ctx, shard);
     /* TODO(ctiller): GPR_ASSERT(shard->count == 0); */
     if (shard->count != 0) {
       gpr_log(GPR_DEBUG, "WARNING: %" PRIuPTR " metadata elements were leaked",
@@ -316,12 +317,13 @@ static void grow_strtab(strtab_shard *shard) {
   GPR_TIMER_END("grow_strtab", 0);
 }
 
-static void internal_destroy_string(strtab_shard *shard, internal_string *is) {
+static void internal_destroy_string(grpc_exec_ctx *exec_ctx,
+                                    strtab_shard *shard, internal_string *is) {
   internal_string **prev_next;
   internal_string *cur;
   GPR_TIMER_BEGIN("internal_destroy_string", 0);
   if (is->has_base64_and_huffman_encoded) {
-    grpc_slice_unref(is->base64_and_huffman);
+    grpc_slice_unref_internal(exec_ctx, is->base64_and_huffman);
   }
   for (prev_next = &shard->strs[TABLE_IDX(is->hash, LOG2_STRTAB_SHARD_COUNT,
                                           shard->capacity)],
@@ -340,20 +342,20 @@ static void slice_ref(void *p) {
   GRPC_MDSTR_REF((grpc_mdstr *)(is));
 }
 
-static void slice_unref(void *p) {
+static void slice_unref(grpc_exec_ctx *exec_ctx, void *p) {
   internal_string *is =
       (internal_string *)((char *)p - offsetof(internal_string, refcount));
-  GRPC_MDSTR_UNREF((grpc_mdstr *)(is));
+  GRPC_MDSTR_UNREF(exec_ctx, (grpc_mdstr *)(is));
 }
 
 grpc_mdstr *grpc_mdstr_from_string(const char *str) {
   return grpc_mdstr_from_buffer((const uint8_t *)str, strlen(str));
 }
 
-grpc_mdstr *grpc_mdstr_from_slice(grpc_slice slice) {
+grpc_mdstr *grpc_mdstr_from_slice(grpc_exec_ctx *exec_ctx, grpc_slice slice) {
   grpc_mdstr *result = grpc_mdstr_from_buffer(GRPC_SLICE_START_PTR(slice),
                                               GRPC_SLICE_LENGTH(slice));
-  grpc_slice_unref(slice);
+  grpc_slice_unref_internal(exec_ctx, slice);
   return result;
 }
 
@@ -444,7 +446,7 @@ grpc_mdstr *grpc_mdstr_from_buffer(const uint8_t *buf, size_t length) {
   return (grpc_mdstr *)s;
 }
 
-static void gc_mdtab(mdtab_shard *shard) {
+static void gc_mdtab(grpc_exec_ctx *exec_ctx, mdtab_shard *shard) {
   size_t i;
   internal_metadata **prev_next;
   internal_metadata *md, *next;
@@ -457,8 +459,8 @@ static void gc_mdtab(mdtab_shard *shard) {
       void *user_data = (void *)gpr_atm_no_barrier_load(&md->user_data);
       next = md->bucket_next;
       if (gpr_atm_acq_load(&md->refcnt) == 0) {
-        GRPC_MDSTR_UNREF((grpc_mdstr *)md->key);
-        GRPC_MDSTR_UNREF((grpc_mdstr *)md->value);
+        GRPC_MDSTR_UNREF(exec_ctx, (grpc_mdstr *)md->key);
+        GRPC_MDSTR_UNREF(exec_ctx, (grpc_mdstr *)md->value);
         if (md->user_data) {
           ((destroy_user_data_func)gpr_atm_no_barrier_load(
               &md->destroy_user_data))(user_data);
@@ -506,16 +508,17 @@ static void grow_mdtab(mdtab_shard *shard) {
   GPR_TIMER_END("grow_mdtab", 0);
 }
 
-static void rehash_mdtab(mdtab_shard *shard) {
+static void rehash_mdtab(grpc_exec_ctx *exec_ctx, mdtab_shard *shard) {
   if (gpr_atm_no_barrier_load(&shard->free_estimate) >
       (gpr_atm)(shard->capacity / 4)) {
-    gc_mdtab(shard);
+    gc_mdtab(exec_ctx, shard);
   } else {
     grow_mdtab(shard);
   }
 }
 
-grpc_mdelem *grpc_mdelem_from_metadata_strings(grpc_mdstr *mkey,
+grpc_mdelem *grpc_mdelem_from_metadata_strings(grpc_exec_ctx *exec_ctx,
+                                               grpc_mdstr *mkey,
                                                grpc_mdstr *mvalue) {
   internal_string *key = (internal_string *)mkey;
   internal_string *value = (internal_string *)mvalue;
@@ -547,8 +550,8 @@ grpc_mdelem *grpc_mdelem_from_metadata_strings(grpc_mdstr *mkey,
   for (md = shard->elems[idx]; md; md = md->bucket_next) {
     if (md->key == key && md->value == value) {
       REF_MD_LOCKED(shard, md);
-      GRPC_MDSTR_UNREF((grpc_mdstr *)key);
-      GRPC_MDSTR_UNREF((grpc_mdstr *)value);
+      GRPC_MDSTR_UNREF(exec_ctx, (grpc_mdstr *)key);
+      GRPC_MDSTR_UNREF(exec_ctx, (grpc_mdstr *)value);
       gpr_mu_unlock(&shard->mu);
       GPR_TIMER_END("grpc_mdelem_from_metadata_strings", 0);
       return (grpc_mdelem *)md;
@@ -574,7 +577,7 @@ grpc_mdelem *grpc_mdelem_from_metadata_strings(grpc_mdstr *mkey,
   shard->count++;
 
   if (shard->count > shard->capacity * 2) {
-    rehash_mdtab(shard);
+    rehash_mdtab(exec_ctx, shard);
   }
 
   gpr_mu_unlock(&shard->mu);
@@ -584,21 +587,26 @@ grpc_mdelem *grpc_mdelem_from_metadata_strings(grpc_mdstr *mkey,
   return (grpc_mdelem *)md;
 }
 
-grpc_mdelem *grpc_mdelem_from_strings(const char *key, const char *value) {
-  return grpc_mdelem_from_metadata_strings(grpc_mdstr_from_string(key),
-                                           grpc_mdstr_from_string(value));
+grpc_mdelem *grpc_mdelem_from_strings(grpc_exec_ctx *exec_ctx, const char *key,
+                                      const char *value) {
+  return grpc_mdelem_from_metadata_strings(
+      exec_ctx, grpc_mdstr_from_string(key), grpc_mdstr_from_string(value));
 }
 
-grpc_mdelem *grpc_mdelem_from_slices(grpc_slice key, grpc_slice value) {
-  return grpc_mdelem_from_metadata_strings(grpc_mdstr_from_slice(key),
-                                           grpc_mdstr_from_slice(value));
+grpc_mdelem *grpc_mdelem_from_slices(grpc_exec_ctx *exec_ctx, grpc_slice key,
+                                     grpc_slice value) {
+  return grpc_mdelem_from_metadata_strings(
+      exec_ctx, grpc_mdstr_from_slice(exec_ctx, key),
+      grpc_mdstr_from_slice(exec_ctx, value));
 }
 
-grpc_mdelem *grpc_mdelem_from_string_and_buffer(const char *key,
+grpc_mdelem *grpc_mdelem_from_string_and_buffer(grpc_exec_ctx *exec_ctx,
+                                                const char *key,
                                                 const uint8_t *value,
                                                 size_t value_length) {
   return grpc_mdelem_from_metadata_strings(
-      grpc_mdstr_from_string(key), grpc_mdstr_from_buffer(value, value_length));
+      exec_ctx, grpc_mdstr_from_string(key),
+      grpc_mdstr_from_buffer(value, value_length));
 }
 
 static size_t get_base64_encoded_size(size_t raw_length) {
@@ -654,7 +662,7 @@ grpc_mdelem *grpc_mdelem_ref(grpc_mdelem *gmd DEBUG_ARGS) {
   return gmd;
 }
 
-void grpc_mdelem_unref(grpc_mdelem *gmd DEBUG_ARGS) {
+void grpc_mdelem_unref(grpc_exec_ctx *exec_ctx, grpc_mdelem *gmd DEBUG_ARGS) {
   internal_metadata *md = (internal_metadata *)gmd;
   if (!md) return;
   if (is_mdelem_static(gmd)) return;
@@ -696,7 +704,7 @@ grpc_mdstr *grpc_mdstr_ref(grpc_mdstr *gs DEBUG_ARGS) {
   return gs;
 }
 
-void grpc_mdstr_unref(grpc_mdstr *gs DEBUG_ARGS) {
+void grpc_mdstr_unref(grpc_exec_ctx *exec_ctx, grpc_mdstr *gs DEBUG_ARGS) {
   internal_string *s = (internal_string *)gs;
   if (is_mdstr_static(gs)) return;
 #ifdef GRPC_METADATA_REFCOUNT_DEBUG
@@ -709,7 +717,7 @@ void grpc_mdstr_unref(grpc_mdstr *gs DEBUG_ARGS) {
         &g_strtab_shard[SHARD_IDX(s->hash, LOG2_STRTAB_SHARD_COUNT)];
     gpr_mu_lock(&shard->mu);
     GPR_ASSERT(0 == gpr_atm_no_barrier_load(&s->refcnt));
-    internal_destroy_string(shard, s);
+    internal_destroy_string(exec_ctx, shard, s);
     gpr_mu_unlock(&shard->mu);
   }
 }
diff --git a/src/core/lib/transport/metadata.h b/src/core/lib/transport/metadata.h
index a4955a1ea7..991eee96f1 100644
--- a/src/core/lib/transport/metadata.h
+++ b/src/core/lib/transport/metadata.h
@@ -37,6 +37,8 @@
 #include <grpc/slice.h>
 #include <grpc/support/useful.h>
 
+#include "src/core/lib/iomgr/exec_ctx.h"
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -96,7 +98,7 @@ void grpc_test_only_set_metadata_hash_seed(uint32_t seed);
    clients may have handy */
 grpc_mdstr *grpc_mdstr_from_string(const char *str);
 /* Unrefs the slice. */
-grpc_mdstr *grpc_mdstr_from_slice(grpc_slice slice);
+grpc_mdstr *grpc_mdstr_from_slice(grpc_exec_ctx *exec_ctx, grpc_slice slice);
 grpc_mdstr *grpc_mdstr_from_buffer(const uint8_t *str, size_t length);
 
 /* Returns a borrowed slice from the mdstr with its contents base64 encoded
@@ -105,12 +107,16 @@ grpc_slice grpc_mdstr_as_base64_encoded_and_huffman_compressed(grpc_mdstr *str);
 
 /* Constructors for grpc_mdelem instances; take a variety of data types that
    clients may have handy */
-grpc_mdelem *grpc_mdelem_from_metadata_strings(grpc_mdstr *key,
+grpc_mdelem *grpc_mdelem_from_metadata_strings(grpc_exec_ctx *exec_ctx,
+                                               grpc_mdstr *key,
                                                grpc_mdstr *value);
-grpc_mdelem *grpc_mdelem_from_strings(const char *key, const char *value);
+grpc_mdelem *grpc_mdelem_from_strings(grpc_exec_ctx *exec_ctx, const char *key,
+                                      const char *value);
 /* Unrefs the slices. */
-grpc_mdelem *grpc_mdelem_from_slices(grpc_slice key, grpc_slice value);
-grpc_mdelem *grpc_mdelem_from_string_and_buffer(const char *key,
+grpc_mdelem *grpc_mdelem_from_slices(grpc_exec_ctx *exec_ctx, grpc_slice key,
+                                     grpc_slice value);
+grpc_mdelem *grpc_mdelem_from_string_and_buffer(grpc_exec_ctx *exec_ctx,
+                                                const char *key,
                                                 const uint8_t *value,
                                                 size_t value_length);
 
@@ -127,22 +133,26 @@ void *grpc_mdelem_set_user_data(grpc_mdelem *md, void (*destroy_func)(void *),
 //#define GRPC_METADATA_REFCOUNT_DEBUG
 #ifdef GRPC_METADATA_REFCOUNT_DEBUG
 #define GRPC_MDSTR_REF(s) grpc_mdstr_ref((s), __FILE__, __LINE__)
-#define GRPC_MDSTR_UNREF(s) grpc_mdstr_unref((s), __FILE__, __LINE__)
+#define GRPC_MDSTR_UNREF(exec_ctx, s) \
+  grpc_mdstr_unref((exec_ctx), (s), __FILE__, __LINE__)
 #define GRPC_MDELEM_REF(s) grpc_mdelem_ref((s), __FILE__, __LINE__)
-#define GRPC_MDELEM_UNREF(s) grpc_mdelem_unref((s), __FILE__, __LINE__)
+#define GRPC_MDELEM_UNREF(exec_ctx, s) \
+  grpc_mdelem_unref((exec_ctx), (s), __FILE__, __LINE__)
 grpc_mdstr *grpc_mdstr_ref(grpc_mdstr *s, const char *file, int line);
-void grpc_mdstr_unref(grpc_mdstr *s, const char *file, int line);
+void grpc_mdstr_unref(grpc_exec_ctx *exec_ctx, grpc_mdstr *s, const char *file,
+                      int line);
 grpc_mdelem *grpc_mdelem_ref(grpc_mdelem *md, const char *file, int line);
-void grpc_mdelem_unref(grpc_mdelem *md, const char *file, int line);
+void grpc_mdelem_unref(grpc_exec_ctx *exec_ctx, grpc_mdelem *md,
+                       const char *file, int line);
 #else
 #define GRPC_MDSTR_REF(s) grpc_mdstr_ref((s))
-#define GRPC_MDSTR_UNREF(s) grpc_mdstr_unref((s))
+#define GRPC_MDSTR_UNREF(exec_ctx, s) grpc_mdstr_unref((exec_ctx), (s))
 #define GRPC_MDELEM_REF(s) grpc_mdelem_ref((s))
-#define GRPC_MDELEM_UNREF(s) grpc_mdelem_unref((s))
+#define GRPC_MDELEM_UNREF(exec_ctx, s) grpc_mdelem_unref((exec_ctx), (s))
 grpc_mdstr *grpc_mdstr_ref(grpc_mdstr *s);
-void grpc_mdstr_unref(grpc_mdstr *s);
+void grpc_mdstr_unref(grpc_exec_ctx *exec_ctx, grpc_mdstr *s);
 grpc_mdelem *grpc_mdelem_ref(grpc_mdelem *md);
-void grpc_mdelem_unref(grpc_mdelem *md);
+void grpc_mdelem_unref(grpc_exec_ctx *exec_ctx, grpc_mdelem *md);
 #endif
 
 /* Recover a char* from a grpc_mdstr. The returned string is null terminated.
@@ -162,7 +172,7 @@ int grpc_mdstr_is_bin_suffixed(grpc_mdstr *s);
 #define GRPC_MDSTR_KV_HASH(k_hash, v_hash) (GPR_ROTL((k_hash), 2) ^ (v_hash))
 
 void grpc_mdctx_global_init(void);
-void grpc_mdctx_global_shutdown(void);
+void grpc_mdctx_global_shutdown(grpc_exec_ctx *exec_ctx);
 
 /* Implementation provided by chttp2_transport */
 extern grpc_slice (*grpc_chttp2_base64_encode_and_huffman_compress)(
diff --git a/src/core/lib/transport/metadata_batch.c b/src/core/lib/transport/metadata_batch.c
index 84b5a74d51..b62ecc3aa6 100644
--- a/src/core/lib/transport/metadata_batch.c
+++ b/src/core/lib/transport/metadata_batch.c
@@ -72,10 +72,11 @@ void grpc_metadata_batch_init(grpc_metadata_batch *batch) {
   batch->deadline = gpr_inf_future(GPR_CLOCK_REALTIME);
 }
 
-void grpc_metadata_batch_destroy(grpc_metadata_batch *batch) {
+void grpc_metadata_batch_destroy(grpc_exec_ctx *exec_ctx,
+                                 grpc_metadata_batch *batch) {
   grpc_linked_mdelem *l;
   for (l = batch->list.head; l; l = l->next) {
-    GRPC_MDELEM_UNREF(l->md);
+    GRPC_MDELEM_UNREF(exec_ctx, l->md);
   }
 }
 
@@ -140,8 +141,10 @@ void grpc_metadata_batch_move(grpc_metadata_batch *dst,
   memset(src, 0, sizeof(grpc_metadata_batch));
 }
 
-void grpc_metadata_batch_filter(grpc_metadata_batch *batch,
-                                grpc_mdelem *(*filter)(void *user_data,
+void grpc_metadata_batch_filter(grpc_exec_ctx *exec_ctx,
+                                grpc_metadata_batch *batch,
+                                grpc_mdelem *(*filter)(grpc_exec_ctx *exec_ctx,
+                                                       void *user_data,
                                                        grpc_mdelem *elem),
                                 void *user_data) {
   grpc_linked_mdelem *l;
@@ -152,7 +155,7 @@ void grpc_metadata_batch_filter(grpc_metadata_batch *batch,
   assert_valid_list(&batch->list);
   for (l = batch->list.head; l; l = next) {
     grpc_mdelem *orig = l->md;
-    grpc_mdelem *filt = filter(user_data, orig);
+    grpc_mdelem *filt = filter(exec_ctx, user_data, orig);
     next = l->next;
     if (filt == NULL) {
       if (l->prev) {
@@ -168,9 +171,9 @@ void grpc_metadata_batch_filter(grpc_metadata_batch *batch,
         batch->list.tail = l->prev;
       }
       assert_valid_list(&batch->list);
-      GRPC_MDELEM_UNREF(l->md);
+      GRPC_MDELEM_UNREF(exec_ctx, l->md);
     } else if (filt != orig) {
-      GRPC_MDELEM_UNREF(orig);
+      GRPC_MDELEM_UNREF(exec_ctx, orig);
       l->md = filt;
     }
   }
@@ -179,13 +182,15 @@ void grpc_metadata_batch_filter(grpc_metadata_batch *batch,
   GPR_TIMER_END("grpc_metadata_batch_filter", 0);
 }
 
-static grpc_mdelem *no_metadata_for_you(void *user_data, grpc_mdelem *elem) {
+static grpc_mdelem *no_metadata_for_you(grpc_exec_ctx *exec_ctx,
+                                        void *user_data, grpc_mdelem *elem) {
   return NULL;
 }
 
-void grpc_metadata_batch_clear(grpc_metadata_batch *batch) {
+void grpc_metadata_batch_clear(grpc_exec_ctx *exec_ctx,
+                               grpc_metadata_batch *batch) {
   batch->deadline = gpr_inf_future(GPR_CLOCK_REALTIME);
-  grpc_metadata_batch_filter(batch, no_metadata_for_you, NULL);
+  grpc_metadata_batch_filter(exec_ctx, batch, no_metadata_for_you, NULL);
 }
 
 bool grpc_metadata_batch_is_empty(grpc_metadata_batch *batch) {
diff --git a/src/core/lib/transport/metadata_batch.h b/src/core/lib/transport/metadata_batch.h
index 7a9ccb4bc8..c0bd5174ab 100644
--- a/src/core/lib/transport/metadata_batch.h
+++ b/src/core/lib/transport/metadata_batch.h
@@ -68,8 +68,10 @@ typedef struct grpc_metadata_batch {
 } grpc_metadata_batch;
 
 void grpc_metadata_batch_init(grpc_metadata_batch *batch);
-void grpc_metadata_batch_destroy(grpc_metadata_batch *batch);
-void grpc_metadata_batch_clear(grpc_metadata_batch *batch);
+void grpc_metadata_batch_destroy(grpc_exec_ctx *exec_ctx,
+                                 grpc_metadata_batch *batch);
+void grpc_metadata_batch_clear(grpc_exec_ctx *exec_ctx,
+                               grpc_metadata_batch *batch);
 bool grpc_metadata_batch_is_empty(grpc_metadata_batch *batch);
 
 /* Returns the transport size of the batch. */
@@ -118,8 +120,10 @@ void grpc_metadata_batch_add_tail(grpc_metadata_batch *batch,
     The return value from \a filter will be substituted for the
     grpc_mdelem passed to \a filter. If \a filter returns NULL,
     the element will be moved to the garbage list. */
-void grpc_metadata_batch_filter(grpc_metadata_batch *batch,
-                                grpc_mdelem *(*filter)(void *user_data,
+void grpc_metadata_batch_filter(grpc_exec_ctx *exec_ctx,
+                                grpc_metadata_batch *batch,
+                                grpc_mdelem *(*filter)(grpc_exec_ctx *exec_ctx,
+                                                       void *user_data,
                                                        grpc_mdelem *elem),
                                 void *user_data);
 
diff --git a/src/core/lib/transport/method_config.c b/src/core/lib/transport/method_config.c
new file mode 100644
index 0000000000..25fb54b37d
--- /dev/null
+++ b/src/core/lib/transport/method_config.c
@@ -0,0 +1,347 @@
+//
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+
+#include "src/core/lib/transport/method_config.h"
+
+#include <string.h>
+
+#include <grpc/impl/codegen/grpc_types.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+#include <grpc/support/time.h>
+
+#include "src/core/lib/transport/mdstr_hash_table.h"
+#include "src/core/lib/transport/metadata.h"
+
+//
+// grpc_method_config
+//
+
+// bool vtable
+
+static void* bool_copy(void* valuep) {
+  bool value = *(bool*)valuep;
+  bool* new_value = gpr_malloc(sizeof(bool));
+  *new_value = value;
+  return new_value;
+}
+
+static int bool_cmp(void* v1, void* v2) {
+  bool b1 = *(bool*)v1;
+  bool b2 = *(bool*)v2;
+  if (!b1 && b2) return -1;
+  if (b1 && !b2) return 1;
+  return 0;
+}
+
+static void free_mem(grpc_exec_ctx* exec_ctx, void* p) { gpr_free(p); }
+
+static grpc_mdstr_hash_table_vtable bool_vtable = {free_mem, bool_copy,
+                                                   bool_cmp};
+
+// timespec vtable
+
+static void* timespec_copy(void* valuep) {
+  gpr_timespec value = *(gpr_timespec*)valuep;
+  gpr_timespec* new_value = gpr_malloc(sizeof(gpr_timespec));
+  *new_value = value;
+  return new_value;
+}
+
+static int timespec_cmp(void* v1, void* v2) {
+  return gpr_time_cmp(*(gpr_timespec*)v1, *(gpr_timespec*)v2);
+}
+
+static grpc_mdstr_hash_table_vtable timespec_vtable = {free_mem, timespec_copy,
+                                                       timespec_cmp};
+
+// int32 vtable
+
+static void* int32_copy(void* valuep) {
+  int32_t value = *(int32_t*)valuep;
+  int32_t* new_value = gpr_malloc(sizeof(int32_t));
+  *new_value = value;
+  return new_value;
+}
+
+static int int32_cmp(void* v1, void* v2) {
+  int32_t i1 = *(int32_t*)v1;
+  int32_t i2 = *(int32_t*)v2;
+  if (i1 < i2) return -1;
+  if (i1 > i2) return 1;
+  return 0;
+}
+
+static grpc_mdstr_hash_table_vtable int32_vtable = {free_mem, int32_copy,
+                                                    int32_cmp};
+
+// Hash table keys.
+#define GRPC_METHOD_CONFIG_WAIT_FOR_READY "grpc.wait_for_ready"  // bool
+#define GRPC_METHOD_CONFIG_TIMEOUT "grpc.timeout"                // gpr_timespec
+#define GRPC_METHOD_CONFIG_MAX_REQUEST_MESSAGE_BYTES \
+  "grpc.max_request_message_bytes"  // int32
+#define GRPC_METHOD_CONFIG_MAX_RESPONSE_MESSAGE_BYTES \
+  "grpc.max_response_message_bytes"  // int32
+
+struct grpc_method_config {
+  grpc_mdstr_hash_table* table;
+  grpc_mdstr* wait_for_ready_key;
+  grpc_mdstr* timeout_key;
+  grpc_mdstr* max_request_message_bytes_key;
+  grpc_mdstr* max_response_message_bytes_key;
+};
+
+grpc_method_config* grpc_method_config_create(
+    bool* wait_for_ready, gpr_timespec* timeout,
+    int32_t* max_request_message_bytes, int32_t* max_response_message_bytes) {
+  grpc_method_config* method_config = gpr_malloc(sizeof(grpc_method_config));
+  memset(method_config, 0, sizeof(grpc_method_config));
+  method_config->wait_for_ready_key =
+      grpc_mdstr_from_string(GRPC_METHOD_CONFIG_WAIT_FOR_READY);
+  method_config->timeout_key =
+      grpc_mdstr_from_string(GRPC_METHOD_CONFIG_TIMEOUT);
+  method_config->max_request_message_bytes_key =
+      grpc_mdstr_from_string(GRPC_METHOD_CONFIG_MAX_REQUEST_MESSAGE_BYTES);
+  method_config->max_response_message_bytes_key =
+      grpc_mdstr_from_string(GRPC_METHOD_CONFIG_MAX_RESPONSE_MESSAGE_BYTES);
+  grpc_mdstr_hash_table_entry entries[4];
+  size_t num_entries = 0;
+  if (wait_for_ready != NULL) {
+    entries[num_entries].key = method_config->wait_for_ready_key;
+    entries[num_entries].value = wait_for_ready;
+    entries[num_entries].vtable = &bool_vtable;
+    ++num_entries;
+  }
+  if (timeout != NULL) {
+    entries[num_entries].key = method_config->timeout_key;
+    entries[num_entries].value = timeout;
+    entries[num_entries].vtable = &timespec_vtable;
+    ++num_entries;
+  }
+  if (max_request_message_bytes != NULL) {
+    entries[num_entries].key = method_config->max_request_message_bytes_key;
+    entries[num_entries].value = max_request_message_bytes;
+    entries[num_entries].vtable = &int32_vtable;
+    ++num_entries;
+  }
+  if (max_response_message_bytes != NULL) {
+    entries[num_entries].key = method_config->max_response_message_bytes_key;
+    entries[num_entries].value = max_response_message_bytes;
+    entries[num_entries].vtable = &int32_vtable;
+    ++num_entries;
+  }
+  method_config->table = grpc_mdstr_hash_table_create(num_entries, entries);
+  return method_config;
+}
+
+grpc_method_config* grpc_method_config_ref(grpc_method_config* method_config) {
+  grpc_mdstr_hash_table_ref(method_config->table);
+  return method_config;
+}
+
+void grpc_method_config_unref(grpc_exec_ctx* exec_ctx,
+                              grpc_method_config* method_config) {
+  if (grpc_mdstr_hash_table_unref(exec_ctx, method_config->table)) {
+    GRPC_MDSTR_UNREF(exec_ctx, method_config->wait_for_ready_key);
+    GRPC_MDSTR_UNREF(exec_ctx, method_config->timeout_key);
+    GRPC_MDSTR_UNREF(exec_ctx, method_config->max_request_message_bytes_key);
+    GRPC_MDSTR_UNREF(exec_ctx, method_config->max_response_message_bytes_key);
+    gpr_free(method_config);
+  }
+}
+
+int grpc_method_config_cmp(const grpc_method_config* method_config1,
+                           const grpc_method_config* method_config2) {
+  return grpc_mdstr_hash_table_cmp(method_config1->table,
+                                   method_config2->table);
+}
+
+const bool* grpc_method_config_get_wait_for_ready(
+    const grpc_method_config* method_config) {
+  return grpc_mdstr_hash_table_get(method_config->table,
+                                   method_config->wait_for_ready_key);
+}
+
+const gpr_timespec* grpc_method_config_get_timeout(
+    const grpc_method_config* method_config) {
+  return grpc_mdstr_hash_table_get(method_config->table,
+                                   method_config->timeout_key);
+}
+
+const int32_t* grpc_method_config_get_max_request_message_bytes(
+    const grpc_method_config* method_config) {
+  return grpc_mdstr_hash_table_get(
+      method_config->table, method_config->max_request_message_bytes_key);
+}
+
+const int32_t* grpc_method_config_get_max_response_message_bytes(
+    const grpc_method_config* method_config) {
+  return grpc_mdstr_hash_table_get(
+      method_config->table, method_config->max_response_message_bytes_key);
+}
+
+//
+// grpc_method_config_table
+//
+
+static void method_config_unref(grpc_exec_ctx* exec_ctx, void* valuep) {
+  grpc_method_config_unref(exec_ctx, valuep);
+}
+
+static void* method_config_ref(void* valuep) {
+  return grpc_method_config_ref(valuep);
+}
+
+static int method_config_cmp(void* valuep1, void* valuep2) {
+  return grpc_method_config_cmp(valuep1, valuep2);
+}
+
+static const grpc_mdstr_hash_table_vtable method_config_table_vtable = {
+    method_config_unref, method_config_ref, method_config_cmp};
+
+grpc_method_config_table* grpc_method_config_table_create(
+    size_t num_entries, grpc_method_config_table_entry* entries) {
+  grpc_mdstr_hash_table_entry* hash_table_entries =
+      gpr_malloc(sizeof(grpc_mdstr_hash_table_entry) * num_entries);
+  for (size_t i = 0; i < num_entries; ++i) {
+    hash_table_entries[i].key = entries[i].method_name;
+    hash_table_entries[i].value = entries[i].method_config;
+    hash_table_entries[i].vtable = &method_config_table_vtable;
+  }
+  grpc_method_config_table* method_config_table =
+      grpc_mdstr_hash_table_create(num_entries, hash_table_entries);
+  gpr_free(hash_table_entries);
+  return method_config_table;
+}
+
+grpc_method_config_table* grpc_method_config_table_ref(
+    grpc_method_config_table* table) {
+  return grpc_mdstr_hash_table_ref(table);
+}
+
+void grpc_method_config_table_unref(grpc_exec_ctx* exec_ctx,
+                                    grpc_method_config_table* table) {
+  grpc_mdstr_hash_table_unref(exec_ctx, table);
+}
+
+int grpc_method_config_table_cmp(const grpc_method_config_table* table1,
+                                 const grpc_method_config_table* table2) {
+  return grpc_mdstr_hash_table_cmp(table1, table2);
+}
+
+void* grpc_method_config_table_get(grpc_exec_ctx* exec_ctx,
+                                   const grpc_mdstr_hash_table* table,
+                                   const grpc_mdstr* path) {
+  void* value = grpc_mdstr_hash_table_get(table, path);
+  // If we didn't find a match for the path, try looking for a wildcard
+  // entry (i.e., change "/service/method" to "/service/*").
+  if (value == NULL) {
+    const char* path_str = grpc_mdstr_as_c_string(path);
+    const char* sep = strrchr(path_str, '/') + 1;
+    const size_t len = (size_t)(sep - path_str);
+    char* buf = gpr_malloc(len + 2);  // '*' and NUL
+    memcpy(buf, path_str, len);
+    buf[len] = '*';
+    buf[len + 1] = '\0';
+    grpc_mdstr* wildcard_path = grpc_mdstr_from_string(buf);
+    gpr_free(buf);
+    value = grpc_mdstr_hash_table_get(table, wildcard_path);
+    GRPC_MDSTR_UNREF(exec_ctx, wildcard_path);
+  }
+  return value;
+}
+
+static void* copy_arg(void* p) { return grpc_method_config_table_ref(p); }
+
+static void destroy_arg(grpc_exec_ctx* exec_ctx, void* p) {
+  grpc_method_config_table_unref(exec_ctx, p);
+}
+
+static int cmp_arg(void* p1, void* p2) {
+  return grpc_method_config_table_cmp(p1, p2);
+}
+
+static grpc_arg_pointer_vtable arg_vtable = {copy_arg, destroy_arg, cmp_arg};
+
+grpc_arg grpc_method_config_table_create_channel_arg(
+    grpc_method_config_table* table) {
+  grpc_arg arg;
+  arg.type = GRPC_ARG_POINTER;
+  arg.key = GRPC_ARG_SERVICE_CONFIG;
+  arg.value.pointer.p = table;
+  arg.value.pointer.vtable = &arg_vtable;
+  return arg;
+}
+
+// State used by convert_entry() below.
+typedef struct conversion_state {
+  void* (*convert_value)(const grpc_method_config* method_config);
+  const grpc_mdstr_hash_table_vtable* vtable;
+  size_t num_entries;
+  grpc_mdstr_hash_table_entry* entries;
+} conversion_state;
+
+// A function to be passed to grpc_mdstr_hash_table_iterate() to create
+// a copy of the entries.
+static void convert_entry(const grpc_mdstr_hash_table_entry* entry,
+                          void* user_data) {
+  conversion_state* state = user_data;
+  state->entries[state->num_entries].key = GRPC_MDSTR_REF(entry->key);
+  state->entries[state->num_entries].value = state->convert_value(entry->value);
+  state->entries[state->num_entries].vtable = state->vtable;
+  ++state->num_entries;
+}
+
+grpc_mdstr_hash_table* grpc_method_config_table_convert(
+    grpc_exec_ctx* exec_ctx, const grpc_method_config_table* table,
+    void* (*convert_value)(const grpc_method_config* method_config),
+    const grpc_mdstr_hash_table_vtable* vtable) {
+  // Create an array of the entries in the table with converted values.
+  conversion_state state;
+  state.convert_value = convert_value;
+  state.vtable = vtable;
+  state.num_entries = 0;
+  state.entries = gpr_malloc(sizeof(grpc_mdstr_hash_table_entry) *
+                             grpc_mdstr_hash_table_num_entries(table));
+  grpc_mdstr_hash_table_iterate(table, convert_entry, &state);
+  // Create a new table based on the array we just constructed.
+  grpc_mdstr_hash_table* new_table =
+      grpc_mdstr_hash_table_create(state.num_entries, state.entries);
+  // Clean up the array.
+  for (size_t i = 0; i < state.num_entries; ++i) {
+    GRPC_MDSTR_UNREF(exec_ctx, state.entries[i].key);
+    vtable->destroy_value(exec_ctx, state.entries[i].value);
+  }
+  gpr_free(state.entries);
+  // Return the new table.
+  return new_table;
+}
diff --git a/src/core/lib/transport/method_config.h b/src/core/lib/transport/method_config.h
new file mode 100644
index 0000000000..d17a493fd4
--- /dev/null
+++ b/src/core/lib/transport/method_config.h
@@ -0,0 +1,139 @@
+//
+// Copyright 2016, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+
+#ifndef GRPC_CORE_LIB_TRANSPORT_METHOD_CONFIG_H
+#define GRPC_CORE_LIB_TRANSPORT_METHOD_CONFIG_H
+
+#include <stdbool.h>
+
+#include <grpc/impl/codegen/gpr_types.h>
+#include <grpc/impl/codegen/grpc_types.h>
+
+#include "src/core/lib/transport/mdstr_hash_table.h"
+#include "src/core/lib/transport/metadata.h"
+
+/// Per-method configuration.
+typedef struct grpc_method_config grpc_method_config;
+
+/// Creates a grpc_method_config with the specified parameters.
+/// Any parameter may be NULL to indicate that the value is unset.
+///
+/// \a wait_for_ready indicates whether the client should wait until the
+/// request deadline for the channel to become ready, even if there is a
+/// temporary failure before the deadline while attempting to connect.
+///
+/// \a timeout indicates the timeout for calls.
+///
+/// \a max_request_message_bytes and \a max_response_message_bytes
+/// indicate the maximum sizes of the request (checked when sending) and
+/// response (checked when receiving) messages.
+grpc_method_config* grpc_method_config_create(
+    bool* wait_for_ready, gpr_timespec* timeout,
+    int32_t* max_request_message_bytes, int32_t* max_response_message_bytes);
+
+grpc_method_config* grpc_method_config_ref(grpc_method_config* method_config);
+void grpc_method_config_unref(grpc_exec_ctx* exec_ctx,
+                              grpc_method_config* method_config);
+
+/// Compares two grpc_method_configs.
+/// The sort order is stable but undefined.
+int grpc_method_config_cmp(const grpc_method_config* method_config1,
+                           const grpc_method_config* method_config2);
+
+/// These methods return NULL if the requested field is unset.
+/// The caller does NOT take ownership of the result.
+const bool* grpc_method_config_get_wait_for_ready(
+    const grpc_method_config* method_config);
+const gpr_timespec* grpc_method_config_get_timeout(
+    const grpc_method_config* method_config);
+const int32_t* grpc_method_config_get_max_request_message_bytes(
+    const grpc_method_config* method_config);
+const int32_t* grpc_method_config_get_max_response_message_bytes(
+    const grpc_method_config* method_config);
+
+/// A table of method configs.
+typedef grpc_mdstr_hash_table grpc_method_config_table;
+
+typedef struct grpc_method_config_table_entry {
+  /// The name is of one of the following forms:
+  ///   service/method -- specifies exact service and method name
+  ///   service/*      -- matches all methods for the specified service
+  grpc_mdstr* method_name;
+  grpc_method_config* method_config;
+} grpc_method_config_table_entry;
+
+/// Takes new references to all keys and values in \a entries.
+grpc_method_config_table* grpc_method_config_table_create(
+    size_t num_entries, grpc_method_config_table_entry* entries);
+
+grpc_method_config_table* grpc_method_config_table_ref(
+    grpc_method_config_table* table);
+void grpc_method_config_table_unref(grpc_exec_ctx* exec_ctx,
+                                    grpc_method_config_table* table);
+
+/// Compares two grpc_method_config_tables.
+/// The sort order is stable but undefined.
+int grpc_method_config_table_cmp(const grpc_method_config_table* table1,
+                                 const grpc_method_config_table* table2);
+
+/// Gets the method config for the specified \a path, which should be of
+/// the form "/service/method".
+/// Returns NULL if the method has no config.
+/// Caller does NOT own a reference to the result.
+///
+/// Note: This returns a void* instead of a grpc_method_config* so that
+/// it can also be used for tables constructed via
+/// grpc_method_config_table_convert().
+void* grpc_method_config_table_get(grpc_exec_ctx* exec_ctx,
+                                   const grpc_mdstr_hash_table* table,
+                                   const grpc_mdstr* path);
+
+/// Returns a channel arg containing \a table.
+grpc_arg grpc_method_config_table_create_channel_arg(
+    grpc_method_config_table* table);
+
+/// Generates a new table from \a table whose values are converted to a
+/// new form via the \a convert_value function.  The new table will use
+/// \a vtable for its values.
+///
+/// This is generally used to convert the table's value type from
+/// grpc_method_config to a simple struct containing only the parameters
+/// relevant to a particular filter, thus avoiding the need for a hash
+/// table lookup on the fast path.  In that scenario, \a convert_value
+/// will return a new instance of the struct containing the values from
+/// the grpc_method_config, and \a vtable provides the methods for
+/// operating on the struct type.
+grpc_mdstr_hash_table* grpc_method_config_table_convert(
+    grpc_exec_ctx* exec_ctx, const grpc_method_config_table* table,
+    void* (*convert_value)(const grpc_method_config* method_config),
+    const grpc_mdstr_hash_table_vtable* vtable);
+
+#endif /* GRPC_CORE_LIB_TRANSPORT_METHOD_CONFIG_H */
diff --git a/src/core/lib/transport/pid_controller.h b/src/core/lib/transport/pid_controller.h
index 059b5b0834..83c82d6471 100644
--- a/src/core/lib/transport/pid_controller.h
+++ b/src/core/lib/transport/pid_controller.h
@@ -61,4 +61,4 @@ void grpc_pid_controller_reset(grpc_pid_controller *pid_controller);
 double grpc_pid_controller_update(grpc_pid_controller *pid_controller,
                                   double error, double dt);
 
-#endif
+#endif /* GRPC_CORE_LIB_TRANSPORT_PID_CONTROLLER_H */
diff --git a/src/core/lib/transport/service_config.c b/src/core/lib/transport/service_config.c
index 2e2b59e3f7..552d3ec856 100644
--- a/src/core/lib/transport/service_config.c
+++ b/src/core/lib/transport/service_config.c
@@ -146,7 +146,8 @@ static char* parse_json_method_name(grpc_json* json) {
 // each name found, incrementing \a idx for each entry added.
 // Returns false on error.
 static bool parse_json_method_config(
-    grpc_json* json, void* (*create_value)(const grpc_json* method_config_json),
+    grpc_exec_ctx* exec_ctx, grpc_json* json,
+    void* (*create_value)(const grpc_json* method_config_json),
     const grpc_mdstr_hash_table_vtable* vtable,
     grpc_mdstr_hash_table_entry* entries, size_t* idx) {
   // Construct value.
@@ -176,13 +177,13 @@ static bool parse_json_method_config(
   }
   success = true;
 done:
-  vtable->destroy_value(method_config);
+  vtable->destroy_value(exec_ctx, method_config);
   gpr_strvec_destroy(&paths);
   return success;
 }
 
 grpc_mdstr_hash_table* grpc_service_config_create_method_config_table(
-    const grpc_service_config* service_config,
+    grpc_exec_ctx* exec_ctx, const grpc_service_config* service_config,
     void* (*create_value)(const grpc_json* method_config_json),
     const grpc_mdstr_hash_table_vtable* vtable) {
   const grpc_json* json = service_config->json_tree;
@@ -205,8 +206,8 @@ grpc_mdstr_hash_table* grpc_service_config_create_method_config_table(
       size_t idx = 0;
       for (grpc_json* method = field->child; method != NULL;
            method = method->next) {
-        if (!parse_json_method_config(method, create_value, vtable, entries,
-                                      &idx)) {
+        if (!parse_json_method_config(exec_ctx, method, create_value, vtable,
+                                      entries, &idx)) {
           return NULL;
         }
       }
@@ -219,15 +220,16 @@ grpc_mdstr_hash_table* grpc_service_config_create_method_config_table(
     method_config_table = grpc_mdstr_hash_table_create(num_entries, entries);
     // Clean up.
     for (size_t i = 0; i < num_entries; ++i) {
-      GRPC_MDSTR_UNREF(entries[i].key);
-      vtable->destroy_value(entries[i].value);
+      GRPC_MDSTR_UNREF(exec_ctx, entries[i].key);
+      vtable->destroy_value(exec_ctx, entries[i].value);
     }
     gpr_free(entries);
   }
   return method_config_table;
 }
 
-void* grpc_method_config_table_get(const grpc_mdstr_hash_table* table,
+void* grpc_method_config_table_get(grpc_exec_ctx* exec_ctx,
+                                   const grpc_mdstr_hash_table* table,
                                    const grpc_mdstr* path) {
   void* value = grpc_mdstr_hash_table_get(table, path);
   // If we didn't find a match for the path, try looking for a wildcard
@@ -243,7 +245,7 @@ void* grpc_method_config_table_get(const grpc_mdstr_hash_table* table,
     grpc_mdstr* wildcard_path = grpc_mdstr_from_string(buf);
     gpr_free(buf);
     value = grpc_mdstr_hash_table_get(table, wildcard_path);
-    GRPC_MDSTR_UNREF(wildcard_path);
+    GRPC_MDSTR_UNREF(exec_ctx, wildcard_path);
   }
   return value;
 }
diff --git a/src/core/lib/transport/service_config.h b/src/core/lib/transport/service_config.h
index 2ffe475193..f0897170fa 100644
--- a/src/core/lib/transport/service_config.h
+++ b/src/core/lib/transport/service_config.h
@@ -54,7 +54,7 @@ const char* grpc_service_config_get_lb_policy_name(
 /// \a vtable provides methods used to manage the values.
 /// Returns NULL on error.
 grpc_mdstr_hash_table* grpc_service_config_create_method_config_table(
-    const grpc_service_config* service_config,
+    grpc_exec_ctx* exec_ctx, const grpc_service_config* service_config,
     void* (*create_value)(const grpc_json* method_config_json),
     const grpc_mdstr_hash_table_vtable* vtable);
 
@@ -64,7 +64,8 @@ grpc_mdstr_hash_table* grpc_service_config_create_method_config_table(
 /// the form "/service/method".
 /// Returns NULL if the method has no config.
 /// Caller does NOT own a reference to the result.
-void* grpc_method_config_table_get(const grpc_mdstr_hash_table* table,
+void* grpc_method_config_table_get(grpc_exec_ctx* exec_ctx,
+                                   const grpc_mdstr_hash_table* table,
                                    const grpc_mdstr* path);
 
 #endif /* GRPC_CORE_LIB_TRANSPORT_SERVICE_CONFIG_H */
diff --git a/src/core/lib/transport/transport.c b/src/core/lib/transport/transport.c
index b448126da8..055edbb39f 100644
--- a/src/core/lib/transport/transport.c
+++ b/src/core/lib/transport/transport.c
@@ -40,6 +40,7 @@
 #include <grpc/support/log.h>
 #include <grpc/support/sync.h>
 
+#include "src/core/lib/slice/slice_internal.h"
 #include "src/core/lib/slice/slice_string_helpers.h"
 #include "src/core/lib/support/string.h"
 #include "src/core/lib/transport/transport_impl.h"
@@ -68,7 +69,7 @@ void grpc_stream_unref(grpc_exec_ctx *exec_ctx,
                        grpc_stream_refcount *refcount) {
 #endif
   if (gpr_unref(&refcount->refs)) {
-    grpc_exec_ctx_sched(exec_ctx, &refcount->destroy, GRPC_ERROR_NONE, NULL);
+    grpc_closure_sched(exec_ctx, &refcount->destroy, GRPC_ERROR_NONE);
   }
 }
 
@@ -82,7 +83,7 @@ void grpc_stream_ref_init(grpc_stream_refcount *refcount, int initial_refs,
                           grpc_iomgr_cb_func cb, void *cb_arg) {
 #endif
   gpr_ref_init(&refcount->refs, initial_refs);
-  grpc_closure_init(&refcount->destroy, cb, cb_arg);
+  grpc_closure_init(&refcount->destroy, cb, cb_arg, grpc_schedule_on_exec_ctx);
 }
 
 static void move64(uint64_t *from, uint64_t *to) {
@@ -168,11 +169,10 @@ grpc_endpoint *grpc_transport_get_endpoint(grpc_exec_ctx *exec_ctx,
 void grpc_transport_stream_op_finish_with_failure(grpc_exec_ctx *exec_ctx,
                                                   grpc_transport_stream_op *op,
                                                   grpc_error *error) {
-  grpc_exec_ctx_sched(exec_ctx, op->recv_message_ready, GRPC_ERROR_REF(error),
-                      NULL);
-  grpc_exec_ctx_sched(exec_ctx, op->recv_initial_metadata_ready,
-                      GRPC_ERROR_REF(error), NULL);
-  grpc_exec_ctx_sched(exec_ctx, op->on_complete, error, NULL);
+  grpc_closure_sched(exec_ctx, op->recv_message_ready, GRPC_ERROR_REF(error));
+  grpc_closure_sched(exec_ctx, op->recv_initial_metadata_ready,
+                     GRPC_ERROR_REF(error));
+  grpc_closure_sched(exec_ctx, op->on_complete, error);
 }
 
 typedef struct {
@@ -196,7 +196,8 @@ static void add_error(grpc_transport_stream_op *op, grpc_error **which,
   cmd = gpr_malloc(sizeof(*cmd));
   cmd->error = error;
   cmd->then_call = op->on_complete;
-  grpc_closure_init(&cmd->closure, free_message, cmd);
+  grpc_closure_init(&cmd->closure, free_message, cmd,
+                    grpc_schedule_on_exec_ctx);
   op->on_complete = &cmd->closure;
   *which = error;
 }
@@ -212,12 +213,12 @@ void grpc_transport_stream_op_add_cancellation(grpc_transport_stream_op *op,
 }
 
 void grpc_transport_stream_op_add_cancellation_with_message(
-    grpc_transport_stream_op *op, grpc_status_code status,
-    grpc_slice *optional_message) {
+    grpc_exec_ctx *exec_ctx, grpc_transport_stream_op *op,
+    grpc_status_code status, grpc_slice *optional_message) {
   GPR_ASSERT(status != GRPC_STATUS_OK);
   if (op->cancel_error != GRPC_ERROR_NONE) {
     if (optional_message) {
-      grpc_slice_unref(*optional_message);
+      grpc_slice_unref_internal(exec_ctx, *optional_message);
     }
     return;
   }
@@ -227,7 +228,7 @@ void grpc_transport_stream_op_add_cancellation_with_message(
     error = grpc_error_set_str(GRPC_ERROR_CREATE(msg),
                                GRPC_ERROR_STR_GRPC_MESSAGE, msg);
     gpr_free(msg);
-    grpc_slice_unref(*optional_message);
+    grpc_slice_unref_internal(exec_ctx, *optional_message);
   } else {
     error = GRPC_ERROR_CREATE("Call cancelled");
   }
@@ -235,14 +236,15 @@ void grpc_transport_stream_op_add_cancellation_with_message(
   add_error(op, &op->cancel_error, error);
 }
 
-void grpc_transport_stream_op_add_close(grpc_transport_stream_op *op,
+void grpc_transport_stream_op_add_close(grpc_exec_ctx *exec_ctx,
+                                        grpc_transport_stream_op *op,
                                         grpc_status_code status,
                                         grpc_slice *optional_message) {
   GPR_ASSERT(status != GRPC_STATUS_OK);
   if (op->cancel_error != GRPC_ERROR_NONE ||
       op->close_error != GRPC_ERROR_NONE) {
     if (optional_message) {
-      grpc_slice_unref(*optional_message);
+      grpc_slice_unref_internal(exec_ctx, *optional_message);
     }
     return;
   }
@@ -252,7 +254,7 @@ void grpc_transport_stream_op_add_close(grpc_transport_stream_op *op,
     error = grpc_error_set_str(GRPC_ERROR_CREATE(msg),
                                GRPC_ERROR_STR_GRPC_MESSAGE, msg);
     gpr_free(msg);
-    grpc_slice_unref(*optional_message);
+    grpc_slice_unref_internal(exec_ctx, *optional_message);
   } else {
     error = GRPC_ERROR_CREATE("Call force closed");
   }
@@ -269,14 +271,14 @@ typedef struct {
 static void destroy_made_transport_op(grpc_exec_ctx *exec_ctx, void *arg,
                                       grpc_error *error) {
   made_transport_op *op = arg;
-  grpc_exec_ctx_sched(exec_ctx, op->inner_on_complete, GRPC_ERROR_REF(error),
-                      NULL);
+  grpc_closure_sched(exec_ctx, op->inner_on_complete, GRPC_ERROR_REF(error));
   gpr_free(op);
 }
 
 grpc_transport_op *grpc_make_transport_op(grpc_closure *on_complete) {
   made_transport_op *op = gpr_malloc(sizeof(*op));
-  grpc_closure_init(&op->outer_on_complete, destroy_made_transport_op, op);
+  grpc_closure_init(&op->outer_on_complete, destroy_made_transport_op, op,
+                    grpc_schedule_on_exec_ctx);
   op->inner_on_complete = on_complete;
   memset(&op->op, 0, sizeof(op->op));
   op->op.on_consumed = &op->outer_on_complete;
@@ -292,8 +294,7 @@ typedef struct {
 static void destroy_made_transport_stream_op(grpc_exec_ctx *exec_ctx, void *arg,
                                              grpc_error *error) {
   made_transport_stream_op *op = arg;
-  grpc_exec_ctx_sched(exec_ctx, op->inner_on_complete, GRPC_ERROR_REF(error),
-                      NULL);
+  grpc_closure_sched(exec_ctx, op->inner_on_complete, GRPC_ERROR_REF(error));
   gpr_free(op);
 }
 
@@ -301,7 +302,7 @@ grpc_transport_stream_op *grpc_make_transport_stream_op(
     grpc_closure *on_complete) {
   made_transport_stream_op *op = gpr_malloc(sizeof(*op));
   grpc_closure_init(&op->outer_on_complete, destroy_made_transport_stream_op,
-                    op);
+                    op, grpc_schedule_on_exec_ctx);
   op->inner_on_complete = on_complete;
   memset(&op->op, 0, sizeof(op->op));
   op->op.on_complete = &op->outer_on_complete;
diff --git a/src/core/lib/transport/transport.h b/src/core/lib/transport/transport.h
index 96c26749c8..d1281830aa 100644
--- a/src/core/lib/transport/transport.h
+++ b/src/core/lib/transport/transport.h
@@ -249,10 +249,11 @@ void grpc_transport_stream_op_add_cancellation(grpc_transport_stream_op *op,
                                                grpc_status_code status);
 
 void grpc_transport_stream_op_add_cancellation_with_message(
-    grpc_transport_stream_op *op, grpc_status_code status,
-    grpc_slice *optional_message);
+    grpc_exec_ctx *exec_ctx, grpc_transport_stream_op *op,
+    grpc_status_code status, grpc_slice *optional_message);
 
-void grpc_transport_stream_op_add_close(grpc_transport_stream_op *op,
+void grpc_transport_stream_op_add_close(grpc_exec_ctx *exec_ctx,
+                                        grpc_transport_stream_op *op,
                                         grpc_status_code status,
                                         grpc_slice *optional_message);
 
diff --git a/src/core/lib/tsi/README.md b/src/core/lib/tsi/README.md
new file mode 100644
index 0000000000..3ca3c1ef38
--- /dev/null
+++ b/src/core/lib/tsi/README.md
@@ -0,0 +1,2 @@
+# Transport Security Interface
+An abstraction library over crypto and auth modules (typically OpenSSL)
diff --git a/src/cpp/common/channel_arguments.cc b/src/cpp/common/channel_arguments.cc
index 0301b5b8ec..1fdd106130 100644
--- a/src/cpp/common/channel_arguments.cc
+++ b/src/cpp/common/channel_arguments.cc
@@ -38,8 +38,11 @@
 #include <grpc++/resource_quota.h>
 #include <grpc/impl/codegen/grpc_types.h>
 #include <grpc/support/log.h>
+extern "C" {
 #include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/iomgr/socket_mutator.h"
+}
 namespace grpc {
 
 ChannelArguments::ChannelArguments() {
@@ -94,13 +97,15 @@ void ChannelArguments::SetSocketMutator(grpc_socket_mutator* mutator) {
   }
   grpc_arg mutator_arg = grpc_socket_mutator_to_arg(mutator);
   bool replaced = false;
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   for (auto it = args_.begin(); it != args_.end(); ++it) {
     if (it->type == mutator_arg.type &&
         grpc::string(it->key) == grpc::string(mutator_arg.key)) {
-      it->value.pointer.vtable->destroy(it->value.pointer.p);
+      it->value.pointer.vtable->destroy(&exec_ctx, it->value.pointer.p);
       it->value.pointer = mutator_arg.value.pointer;
     }
   }
+  grpc_exec_ctx_finish(&exec_ctx);
   if (!replaced) {
     args_.push_back(mutator_arg);
   }
diff --git a/src/cpp/common/channel_filter.cc b/src/cpp/common/channel_filter.cc
index ad2c0f2295..c0dc9dd63e 100644
--- a/src/cpp/common/channel_filter.cc
+++ b/src/cpp/common/channel_filter.cc
@@ -40,11 +40,12 @@ namespace grpc {
 
 // MetadataBatch
 
-grpc_linked_mdelem *MetadataBatch::AddMetadata(const string &key,
+grpc_linked_mdelem *MetadataBatch::AddMetadata(grpc_exec_ctx *exec_ctx,
+                                               const string &key,
                                                const string &value) {
   grpc_linked_mdelem *storage = new grpc_linked_mdelem;
   memset(storage, 0, sizeof(grpc_linked_mdelem));
-  storage->md = grpc_mdelem_from_strings(key.c_str(), value.c_str());
+  storage->md = grpc_mdelem_from_strings(exec_ctx, key.c_str(), value.c_str());
   grpc_metadata_batch_link_head(batch_, storage);
   return storage;
 }
@@ -89,7 +90,8 @@ std::vector<FilterRecord> *channel_filters;
 
 namespace {
 
-bool MaybeAddFilter(grpc_channel_stack_builder *builder, void *arg) {
+bool MaybeAddFilter(grpc_exec_ctx *exec_ctx,
+                    grpc_channel_stack_builder *builder, void *arg) {
   const FilterRecord &filter = *(FilterRecord *)arg;
   if (filter.include_filter) {
     const grpc_channel_args *args =
diff --git a/src/cpp/common/channel_filter.h b/src/cpp/common/channel_filter.h
index e420efc71c..5de8f5e463 100644
--- a/src/cpp/common/channel_filter.h
+++ b/src/cpp/common/channel_filter.h
@@ -70,7 +70,8 @@ class MetadataBatch {
   /// Adds metadata and returns the newly allocated storage.
   /// The caller takes ownership of the result, which must exist for the
   /// lifetime of the gRPC call.
-  grpc_linked_mdelem *AddMetadata(const string &key, const string &value);
+  grpc_linked_mdelem *AddMetadata(grpc_exec_ctx *exec_ctx, const string &key,
+                                  const string &value);
 
   class const_iterator : public std::iterator<std::bidirectional_iterator_tag,
                                               const grpc_mdelem> {
@@ -216,12 +217,13 @@ class TransportStreamOp {
 /// Represents channel data.
 class ChannelData {
  public:
-  virtual ~ChannelData() {
-    if (peer_) gpr_free((void *)peer_);
-  }
+  virtual ~ChannelData() {}
 
-  /// Caller does NOT take ownership of result.
-  const char *peer() const { return peer_; }
+  /// Initializes the call data.
+  virtual grpc_error *Init(grpc_exec_ctx *exec_ctx,
+                           grpc_channel_element_args *args) {
+    return GRPC_ERROR_NONE;
+  }
 
   // TODO(roth): Find a way to avoid passing elem into these methods.
 
@@ -232,11 +234,7 @@ class ChannelData {
                        const grpc_channel_info *channel_info);
 
  protected:
-  /// Takes ownership of \a peer.
-  ChannelData(const grpc_channel_args &args, const char *peer) : peer_(peer) {}
-
- private:
-  const char *peer_;
+  ChannelData() {}
 };
 
 /// Represents call data.
@@ -245,7 +243,10 @@ class CallData {
   virtual ~CallData() {}
 
   /// Initializes the call data.
-  virtual grpc_error *Init() { return GRPC_ERROR_NONE; }
+  virtual grpc_error *Init(grpc_exec_ctx *exec_ctx, ChannelData *channel_data,
+                           grpc_call_element_args *args) {
+    return GRPC_ERROR_NONE;
+  }
 
   // TODO(roth): Find a way to avoid passing elem into these methods.
 
@@ -263,7 +264,7 @@ class CallData {
   virtual char *GetPeer(grpc_exec_ctx *exec_ctx, grpc_call_element *elem);
 
  protected:
-  explicit CallData(const ChannelData &) {}
+  CallData() {}
 };
 
 namespace internal {
@@ -276,15 +277,11 @@ class ChannelFilter final {
  public:
   static const size_t channel_data_size = sizeof(ChannelDataType);
 
-  static void InitChannelElement(grpc_exec_ctx *exec_ctx,
-                                 grpc_channel_element *elem,
-                                 grpc_channel_element_args *args) {
-    const char *peer =
-        args->optional_transport
-            ? grpc_transport_get_peer(exec_ctx, args->optional_transport)
-            : nullptr;
-    // Construct the object in the already-allocated memory.
-    new (elem->channel_data) ChannelDataType(*args->channel_args, peer);
+  static grpc_error *InitChannelElement(grpc_exec_ctx *exec_ctx,
+                                        grpc_channel_element *elem,
+                                        grpc_channel_element_args *args) {
+    ChannelDataType *channel_data = new (elem->channel_data) ChannelDataType();
+    return channel_data->Init(exec_ctx, args);
   }
 
   static void DestroyChannelElement(grpc_exec_ctx *exec_ctx,
@@ -312,11 +309,10 @@ class ChannelFilter final {
   static grpc_error *InitCallElement(grpc_exec_ctx *exec_ctx,
                                      grpc_call_element *elem,
                                      grpc_call_element_args *args) {
-    const ChannelDataType &channel_data =
-        *(ChannelDataType *)elem->channel_data;
+    ChannelDataType *channel_data = (ChannelDataType *)elem->channel_data;
     // Construct the object in the already-allocated memory.
-    CallDataType *call_data = new (elem->call_data) CallDataType(channel_data);
-    return call_data->Init();
+    CallDataType *call_data = new (elem->call_data) CallDataType();
+    return call_data->Init(exec_ctx, channel_data, args);
   }
 
   static void DestroyCallElement(grpc_exec_ctx *exec_ctx,
diff --git a/src/cpp/common/completion_queue_cc.cc b/src/cpp/common/completion_queue_cc.cc
index 00cc102f92..0408a41085 100644
--- a/src/cpp/common/completion_queue_cc.cc
+++ b/src/cpp/common/completion_queue_cc.cc
@@ -43,11 +43,21 @@ namespace grpc {
 
 static internal::GrpcLibraryInitializer g_gli_initializer;
 
-CompletionQueue::CompletionQueue(grpc_completion_queue* take) : cq_(take) {}
+CompletionQueue::CompletionQueue(grpc_completion_queue* take) : cq_(take) {
+  InitialAvalanching();
+}
 
 void CompletionQueue::Shutdown() {
   g_gli_initializer.summon();
-  grpc_completion_queue_shutdown(cq_);
+  CompleteAvalanching();
+}
+
+void CompletionQueue::CompleteAvalanching() {
+  // Check if this was the last avalanching operation
+  if (gpr_atm_no_barrier_fetch_add(&avalanches_in_flight_,
+                                   static_cast<gpr_atm>(-1)) == 1) {
+    grpc_completion_queue_shutdown(cq_);
+  }
 }
 
 CompletionQueue::NextStatus CompletionQueue::AsyncNextInternal(
diff --git a/src/cpp/server/server_cc.cc b/src/cpp/server/server_cc.cc
index b7cfd6dbf1..817d85a81c 100644
--- a/src/cpp/server/server_cc.cc
+++ b/src/cpp/server/server_cc.cc
@@ -510,12 +510,6 @@ void Server::ShutdownInternal(gpr_timespec deadline) {
     ShutdownTag shutdown_tag;  // Dummy shutdown tag
     grpc_server_shutdown_and_notify(server_, shutdown_cq.cq(), &shutdown_tag);
 
-    // Shutdown all ThreadManagers. This will try to gracefully stop all the
-    // threads in the ThreadManagers (once they process any inflight requests)
-    for (auto it = sync_req_mgrs_.begin(); it != sync_req_mgrs_.end(); it++) {
-      (*it)->Shutdown();  // ThreadManager's Shutdown()
-    }
-
     shutdown_cq.Shutdown();
 
     void* tag;
@@ -531,6 +525,12 @@ void Server::ShutdownInternal(gpr_timespec deadline) {
     // Else in case of SHUTDOWN or GOT_EVENT, it means that the server has
     // successfully shutdown
 
+    // Shutdown all ThreadManagers. This will try to gracefully stop all the
+    // threads in the ThreadManagers (once they process any inflight requests)
+    for (auto it = sync_req_mgrs_.begin(); it != sync_req_mgrs_.end(); it++) {
+      (*it)->Shutdown();  // ThreadManager's Shutdown()
+    }
+
     // Wait for threads in all ThreadManagers to terminate
     for (auto it = sync_req_mgrs_.begin(); it != sync_req_mgrs_.end(); it++) {
       (*it)->Wait();
@@ -575,9 +575,14 @@ ServerInterface::BaseAsyncRequest::BaseAsyncRequest(
       tag_(tag),
       delete_on_finalize_(delete_on_finalize),
       call_(nullptr) {
+  call_cq_->RegisterAvalanching();  // This op will trigger more ops
   memset(&initial_metadata_array_, 0, sizeof(initial_metadata_array_));
 }
 
+ServerInterface::BaseAsyncRequest::~BaseAsyncRequest() {
+  call_cq_->CompleteAvalanching();
+}
+
 bool ServerInterface::BaseAsyncRequest::FinalizeResult(void** tag,
                                                        bool* status) {
   if (*status) {
diff --git a/src/csharp/Grpc.Auth/Grpc.Auth.csproj b/src/csharp/Grpc.Auth/Grpc.Auth.csproj
index 99e8c1a3da..db55ed5a6c 100644
--- a/src/csharp/Grpc.Auth/Grpc.Auth.csproj
+++ b/src/csharp/Grpc.Auth/Grpc.Auth.csproj
@@ -29,15 +29,6 @@
     <WarningLevel>4</WarningLevel>
     <ConsolePause>false</ConsolePause>
   </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'ReleaseSigned|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\ReleaseSigned</OutputPath>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-    <SignAssembly>True</SignAssembly>
-    <AssemblyOriginatorKeyFile>..\keys\Grpc.snk</AssemblyOriginatorKeyFile>
-  </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Net" />
diff --git a/src/csharp/Grpc.Core.Tests/CallOptionsTest.cs b/src/csharp/Grpc.Core.Tests/CallOptionsTest.cs
index 99a2d47e6e..3c3b9f7745 100644
--- a/src/csharp/Grpc.Core.Tests/CallOptionsTest.cs
+++ b/src/csharp/Grpc.Core.Tests/CallOptionsTest.cs
@@ -67,6 +67,9 @@ namespace Grpc.Core.Tests
             var credentials = new FakeCallCredentials();
             Assert.AreSame(credentials, options.WithCredentials(credentials).Credentials);
 
+            var flags = CallFlags.WaitForReady | CallFlags.CacheableRequest;
+            Assert.AreEqual(flags, options.WithFlags(flags).Flags);
+
             // Check that the original instance is unchanged.
             Assert.IsNull(options.Headers);
             Assert.IsNull(options.Deadline);
@@ -74,6 +77,7 @@ namespace Grpc.Core.Tests
             Assert.IsNull(options.WriteOptions);
             Assert.IsNull(options.PropagationToken);
             Assert.IsNull(options.Credentials);
+            Assert.AreEqual(default(CallFlags), options.Flags);
         }
 
         [Test]
@@ -94,5 +98,16 @@ namespace Grpc.Core.Tests
             Assert.AreEqual(token, new CallOptions(propagationToken: propagationToken2).Normalize().CancellationToken);
             Assert.Throws(typeof(ArgumentException), () => new CallOptions(cancellationToken: token, propagationToken: propagationToken2).Normalize());
         }
+
+        [Test]
+        public void WaitForReady()
+        {
+            var callOptions = new CallOptions();
+            Assert.IsFalse(callOptions.IsWaitForReady);
+
+            Assert.AreEqual(CallFlags.WaitForReady, callOptions.WithWaitForReady().Flags);
+            Assert.IsTrue(callOptions.WithWaitForReady().IsWaitForReady);
+            Assert.IsFalse(callOptions.WithWaitForReady(true).WithWaitForReady(false).IsWaitForReady);
+        }
     }
 }
diff --git a/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj b/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
index 19a68ab9ea..646effe21a 100644
--- a/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
+++ b/src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj
@@ -25,15 +25,6 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'ReleaseSigned|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\ReleaseSigned</OutputPath>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-    <SignAssembly>True</SignAssembly>
-    <AssemblyOriginatorKeyFile>..\keys\Grpc.snk</AssemblyOriginatorKeyFile>
-  </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="nunit.framework">
diff --git a/src/csharp/Grpc.Core.Tests/Internal/FakeNativeCall.cs b/src/csharp/Grpc.Core.Tests/Internal/FakeNativeCall.cs
index 909112a47c..fe067fe8b0 100644
--- a/src/csharp/Grpc.Core.Tests/Internal/FakeNativeCall.cs
+++ b/src/csharp/Grpc.Core.Tests/Internal/FakeNativeCall.cs
@@ -115,27 +115,27 @@ namespace Grpc.Core.Internal.Tests
             return "PEER";
         }
 
-        public void StartUnary(UnaryResponseClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+        public void StartUnary(UnaryResponseClientHandler callback, byte[] payload, WriteFlags writeFlags, MetadataArraySafeHandle metadataArray, CallFlags callFlags)
         {
             UnaryResponseClientHandler = callback;
         }
 
-        public void StartUnary(BatchContextSafeHandle ctx, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+        public void StartUnary(BatchContextSafeHandle ctx, byte[] payload, WriteFlags writeFlags, MetadataArraySafeHandle metadataArray, CallFlags callFlags)
         {
             throw new NotImplementedException();
         }
 
-        public void StartClientStreaming(UnaryResponseClientHandler callback, MetadataArraySafeHandle metadataArray)
+        public void StartClientStreaming(UnaryResponseClientHandler callback, MetadataArraySafeHandle metadataArray, CallFlags callFlags)
         {
             UnaryResponseClientHandler = callback;
         }
 
-        public void StartServerStreaming(ReceivedStatusOnClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+        public void StartServerStreaming(ReceivedStatusOnClientHandler callback, byte[] payload, WriteFlags writeFlags, MetadataArraySafeHandle metadataArray, CallFlags callFlags)
         {
             ReceivedStatusOnClientHandler = callback;
         }
 
-        public void StartDuplexStreaming(ReceivedStatusOnClientHandler callback, MetadataArraySafeHandle metadataArray)
+        public void StartDuplexStreaming(ReceivedStatusOnClientHandler callback, MetadataArraySafeHandle metadataArray, CallFlags callFlags)
         {
             ReceivedStatusOnClientHandler = callback;
         }
diff --git a/src/csharp/Grpc.Core/CallOptions.cs b/src/csharp/Grpc.Core/CallOptions.cs
index 35548cfc96..ce43dae171 100644
--- a/src/csharp/Grpc.Core/CallOptions.cs
+++ b/src/csharp/Grpc.Core/CallOptions.cs
@@ -50,6 +50,7 @@ namespace Grpc.Core
         WriteOptions writeOptions;
         ContextPropagationToken propagationToken;
         CallCredentials credentials;
+        CallFlags flags;
 
         /// <summary>
         /// Creates a new instance of <c>CallOptions</c> struct.
@@ -69,6 +70,7 @@ namespace Grpc.Core
             this.writeOptions = writeOptions;
             this.propagationToken = propagationToken;
             this.credentials = credentials;
+            this.flags = default(CallFlags);
         }
 
         /// <summary>
@@ -126,6 +128,24 @@ namespace Grpc.Core
         }
 
         /// <summary>
+        /// If <c>true</c> and and channel is in <c>ChannelState.TransientFailure</c>, the call will attempt waiting for the channel to recover
+        /// instead of failing immediately (which is the default "FailFast" semantics).
+        /// Note: experimental API that can change or be removed without any prior notice.
+        /// </summary>
+        public bool IsWaitForReady
+        {
+            get { return (this.flags & CallFlags.WaitForReady) == CallFlags.WaitForReady; }
+        }
+
+        /// <summary>
+        /// Flags to use for this call.
+        /// </summary>
+        internal CallFlags Flags
+        {
+            get { return this.flags; }
+        }
+
+        /// <summary>
         /// Returns new instance of <see cref="CallOptions"/> with
         /// <c>Headers</c> set to the value provided. Values of all other fields are preserved.
         /// </summary>
@@ -198,6 +218,32 @@ namespace Grpc.Core
         }
 
         /// <summary>
+        /// Returns new instance of <see cref="CallOptions"/> with "WaitForReady" semantics enabled/disabled.
+        /// <see cref="IsWaitForReady"/>.
+        /// Note: experimental API that can change or be removed without any prior notice.
+        /// </summary>
+        public CallOptions WithWaitForReady(bool waitForReady = true)
+        {
+            if (waitForReady)
+            {
+                return WithFlags(this.flags | CallFlags.WaitForReady);
+            }
+            return WithFlags(this.flags & ~CallFlags.WaitForReady);
+        }
+
+        /// <summary>
+        /// Returns new instance of <see cref="CallOptions"/> with
+        /// <c>Flags</c> set to the value provided. Values of all other fields are preserved.
+        /// </summary>
+        /// <param name="flags">The call flags.</param>
+        internal CallOptions WithFlags(CallFlags flags)
+        {
+            var newOptions = this;
+            newOptions.flags = flags;
+            return newOptions;
+        }
+
+        /// <summary>
         /// Returns a new instance of <see cref="CallOptions"/> with 
         /// all previously unset values set to their defaults and deadline and cancellation
         /// token propagated when appropriate.
diff --git a/src/csharp/Grpc.Core/Grpc.Core.csproj b/src/csharp/Grpc.Core/Grpc.Core.csproj
index 51e627044f..23e1ddcf7f 100644
--- a/src/csharp/Grpc.Core/Grpc.Core.csproj
+++ b/src/csharp/Grpc.Core/Grpc.Core.csproj
@@ -27,16 +27,6 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'ReleaseSigned|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\ReleaseSigned</OutputPath>
-    <DefineConstants>SIGNED</DefineConstants>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-    <SignAssembly>True</SignAssembly>
-    <AssemblyOriginatorKeyFile>..\keys\Grpc.snk</AssemblyOriginatorKeyFile>
-  </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Interactive.Async">
@@ -140,6 +130,7 @@
     <Compile Include="Logging\LogLevelFilterLogger.cs" />
     <Compile Include="Internal\RequestCallContextSafeHandle.cs" />
     <Compile Include="Utils\TaskUtils.cs" />
+    <Compile Include="Internal\CallFlags.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="Grpc.Core.project.json" />
@@ -153,4 +144,4 @@
       <Link>roots.pem</Link>
     </EmbeddedResource>
   </ItemGroup>
-</Project>
+</Project>
\ No newline at end of file
diff --git a/src/csharp/Grpc.Core/Internal/AsyncCall.cs b/src/csharp/Grpc.Core/Internal/AsyncCall.cs
index da45c4829d..1f738a3b6f 100644
--- a/src/csharp/Grpc.Core/Internal/AsyncCall.cs
+++ b/src/csharp/Grpc.Core/Internal/AsyncCall.cs
@@ -106,7 +106,7 @@ namespace Grpc.Core.Internal
                 using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
                 using (var ctx = BatchContextSafeHandle.Create())
                 {
-                    call.StartUnary(ctx, payload, metadataArray, GetWriteFlagsForCall());
+                    call.StartUnary(ctx, payload, GetWriteFlagsForCall(), metadataArray, details.Options.Flags);
 
                     var ev = cq.Pluck(ctx.Handle);
 
@@ -150,7 +150,7 @@ namespace Grpc.Core.Internal
                 unaryResponseTcs = new TaskCompletionSource<TResponse>();
                 using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
                 {
-                    call.StartUnary(HandleUnaryResponse, payload, metadataArray, GetWriteFlagsForCall());
+                    call.StartUnary(HandleUnaryResponse, payload, GetWriteFlagsForCall(), metadataArray, details.Options.Flags);
                 }
                 return unaryResponseTcs.Task;
             }
@@ -174,7 +174,7 @@ namespace Grpc.Core.Internal
                 unaryResponseTcs = new TaskCompletionSource<TResponse>();
                 using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
                 {
-                    call.StartClientStreaming(HandleUnaryResponse, metadataArray);
+                    call.StartClientStreaming(HandleUnaryResponse, metadataArray, details.Options.Flags);
                 }
 
                 return unaryResponseTcs.Task;
@@ -200,7 +200,7 @@ namespace Grpc.Core.Internal
                 streamingResponseCallFinishedTcs = new TaskCompletionSource<object>();
                 using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
                 {
-                    call.StartServerStreaming(HandleFinished, payload, metadataArray, GetWriteFlagsForCall());
+                    call.StartServerStreaming(HandleFinished, payload, GetWriteFlagsForCall(), metadataArray, details.Options.Flags);
                 }
                 call.StartReceiveInitialMetadata(HandleReceivedResponseHeaders);
             }
@@ -222,7 +222,7 @@ namespace Grpc.Core.Internal
                 streamingResponseCallFinishedTcs = new TaskCompletionSource<object>();
                 using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
                 {
-                    call.StartDuplexStreaming(HandleFinished, metadataArray);
+                    call.StartDuplexStreaming(HandleFinished, metadataArray, details.Options.Flags);
                 }
                 call.StartReceiveInitialMetadata(HandleReceivedResponseHeaders);
             }
diff --git a/src/csharp/Grpc.Core/Internal/CallFlags.cs b/src/csharp/Grpc.Core/Internal/CallFlags.cs
new file mode 100644
index 0000000000..454fa9b1f4
--- /dev/null
+++ b/src/csharp/Grpc.Core/Internal/CallFlags.cs
@@ -0,0 +1,60 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+
+namespace Grpc.Core.Internal
+{
+    /// <summary>
+    /// Flags to enable special call behaviors (client-side only).
+    /// </summary>
+    [Flags]
+    internal enum CallFlags
+    {
+        /// <summary>
+        /// The call is idempotent (retrying the call doesn't change the outcome of the operation).
+        /// </summary>
+        IdempotentRequest = 0x10,
+
+        /// <summary>
+        /// If channel is in <c>ChannelState.TransientFailure</c>, attempt waiting for the channel to recover
+        /// instead of failing the call immediately.
+        /// </summary>
+        WaitForReady = 0x20,
+
+        /// <summary>
+        /// The call is cacheable. gRPC is free to use GET verb */
+        /// </summary>
+        CacheableRequest = 0x40
+    }
+}
diff --git a/src/csharp/Grpc.Core/Internal/CallSafeHandle.cs b/src/csharp/Grpc.Core/Internal/CallSafeHandle.cs
index f817a61bce..6bfcc7fa74 100644
--- a/src/csharp/Grpc.Core/Internal/CallSafeHandle.cs
+++ b/src/csharp/Grpc.Core/Internal/CallSafeHandle.cs
@@ -63,50 +63,50 @@ namespace Grpc.Core.Internal
             Native.grpcsharp_call_set_credentials(this, credentials).CheckOk();
         }
 
-        public void StartUnary(UnaryResponseClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+        public void StartUnary(UnaryResponseClientHandler callback, byte[] payload, WriteFlags writeFlags, MetadataArraySafeHandle metadataArray, CallFlags callFlags)
         {
             using (completionQueue.NewScope())
             {
                 var ctx = BatchContextSafeHandle.Create();
                 completionQueue.CompletionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedStatusOnClient(), context.GetReceivedMessage(), context.GetReceivedInitialMetadata()));
-                Native.grpcsharp_call_start_unary(this, ctx, payload, new UIntPtr((ulong)payload.Length), metadataArray, writeFlags)
+                Native.grpcsharp_call_start_unary(this, ctx, payload, new UIntPtr((ulong)payload.Length), writeFlags, metadataArray, callFlags)
                     .CheckOk();
             }
         }
 
-        public void StartUnary(BatchContextSafeHandle ctx, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+        public void StartUnary(BatchContextSafeHandle ctx, byte[] payload, WriteFlags writeFlags, MetadataArraySafeHandle metadataArray, CallFlags callFlags)
         {
-            Native.grpcsharp_call_start_unary(this, ctx, payload, new UIntPtr((ulong)payload.Length), metadataArray, writeFlags)
+            Native.grpcsharp_call_start_unary(this, ctx, payload, new UIntPtr((ulong)payload.Length), writeFlags, metadataArray, callFlags)
                 .CheckOk();
         }
 
-        public void StartClientStreaming(UnaryResponseClientHandler callback, MetadataArraySafeHandle metadataArray)
+        public void StartClientStreaming(UnaryResponseClientHandler callback, MetadataArraySafeHandle metadataArray, CallFlags callFlags)
         {
             using (completionQueue.NewScope())
             {
                 var ctx = BatchContextSafeHandle.Create();
                 completionQueue.CompletionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedStatusOnClient(), context.GetReceivedMessage(), context.GetReceivedInitialMetadata()));
-                Native.grpcsharp_call_start_client_streaming(this, ctx, metadataArray).CheckOk();
+                Native.grpcsharp_call_start_client_streaming(this, ctx, metadataArray, callFlags).CheckOk();
             }
         }
 
-        public void StartServerStreaming(ReceivedStatusOnClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+        public void StartServerStreaming(ReceivedStatusOnClientHandler callback, byte[] payload, WriteFlags writeFlags, MetadataArraySafeHandle metadataArray, CallFlags callFlags)
         {
             using (completionQueue.NewScope())
             {
                 var ctx = BatchContextSafeHandle.Create();
                 completionQueue.CompletionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedStatusOnClient()));
-                Native.grpcsharp_call_start_server_streaming(this, ctx, payload, new UIntPtr((ulong)payload.Length), metadataArray, writeFlags).CheckOk();
+                Native.grpcsharp_call_start_server_streaming(this, ctx, payload, new UIntPtr((ulong)payload.Length), writeFlags, metadataArray, callFlags).CheckOk();
             }
         }
 
-        public void StartDuplexStreaming(ReceivedStatusOnClientHandler callback, MetadataArraySafeHandle metadataArray)
+        public void StartDuplexStreaming(ReceivedStatusOnClientHandler callback, MetadataArraySafeHandle metadataArray, CallFlags callFlags)
         {
             using (completionQueue.NewScope())
             {
                 var ctx = BatchContextSafeHandle.Create();
                 completionQueue.CompletionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedStatusOnClient()));
-                Native.grpcsharp_call_start_duplex_streaming(this, ctx, metadataArray).CheckOk();
+                Native.grpcsharp_call_start_duplex_streaming(this, ctx, metadataArray, callFlags).CheckOk();
             }
         }
 
diff --git a/src/csharp/Grpc.Core/Internal/INativeCall.cs b/src/csharp/Grpc.Core/Internal/INativeCall.cs
index cd3719cb50..94fbb08feb 100644
--- a/src/csharp/Grpc.Core/Internal/INativeCall.cs
+++ b/src/csharp/Grpc.Core/Internal/INativeCall.cs
@@ -31,6 +31,7 @@
 #endregion
 
 using System;
+using Grpc.Core;
 
 namespace Grpc.Core.Internal
 {
@@ -54,19 +55,19 @@ namespace Grpc.Core.Internal
     {
         void Cancel();
 
-        void CancelWithStatus(Grpc.Core.Status status);
+        void CancelWithStatus(Status status);
 
         string GetPeer();
 
-        void StartUnary(UnaryResponseClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, Grpc.Core.WriteFlags writeFlags);
+        void StartUnary(UnaryResponseClientHandler callback, byte[] payload, WriteFlags writeFlags, MetadataArraySafeHandle metadataArray, CallFlags callFlags);
 
-        void StartUnary(BatchContextSafeHandle ctx, byte[] payload, MetadataArraySafeHandle metadataArray, Grpc.Core.WriteFlags writeFlags);
+        void StartUnary(BatchContextSafeHandle ctx, byte[] payload, WriteFlags writeFlags, MetadataArraySafeHandle metadataArray, CallFlags callFlags);
 
-        void StartClientStreaming(UnaryResponseClientHandler callback, MetadataArraySafeHandle metadataArray);
+        void StartClientStreaming(UnaryResponseClientHandler callback, MetadataArraySafeHandle metadataArray, CallFlags callFlags);
 
-        void StartServerStreaming(ReceivedStatusOnClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, Grpc.Core.WriteFlags writeFlags);
+        void StartServerStreaming(ReceivedStatusOnClientHandler callback, byte[] payload, WriteFlags writeFlags, MetadataArraySafeHandle metadataArray, CallFlags callFlags);
 
-        void StartDuplexStreaming(ReceivedStatusOnClientHandler callback, MetadataArraySafeHandle metadataArray);
+        void StartDuplexStreaming(ReceivedStatusOnClientHandler callback, MetadataArraySafeHandle metadataArray, CallFlags callFlags);
 
         void StartReceiveMessage(ReceivedMessageHandler callback);
 
@@ -74,11 +75,11 @@ namespace Grpc.Core.Internal
 
         void StartSendInitialMetadata(SendCompletionHandler callback, MetadataArraySafeHandle metadataArray);
 
-        void StartSendMessage(SendCompletionHandler callback, byte[] payload, Grpc.Core.WriteFlags writeFlags, bool sendEmptyInitialMetadata);
+        void StartSendMessage(SendCompletionHandler callback, byte[] payload, WriteFlags writeFlags, bool sendEmptyInitialMetadata);
 
         void StartSendCloseFromClient(SendCompletionHandler callback);
 
-        void StartSendStatusFromServer(SendCompletionHandler callback, Grpc.Core.Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata, byte[] optionalPayload, Grpc.Core.WriteFlags writeFlags);
+        void StartSendStatusFromServer(SendCompletionHandler callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata, byte[] optionalPayload, WriteFlags writeFlags);
 
         void StartServerSide(ReceivedCloseOnServerHandler callback);
     }
diff --git a/src/csharp/Grpc.Core/Internal/NativeMethods.cs b/src/csharp/Grpc.Core/Internal/NativeMethods.cs
index 40ba7e30cb..ce38e37093 100644
--- a/src/csharp/Grpc.Core/Internal/NativeMethods.cs
+++ b/src/csharp/Grpc.Core/Internal/NativeMethods.cs
@@ -325,14 +325,14 @@ namespace Grpc.Core.Internal
             public delegate CallError grpcsharp_call_cancel_delegate(CallSafeHandle call);
             public delegate CallError grpcsharp_call_cancel_with_status_delegate(CallSafeHandle call, StatusCode status, string description);
             public delegate CallError grpcsharp_call_start_unary_delegate(CallSafeHandle call,
-                BatchContextSafeHandle ctx, byte[] sendBuffer, UIntPtr sendBufferLen, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags);
+                BatchContextSafeHandle ctx, byte[] sendBuffer, UIntPtr sendBufferLen, WriteFlags writeFlags, MetadataArraySafeHandle metadataArray, CallFlags metadataFlags);
             public delegate CallError grpcsharp_call_start_client_streaming_delegate(CallSafeHandle call,
-                BatchContextSafeHandle ctx, MetadataArraySafeHandle metadataArray);
+                BatchContextSafeHandle ctx, MetadataArraySafeHandle metadataArray, CallFlags metadataFlags);
             public delegate CallError grpcsharp_call_start_server_streaming_delegate(CallSafeHandle call,
-                BatchContextSafeHandle ctx, byte[] sendBuffer, UIntPtr sendBufferLen,
-                MetadataArraySafeHandle metadataArray, WriteFlags writeFlags);
+                BatchContextSafeHandle ctx, byte[] sendBuffer, UIntPtr sendBufferLen, WriteFlags writeFlags,
+                MetadataArraySafeHandle metadataArray, CallFlags metadataFlags);
             public delegate CallError grpcsharp_call_start_duplex_streaming_delegate(CallSafeHandle call,
-                BatchContextSafeHandle ctx, MetadataArraySafeHandle metadataArray);
+                BatchContextSafeHandle ctx, MetadataArraySafeHandle metadataArray, CallFlags metadataFlags);
             public delegate CallError grpcsharp_call_send_message_delegate(CallSafeHandle call,
                 BatchContextSafeHandle ctx, byte[] sendBuffer, UIntPtr sendBufferLen, WriteFlags writeFlags, bool sendEmptyInitialMetadata);
             public delegate CallError grpcsharp_call_send_close_from_client_delegate(CallSafeHandle call,
diff --git a/src/csharp/Grpc.Core/NativeDeps.targets b/src/csharp/Grpc.Core/NativeDeps.targets
index 66c5ec1292..e187f72d26 100644
--- a/src/csharp/Grpc.Core/NativeDeps.targets
+++ b/src/csharp/Grpc.Core/NativeDeps.targets
@@ -4,13 +4,11 @@
   <PropertyGroup Condition=" '$(NativeDependenciesConfiguration)' == '' ">
     <NativeDependenciesConfiguration Condition=" '$(Configuration)' == 'Debug' ">Debug</NativeDependenciesConfiguration>
     <NativeDependenciesConfiguration Condition=" '$(Configuration)' == 'Release' ">Release</NativeDependenciesConfiguration>
-    <NativeDependenciesConfiguration Condition=" '$(Configuration)' == 'ReleaseSigned' ">Release</NativeDependenciesConfiguration>
   </PropertyGroup>
 
   <PropertyGroup Condition=" '$(NativeDependenciesConfigurationUnix)' == '' ">
     <NativeDependenciesConfigurationUnix Condition=" '$(Configuration)' == 'Debug' ">dbg</NativeDependenciesConfigurationUnix>
     <NativeDependenciesConfigurationUnix Condition=" '$(Configuration)' == 'Release' ">opt</NativeDependenciesConfigurationUnix>
-    <NativeDependenciesConfigurationUnix Condition=" '$(Configuration)' == 'ReleaseSigned' ">opt</NativeDependenciesConfigurationUnix>
   </PropertyGroup>
 
   <!-- Autodetect platform -->
diff --git a/src/csharp/Grpc.Examples.MathClient/Grpc.Examples.MathClient.csproj b/src/csharp/Grpc.Examples.MathClient/Grpc.Examples.MathClient.csproj
index 65bf236def..de4005c2f6 100644
--- a/src/csharp/Grpc.Examples.MathClient/Grpc.Examples.MathClient.csproj
+++ b/src/csharp/Grpc.Examples.MathClient/Grpc.Examples.MathClient.csproj
@@ -27,15 +27,6 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'ReleaseSigned|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\ReleaseSigned</OutputPath>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-    <SignAssembly>True</SignAssembly>
-    <AssemblyOriginatorKeyFile>..\keys\Grpc.snk</AssemblyOriginatorKeyFile>
-  </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
   </ItemGroup>
diff --git a/src/csharp/Grpc.Examples.MathServer/Grpc.Examples.MathServer.csproj b/src/csharp/Grpc.Examples.MathServer/Grpc.Examples.MathServer.csproj
index 26b42b6936..3f38de2b71 100644
--- a/src/csharp/Grpc.Examples.MathServer/Grpc.Examples.MathServer.csproj
+++ b/src/csharp/Grpc.Examples.MathServer/Grpc.Examples.MathServer.csproj
@@ -27,15 +27,6 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'ReleaseSigned|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\ReleaseSigned</OutputPath>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-    <SignAssembly>True</SignAssembly>
-    <AssemblyOriginatorKeyFile>..\keys\Grpc.snk</AssemblyOriginatorKeyFile>
-  </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
   </ItemGroup>
diff --git a/src/csharp/Grpc.Examples.Tests/Grpc.Examples.Tests.csproj b/src/csharp/Grpc.Examples.Tests/Grpc.Examples.Tests.csproj
index 16d7a44f92..d22fe87825 100644
--- a/src/csharp/Grpc.Examples.Tests/Grpc.Examples.Tests.csproj
+++ b/src/csharp/Grpc.Examples.Tests/Grpc.Examples.Tests.csproj
@@ -25,15 +25,6 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'ReleaseSigned|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\ReleaseSigned</OutputPath>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-    <SignAssembly>True</SignAssembly>
-    <AssemblyOriginatorKeyFile>..\keys\Grpc.snk</AssemblyOriginatorKeyFile>
-  </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="nunit.framework">
diff --git a/src/csharp/Grpc.Examples/Grpc.Examples.csproj b/src/csharp/Grpc.Examples/Grpc.Examples.csproj
index c1ea2e2833..44acb6c2e3 100644
--- a/src/csharp/Grpc.Examples/Grpc.Examples.csproj
+++ b/src/csharp/Grpc.Examples/Grpc.Examples.csproj
@@ -27,15 +27,6 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'ReleaseSigned|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\ReleaseSigned</OutputPath>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-    <SignAssembly>True</SignAssembly>
-    <AssemblyOriginatorKeyFile>..\keys\Grpc.snk</AssemblyOriginatorKeyFile>
-  </PropertyGroup>
   <ItemGroup>
     <Reference Include="nunit.framework">
       <HintPath>..\packages\NUnit.3.2.0\lib\net45\nunit.framework.dll</HintPath>
diff --git a/src/csharp/Grpc.Examples/MathGrpc.cs b/src/csharp/Grpc.Examples/MathGrpc.cs
index 8b431c7218..3364b8ce8e 100644
--- a/src/csharp/Grpc.Examples/MathGrpc.cs
+++ b/src/csharp/Grpc.Examples/MathGrpc.cs
@@ -85,39 +85,53 @@ namespace Math {
     public abstract partial class MathBase
     {
       /// <summary>
-      ///  Div divides DivArgs.dividend by DivArgs.divisor and returns the quotient
-      ///  and remainder.
+      /// Div divides DivArgs.dividend by DivArgs.divisor and returns the quotient
+      /// and remainder.
       /// </summary>
+      /// <param name="request">The request received from the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>The response to send back to the client (wrapped by a task).</returns>
       public virtual global::System.Threading.Tasks.Task<global::Math.DivReply> Div(global::Math.DivArgs request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
 
       /// <summary>
-      ///  DivMany accepts an arbitrary number of division args from the client stream
-      ///  and sends back the results in the reply stream.  The stream continues until
-      ///  the client closes its end; the server does the same after sending all the
-      ///  replies.  The stream ends immediately if either end aborts.
+      /// DivMany accepts an arbitrary number of division args from the client stream
+      /// and sends back the results in the reply stream.  The stream continues until
+      /// the client closes its end; the server does the same after sending all the
+      /// replies.  The stream ends immediately if either end aborts.
       /// </summary>
+      /// <param name="requestStream">Used for reading requests from the client.</param>
+      /// <param name="responseStream">Used for sending responses back to the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>A task indicating completion of the handler.</returns>
       public virtual global::System.Threading.Tasks.Task DivMany(IAsyncStreamReader<global::Math.DivArgs> requestStream, IServerStreamWriter<global::Math.DivReply> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
 
       /// <summary>
-      ///  Fib generates numbers in the Fibonacci sequence.  If FibArgs.limit > 0, Fib
-      ///  generates up to limit numbers; otherwise it continues until the call is
-      ///  canceled.  Unlike Fib above, Fib has no final FibReply.
+      /// Fib generates numbers in the Fibonacci sequence.  If FibArgs.limit > 0, Fib
+      /// generates up to limit numbers; otherwise it continues until the call is
+      /// canceled.  Unlike Fib above, Fib has no final FibReply.
       /// </summary>
+      /// <param name="request">The request received from the client.</param>
+      /// <param name="responseStream">Used for sending responses back to the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>A task indicating completion of the handler.</returns>
       public virtual global::System.Threading.Tasks.Task Fib(global::Math.FibArgs request, IServerStreamWriter<global::Math.Num> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
 
       /// <summary>
-      ///  Sum sums a stream of numbers, returning the final result once the stream
-      ///  is closed.
+      /// Sum sums a stream of numbers, returning the final result once the stream
+      /// is closed.
       /// </summary>
+      /// <param name="requestStream">Used for reading requests from the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>The response to send back to the client (wrapped by a task).</returns>
       public virtual global::System.Threading.Tasks.Task<global::Math.Num> Sum(IAsyncStreamReader<global::Math.Num> requestStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
@@ -149,87 +163,123 @@ namespace Math {
       }
 
       /// <summary>
-      ///  Div divides DivArgs.dividend by DivArgs.divisor and returns the quotient
-      ///  and remainder.
+      /// Div divides DivArgs.dividend by DivArgs.divisor and returns the quotient
+      /// and remainder.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Math.DivReply Div(global::Math.DivArgs request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return Div(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  Div divides DivArgs.dividend by DivArgs.divisor and returns the quotient
-      ///  and remainder.
+      /// Div divides DivArgs.dividend by DivArgs.divisor and returns the quotient
+      /// and remainder.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Math.DivReply Div(global::Math.DivArgs request, CallOptions options)
       {
         return CallInvoker.BlockingUnaryCall(__Method_Div, null, options, request);
       }
       /// <summary>
-      ///  Div divides DivArgs.dividend by DivArgs.divisor and returns the quotient
-      ///  and remainder.
+      /// Div divides DivArgs.dividend by DivArgs.divisor and returns the quotient
+      /// and remainder.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Math.DivReply> DivAsync(global::Math.DivArgs request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return DivAsync(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  Div divides DivArgs.dividend by DivArgs.divisor and returns the quotient
-      ///  and remainder.
+      /// Div divides DivArgs.dividend by DivArgs.divisor and returns the quotient
+      /// and remainder.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Math.DivReply> DivAsync(global::Math.DivArgs request, CallOptions options)
       {
         return CallInvoker.AsyncUnaryCall(__Method_Div, null, options, request);
       }
       /// <summary>
-      ///  DivMany accepts an arbitrary number of division args from the client stream
-      ///  and sends back the results in the reply stream.  The stream continues until
-      ///  the client closes its end; the server does the same after sending all the
-      ///  replies.  The stream ends immediately if either end aborts.
+      /// DivMany accepts an arbitrary number of division args from the client stream
+      /// and sends back the results in the reply stream.  The stream continues until
+      /// the client closes its end; the server does the same after sending all the
+      /// replies.  The stream ends immediately if either end aborts.
       /// </summary>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncDuplexStreamingCall<global::Math.DivArgs, global::Math.DivReply> DivMany(Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return DivMany(new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  DivMany accepts an arbitrary number of division args from the client stream
-      ///  and sends back the results in the reply stream.  The stream continues until
-      ///  the client closes its end; the server does the same after sending all the
-      ///  replies.  The stream ends immediately if either end aborts.
+      /// DivMany accepts an arbitrary number of division args from the client stream
+      /// and sends back the results in the reply stream.  The stream continues until
+      /// the client closes its end; the server does the same after sending all the
+      /// replies.  The stream ends immediately if either end aborts.
       /// </summary>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncDuplexStreamingCall<global::Math.DivArgs, global::Math.DivReply> DivMany(CallOptions options)
       {
         return CallInvoker.AsyncDuplexStreamingCall(__Method_DivMany, null, options);
       }
       /// <summary>
-      ///  Fib generates numbers in the Fibonacci sequence.  If FibArgs.limit > 0, Fib
-      ///  generates up to limit numbers; otherwise it continues until the call is
-      ///  canceled.  Unlike Fib above, Fib has no final FibReply.
+      /// Fib generates numbers in the Fibonacci sequence.  If FibArgs.limit > 0, Fib
+      /// generates up to limit numbers; otherwise it continues until the call is
+      /// canceled.  Unlike Fib above, Fib has no final FibReply.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncServerStreamingCall<global::Math.Num> Fib(global::Math.FibArgs request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return Fib(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  Fib generates numbers in the Fibonacci sequence.  If FibArgs.limit > 0, Fib
-      ///  generates up to limit numbers; otherwise it continues until the call is
-      ///  canceled.  Unlike Fib above, Fib has no final FibReply.
+      /// Fib generates numbers in the Fibonacci sequence.  If FibArgs.limit > 0, Fib
+      /// generates up to limit numbers; otherwise it continues until the call is
+      /// canceled.  Unlike Fib above, Fib has no final FibReply.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncServerStreamingCall<global::Math.Num> Fib(global::Math.FibArgs request, CallOptions options)
       {
         return CallInvoker.AsyncServerStreamingCall(__Method_Fib, null, options, request);
       }
       /// <summary>
-      ///  Sum sums a stream of numbers, returning the final result once the stream
-      ///  is closed.
+      /// Sum sums a stream of numbers, returning the final result once the stream
+      /// is closed.
       /// </summary>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncClientStreamingCall<global::Math.Num, global::Math.Num> Sum(Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return Sum(new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  Sum sums a stream of numbers, returning the final result once the stream
-      ///  is closed.
+      /// Sum sums a stream of numbers, returning the final result once the stream
+      /// is closed.
       /// </summary>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncClientStreamingCall<global::Math.Num, global::Math.Num> Sum(CallOptions options)
       {
         return CallInvoker.AsyncClientStreamingCall(__Method_Sum, null, options);
@@ -242,6 +292,7 @@ namespace Math {
     }
 
     /// <summary>Creates service definition that can be registered with a server</summary>
+    /// <param name="serviceImpl">An object implementing the server-side handling logic.</param>
     public static ServerServiceDefinition BindService(MathBase serviceImpl)
     {
       return ServerServiceDefinition.CreateBuilder()
diff --git a/src/csharp/Grpc.HealthCheck.Tests/Grpc.HealthCheck.Tests.csproj b/src/csharp/Grpc.HealthCheck.Tests/Grpc.HealthCheck.Tests.csproj
index 93c3b3a55f..b82f976861 100644
--- a/src/csharp/Grpc.HealthCheck.Tests/Grpc.HealthCheck.Tests.csproj
+++ b/src/csharp/Grpc.HealthCheck.Tests/Grpc.HealthCheck.Tests.csproj
@@ -27,15 +27,6 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'ReleaseSigned|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\ReleaseSigned</OutputPath>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-    <SignAssembly>True</SignAssembly>
-    <AssemblyOriginatorKeyFile>..\keys\Grpc.snk</AssemblyOriginatorKeyFile>
-  </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Core" />
diff --git a/src/csharp/Grpc.HealthCheck/Grpc.HealthCheck.csproj b/src/csharp/Grpc.HealthCheck/Grpc.HealthCheck.csproj
index 7418768316..63aa18584d 100644
--- a/src/csharp/Grpc.HealthCheck/Grpc.HealthCheck.csproj
+++ b/src/csharp/Grpc.HealthCheck/Grpc.HealthCheck.csproj
@@ -28,15 +28,6 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'ReleaseSigned|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\ReleaseSigned</OutputPath>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-    <SignAssembly>True</SignAssembly>
-    <AssemblyOriginatorKeyFile>..\keys\Grpc.snk</AssemblyOriginatorKeyFile>
-  </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Core" />
diff --git a/src/csharp/Grpc.HealthCheck/HealthGrpc.cs b/src/csharp/Grpc.HealthCheck/HealthGrpc.cs
index ad5cf11b75..020c2df565 100644
--- a/src/csharp/Grpc.HealthCheck/HealthGrpc.cs
+++ b/src/csharp/Grpc.HealthCheck/HealthGrpc.cs
@@ -115,6 +115,7 @@ namespace Grpc.Health.V1 {
     }
 
     /// <summary>Creates service definition that can be registered with a server</summary>
+    /// <param name="serviceImpl">An object implementing the server-side handling logic.</param>
     public static ServerServiceDefinition BindService(HealthBase serviceImpl)
     {
       return ServerServiceDefinition.CreateBuilder()
diff --git a/src/csharp/Grpc.IntegrationTesting.Client/Grpc.IntegrationTesting.Client.csproj b/src/csharp/Grpc.IntegrationTesting.Client/Grpc.IntegrationTesting.Client.csproj
index ae58073b52..6bb5f33966 100644
--- a/src/csharp/Grpc.IntegrationTesting.Client/Grpc.IntegrationTesting.Client.csproj
+++ b/src/csharp/Grpc.IntegrationTesting.Client/Grpc.IntegrationTesting.Client.csproj
@@ -29,15 +29,6 @@
     <WarningLevel>4</WarningLevel>
     <PlatformTarget>AnyCPU</PlatformTarget>
   </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'ReleaseSigned|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\ReleaseSigned</OutputPath>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-    <SignAssembly>True</SignAssembly>
-    <AssemblyOriginatorKeyFile>..\keys\Grpc.snk</AssemblyOriginatorKeyFile>
-  </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Net" />
diff --git a/src/csharp/Grpc.IntegrationTesting.QpsWorker/Grpc.IntegrationTesting.QpsWorker.csproj b/src/csharp/Grpc.IntegrationTesting.QpsWorker/Grpc.IntegrationTesting.QpsWorker.csproj
index 593bf0939d..3b9587e315 100644
--- a/src/csharp/Grpc.IntegrationTesting.QpsWorker/Grpc.IntegrationTesting.QpsWorker.csproj
+++ b/src/csharp/Grpc.IntegrationTesting.QpsWorker/Grpc.IntegrationTesting.QpsWorker.csproj
@@ -27,15 +27,6 @@
     <WarningLevel>4</WarningLevel>
     <PlatformTarget>AnyCPU</PlatformTarget>
   </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'ReleaseSigned|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\ReleaseSigned</OutputPath>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-    <SignAssembly>True</SignAssembly>
-    <AssemblyOriginatorKeyFile>..\keys\Grpc.snk</AssemblyOriginatorKeyFile>
-  </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
   </ItemGroup>
diff --git a/src/csharp/Grpc.IntegrationTesting.Server/Grpc.IntegrationTesting.Server.csproj b/src/csharp/Grpc.IntegrationTesting.Server/Grpc.IntegrationTesting.Server.csproj
index d5c40ba948..081dc24fbf 100644
--- a/src/csharp/Grpc.IntegrationTesting.Server/Grpc.IntegrationTesting.Server.csproj
+++ b/src/csharp/Grpc.IntegrationTesting.Server/Grpc.IntegrationTesting.Server.csproj
@@ -29,15 +29,6 @@
     <WarningLevel>4</WarningLevel>
     <PlatformTarget>AnyCPU</PlatformTarget>
   </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'ReleaseSigned|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\ReleaseSigned</OutputPath>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-    <SignAssembly>True</SignAssembly>
-    <AssemblyOriginatorKeyFile>..\keys\Grpc.snk</AssemblyOriginatorKeyFile>
-  </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Net" />
diff --git a/src/csharp/Grpc.IntegrationTesting.StressClient/Grpc.IntegrationTesting.StressClient.csproj b/src/csharp/Grpc.IntegrationTesting.StressClient/Grpc.IntegrationTesting.StressClient.csproj
index 8bd3d78913..0f28340450 100644
--- a/src/csharp/Grpc.IntegrationTesting.StressClient/Grpc.IntegrationTesting.StressClient.csproj
+++ b/src/csharp/Grpc.IntegrationTesting.StressClient/Grpc.IntegrationTesting.StressClient.csproj
@@ -27,15 +27,6 @@
     <WarningLevel>4</WarningLevel>
     <PlatformTarget>AnyCPU</PlatformTarget>
   </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'ReleaseSigned|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\ReleaseSigned</OutputPath>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-    <SignAssembly>True</SignAssembly>
-    <AssemblyOriginatorKeyFile>..\keys\Grpc.snk</AssemblyOriginatorKeyFile>
-  </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
   </ItemGroup>
diff --git a/src/csharp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj b/src/csharp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj
index 161b015300..f7abcf8046 100644
--- a/src/csharp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj
+++ b/src/csharp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj
@@ -28,15 +28,6 @@
     <WarningLevel>4</WarningLevel>
     <PlatformTarget>AnyCPU</PlatformTarget>
   </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'ReleaseSigned|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\ReleaseSigned</OutputPath>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-    <SignAssembly>True</SignAssembly>
-    <AssemblyOriginatorKeyFile>..\keys\Grpc.snk</AssemblyOriginatorKeyFile>
-  </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Net" />
diff --git a/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs b/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs
index d0bf0afc1d..8b58622d53 100644
--- a/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs
@@ -76,17 +76,24 @@ namespace Grpc.Testing {
     public abstract partial class MetricsServiceBase
     {
       /// <summary>
-      ///  Returns the values of all the gauges that are currently being maintained by
-      ///  the service
+      /// Returns the values of all the gauges that are currently being maintained by
+      /// the service
       /// </summary>
+      /// <param name="request">The request received from the client.</param>
+      /// <param name="responseStream">Used for sending responses back to the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>A task indicating completion of the handler.</returns>
       public virtual global::System.Threading.Tasks.Task GetAllGauges(global::Grpc.Testing.EmptyMessage request, IServerStreamWriter<global::Grpc.Testing.GaugeResponse> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
 
       /// <summary>
-      ///  Returns the value of one gauge
+      /// Returns the value of one gauge
       /// </summary>
+      /// <param name="request">The request received from the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>The response to send back to the client (wrapped by a task).</returns>
       public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.GaugeResponse> GetGauge(global::Grpc.Testing.GaugeRequest request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
@@ -118,45 +125,69 @@ namespace Grpc.Testing {
       }
 
       /// <summary>
-      ///  Returns the values of all the gauges that are currently being maintained by
-      ///  the service
+      /// Returns the values of all the gauges that are currently being maintained by
+      /// the service
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncServerStreamingCall<global::Grpc.Testing.GaugeResponse> GetAllGauges(global::Grpc.Testing.EmptyMessage request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return GetAllGauges(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  Returns the values of all the gauges that are currently being maintained by
-      ///  the service
+      /// Returns the values of all the gauges that are currently being maintained by
+      /// the service
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncServerStreamingCall<global::Grpc.Testing.GaugeResponse> GetAllGauges(global::Grpc.Testing.EmptyMessage request, CallOptions options)
       {
         return CallInvoker.AsyncServerStreamingCall(__Method_GetAllGauges, null, options, request);
       }
       /// <summary>
-      ///  Returns the value of one gauge
+      /// Returns the value of one gauge
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.GaugeResponse GetGauge(global::Grpc.Testing.GaugeRequest request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return GetGauge(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  Returns the value of one gauge
+      /// Returns the value of one gauge
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.GaugeResponse GetGauge(global::Grpc.Testing.GaugeRequest request, CallOptions options)
       {
         return CallInvoker.BlockingUnaryCall(__Method_GetGauge, null, options, request);
       }
       /// <summary>
-      ///  Returns the value of one gauge
+      /// Returns the value of one gauge
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.GaugeResponse> GetGaugeAsync(global::Grpc.Testing.GaugeRequest request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return GetGaugeAsync(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  Returns the value of one gauge
+      /// Returns the value of one gauge
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.GaugeResponse> GetGaugeAsync(global::Grpc.Testing.GaugeRequest request, CallOptions options)
       {
         return CallInvoker.AsyncUnaryCall(__Method_GetGauge, null, options, request);
@@ -169,6 +200,7 @@ namespace Grpc.Testing {
     }
 
     /// <summary>Creates service definition that can be registered with a server</summary>
+    /// <param name="serviceImpl">An object implementing the server-side handling logic.</param>
     public static ServerServiceDefinition BindService(MetricsServiceBase serviceImpl)
     {
       return ServerServiceDefinition.CreateBuilder()
diff --git a/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs b/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs
index 3cc4ed9f3c..5135d9ab66 100644
--- a/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/ServicesGrpc.cs
@@ -71,18 +71,25 @@ namespace Grpc.Testing {
     public abstract partial class BenchmarkServiceBase
     {
       /// <summary>
-      ///  One request followed by one response.
-      ///  The server returns the client payload as-is.
+      /// One request followed by one response.
+      /// The server returns the client payload as-is.
       /// </summary>
+      /// <param name="request">The request received from the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>The response to send back to the client (wrapped by a task).</returns>
       public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
 
       /// <summary>
-      ///  One request followed by one response.
-      ///  The server returns the client payload as-is.
+      /// One request followed by one response.
+      /// The server returns the client payload as-is.
       /// </summary>
+      /// <param name="requestStream">Used for reading requests from the client.</param>
+      /// <param name="responseStream">Used for sending responses back to the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>A task indicating completion of the handler.</returns>
       public virtual global::System.Threading.Tasks.Task StreamingCall(IAsyncStreamReader<global::Grpc.Testing.SimpleRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.SimpleResponse> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
@@ -114,49 +121,71 @@ namespace Grpc.Testing {
       }
 
       /// <summary>
-      ///  One request followed by one response.
-      ///  The server returns the client payload as-is.
+      /// One request followed by one response.
+      /// The server returns the client payload as-is.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.SimpleResponse UnaryCall(global::Grpc.Testing.SimpleRequest request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return UnaryCall(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  One request followed by one response.
-      ///  The server returns the client payload as-is.
+      /// One request followed by one response.
+      /// The server returns the client payload as-is.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.SimpleResponse UnaryCall(global::Grpc.Testing.SimpleRequest request, CallOptions options)
       {
         return CallInvoker.BlockingUnaryCall(__Method_UnaryCall, null, options, request);
       }
       /// <summary>
-      ///  One request followed by one response.
-      ///  The server returns the client payload as-is.
+      /// One request followed by one response.
+      /// The server returns the client payload as-is.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.SimpleResponse> UnaryCallAsync(global::Grpc.Testing.SimpleRequest request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return UnaryCallAsync(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  One request followed by one response.
-      ///  The server returns the client payload as-is.
+      /// One request followed by one response.
+      /// The server returns the client payload as-is.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.SimpleResponse> UnaryCallAsync(global::Grpc.Testing.SimpleRequest request, CallOptions options)
       {
         return CallInvoker.AsyncUnaryCall(__Method_UnaryCall, null, options, request);
       }
       /// <summary>
-      ///  One request followed by one response.
-      ///  The server returns the client payload as-is.
+      /// One request followed by one response.
+      /// The server returns the client payload as-is.
       /// </summary>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncDuplexStreamingCall<global::Grpc.Testing.SimpleRequest, global::Grpc.Testing.SimpleResponse> StreamingCall(Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return StreamingCall(new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  One request followed by one response.
-      ///  The server returns the client payload as-is.
+      /// One request followed by one response.
+      /// The server returns the client payload as-is.
       /// </summary>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncDuplexStreamingCall<global::Grpc.Testing.SimpleRequest, global::Grpc.Testing.SimpleResponse> StreamingCall(CallOptions options)
       {
         return CallInvoker.AsyncDuplexStreamingCall(__Method_StreamingCall, null, options);
@@ -169,6 +198,7 @@ namespace Grpc.Testing {
     }
 
     /// <summary>Creates service definition that can be registered with a server</summary>
+    /// <param name="serviceImpl">An object implementing the server-side handling logic.</param>
     public static ServerServiceDefinition BindService(BenchmarkServiceBase serviceImpl)
     {
       return ServerServiceDefinition.CreateBuilder()
@@ -227,42 +257,56 @@ namespace Grpc.Testing {
     public abstract partial class WorkerServiceBase
     {
       /// <summary>
-      ///  Start server with specified workload.
-      ///  First request sent specifies the ServerConfig followed by ServerStatus
-      ///  response. After that, a "Mark" can be sent anytime to request the latest
-      ///  stats. Closing the stream will initiate shutdown of the test server
-      ///  and once the shutdown has finished, the OK status is sent to terminate
-      ///  this RPC.
+      /// Start server with specified workload.
+      /// First request sent specifies the ServerConfig followed by ServerStatus
+      /// response. After that, a "Mark" can be sent anytime to request the latest
+      /// stats. Closing the stream will initiate shutdown of the test server
+      /// and once the shutdown has finished, the OK status is sent to terminate
+      /// this RPC.
       /// </summary>
+      /// <param name="requestStream">Used for reading requests from the client.</param>
+      /// <param name="responseStream">Used for sending responses back to the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>A task indicating completion of the handler.</returns>
       public virtual global::System.Threading.Tasks.Task RunServer(IAsyncStreamReader<global::Grpc.Testing.ServerArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ServerStatus> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
 
       /// <summary>
-      ///  Start client with specified workload.
-      ///  First request sent specifies the ClientConfig followed by ClientStatus
-      ///  response. After that, a "Mark" can be sent anytime to request the latest
-      ///  stats. Closing the stream will initiate shutdown of the test client
-      ///  and once the shutdown has finished, the OK status is sent to terminate
-      ///  this RPC.
+      /// Start client with specified workload.
+      /// First request sent specifies the ClientConfig followed by ClientStatus
+      /// response. After that, a "Mark" can be sent anytime to request the latest
+      /// stats. Closing the stream will initiate shutdown of the test client
+      /// and once the shutdown has finished, the OK status is sent to terminate
+      /// this RPC.
       /// </summary>
+      /// <param name="requestStream">Used for reading requests from the client.</param>
+      /// <param name="responseStream">Used for sending responses back to the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>A task indicating completion of the handler.</returns>
       public virtual global::System.Threading.Tasks.Task RunClient(IAsyncStreamReader<global::Grpc.Testing.ClientArgs> requestStream, IServerStreamWriter<global::Grpc.Testing.ClientStatus> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
 
       /// <summary>
-      ///  Just return the core count - unary call
+      /// Just return the core count - unary call
       /// </summary>
+      /// <param name="request">The request received from the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>The response to send back to the client (wrapped by a task).</returns>
       public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.CoreResponse> CoreCount(global::Grpc.Testing.CoreRequest request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
 
       /// <summary>
-      ///  Quit this worker
+      /// Quit this worker
       /// </summary>
+      /// <param name="request">The request received from the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>The response to send back to the client (wrapped by a task).</returns>
       public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.Void> QuitWorker(global::Grpc.Testing.Void request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
@@ -294,105 +338,149 @@ namespace Grpc.Testing {
       }
 
       /// <summary>
-      ///  Start server with specified workload.
-      ///  First request sent specifies the ServerConfig followed by ServerStatus
-      ///  response. After that, a "Mark" can be sent anytime to request the latest
-      ///  stats. Closing the stream will initiate shutdown of the test server
-      ///  and once the shutdown has finished, the OK status is sent to terminate
-      ///  this RPC.
+      /// Start server with specified workload.
+      /// First request sent specifies the ServerConfig followed by ServerStatus
+      /// response. After that, a "Mark" can be sent anytime to request the latest
+      /// stats. Closing the stream will initiate shutdown of the test server
+      /// and once the shutdown has finished, the OK status is sent to terminate
+      /// this RPC.
       /// </summary>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncDuplexStreamingCall<global::Grpc.Testing.ServerArgs, global::Grpc.Testing.ServerStatus> RunServer(Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return RunServer(new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  Start server with specified workload.
-      ///  First request sent specifies the ServerConfig followed by ServerStatus
-      ///  response. After that, a "Mark" can be sent anytime to request the latest
-      ///  stats. Closing the stream will initiate shutdown of the test server
-      ///  and once the shutdown has finished, the OK status is sent to terminate
-      ///  this RPC.
+      /// Start server with specified workload.
+      /// First request sent specifies the ServerConfig followed by ServerStatus
+      /// response. After that, a "Mark" can be sent anytime to request the latest
+      /// stats. Closing the stream will initiate shutdown of the test server
+      /// and once the shutdown has finished, the OK status is sent to terminate
+      /// this RPC.
       /// </summary>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncDuplexStreamingCall<global::Grpc.Testing.ServerArgs, global::Grpc.Testing.ServerStatus> RunServer(CallOptions options)
       {
         return CallInvoker.AsyncDuplexStreamingCall(__Method_RunServer, null, options);
       }
       /// <summary>
-      ///  Start client with specified workload.
-      ///  First request sent specifies the ClientConfig followed by ClientStatus
-      ///  response. After that, a "Mark" can be sent anytime to request the latest
-      ///  stats. Closing the stream will initiate shutdown of the test client
-      ///  and once the shutdown has finished, the OK status is sent to terminate
-      ///  this RPC.
+      /// Start client with specified workload.
+      /// First request sent specifies the ClientConfig followed by ClientStatus
+      /// response. After that, a "Mark" can be sent anytime to request the latest
+      /// stats. Closing the stream will initiate shutdown of the test client
+      /// and once the shutdown has finished, the OK status is sent to terminate
+      /// this RPC.
       /// </summary>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncDuplexStreamingCall<global::Grpc.Testing.ClientArgs, global::Grpc.Testing.ClientStatus> RunClient(Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return RunClient(new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  Start client with specified workload.
-      ///  First request sent specifies the ClientConfig followed by ClientStatus
-      ///  response. After that, a "Mark" can be sent anytime to request the latest
-      ///  stats. Closing the stream will initiate shutdown of the test client
-      ///  and once the shutdown has finished, the OK status is sent to terminate
-      ///  this RPC.
+      /// Start client with specified workload.
+      /// First request sent specifies the ClientConfig followed by ClientStatus
+      /// response. After that, a "Mark" can be sent anytime to request the latest
+      /// stats. Closing the stream will initiate shutdown of the test client
+      /// and once the shutdown has finished, the OK status is sent to terminate
+      /// this RPC.
       /// </summary>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncDuplexStreamingCall<global::Grpc.Testing.ClientArgs, global::Grpc.Testing.ClientStatus> RunClient(CallOptions options)
       {
         return CallInvoker.AsyncDuplexStreamingCall(__Method_RunClient, null, options);
       }
       /// <summary>
-      ///  Just return the core count - unary call
+      /// Just return the core count - unary call
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.CoreResponse CoreCount(global::Grpc.Testing.CoreRequest request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return CoreCount(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  Just return the core count - unary call
+      /// Just return the core count - unary call
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.CoreResponse CoreCount(global::Grpc.Testing.CoreRequest request, CallOptions options)
       {
         return CallInvoker.BlockingUnaryCall(__Method_CoreCount, null, options, request);
       }
       /// <summary>
-      ///  Just return the core count - unary call
+      /// Just return the core count - unary call
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.CoreResponse> CoreCountAsync(global::Grpc.Testing.CoreRequest request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return CoreCountAsync(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  Just return the core count - unary call
+      /// Just return the core count - unary call
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.CoreResponse> CoreCountAsync(global::Grpc.Testing.CoreRequest request, CallOptions options)
       {
         return CallInvoker.AsyncUnaryCall(__Method_CoreCount, null, options, request);
       }
       /// <summary>
-      ///  Quit this worker
+      /// Quit this worker
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.Void QuitWorker(global::Grpc.Testing.Void request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return QuitWorker(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  Quit this worker
+      /// Quit this worker
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.Void QuitWorker(global::Grpc.Testing.Void request, CallOptions options)
       {
         return CallInvoker.BlockingUnaryCall(__Method_QuitWorker, null, options, request);
       }
       /// <summary>
-      ///  Quit this worker
+      /// Quit this worker
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.Void> QuitWorkerAsync(global::Grpc.Testing.Void request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return QuitWorkerAsync(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  Quit this worker
+      /// Quit this worker
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.Void> QuitWorkerAsync(global::Grpc.Testing.Void request, CallOptions options)
       {
         return CallInvoker.AsyncUnaryCall(__Method_QuitWorker, null, options, request);
@@ -405,6 +493,7 @@ namespace Grpc.Testing {
     }
 
     /// <summary>Creates service definition that can be registered with a server</summary>
+    /// <param name="serviceImpl">An object implementing the server-side handling logic.</param>
     public static ServerServiceDefinition BindService(WorkerServiceBase serviceImpl)
     {
       return ServerServiceDefinition.CreateBuilder()
diff --git a/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs b/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs
index 43dbc2865f..0265f8e821 100644
--- a/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs
@@ -42,8 +42,8 @@ using Grpc.Core;
 
 namespace Grpc.Testing {
   /// <summary>
-  ///  A simple service to test the various types of RPCs and experiment with
-  ///  performance with various types of payload.
+  /// A simple service to test the various types of RPCs and experiment with
+  /// performance with various types of payload.
   /// </summary>
   public static partial class TestService
   {
@@ -123,74 +123,101 @@ namespace Grpc.Testing {
     public abstract partial class TestServiceBase
     {
       /// <summary>
-      ///  One empty request followed by one empty response.
+      /// One empty request followed by one empty response.
       /// </summary>
+      /// <param name="request">The request received from the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>The response to send back to the client (wrapped by a task).</returns>
       public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.Empty> EmptyCall(global::Grpc.Testing.Empty request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
 
       /// <summary>
-      ///  One request followed by one response.
+      /// One request followed by one response.
       /// </summary>
+      /// <param name="request">The request received from the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>The response to send back to the client (wrapped by a task).</returns>
       public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.SimpleResponse> UnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
 
       /// <summary>
-      ///  One request followed by one response. Response has cache control
-      ///  headers set such that a caching HTTP proxy (such as GFE) can
-      ///  satisfy subsequent requests.
+      /// One request followed by one response. Response has cache control
+      /// headers set such that a caching HTTP proxy (such as GFE) can
+      /// satisfy subsequent requests.
       /// </summary>
+      /// <param name="request">The request received from the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>The response to send back to the client (wrapped by a task).</returns>
       public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.SimpleResponse> CacheableUnaryCall(global::Grpc.Testing.SimpleRequest request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
 
       /// <summary>
-      ///  One request followed by a sequence of responses (streamed download).
-      ///  The server returns the payload with client desired type and sizes.
+      /// One request followed by a sequence of responses (streamed download).
+      /// The server returns the payload with client desired type and sizes.
       /// </summary>
+      /// <param name="request">The request received from the client.</param>
+      /// <param name="responseStream">Used for sending responses back to the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>A task indicating completion of the handler.</returns>
       public virtual global::System.Threading.Tasks.Task StreamingOutputCall(global::Grpc.Testing.StreamingOutputCallRequest request, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
 
       /// <summary>
-      ///  A sequence of requests followed by one response (streamed upload).
-      ///  The server returns the aggregated size of client payload as the result.
+      /// A sequence of requests followed by one response (streamed upload).
+      /// The server returns the aggregated size of client payload as the result.
       /// </summary>
+      /// <param name="requestStream">Used for reading requests from the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>The response to send back to the client (wrapped by a task).</returns>
       public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.StreamingInputCallResponse> StreamingInputCall(IAsyncStreamReader<global::Grpc.Testing.StreamingInputCallRequest> requestStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
 
       /// <summary>
-      ///  A sequence of requests with each request served by the server immediately.
-      ///  As one request could lead to multiple responses, this interface
-      ///  demonstrates the idea of full duplexing.
+      /// A sequence of requests with each request served by the server immediately.
+      /// As one request could lead to multiple responses, this interface
+      /// demonstrates the idea of full duplexing.
       /// </summary>
+      /// <param name="requestStream">Used for reading requests from the client.</param>
+      /// <param name="responseStream">Used for sending responses back to the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>A task indicating completion of the handler.</returns>
       public virtual global::System.Threading.Tasks.Task FullDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
 
       /// <summary>
-      ///  A sequence of requests followed by a sequence of responses.
-      ///  The server buffers all the client requests and then serves them in order. A
-      ///  stream of responses are returned to the client when the server starts with
-      ///  first request.
+      /// A sequence of requests followed by a sequence of responses.
+      /// The server buffers all the client requests and then serves them in order. A
+      /// stream of responses are returned to the client when the server starts with
+      /// first request.
       /// </summary>
+      /// <param name="requestStream">Used for reading requests from the client.</param>
+      /// <param name="responseStream">Used for sending responses back to the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>A task indicating completion of the handler.</returns>
       public virtual global::System.Threading.Tasks.Task HalfDuplexCall(IAsyncStreamReader<global::Grpc.Testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::Grpc.Testing.StreamingOutputCallResponse> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
       }
 
       /// <summary>
-      ///  The test server will not implement this method. It will be used
-      ///  to test the behavior when clients call unimplemented methods.
+      /// The test server will not implement this method. It will be used
+      /// to test the behavior when clients call unimplemented methods.
       /// </summary>
+      /// <param name="request">The request received from the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>The response to send back to the client (wrapped by a task).</returns>
       public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.Empty> UnimplementedCall(global::Grpc.Testing.Empty request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
@@ -222,195 +249,285 @@ namespace Grpc.Testing {
       }
 
       /// <summary>
-      ///  One empty request followed by one empty response.
+      /// One empty request followed by one empty response.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.Empty EmptyCall(global::Grpc.Testing.Empty request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return EmptyCall(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  One empty request followed by one empty response.
+      /// One empty request followed by one empty response.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.Empty EmptyCall(global::Grpc.Testing.Empty request, CallOptions options)
       {
         return CallInvoker.BlockingUnaryCall(__Method_EmptyCall, null, options, request);
       }
       /// <summary>
-      ///  One empty request followed by one empty response.
+      /// One empty request followed by one empty response.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.Empty> EmptyCallAsync(global::Grpc.Testing.Empty request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return EmptyCallAsync(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  One empty request followed by one empty response.
+      /// One empty request followed by one empty response.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.Empty> EmptyCallAsync(global::Grpc.Testing.Empty request, CallOptions options)
       {
         return CallInvoker.AsyncUnaryCall(__Method_EmptyCall, null, options, request);
       }
       /// <summary>
-      ///  One request followed by one response.
+      /// One request followed by one response.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.SimpleResponse UnaryCall(global::Grpc.Testing.SimpleRequest request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return UnaryCall(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  One request followed by one response.
+      /// One request followed by one response.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.SimpleResponse UnaryCall(global::Grpc.Testing.SimpleRequest request, CallOptions options)
       {
         return CallInvoker.BlockingUnaryCall(__Method_UnaryCall, null, options, request);
       }
       /// <summary>
-      ///  One request followed by one response.
+      /// One request followed by one response.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.SimpleResponse> UnaryCallAsync(global::Grpc.Testing.SimpleRequest request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return UnaryCallAsync(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  One request followed by one response.
+      /// One request followed by one response.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.SimpleResponse> UnaryCallAsync(global::Grpc.Testing.SimpleRequest request, CallOptions options)
       {
         return CallInvoker.AsyncUnaryCall(__Method_UnaryCall, null, options, request);
       }
       /// <summary>
-      ///  One request followed by one response. Response has cache control
-      ///  headers set such that a caching HTTP proxy (such as GFE) can
-      ///  satisfy subsequent requests.
+      /// One request followed by one response. Response has cache control
+      /// headers set such that a caching HTTP proxy (such as GFE) can
+      /// satisfy subsequent requests.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.SimpleResponse CacheableUnaryCall(global::Grpc.Testing.SimpleRequest request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return CacheableUnaryCall(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  One request followed by one response. Response has cache control
-      ///  headers set such that a caching HTTP proxy (such as GFE) can
-      ///  satisfy subsequent requests.
+      /// One request followed by one response. Response has cache control
+      /// headers set such that a caching HTTP proxy (such as GFE) can
+      /// satisfy subsequent requests.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.SimpleResponse CacheableUnaryCall(global::Grpc.Testing.SimpleRequest request, CallOptions options)
       {
         return CallInvoker.BlockingUnaryCall(__Method_CacheableUnaryCall, null, options, request);
       }
       /// <summary>
-      ///  One request followed by one response. Response has cache control
-      ///  headers set such that a caching HTTP proxy (such as GFE) can
-      ///  satisfy subsequent requests.
+      /// One request followed by one response. Response has cache control
+      /// headers set such that a caching HTTP proxy (such as GFE) can
+      /// satisfy subsequent requests.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.SimpleResponse> CacheableUnaryCallAsync(global::Grpc.Testing.SimpleRequest request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return CacheableUnaryCallAsync(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  One request followed by one response. Response has cache control
-      ///  headers set such that a caching HTTP proxy (such as GFE) can
-      ///  satisfy subsequent requests.
+      /// One request followed by one response. Response has cache control
+      /// headers set such that a caching HTTP proxy (such as GFE) can
+      /// satisfy subsequent requests.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.SimpleResponse> CacheableUnaryCallAsync(global::Grpc.Testing.SimpleRequest request, CallOptions options)
       {
         return CallInvoker.AsyncUnaryCall(__Method_CacheableUnaryCall, null, options, request);
       }
       /// <summary>
-      ///  One request followed by a sequence of responses (streamed download).
-      ///  The server returns the payload with client desired type and sizes.
+      /// One request followed by a sequence of responses (streamed download).
+      /// The server returns the payload with client desired type and sizes.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncServerStreamingCall<global::Grpc.Testing.StreamingOutputCallResponse> StreamingOutputCall(global::Grpc.Testing.StreamingOutputCallRequest request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return StreamingOutputCall(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  One request followed by a sequence of responses (streamed download).
-      ///  The server returns the payload with client desired type and sizes.
+      /// One request followed by a sequence of responses (streamed download).
+      /// The server returns the payload with client desired type and sizes.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncServerStreamingCall<global::Grpc.Testing.StreamingOutputCallResponse> StreamingOutputCall(global::Grpc.Testing.StreamingOutputCallRequest request, CallOptions options)
       {
         return CallInvoker.AsyncServerStreamingCall(__Method_StreamingOutputCall, null, options, request);
       }
       /// <summary>
-      ///  A sequence of requests followed by one response (streamed upload).
-      ///  The server returns the aggregated size of client payload as the result.
+      /// A sequence of requests followed by one response (streamed upload).
+      /// The server returns the aggregated size of client payload as the result.
       /// </summary>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncClientStreamingCall<global::Grpc.Testing.StreamingInputCallRequest, global::Grpc.Testing.StreamingInputCallResponse> StreamingInputCall(Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return StreamingInputCall(new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  A sequence of requests followed by one response (streamed upload).
-      ///  The server returns the aggregated size of client payload as the result.
+      /// A sequence of requests followed by one response (streamed upload).
+      /// The server returns the aggregated size of client payload as the result.
       /// </summary>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncClientStreamingCall<global::Grpc.Testing.StreamingInputCallRequest, global::Grpc.Testing.StreamingInputCallResponse> StreamingInputCall(CallOptions options)
       {
         return CallInvoker.AsyncClientStreamingCall(__Method_StreamingInputCall, null, options);
       }
       /// <summary>
-      ///  A sequence of requests with each request served by the server immediately.
-      ///  As one request could lead to multiple responses, this interface
-      ///  demonstrates the idea of full duplexing.
+      /// A sequence of requests with each request served by the server immediately.
+      /// As one request could lead to multiple responses, this interface
+      /// demonstrates the idea of full duplexing.
       /// </summary>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncDuplexStreamingCall<global::Grpc.Testing.StreamingOutputCallRequest, global::Grpc.Testing.StreamingOutputCallResponse> FullDuplexCall(Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return FullDuplexCall(new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  A sequence of requests with each request served by the server immediately.
-      ///  As one request could lead to multiple responses, this interface
-      ///  demonstrates the idea of full duplexing.
+      /// A sequence of requests with each request served by the server immediately.
+      /// As one request could lead to multiple responses, this interface
+      /// demonstrates the idea of full duplexing.
       /// </summary>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncDuplexStreamingCall<global::Grpc.Testing.StreamingOutputCallRequest, global::Grpc.Testing.StreamingOutputCallResponse> FullDuplexCall(CallOptions options)
       {
         return CallInvoker.AsyncDuplexStreamingCall(__Method_FullDuplexCall, null, options);
       }
       /// <summary>
-      ///  A sequence of requests followed by a sequence of responses.
-      ///  The server buffers all the client requests and then serves them in order. A
-      ///  stream of responses are returned to the client when the server starts with
-      ///  first request.
+      /// A sequence of requests followed by a sequence of responses.
+      /// The server buffers all the client requests and then serves them in order. A
+      /// stream of responses are returned to the client when the server starts with
+      /// first request.
       /// </summary>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncDuplexStreamingCall<global::Grpc.Testing.StreamingOutputCallRequest, global::Grpc.Testing.StreamingOutputCallResponse> HalfDuplexCall(Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return HalfDuplexCall(new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  A sequence of requests followed by a sequence of responses.
-      ///  The server buffers all the client requests and then serves them in order. A
-      ///  stream of responses are returned to the client when the server starts with
-      ///  first request.
+      /// A sequence of requests followed by a sequence of responses.
+      /// The server buffers all the client requests and then serves them in order. A
+      /// stream of responses are returned to the client when the server starts with
+      /// first request.
       /// </summary>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncDuplexStreamingCall<global::Grpc.Testing.StreamingOutputCallRequest, global::Grpc.Testing.StreamingOutputCallResponse> HalfDuplexCall(CallOptions options)
       {
         return CallInvoker.AsyncDuplexStreamingCall(__Method_HalfDuplexCall, null, options);
       }
       /// <summary>
-      ///  The test server will not implement this method. It will be used
-      ///  to test the behavior when clients call unimplemented methods.
+      /// The test server will not implement this method. It will be used
+      /// to test the behavior when clients call unimplemented methods.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.Empty UnimplementedCall(global::Grpc.Testing.Empty request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return UnimplementedCall(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  The test server will not implement this method. It will be used
-      ///  to test the behavior when clients call unimplemented methods.
+      /// The test server will not implement this method. It will be used
+      /// to test the behavior when clients call unimplemented methods.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.Empty UnimplementedCall(global::Grpc.Testing.Empty request, CallOptions options)
       {
         return CallInvoker.BlockingUnaryCall(__Method_UnimplementedCall, null, options, request);
       }
       /// <summary>
-      ///  The test server will not implement this method. It will be used
-      ///  to test the behavior when clients call unimplemented methods.
+      /// The test server will not implement this method. It will be used
+      /// to test the behavior when clients call unimplemented methods.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.Empty> UnimplementedCallAsync(global::Grpc.Testing.Empty request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return UnimplementedCallAsync(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  The test server will not implement this method. It will be used
-      ///  to test the behavior when clients call unimplemented methods.
+      /// The test server will not implement this method. It will be used
+      /// to test the behavior when clients call unimplemented methods.
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.Empty> UnimplementedCallAsync(global::Grpc.Testing.Empty request, CallOptions options)
       {
         return CallInvoker.AsyncUnaryCall(__Method_UnimplementedCall, null, options, request);
@@ -423,6 +540,7 @@ namespace Grpc.Testing {
     }
 
     /// <summary>Creates service definition that can be registered with a server</summary>
+    /// <param name="serviceImpl">An object implementing the server-side handling logic.</param>
     public static ServerServiceDefinition BindService(TestServiceBase serviceImpl)
     {
       return ServerServiceDefinition.CreateBuilder()
@@ -438,8 +556,8 @@ namespace Grpc.Testing {
 
   }
   /// <summary>
-  ///  A simple service NOT implemented at servers so clients can test for
-  ///  that case.
+  /// A simple service NOT implemented at servers so clients can test for
+  /// that case.
   /// </summary>
   public static partial class UnimplementedService
   {
@@ -464,8 +582,11 @@ namespace Grpc.Testing {
     public abstract partial class UnimplementedServiceBase
     {
       /// <summary>
-      ///  A call that no server should implement
+      /// A call that no server should implement
       /// </summary>
+      /// <param name="request">The request received from the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>The response to send back to the client (wrapped by a task).</returns>
       public virtual global::System.Threading.Tasks.Task<global::Grpc.Testing.Empty> UnimplementedCall(global::Grpc.Testing.Empty request, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
@@ -497,29 +618,45 @@ namespace Grpc.Testing {
       }
 
       /// <summary>
-      ///  A call that no server should implement
+      /// A call that no server should implement
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.Empty UnimplementedCall(global::Grpc.Testing.Empty request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return UnimplementedCall(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  A call that no server should implement
+      /// A call that no server should implement
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The response received from the server.</returns>
       public virtual global::Grpc.Testing.Empty UnimplementedCall(global::Grpc.Testing.Empty request, CallOptions options)
       {
         return CallInvoker.BlockingUnaryCall(__Method_UnimplementedCall, null, options, request);
       }
       /// <summary>
-      ///  A call that no server should implement
+      /// A call that no server should implement
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.Empty> UnimplementedCallAsync(global::Grpc.Testing.Empty request, Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return UnimplementedCallAsync(request, new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  A call that no server should implement
+      /// A call that no server should implement
       /// </summary>
+      /// <param name="request">The request to send to the server.</param>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncUnaryCall<global::Grpc.Testing.Empty> UnimplementedCallAsync(global::Grpc.Testing.Empty request, CallOptions options)
       {
         return CallInvoker.AsyncUnaryCall(__Method_UnimplementedCall, null, options, request);
@@ -532,6 +669,7 @@ namespace Grpc.Testing {
     }
 
     /// <summary>Creates service definition that can be registered with a server</summary>
+    /// <param name="serviceImpl">An object implementing the server-side handling logic.</param>
     public static ServerServiceDefinition BindService(UnimplementedServiceBase serviceImpl)
     {
       return ServerServiceDefinition.CreateBuilder()
@@ -540,7 +678,7 @@ namespace Grpc.Testing {
 
   }
   /// <summary>
-  ///  A service used to control reconnect server.
+  /// A service used to control reconnect server.
   /// </summary>
   public static partial class ReconnectService
   {
@@ -648,6 +786,7 @@ namespace Grpc.Testing {
     }
 
     /// <summary>Creates service definition that can be registered with a server</summary>
+    /// <param name="serviceImpl">An object implementing the server-side handling logic.</param>
     public static ServerServiceDefinition BindService(ReconnectServiceBase serviceImpl)
     {
       return ServerServiceDefinition.CreateBuilder()
diff --git a/src/csharp/Grpc.Reflection.Tests/Grpc.Reflection.Tests.csproj b/src/csharp/Grpc.Reflection.Tests/Grpc.Reflection.Tests.csproj
index cebcf59ce8..c5918b194e 100644
--- a/src/csharp/Grpc.Reflection.Tests/Grpc.Reflection.Tests.csproj
+++ b/src/csharp/Grpc.Reflection.Tests/Grpc.Reflection.Tests.csproj
@@ -27,15 +27,6 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'ReleaseSigned|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\ReleaseSigned</OutputPath>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-    <SignAssembly>True</SignAssembly>
-    <AssemblyOriginatorKeyFile>..\keys\Grpc.snk</AssemblyOriginatorKeyFile>
-  </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Core" />
diff --git a/src/csharp/Grpc.Reflection/Grpc.Reflection.csproj b/src/csharp/Grpc.Reflection/Grpc.Reflection.csproj
index ea65998ce3..4e254a0b53 100644
--- a/src/csharp/Grpc.Reflection/Grpc.Reflection.csproj
+++ b/src/csharp/Grpc.Reflection/Grpc.Reflection.csproj
@@ -28,15 +28,6 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
-  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'ReleaseSigned|AnyCPU' ">
-    <DebugType>pdbonly</DebugType>
-    <Optimize>true</Optimize>
-    <OutputPath>bin\ReleaseSigned</OutputPath>
-    <ErrorReport>prompt</ErrorReport>
-    <WarningLevel>4</WarningLevel>
-    <SignAssembly>True</SignAssembly>
-    <AssemblyOriginatorKeyFile>..\keys\Grpc.snk</AssemblyOriginatorKeyFile>
-  </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Core" />
diff --git a/src/csharp/Grpc.Reflection/ReflectionGrpc.cs b/src/csharp/Grpc.Reflection/ReflectionGrpc.cs
index 1b6f96ce7c..5bd7558be5 100644
--- a/src/csharp/Grpc.Reflection/ReflectionGrpc.cs
+++ b/src/csharp/Grpc.Reflection/ReflectionGrpc.cs
@@ -64,9 +64,13 @@ namespace Grpc.Reflection.V1Alpha {
     public abstract partial class ServerReflectionBase
     {
       /// <summary>
-      ///  The reflection service is structured as a bidirectional stream, ensuring
-      ///  all related requests go to a single server.
+      /// The reflection service is structured as a bidirectional stream, ensuring
+      /// all related requests go to a single server.
       /// </summary>
+      /// <param name="requestStream">Used for reading requests from the client.</param>
+      /// <param name="responseStream">Used for sending responses back to the client.</param>
+      /// <param name="context">The context of the server-side call handler being invoked.</param>
+      /// <returns>A task indicating completion of the handler.</returns>
       public virtual global::System.Threading.Tasks.Task ServerReflectionInfo(IAsyncStreamReader<global::Grpc.Reflection.V1Alpha.ServerReflectionRequest> requestStream, IServerStreamWriter<global::Grpc.Reflection.V1Alpha.ServerReflectionResponse> responseStream, ServerCallContext context)
       {
         throw new RpcException(new Status(StatusCode.Unimplemented, ""));
@@ -98,17 +102,23 @@ namespace Grpc.Reflection.V1Alpha {
       }
 
       /// <summary>
-      ///  The reflection service is structured as a bidirectional stream, ensuring
-      ///  all related requests go to a single server.
+      /// The reflection service is structured as a bidirectional stream, ensuring
+      /// all related requests go to a single server.
       /// </summary>
+      /// <param name="headers">The initial metadata to send with the call. This parameter is optional.</param>
+      /// <param name="deadline">An optional deadline for the call. The call will be cancelled if deadline is hit.</param>
+      /// <param name="cancellationToken">An optional token for canceling the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncDuplexStreamingCall<global::Grpc.Reflection.V1Alpha.ServerReflectionRequest, global::Grpc.Reflection.V1Alpha.ServerReflectionResponse> ServerReflectionInfo(Metadata headers = null, DateTime? deadline = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         return ServerReflectionInfo(new CallOptions(headers, deadline, cancellationToken));
       }
       /// <summary>
-      ///  The reflection service is structured as a bidirectional stream, ensuring
-      ///  all related requests go to a single server.
+      /// The reflection service is structured as a bidirectional stream, ensuring
+      /// all related requests go to a single server.
       /// </summary>
+      /// <param name="options">The options for the call.</param>
+      /// <returns>The call object.</returns>
       public virtual AsyncDuplexStreamingCall<global::Grpc.Reflection.V1Alpha.ServerReflectionRequest, global::Grpc.Reflection.V1Alpha.ServerReflectionResponse> ServerReflectionInfo(CallOptions options)
       {
         return CallInvoker.AsyncDuplexStreamingCall(__Method_ServerReflectionInfo, null, options);
@@ -121,6 +131,7 @@ namespace Grpc.Reflection.V1Alpha {
     }
 
     /// <summary>Creates service definition that can be registered with a server</summary>
+    /// <param name="serviceImpl">An object implementing the server-side handling logic.</param>
     public static ServerServiceDefinition BindService(ServerReflectionBase serviceImpl)
     {
       return ServerServiceDefinition.CreateBuilder()
diff --git a/src/csharp/Grpc.sln b/src/csharp/Grpc.sln
index 2e6a8fd435..179e731380 100644
--- a/src/csharp/Grpc.sln
+++ b/src/csharp/Grpc.sln
@@ -44,105 +44,72 @@ Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution

 		Debug|Any CPU = Debug|Any CPU

 		Release|Any CPU = Release|Any CPU

-		ReleaseSigned|Any CPU = ReleaseSigned|Any CPU

 	EndGlobalSection

 	GlobalSection(ProjectConfigurationPlatforms) = postSolution

 		{143B1C29-C442-4BE0-BF3F-A8F92288AC9F}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

 		{143B1C29-C442-4BE0-BF3F-A8F92288AC9F}.Debug|Any CPU.Build.0 = Debug|Any CPU

 		{143B1C29-C442-4BE0-BF3F-A8F92288AC9F}.Release|Any CPU.ActiveCfg = Release|Any CPU

 		{143B1C29-C442-4BE0-BF3F-A8F92288AC9F}.Release|Any CPU.Build.0 = Release|Any CPU

-		{143B1C29-C442-4BE0-BF3F-A8F92288AC9F}.ReleaseSigned|Any CPU.ActiveCfg = ReleaseSigned|Any CPU

-		{143B1C29-C442-4BE0-BF3F-A8F92288AC9F}.ReleaseSigned|Any CPU.Build.0 = ReleaseSigned|Any CPU

 		{3D166931-BA2D-416E-95A3-D36E8F6E90B9}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

 		{3D166931-BA2D-416E-95A3-D36E8F6E90B9}.Debug|Any CPU.Build.0 = Debug|Any CPU

 		{3D166931-BA2D-416E-95A3-D36E8F6E90B9}.Release|Any CPU.ActiveCfg = Release|Any CPU

 		{3D166931-BA2D-416E-95A3-D36E8F6E90B9}.Release|Any CPU.Build.0 = Release|Any CPU

-		{3D166931-BA2D-416E-95A3-D36E8F6E90B9}.ReleaseSigned|Any CPU.ActiveCfg = ReleaseSigned|Any CPU

-		{3D166931-BA2D-416E-95A3-D36E8F6E90B9}.ReleaseSigned|Any CPU.Build.0 = ReleaseSigned|Any CPU

 		{4F18CF52-B3DB-4A77-97C5-7F7F4B6C1715}.Debug|Any CPU.ActiveCfg = Debug|Any CPU

 		{4F18CF52-B3DB-4A77-97C5-7F7F4B6C1715}.Debug|Any CPU.Build.0 = Debug|Any CPU

 		{4F18CF52-B3DB-4A77-97C5-7F7F4B6C1715}.Release|Any CPU.ActiveCfg = Release|Any CPU

 		{4F18CF52-B3DB-4A77-97C5-7F7F4B6C1715}.Release|Any CPU.Build.0 = Release|Any CPU

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 	EndGlobalSection

 	GlobalSection(NestedProjects) = preSolution

 	EndGlobalSection

diff --git a/src/csharp/ext/grpc_csharp_ext.c b/src/csharp/ext/grpc_csharp_ext.c
index 37d04eb100..946f5872c0 100644
--- a/src/csharp/ext/grpc_csharp_ext.c
+++ b/src/csharp/ext/grpc_csharp_ext.c
@@ -521,8 +521,8 @@ GPR_EXPORT void GPR_CALLTYPE grpcsharp_call_destroy(grpc_call *call) {
 
 GPR_EXPORT grpc_call_error GPR_CALLTYPE
 grpcsharp_call_start_unary(grpc_call *call, grpcsharp_batch_context *ctx,
-                           const char *send_buffer, size_t send_buffer_len,
-                           grpc_metadata_array *initial_metadata, uint32_t write_flags) {
+                           const char *send_buffer, size_t send_buffer_len, uint32_t write_flags,
+                           grpc_metadata_array *initial_metadata, uint32_t initial_metadata_flags) {
   /* TODO: don't use magic number */
   grpc_op ops[6];
   memset(ops, 0, sizeof(ops));
@@ -532,7 +532,7 @@ grpcsharp_call_start_unary(grpc_call *call, grpcsharp_batch_context *ctx,
   ops[0].data.send_initial_metadata.count = ctx->send_initial_metadata.count;
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
-  ops[0].flags = 0;
+  ops[0].flags = initial_metadata_flags;
   ops[0].reserved = NULL;
 
   ops[1].op = GRPC_OP_SEND_MESSAGE;
@@ -575,7 +575,8 @@ grpcsharp_call_start_unary(grpc_call *call, grpcsharp_batch_context *ctx,
 GPR_EXPORT grpc_call_error GPR_CALLTYPE
 grpcsharp_call_start_client_streaming(grpc_call *call,
                                       grpcsharp_batch_context *ctx,
-                                      grpc_metadata_array *initial_metadata) {
+                                      grpc_metadata_array *initial_metadata,
+                                      uint32_t initial_metadata_flags) {
   /* TODO: don't use magic number */
   grpc_op ops[4];
   memset(ops, 0, sizeof(ops));
@@ -585,7 +586,7 @@ grpcsharp_call_start_client_streaming(grpc_call *call,
   ops[0].data.send_initial_metadata.count = ctx->send_initial_metadata.count;
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
-  ops[0].flags = 0;
+  ops[0].flags = initial_metadata_flags;
   ops[0].reserved = NULL;
 
   ops[1].op = GRPC_OP_RECV_INITIAL_METADATA;
@@ -617,7 +618,8 @@ grpcsharp_call_start_client_streaming(grpc_call *call,
 
 GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_start_server_streaming(
     grpc_call *call, grpcsharp_batch_context *ctx, const char *send_buffer,
-    size_t send_buffer_len, grpc_metadata_array *initial_metadata, uint32_t write_flags) {
+    size_t send_buffer_len, uint32_t write_flags,
+    grpc_metadata_array *initial_metadata, uint32_t initial_metadata_flags) {
   /* TODO: don't use magic number */
   grpc_op ops[4];
   memset(ops, 0, sizeof(ops));
@@ -627,7 +629,7 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_start_server_streaming(
   ops[0].data.send_initial_metadata.count = ctx->send_initial_metadata.count;
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
-  ops[0].flags = 0;
+  ops[0].flags = initial_metadata_flags;
   ops[0].reserved = NULL;
 
   ops[1].op = GRPC_OP_SEND_MESSAGE;
@@ -660,7 +662,8 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_start_server_streaming(
 GPR_EXPORT grpc_call_error GPR_CALLTYPE
 grpcsharp_call_start_duplex_streaming(grpc_call *call,
                                       grpcsharp_batch_context *ctx,
-                                      grpc_metadata_array *initial_metadata) {
+                                      grpc_metadata_array *initial_metadata,
+                                      uint32_t initial_metadata_flags) {
   /* TODO: don't use magic number */
   grpc_op ops[2];
   memset(ops, 0, sizeof(ops));
@@ -670,7 +673,7 @@ grpcsharp_call_start_duplex_streaming(grpc_call *call,
   ops[0].data.send_initial_metadata.count = ctx->send_initial_metadata.count;
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
-  ops[0].flags = 0;
+  ops[0].flags = initial_metadata_flags;
   ops[0].reserved = NULL;
 
   ops[1].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
diff --git a/src/node/ext/completion_queue.h b/src/node/ext/completion_queue.h
index bf280f768b..9b01028ef1 100644
--- a/src/node/ext/completion_queue.h
+++ b/src/node/ext/completion_queue.h
@@ -32,6 +32,7 @@
  */
 
 #include <v8.h>
+#include <grpc/grpc.h>
 
 namespace grpc {
 namespace node {
diff --git a/src/node/ext/completion_queue_async_worker.cc b/src/node/ext/completion_queue_threadpool.cc
index f5e03b277b..6302e7a103 100644
--- a/src/node/ext/completion_queue_async_worker.cc
+++ b/src/node/ext/completion_queue_threadpool.cc
@@ -31,18 +31,63 @@
  *
  */
 
+/* I don't like using #ifndef, but I don't see a better way to do this */
+#ifndef GRPC_UV
+
 #include <node.h>
 #include <nan.h>
 
 #include "grpc/grpc.h"
 #include "grpc/support/log.h"
 #include "grpc/support/time.h"
-#include "completion_queue_async_worker.h"
+#include "completion_queue.h"
 #include "call.h"
 
 namespace grpc {
 namespace node {
 
+namespace {
+
+/* A worker that asynchronously calls completion_queue_next, and queues onto the
+   node event loop a call to the function stored in the event's tag. */
+class CompletionQueueAsyncWorker : public Nan::AsyncWorker {
+ public:
+  CompletionQueueAsyncWorker();
+
+  ~CompletionQueueAsyncWorker();
+  /* Calls completion_queue_next with the provided deadline, and stores the
+     event if there was one or sets an error message if there was not */
+  void Execute();
+
+  /* Returns the completion queue attached to this class */
+  static grpc_completion_queue *GetQueue();
+
+  /* Convenience function to create a worker with the given arguments and queue
+     it to run asynchronously */
+  static void Next();
+
+  /* Initialize the CompletionQueueAsyncWorker class */
+  static void Init(v8::Local<v8::Object> exports);
+
+ protected:
+  /* Called when Execute has succeeded (completed without setting an error
+     message). Calls the saved callback with the event that came from
+     completion_queue_next */
+  void HandleOKCallback();
+
+  void HandleErrorCallback();
+
+ private:
+  grpc_event result;
+
+  static grpc_completion_queue *queue;
+
+  // Number of grpc_completion_queue_next calls in the thread pool
+  static int current_threads;
+  // Number of grpc_completion_queue_next calls waiting to enter the thread pool
+  static int waiting_next_calls;
+};
+
 const int max_queue_threads = 2;
 
 using v8::Function;
@@ -137,5 +182,21 @@ void CompletionQueueAsyncWorker::HandleErrorCallback() {
   DestroyTag(result.tag);
 }
 
+}  // namespace
+
+grpc_completion_queue *GetCompletionQueue() {
+  return CompletionQueueAsyncWorker::GetQueue();
+}
+
+void CompletionQueueNext() {
+  CompletionQueueAsyncWorker::Next();
+}
+
+void CompletionQueueInit(Local<Object> exports) {
+  CompletionQueueAsyncWorker::Init(exports);
+}
+
 }  // namespace node
 }  // namespace grpc
+
+#endif  /* GRPC_UV */
diff --git a/src/node/ext/completion_queue.cc b/src/node/ext/completion_queue_uv.cc
index fcfa77b39c..615973a6c9 100644
--- a/src/node/ext/completion_queue.cc
+++ b/src/node/ext/completion_queue_uv.cc
@@ -31,6 +31,8 @@
  *
  */
 
+#ifdef GRPC_UV
+
 #include <uv.h>
 #include <node.h>
 #include <v8.h>
@@ -38,7 +40,6 @@
 
 #include "call.h"
 #include "completion_queue.h"
-#include "completion_queue_async_worker.h"
 
 namespace grpc {
 namespace node {
@@ -81,34 +82,24 @@ void drain_completion_queue(uv_prepare_t *handle) {
 }
 
 grpc_completion_queue *GetCompletionQueue() {
-#ifdef GRPC_UV
   return queue;
-#else
-  return CompletionQueueAsyncWorker::GetQueue();
-#endif
 }
 
 void CompletionQueueNext() {
-#ifdef GRPC_UV
   if (pending_batches == 0) {
     GPR_ASSERT(!uv_is_active((uv_handle_t *)&prepare));
     uv_prepare_start(&prepare, drain_completion_queue);
   }
   pending_batches++;
-#else
-  CompletionQueueAsyncWorker::Next();
-#endif
 }
 
 void CompletionQueueInit(Local<Object> exports) {
-#ifdef GRPC_UV
   queue = grpc_completion_queue_create(NULL);
   uv_prepare_init(uv_default_loop(), &prepare);
   pending_batches = 0;
-#else
-  CompletionQueueAsyncWorker::Init(exports);
-#endif
 }
 
 }  // namespace node
 }  // namespace grpc
+
+#endif /* GRPC_UV */
diff --git a/src/node/interop/interop_client.js b/src/node/interop/interop_client.js
index 46ddecfb1f..75cfb41342 100644
--- a/src/node/interop/interop_client.js
+++ b/src/node/interop/interop_client.js
@@ -312,6 +312,9 @@ function customMetadata(client, done) {
     }
   };
   var streaming_arg = {
+    response_parameters: [
+     {size: 314159}
+    ],
     payload: {
       body: zeroBuffer(271828)
     }
diff --git a/src/node/performance/worker_service_impl.js b/src/node/performance/worker_service_impl.js
index 3f317f6429..38888a7219 100644
--- a/src/node/performance/worker_service_impl.js
+++ b/src/node/performance/worker_service_impl.js
@@ -55,9 +55,8 @@ module.exports = function WorkerServiceImpl(benchmark_impl, server) {
   }
 
   this.quitWorker = function quitWorker(call, callback) {
-    server.tryShutdown(function() {
-      callback(null, {});
-    });
+    callback(null, {});
+    server.tryShutdown(function() {});
   };
 
   this.runClient = function runClient(call) {
diff --git a/src/node/src/client.js b/src/node/src/client.js
index 9c1562e8b8..134ef239c2 100644
--- a/src/node/src/client.js
+++ b/src/node/src/client.js
@@ -99,7 +99,18 @@ function ClientWritableStream(call, serialize) {
 function _write(chunk, encoding, callback) {
   /* jshint validthis: true */
   var batch = {};
-  var message = this.serialize(chunk);
+  var message;
+  try {
+    message = this.serialize(chunk);
+  } catch (e) {
+    /* Sending this error to the server and emitting it immediately on the
+       client may put the call in a slightly weird state on the client side,
+       but passing an object that causes a serialization failure is a misuse
+       of the API anyway, so that's OK. The primary purpose here is to give the
+       programmer a useful error and to stop the stream properly */
+    this.call.cancelWithStatus(grpc.status.INTERNAL, "Serialization failure");
+    callback(e);
+  }
   if (_.isFinite(encoding)) {
     /* Attach the encoding if it is a finite number. This is the closest we
      * can get to checking that it is valid flags */
@@ -184,14 +195,15 @@ function _emitStatusIfDone() {
     } else {
       status = this.received_status;
     }
-    this.emit('status', status);
-    if (status.code !== grpc.status.OK) {
+    if (status.code === grpc.status.OK) {
+      this.push(null);
+    } else {
       var error = new Error(status.details);
       error.code = status.code;
       error.metadata = status.metadata;
       this.emit('error', error);
-      return;
     }
+    this.emit('status', status);
   }
 }
 
@@ -224,9 +236,11 @@ function _read(size) {
     } catch (e) {
       self._readsDone({code: grpc.status.INTERNAL,
                        details: 'Failed to parse server response'});
+      return;
     }
     if (data === null) {
       self._readsDone();
+      return;
     }
     if (self.push(deserialized) && data !== null) {
       var read_batch = {};
@@ -396,6 +410,8 @@ function makeUnaryRequestFunction(method, serialize, deserialize) {
       var status = response.status;
       var error;
       var deserialized;
+      emitter.emit('metadata', Metadata._fromCoreRepresentation(
+          response.metadata));
       if (status.code === grpc.status.OK) {
         if (err) {
           // Got a batch error, but OK status. Something went wrong
@@ -423,8 +439,6 @@ function makeUnaryRequestFunction(method, serialize, deserialize) {
         args.callback(null, deserialized);
       }
       emitter.emit('status', status);
-      emitter.emit('metadata', Metadata._fromCoreRepresentation(
-          response.metadata));
     });
     return emitter;
   }
diff --git a/src/node/src/server.js b/src/node/src/server.js
index b3b414969a..da9c6b2d7f 100644
--- a/src/node/src/server.js
+++ b/src/node/src/server.js
@@ -127,7 +127,14 @@ function sendUnaryResponse(call, value, serialize, metadata, flags) {
         (new Metadata())._getCoreRepresentation();
     call.metadataSent = true;
   }
-  var message = serialize(value);
+  var message;
+  try {
+    message = serialize(value);
+  } catch (e) {
+    e.code = grpc.status.INTERNAL;
+    handleError(e);
+    return;
+  }
   message.grpcWriteFlags = flags;
   end_batch[grpc.opType.SEND_MESSAGE] = message;
   end_batch[grpc.opType.SEND_STATUS_FROM_SERVER] = status;
@@ -278,7 +285,14 @@ function _write(chunk, encoding, callback) {
         (new Metadata())._getCoreRepresentation();
     this.call.metadataSent = true;
   }
-  var message = this.serialize(chunk);
+  var message;
+  try {
+    message = this.serialize(chunk);
+  } catch (e) {
+    e.code = grpc.status.INTERNAL;
+    callback(e);
+    return;
+  }
   if (_.isFinite(encoding)) {
     /* Attach the encoding if it is a finite number. This is the closest we
      * can get to checking that it is valid flags */
diff --git a/src/node/test/surface_test.js b/src/node/test/surface_test.js
index d8b36dc55c..e429a3648b 100644
--- a/src/node/test/surface_test.js
+++ b/src/node/test/surface_test.js
@@ -179,20 +179,22 @@ describe('Server.prototype.addProtoService', function() {
       call.on('data', function(value) {
         assert.fail('No messages expected');
       });
-      call.on('status', function(status) {
-        assert.strictEqual(status.code, grpc.status.UNIMPLEMENTED);
+      call.on('error', function(err) {
+        assert.strictEqual(err.code, grpc.status.UNIMPLEMENTED);
         done();
       });
+      call.on('error', function(status) { /* Do nothing */ });
     });
     it('should respond to a bidi call with UNIMPLEMENTED', function(done) {
       var call = client.divMany();
       call.on('data', function(value) {
         assert.fail('No messages expected');
       });
-      call.on('status', function(status) {
-        assert.strictEqual(status.code, grpc.status.UNIMPLEMENTED);
+      call.on('error', function(err) {
+        assert.strictEqual(err.code, grpc.status.UNIMPLEMENTED);
         done();
       });
+      call.on('error', function(status) { /* Do nothing */ });
       call.end();
     });
   });
diff --git a/src/objective-c/!ProtoCompiler-gRPCPlugin.podspec b/src/objective-c/!ProtoCompiler-gRPCPlugin.podspec
index 6e594fd3ed..bcc2bb6126 100644
--- a/src/objective-c/!ProtoCompiler-gRPCPlugin.podspec
+++ b/src/objective-c/!ProtoCompiler-gRPCPlugin.podspec
@@ -36,7 +36,7 @@ Pod::Spec.new do |s|
   # exclamation mark ensures that other "regular" pods will be able to find it as it'll be installed
   # before them.
   s.name     = '!ProtoCompiler-gRPCPlugin'
-  v = '1.0.1'
+  v = '1.0.2'
   s.version  = v
   s.summary  = 'The gRPC ProtoC plugin generates Objective-C files from .proto services.'
   s.description = <<-DESC
@@ -84,7 +84,10 @@ Pod::Spec.new do |s|
   repo = 'grpc/grpc'
   file = "grpc_objective_c_plugin-#{v}-macos-x86_64.zip"
   s.source = {
-    :http => "https://github.com/#{repo}/releases/download/v#{v}/#{file}",
+    # TODO(mxyan): Change back to "https://github.com/#{repo}/releases/download/v#{v}/#{file}" for
+    # next release
+    # :http => "https://github.com/#{repo}/releases/download/v#{v}/#{file}",
+    :http => "https://github.com/#{repo}/releases/download/objective-c-v#{v}/#{file}",
     # TODO(jcanizales): Add sha1 or sha256
     # :sha1 => '??',
   }
diff --git a/src/objective-c/GRPCClient/private/GRPCHost.m b/src/objective-c/GRPCClient/private/GRPCHost.m
index 31065cbf01..450bec36e0 100644
--- a/src/objective-c/GRPCClient/private/GRPCHost.m
+++ b/src/objective-c/GRPCClient/private/GRPCHost.m
@@ -50,7 +50,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 // TODO(jcanizales): Generate the version in a standalone header, from templates. Like
 // templates/src/core/surface/version.c.template .
-#define GRPC_OBJC_VERSION_STRING @"1.0.1"
+#define GRPC_OBJC_VERSION_STRING @"1.0.2"
 
 static NSMutableDictionary *kHostCache;
 
diff --git a/src/objective-c/GRPCClient/private/GRPCWrappedCall.m b/src/objective-c/GRPCClient/private/GRPCWrappedCall.m
index 627b6aa86d..38fcae0299 100644
--- a/src/objective-c/GRPCClient/private/GRPCWrappedCall.m
+++ b/src/objective-c/GRPCClient/private/GRPCWrappedCall.m
@@ -112,7 +112,7 @@
 }
 
 - (void)dealloc {
-  gpr_free(_op.data.send_message);
+  grpc_byte_buffer_destroy(_op.data.send_message);
 }
 
 @end
diff --git a/src/objective-c/tests/CoreCronetEnd2EndTests/CoreCronetEnd2EndTests.m b/src/objective-c/tests/CoreCronetEnd2EndTests/CoreCronetEnd2EndTests.m
index 4a92cc8e0d..4ba7badd86 100644
--- a/src/objective-c/tests/CoreCronetEnd2EndTests/CoreCronetEnd2EndTests.m
+++ b/src/objective-c/tests/CoreCronetEnd2EndTests/CoreCronetEnd2EndTests.m
@@ -316,7 +316,8 @@ static char *roots_filename;
 }
 
 - (void)testInvokeLargeRequest {
-  [self testIndividualCase:"invoke_large_request"];
+  // NOT SUPPORTED (frame size)
+  // [self testIndividualCase:"invoke_large_request"];
 }
 
 - (void)testLargeMetadata {
@@ -329,7 +330,8 @@ static char *roots_filename;
 }
 
 - (void)testMaxMessageLength {
-  [self testIndividualCase:"max_message_length"];
+  // NOT SUPPORTED (close_error)
+  // [self testIndividualCase:"max_message_length"];
 }
 
 - (void)testNegativeDeadline {
diff --git a/src/objective-c/tests/GRPCClientTests.m b/src/objective-c/tests/GRPCClientTests.m
index 77640525d5..0b72a75f3d 100644
--- a/src/objective-c/tests/GRPCClientTests.m
+++ b/src/objective-c/tests/GRPCClientTests.m
@@ -43,6 +43,8 @@
 #import <RxLibrary/GRXWriteable.h>
 #import <RxLibrary/GRXWriter+Immediate.h>
 
+#define TEST_TIMEOUT 16
+
 static NSString * const kHostAddress = @"localhost:5050";
 static NSString * const kPackage = @"grpc.testing";
 static NSString * const kService = @"TestService";
@@ -137,7 +139,7 @@ static GRPCProtoMethod *kUnaryCallMethod;
 
   [call startWithWriteable:responsesWriteable];
 
-  [self waitForExpectationsWithTimeout:4 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 - (void)testEmptyRPC {
@@ -159,7 +161,7 @@ static GRPCProtoMethod *kUnaryCallMethod;
 
   [call startWithWriteable:responsesWriteable];
 
-  [self waitForExpectationsWithTimeout:8 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 - (void)testSimpleProtoRPC {
@@ -191,7 +193,7 @@ static GRPCProtoMethod *kUnaryCallMethod;
 
   [call startWithWriteable:responsesWriteable];
 
-  [self waitForExpectationsWithTimeout:8 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 - (void)testMetadata {
@@ -225,7 +227,7 @@ static GRPCProtoMethod *kUnaryCallMethod;
 
   [call startWithWriteable:responsesWriteable];
 
-  [self waitForExpectationsWithTimeout:4 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 - (void)testResponseMetadataKVO {
@@ -256,7 +258,7 @@ static GRPCProtoMethod *kUnaryCallMethod;
   
   [call startWithWriteable:responsesWriteable];
   
-  [self waitForExpectationsWithTimeout:8 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 - (void)testUserAgentPrefix {
@@ -287,7 +289,7 @@ static GRPCProtoMethod *kUnaryCallMethod;
 
   [call startWithWriteable:responsesWriteable];
 
-  [self waitForExpectationsWithTimeout:8 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 // TODO(makarandd): Move to a different file that contains only unit tests
@@ -347,7 +349,7 @@ static GRPCProtoMethod *kUnaryCallMethod;
 
   [call startWithWriteable:responsesWriteable];
 
-  [self waitForExpectationsWithTimeout:8 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 @end
diff --git a/src/objective-c/tests/InteropTests.m b/src/objective-c/tests/InteropTests.m
index 9804734d6a..c3935ce1e0 100644
--- a/src/objective-c/tests/InteropTests.m
+++ b/src/objective-c/tests/InteropTests.m
@@ -46,6 +46,8 @@
 #import <RxLibrary/GRXBufferedPipe.h>
 #import <RxLibrary/GRXWriter+Immediate.h>
 
+#define TEST_TIMEOUT 32
+
 // Convenience constructors for the generated proto messages:
 
 @interface RMTStreamingOutputCallRequest (Constructors)
@@ -124,7 +126,7 @@
     [expectation fulfill];
   }];
 
-  [self waitForExpectationsWithTimeout:4 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 - (void)testLargeUnaryRPC {
@@ -147,7 +149,7 @@
     [expectation fulfill];
   }];
 
-  [self waitForExpectationsWithTimeout:16 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 - (void)test4MBResponsesAreAccepted {
@@ -164,7 +166,7 @@
     [expectation fulfill];
   }];
 
-  [self waitForExpectationsWithTimeout:16 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 - (void)testResponsesOverMaxSizeFailWithActionableMessage {
@@ -185,7 +187,7 @@
     [expectation fulfill];
   }];
 
-  [self waitForExpectationsWithTimeout:16 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 - (void)testResponsesOver4MBAreAcceptedIfOptedIn {
@@ -205,7 +207,7 @@
     [expectation fulfill];
   }];
 
-  [self waitForExpectationsWithTimeout:16 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 - (void)testClientStreamingRPC {
@@ -238,7 +240,7 @@
     [expectation fulfill];
   }];
 
-  [self waitForExpectationsWithTimeout:8 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 - (void)testServerStreamingRPC {
@@ -275,7 +277,7 @@
     }
   }];
 
-  [self waitForExpectationsWithTimeout:8 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 - (void)testPingPongRPC {
@@ -319,7 +321,7 @@
       [expectation fulfill];
     }
   }];
-  [self waitForExpectationsWithTimeout:4 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 #ifndef GRPC_COMPILE_WITH_CRONET
@@ -335,7 +337,7 @@
     XCTAssert(done, @"Unexpected response: %@", response);
     [expectation fulfill];
   }];
-  [self waitForExpectationsWithTimeout:2 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 #endif
 
@@ -361,7 +363,7 @@
   [call cancel];
   XCTAssertEqual(call.state, GRXWriterStateFinished);
 
-  [self waitForExpectationsWithTimeout:1 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 - (void)testCancelAfterFirstResponseRPC {
@@ -396,7 +398,7 @@
     }
   }];
   [call start];
-  [self waitForExpectationsWithTimeout:8 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 - (void)testRPCAfterClosingOpenConnections {
@@ -420,7 +422,7 @@
     }];
   }];
 
-  [self waitForExpectationsWithTimeout:4 handler:nil];
+  [self waitForExpectationsWithTimeout:TEST_TIMEOUT handler:nil];
 }
 
 @end
diff --git a/src/php/bin/generate_proto_php.sh b/src/php/bin/generate_proto_php.sh
index c558bc5769..416fa9df97 100755
--- a/src/php/bin/generate_proto_php.sh
+++ b/src/php/bin/generate_proto_php.sh
@@ -39,10 +39,13 @@ protoc --proto_path=src/proto/math \
 
 # replace the Empty message with EmptyMessage
 # because Empty is a PHP reserved word
-sed -i 's/message Empty/message EmptyMessage/g' \
-    src/proto/grpc/testing/empty.proto
-sed -i 's/grpc\.testing\.Empty/grpc\.testing\.EmptyMessage/g' \
-    src/proto/grpc/testing/test.proto
+output_file=$(mktemp)
+sed 's/message Empty/message EmptyMessage/g' \
+  src/proto/grpc/testing/empty.proto > $output_file
+mv $output_file ./src/proto/grpc/testing/empty.proto
+sed 's/grpc\.testing\.Empty/grpc\.testing\.EmptyMessage/g' \
+  src/proto/grpc/testing/test.proto > $output_file
+mv $output_file ./src/proto/grpc/testing/test.proto
 
 protoc --proto_path=. \
        --php_out=src/php/tests/interop \
@@ -53,7 +56,10 @@ protoc --proto_path=. \
        src/proto/grpc/testing/test.proto
 
 # change it back
-sed -i 's/message EmptyMessage/message Empty/g' \
-    src/proto/grpc/testing/empty.proto
-sed -i 's/grpc\.testing\.EmptyMessage/grpc\.testing\.Empty/g' \
-    src/proto/grpc/testing/test.proto
+sed 's/message EmptyMessage/message Empty/g' \
+  src/proto/grpc/testing/empty.proto > $output_file
+mv $output_file ./src/proto/grpc/testing/empty.proto
+sed 's/grpc\.testing\.EmptyMessage/grpc\.testing\.Empty/g' \
+  src/proto/grpc/testing/test.proto > $output_file
+mv $output_file ./src/proto/grpc/testing/test.proto
+
diff --git a/src/php/ext/grpc/call.c b/src/php/ext/grpc/call.c
index 3a49ea8708..64b1137c2a 100644
--- a/src/php/ext/grpc/call.c
+++ b/src/php/ext/grpc/call.c
@@ -478,6 +478,7 @@ PHP_METHOD(Call, startBatch) {
                                    true);
       add_property_zval(result, "status", recv_status);
       PHP_GRPC_DELREF(recv_status);
+      PHP_GRPC_FREE_STD_ZVAL(recv_status);
       break;
     case GRPC_OP_RECV_CLOSE_ON_SERVER:
       add_property_bool(result, "cancelled", cancelled);
@@ -501,6 +502,7 @@ cleanup:
     }
     if (ops[i].op == GRPC_OP_RECV_MESSAGE) {
       grpc_byte_buffer_destroy(message);
+      PHP_GRPC_FREE_STD_ZVAL(message_str);
     }
   }
   RETURN_DESTROY_ZVAL(result);
diff --git a/src/php/ext/grpc/call_credentials.c b/src/php/ext/grpc/call_credentials.c
index 3aafc3a19b..043817facd 100644
--- a/src/php/ext/grpc/call_credentials.c
+++ b/src/php/ext/grpc/call_credentials.c
@@ -111,9 +111,7 @@ PHP_METHOD(CallCredentials, createComposite) {
   grpc_call_credentials *creds =
       grpc_composite_call_credentials_create(cred1->wrapped, cred2->wrapped,
                                              NULL);
-  zval *creds_object;
-  PHP_GRPC_MAKE_STD_ZVAL(creds_object);
-  creds_object = grpc_php_wrap_call_credentials(creds TSRMLS_CC);
+  zval *creds_object = grpc_php_wrap_call_credentials(creds TSRMLS_CC);
   RETURN_DESTROY_ZVAL(creds_object);
 }
 
@@ -155,9 +153,7 @@ PHP_METHOD(CallCredentials, createFromPlugin) {
 
   grpc_call_credentials *creds =
     grpc_metadata_credentials_create_from_plugin(plugin, NULL);
-  zval *creds_object;
-  PHP_GRPC_MAKE_STD_ZVAL(creds_object);
-  creds_object = grpc_php_wrap_call_credentials(creds TSRMLS_CC);
+  zval *creds_object = grpc_php_wrap_call_credentials(creds TSRMLS_CC);
   RETURN_DESTROY_ZVAL(creds_object);
 }
 
@@ -211,6 +207,8 @@ void plugin_destroy_state(void *ptr) {
   plugin_state *state = (plugin_state *)ptr;
   efree(state->fci);
   efree(state->fci_cache);
+  PHP_GRPC_FREE_STD_ZVAL(state->fci->params);
+  PHP_GRPC_FREE_STD_ZVAL(state->fci->retval);
   efree(state);
 }
 
diff --git a/src/php/ext/grpc/channel_credentials.c b/src/php/ext/grpc/channel_credentials.c
index a32c4a4ea2..36a8223b88 100644
--- a/src/php/ext/grpc/channel_credentials.c
+++ b/src/php/ext/grpc/channel_credentials.c
@@ -121,9 +121,7 @@ PHP_METHOD(ChannelCredentials, setDefaultRootsPem) {
  */
 PHP_METHOD(ChannelCredentials, createDefault) {
   grpc_channel_credentials *creds = grpc_google_default_credentials_create();
-  zval *creds_object;
-  PHP_GRPC_MAKE_STD_ZVAL(creds_object);
-  creds_object = grpc_php_wrap_channel_credentials(creds TSRMLS_CC);
+  zval *creds_object = grpc_php_wrap_channel_credentials(creds TSRMLS_CC);
   RETURN_DESTROY_ZVAL(creds_object);
 }
 
@@ -160,9 +158,7 @@ PHP_METHOD(ChannelCredentials, createSsl) {
   grpc_channel_credentials *creds = grpc_ssl_credentials_create(
       pem_root_certs,
       pem_key_cert_pair.private_key == NULL ? NULL : &pem_key_cert_pair, NULL);
-  zval *creds_object;
-  PHP_GRPC_MAKE_STD_ZVAL(creds_object);
-  creds_object = grpc_php_wrap_channel_credentials(creds TSRMLS_CC);
+  zval *creds_object = grpc_php_wrap_channel_credentials(creds TSRMLS_CC);
   RETURN_DESTROY_ZVAL(creds_object);
 }
 
@@ -191,9 +187,7 @@ PHP_METHOD(ChannelCredentials, createComposite) {
   grpc_channel_credentials *creds =
       grpc_composite_channel_credentials_create(cred1->wrapped, cred2->wrapped,
                                                 NULL);
-  zval *creds_object;
-  PHP_GRPC_MAKE_STD_ZVAL(creds_object);
-  creds_object = grpc_php_wrap_channel_credentials(creds TSRMLS_CC);
+  zval *creds_object = grpc_php_wrap_channel_credentials(creds TSRMLS_CC);
   RETURN_DESTROY_ZVAL(creds_object);
 }
 
diff --git a/src/php/ext/grpc/php7_wrapper.h b/src/php/ext/grpc/php7_wrapper.h
index 1d7824113f..72e982d6fc 100644
--- a/src/php/ext/grpc/php7_wrapper.h
+++ b/src/php/ext/grpc/php7_wrapper.h
@@ -50,8 +50,13 @@
 
 #define PHP_GRPC_RETURN_STRING(val, dup) RETURN_STRING(val, dup)
 #define PHP_GRPC_MAKE_STD_ZVAL(pzv) MAKE_STD_ZVAL(pzv)
+#define PHP_GRPC_FREE_STD_ZVAL(pzv)
 #define PHP_GRPC_DELREF(zv) Z_DELREF_P(zv)
 
+#define RETURN_DESTROY_ZVAL(val) \
+  RETURN_ZVAL(val, false /* Don't execute copy constructor */, \
+              true /* Dealloc original before returning */)
+
 #define PHP_GRPC_WRAP_OBJECT_START(name) \
   typedef struct name { \
     zend_object std;
@@ -144,8 +149,15 @@ static inline int php_grpc_zend_hash_find(HashTable *ht, char *key, int len,
 #define PHP_GRPC_RETURN_STRING(val, dup) RETURN_STRING(val)
 #define PHP_GRPC_MAKE_STD_ZVAL(pzv) \
   pzv = (zval *)emalloc(sizeof(zval));
+#define PHP_GRPC_FREE_STD_ZVAL(pzv) efree(pzv);
 #define PHP_GRPC_DELREF(zv)
 
+#define RETURN_DESTROY_ZVAL(val) \
+  RETVAL_ZVAL(val, false /* Don't execute copy constructor */, \
+              true /* Dealloc original before returning */); \
+  efree(val); \
+  return
+
 #define PHP_GRPC_WRAP_OBJECT_START(name) \
   typedef struct name {
 #define PHP_GRPC_WRAP_OBJECT_END(name) \
diff --git a/src/php/ext/grpc/php_grpc.h b/src/php/ext/grpc/php_grpc.h
index e57a06545e..13083b0bc7 100644
--- a/src/php/ext/grpc/php_grpc.h
+++ b/src/php/ext/grpc/php_grpc.h
@@ -61,10 +61,6 @@ extern zend_module_entry grpc_module_entry;
 
 #include "grpc/grpc.h"
 
-#define RETURN_DESTROY_ZVAL(val)                               \
-  RETURN_ZVAL(val, false /* Don't execute copy constructor */, \
-              true /* Dealloc original before returning */)
-
 /* These are all function declarations */
 /* Code that runs at module initialization */
 PHP_MINIT_FUNCTION(grpc);
diff --git a/src/php/ext/grpc/server_credentials.c b/src/php/ext/grpc/server_credentials.c
index 1610c8ebb0..3e39fee246 100644
--- a/src/php/ext/grpc/server_credentials.c
+++ b/src/php/ext/grpc/server_credentials.c
@@ -113,9 +113,7 @@ PHP_METHOD(ServerCredentials, createSsl) {
   grpc_server_credentials *creds = grpc_ssl_server_credentials_create_ex(
       pem_root_certs, &pem_key_cert_pair, 1,
       GRPC_SSL_DONT_REQUEST_CLIENT_CERTIFICATE, NULL);
-  zval *creds_object;
-  PHP_GRPC_MAKE_STD_ZVAL(creds_object);
-  creds_object = grpc_php_wrap_server_credentials(creds TSRMLS_CC);
+  zval *creds_object = grpc_php_wrap_server_credentials(creds TSRMLS_CC);
   RETURN_DESTROY_ZVAL(creds_object);
 }
 
diff --git a/src/php/ext/grpc/timeval.c b/src/php/ext/grpc/timeval.c
index 945231b47f..7ada915aad 100644
--- a/src/php/ext/grpc/timeval.c
+++ b/src/php/ext/grpc/timeval.c
@@ -115,11 +115,9 @@ PHP_METHOD(Timeval, add) {
   }
   wrapped_grpc_timeval *self = Z_WRAPPED_GRPC_TIMEVAL_P(getThis());
   wrapped_grpc_timeval *other = Z_WRAPPED_GRPC_TIMEVAL_P(other_obj);
-  zval *sum;
-  PHP_GRPC_MAKE_STD_ZVAL(sum);
-  sum =
-      grpc_php_wrap_timeval(gpr_time_add(self->wrapped, other->wrapped)
-                            TSRMLS_CC);
+  zval *sum =
+    grpc_php_wrap_timeval(gpr_time_add(self->wrapped, other->wrapped)
+                          TSRMLS_CC);
   RETURN_DESTROY_ZVAL(sum);
 }
 
@@ -141,11 +139,9 @@ PHP_METHOD(Timeval, subtract) {
   }
   wrapped_grpc_timeval *self = Z_WRAPPED_GRPC_TIMEVAL_P(getThis());
   wrapped_grpc_timeval *other = Z_WRAPPED_GRPC_TIMEVAL_P(other_obj);
-  zval *diff;
-  PHP_GRPC_MAKE_STD_ZVAL(diff);
-  diff =
-      grpc_php_wrap_timeval(gpr_time_sub(self->wrapped, other->wrapped)
-                            TSRMLS_CC);
+  zval *diff =
+    grpc_php_wrap_timeval(gpr_time_sub(self->wrapped, other->wrapped)
+                          TSRMLS_CC);
   RETURN_DESTROY_ZVAL(diff);
 }
 
@@ -206,9 +202,7 @@ PHP_METHOD(Timeval, similar) {
  * @return Timeval The current time
  */
 PHP_METHOD(Timeval, now) {
-  zval *now;
-  PHP_GRPC_MAKE_STD_ZVAL(now);
-  now = grpc_php_wrap_timeval(gpr_now(GPR_CLOCK_REALTIME) TSRMLS_CC);
+  zval *now = grpc_php_wrap_timeval(gpr_now(GPR_CLOCK_REALTIME) TSRMLS_CC);
   RETURN_DESTROY_ZVAL(now);
 }
 
@@ -217,13 +211,9 @@ PHP_METHOD(Timeval, now) {
  * @return Timeval Zero length time interval
  */
 PHP_METHOD(Timeval, zero) {
-  zval *grpc_php_timeval_zero;
-  PHP_GRPC_MAKE_STD_ZVAL(grpc_php_timeval_zero);
-  grpc_php_timeval_zero =
-      grpc_php_wrap_timeval(gpr_time_0(GPR_CLOCK_REALTIME) TSRMLS_CC);
-  RETURN_ZVAL(grpc_php_timeval_zero,
-              false, /* Copy original before returning? */
-              true /* Destroy original before returning */);
+  zval *grpc_php_timeval_zero =
+    grpc_php_wrap_timeval(gpr_time_0(GPR_CLOCK_REALTIME) TSRMLS_CC);
+  RETURN_DESTROY_ZVAL(grpc_php_timeval_zero);
 }
 
 /**
@@ -231,10 +221,8 @@ PHP_METHOD(Timeval, zero) {
  * @return Timeval Infinite future time value
  */
 PHP_METHOD(Timeval, infFuture) {
-  zval *grpc_php_timeval_inf_future;
-  PHP_GRPC_MAKE_STD_ZVAL(grpc_php_timeval_inf_future);
-  grpc_php_timeval_inf_future =
-      grpc_php_wrap_timeval(gpr_inf_future(GPR_CLOCK_REALTIME) TSRMLS_CC);
+  zval *grpc_php_timeval_inf_future =
+    grpc_php_wrap_timeval(gpr_inf_future(GPR_CLOCK_REALTIME) TSRMLS_CC);
   RETURN_DESTROY_ZVAL(grpc_php_timeval_inf_future);
 }
 
@@ -243,10 +231,8 @@ PHP_METHOD(Timeval, infFuture) {
  * @return Timeval Infinite past time value
  */
 PHP_METHOD(Timeval, infPast) {
-  zval *grpc_php_timeval_inf_past;
-  PHP_GRPC_MAKE_STD_ZVAL(grpc_php_timeval_inf_past);
-  grpc_php_timeval_inf_past =
-      grpc_php_wrap_timeval(gpr_inf_past(GPR_CLOCK_REALTIME) TSRMLS_CC);
+  zval *grpc_php_timeval_inf_past =
+    grpc_php_wrap_timeval(gpr_inf_past(GPR_CLOCK_REALTIME) TSRMLS_CC);
   RETURN_DESTROY_ZVAL(grpc_php_timeval_inf_past);
 }
 
diff --git a/src/php/lib/Grpc/AbstractCall.php b/src/php/lib/Grpc/AbstractCall.php
index c4d56790f7..9f0b02b8bb 100644
--- a/src/php/lib/Grpc/AbstractCall.php
+++ b/src/php/lib/Grpc/AbstractCall.php
@@ -62,7 +62,7 @@ abstract class AbstractCall
         Channel $channel,
         $method,
         $deserialize,
-        $options = []
+        array $options = []
     ) {
         if (array_key_exists('timeout', $options) &&
             is_numeric($timeout = $options['timeout'])
@@ -89,7 +89,7 @@ abstract class AbstractCall
     }
 
     /**
-     * @return mixed The metadata sent by the server.
+     * @return mixed The metadata sent by the server
      */
     public function getMetadata()
     {
@@ -97,7 +97,7 @@ abstract class AbstractCall
     }
 
     /**
-     * @return mixed The trailing metadata sent by the server.
+     * @return mixed The trailing metadata sent by the server
      */
     public function getTrailingMetadata()
     {
@@ -105,7 +105,7 @@ abstract class AbstractCall
     }
 
     /**
-     * @return string The URI of the endpoint.
+     * @return string The URI of the endpoint
      */
     public function getPeer()
     {
@@ -167,8 +167,7 @@ abstract class AbstractCall
     /**
      * Set the CallCredentials for the underlying Call.
      *
-     * @param CallCredentials $call_credentials The CallCredentials
-     *                                          object
+     * @param CallCredentials $call_credentials The CallCredentials object
      */
     public function setCallCredentials($call_credentials)
     {
diff --git a/src/php/lib/Grpc/BaseStub.php b/src/php/lib/Grpc/BaseStub.php
index d0baeae955..a9e77b9396 100644
--- a/src/php/lib/Grpc/BaseStub.php
+++ b/src/php/lib/Grpc/BaseStub.php
@@ -48,14 +48,14 @@ class BaseStub
     private $update_metadata;
 
     /**
-     * @param $hostname string
-     * @param $opts array
+     * @param string  $hostname
+     * @param array   $opts
      *  - 'update_metadata': (optional) a callback function which takes in a
      * metadata array, and returns an updated metadata array
      *  - 'grpc.primary_user_agent': (optional) a user-agent string
-     * @param $channel Channel An already created Channel object
+     * @param Channel $channel An already created Channel object (optional)
      */
-    public function __construct($hostname, $opts, $channel = null)
+    public function __construct($hostname, $opts, Channel $channel = null)
     {
         $ssl_roots = file_get_contents(
             dirname(__FILE__).'/../../../../etc/roots.pem');
@@ -98,7 +98,7 @@ class BaseStub
     }
 
     /**
-     * @return string The URI of the endpoint.
+     * @return string The URI of the endpoint
      */
     public function getTarget()
     {
@@ -106,7 +106,7 @@ class BaseStub
     }
 
     /**
-     * @param $try_to_connect bool
+     * @param bool $try_to_connect (optional)
      *
      * @return int The grpc connectivity state
      */
@@ -145,6 +145,12 @@ class BaseStub
         return $this->_checkConnectivityState($new_state);
     }
 
+    /**
+     * @param $new_state Connect state
+     *
+     * @return bool true if state is CHANNEL_READY
+     * @throw Exception if state is CHANNEL_FATAL_FAILURE
+     */
     private function _checkConnectivityState($new_state)
     {
         if ($new_state == \Grpc\CHANNEL_READY) {
@@ -167,6 +173,10 @@ class BaseStub
 
     /**
      * constructs the auth uri for the jwt.
+     *
+     * @param string $method The method string
+     *
+     * @return string The URL string
      */
     private function _get_jwt_aud_uri($method)
     {
@@ -191,7 +201,7 @@ class BaseStub
      *
      * @param array $metadata The metadata map
      *
-     * @return $metadata Validated and key-normalized metadata map
+     * @return array $metadata Validated and key-normalized metadata map
      * @throw InvalidArgumentException if key contains invalid characters
      */
     private function _validate_and_normalize_metadata($metadata)
@@ -220,14 +230,16 @@ class BaseStub
      * @param mixed    $argument    The argument to the method
      * @param callable $deserialize A function that deserializes the response
      * @param array    $metadata    A metadata map to send to the server
+     *                              (optional)
+     * @param array    $options     An array of options (optional)
      *
      * @return SimpleSurfaceActiveCall The active call object
      */
     public function _simpleRequest($method,
                                    $argument,
                                    $deserialize,
-                                   $metadata = [],
-                                   $options = [])
+                                   array $metadata = [],
+                                   array $options = [])
     {
         $call = new UnaryCall($this->channel,
                               $method,
@@ -251,17 +263,17 @@ class BaseStub
      * output.
      *
      * @param string   $method      The name of the method to call
-     * @param array    $arguments   An array or Traversable of arguments to stream to the
-     *                              server
      * @param callable $deserialize A function that deserializes the response
      * @param array    $metadata    A metadata map to send to the server
+     *                              (optional)
+     * @param array    $options     An array of options (optional)
      *
      * @return ClientStreamingSurfaceActiveCall The active call object
      */
     public function _clientStreamRequest($method,
-                                         callable $deserialize,
-                                         $metadata = [],
-                                         $options = [])
+                                         $deserialize,
+                                         array $metadata = [],
+                                         array $options = [])
     {
         $call = new ClientStreamingCall($this->channel,
                                         $method,
@@ -281,21 +293,23 @@ class BaseStub
     }
 
     /**
-     * Call a remote method that takes a single argument and returns a stream of
-     * responses.
+     * Call a remote method that takes a single argument and returns a stream
+     * of responses.
      *
      * @param string   $method      The name of the method to call
      * @param mixed    $argument    The argument to the method
      * @param callable $deserialize A function that deserializes the responses
      * @param array    $metadata    A metadata map to send to the server
+     *                              (optional)
+     * @param array    $options     An array of options (optional)
      *
      * @return ServerStreamingSurfaceActiveCall The active call object
      */
     public function _serverStreamRequest($method,
                                          $argument,
-                                         callable $deserialize,
-                                         $metadata = [],
-                                         $options = [])
+                                         $deserialize,
+                                         array $metadata = [],
+                                         array $options = [])
     {
         $call = new ServerStreamingCall($this->channel,
                                         $method,
@@ -320,13 +334,15 @@ class BaseStub
      * @param string   $method      The name of the method to call
      * @param callable $deserialize A function that deserializes the responses
      * @param array    $metadata    A metadata map to send to the server
+     *                              (optional)
+     * @param array    $options     An array of options (optional)
      *
      * @return BidiStreamingSurfaceActiveCall The active call object
      */
     public function _bidiRequest($method,
-                                 callable $deserialize,
-                                 $metadata = [],
-                                 $options = [])
+                                 $deserialize,
+                                 array $metadata = [],
+                                 array $options = [])
     {
         $call = new BidiStreamingCall($this->channel,
                                       $method,
diff --git a/src/php/lib/Grpc/BidiStreamingCall.php b/src/php/lib/Grpc/BidiStreamingCall.php
index f0e1e811de..b03bbd204f 100644
--- a/src/php/lib/Grpc/BidiStreamingCall.php
+++ b/src/php/lib/Grpc/BidiStreamingCall.php
@@ -35,8 +35,8 @@
 namespace Grpc;
 
 /**
- * Represents an active call that allows for sending and recieving messages in
- * streams in any order.
+ * Represents an active call that allows for sending and recieving messages
+ * in streams in any order.
  */
 class BidiStreamingCall extends AbstractCall
 {
@@ -44,6 +44,7 @@ class BidiStreamingCall extends AbstractCall
      * Start the call.
      *
      * @param array $metadata Metadata to send with the call, if applicable
+     *                        (optional)
      */
     public function start(array $metadata = [])
     {
@@ -76,10 +77,10 @@ class BidiStreamingCall extends AbstractCall
      * writesDone is called.
      *
      * @param ByteBuffer $data    The data to write
-     * @param array      $options an array of options, possible keys:
-     *                            'flags' => a number
+     * @param array      $options An array of options, possible keys:
+     *                            'flags' => a number (optional)
      */
-    public function write($data, $options = [])
+    public function write($data, array $options = [])
     {
         $message_array = ['message' => $this->serializeMessage($data)];
         if (array_key_exists('flags', $options)) {
@@ -103,8 +104,8 @@ class BidiStreamingCall extends AbstractCall
     /**
      * Wait for the server to send the status, and return it.
      *
-     * @return \stdClass The status object, with integer $code, string $details,
-     *                   and array $metadata members
+     * @return \stdClass The status object, with integer $code, string
+     *                   $details, and array $metadata members
      */
     public function getStatus()
     {
diff --git a/src/php/lib/Grpc/ClientStreamingCall.php b/src/php/lib/Grpc/ClientStreamingCall.php
index 20db809ea3..c542f08872 100644
--- a/src/php/lib/Grpc/ClientStreamingCall.php
+++ b/src/php/lib/Grpc/ClientStreamingCall.php
@@ -35,8 +35,8 @@
 namespace Grpc;
 
 /**
- * Represents an active call that sends a stream of messages and then gets a
- * single response.
+ * Represents an active call that sends a stream of messages and then gets
+ * a single response.
  */
 class ClientStreamingCall extends AbstractCall
 {
@@ -44,8 +44,9 @@ class ClientStreamingCall extends AbstractCall
      * Start the call.
      *
      * @param array $metadata Metadata to send with the call, if applicable
+     *                        (optional)
      */
-    public function start($metadata = [])
+    public function start(array $metadata = [])
     {
         $this->call->startBatch([
             OP_SEND_INITIAL_METADATA => $metadata,
@@ -57,8 +58,8 @@ class ClientStreamingCall extends AbstractCall
      * wait is called.
      *
      * @param ByteBuffer $data    The data to write
-     * @param array      $options an array of options, possible keys:
-     *                            'flags' => a number
+     * @param array      $options An array of options, possible keys:
+     *                            'flags' => a number (optional)
      */
     public function write($data, array $options = [])
     {
diff --git a/src/php/lib/Grpc/ServerStreamingCall.php b/src/php/lib/Grpc/ServerStreamingCall.php
index 5aeeafa94a..406512bf57 100644
--- a/src/php/lib/Grpc/ServerStreamingCall.php
+++ b/src/php/lib/Grpc/ServerStreamingCall.php
@@ -35,8 +35,8 @@
 namespace Grpc;
 
 /**
- * Represents an active call that sends a single message and then gets a stream
- * of responses.
+ * Represents an active call that sends a single message and then gets a
+ * stream of responses.
  */
 class ServerStreamingCall extends AbstractCall
 {
@@ -45,10 +45,11 @@ class ServerStreamingCall extends AbstractCall
      *
      * @param mixed $data     The data to send
      * @param array $metadata Metadata to send with the call, if applicable
-     * @param array $options  an array of options, possible keys:
-     *                        'flags' => a number
+     *                        (optional)
+     * @param array $options  An array of options, possible keys:
+     *                        'flags' => a number (optional)
      */
-    public function start($data, $metadata = [], $options = [])
+    public function start($data, array $metadata = [], array $options = [])
     {
         $message_array = ['message' => $this->serializeMessage($data)];
         if (array_key_exists('flags', $options)) {
@@ -82,8 +83,8 @@ class ServerStreamingCall extends AbstractCall
     /**
      * Wait for the server to send the status, and return it.
      *
-     * @return \stdClass The status object, with integer $code, string $details,
-     *                   and array $metadata members
+     * @return \stdClass The status object, with integer $code, string
+     *                   $details, and array $metadata members
      */
     public function getStatus()
     {
diff --git a/src/php/lib/Grpc/UnaryCall.php b/src/php/lib/Grpc/UnaryCall.php
index e8eb6487a8..3c1cb158ea 100644
--- a/src/php/lib/Grpc/UnaryCall.php
+++ b/src/php/lib/Grpc/UnaryCall.php
@@ -35,8 +35,8 @@
 namespace Grpc;
 
 /**
- * Represents an active call that sends a single message and then gets a single
- * response.
+ * Represents an active call that sends a single message and then gets a
+ * single response.
  */
 class UnaryCall extends AbstractCall
 {
@@ -45,10 +45,11 @@ class UnaryCall extends AbstractCall
      *
      * @param mixed $data     The data to send
      * @param array $metadata Metadata to send with the call, if applicable
-     * @param array $options  an array of options, possible keys:
-     *                        'flags' => a number
+     *                        (optional)
+     * @param array $options  An array of options, possible keys:
+     *                        'flags' => a number (optional)
      */
-    public function start($data, $metadata = [], $options = [])
+    public function start($data, array $metadata = [], array $options = [])
     {
         $message_array = ['message' => $this->serializeMessage($data)];
         if (isset($options['flags'])) {
diff --git a/src/php/tests/interop/interop_client.php b/src/php/tests/interop/interop_client.php
index d201915d66..2acf5612c7 100755
--- a/src/php/tests/interop/interop_client.php
+++ b/src/php/tests/interop/interop_client.php
@@ -451,11 +451,22 @@ function customMetadata($stub)
 
     $streaming_request = new grpc\testing\StreamingOutputCallRequest();
     $streaming_request->setPayload($payload);
+    $response_parameters = new grpc\testing\ResponseParameters();
+    $response_parameters->setSize($response_len);
+    $streaming_request->getResponseParameters()[] = $response_parameters;
     $streaming_call->write($streaming_request);
     $streaming_call->writesDone();
+    $result = $streaming_call->read();
 
     hardAssertIfStatusOk($streaming_call->getStatus());
 
+    $streaming_initial_metadata = $streaming_call->getMetadata();
+    hardAssert(array_key_exists($ECHO_INITIAL_KEY, $streaming_initial_metadata),
+               'Initial metadata does not contain expected key');
+    hardAssert(
+        $streaming_initial_metadata[$ECHO_INITIAL_KEY][0] === $ECHO_INITIAL_VALUE,
+        'Incorrect initial metadata value');
+
     $streaming_trailing_metadata = $streaming_call->getTrailingMetadata();
     hardAssert(array_key_exists($ECHO_TRAILING_KEY,
                                 $streaming_trailing_metadata),
diff --git a/src/proto/grpc/testing/BUILD b/src/proto/grpc/testing/BUILD
new file mode 100644
index 0000000000..f9f9cbceaf
--- /dev/null
+++ b/src/proto/grpc/testing/BUILD
@@ -0,0 +1,63 @@
+
+package(default_visibility = ["//visibility:public"])
+
+load("//bazel:grpc_build_system.bzl", "grpc_proto_library")
+
+grpc_proto_library(
+    name = "compiler_test_proto",
+    srcs = ["compiler_test.proto"],
+)
+
+grpc_proto_library(
+    name = "control_proto",
+    srcs = ["control.proto"],
+    deps = ["payloads_proto", "stats_proto"],
+)
+
+grpc_proto_library(
+    name = "echo_messages_proto",
+    srcs = ["echo_messages.proto"],
+)
+
+grpc_proto_library(
+    name = "echo_proto",
+    srcs = ["echo.proto"],
+    deps = ["echo_messages_proto"],
+)
+
+grpc_proto_library(
+    name = "empty_proto",
+    srcs = ["empty.proto"],
+)
+
+grpc_proto_library(
+    name = "messages_proto",
+    srcs = ["messages.proto"],
+)
+
+grpc_proto_library(
+    name = "metrics_proto",
+    srcs = ["metrics.proto"],
+)
+
+grpc_proto_library(
+    name = "payloads_proto",
+    srcs = ["payloads.proto"],
+)
+
+grpc_proto_library(
+    name = "services_proto",
+    srcs = ["services.proto"],
+    deps = ["control_proto", "messages_proto"],
+)
+
+grpc_proto_library(
+    name = "stats_proto",
+    srcs = ["stats.proto"],
+)
+
+grpc_proto_library(
+    name = "test_proto",
+    srcs = ["test.proto"],
+    deps = ["empty_proto", "messages_proto"],
+)
diff --git a/src/proto/grpc/testing/control.proto b/src/proto/grpc/testing/control.proto
index be387cf786..529313cfb1 100644
--- a/src/proto/grpc/testing/control.proto
+++ b/src/proto/grpc/testing/control.proto
@@ -78,6 +78,14 @@ message SecurityParams {
   string server_host_override = 2;
 }
 
+message ChannelArg {
+  string name = 1;
+  oneof value {
+    string str_value = 2;
+    int32 int_value = 3;
+  }
+}
+
 message ClientConfig {
   // List of targets to connect to. At least one target needs to be specified.
   repeated string server_targets = 1;
@@ -103,6 +111,8 @@ message ClientConfig {
 
   // If we use an OTHER_CLIENT client_type, this string gives more detail
   string other_client_api = 15;
+
+  repeated ChannelArg channel_args = 16;
 }
 
 message ClientStatus { ClientStats stats = 1; }
diff --git a/src/proto/grpc/testing/duplicate/BUILD b/src/proto/grpc/testing/duplicate/BUILD
new file mode 100644
index 0000000000..255e699bec
--- /dev/null
+++ b/src/proto/grpc/testing/duplicate/BUILD
@@ -0,0 +1,10 @@
+
+package(default_visibility = ["//visibility:public"])
+
+load("//bazel:grpc_build_system.bzl", "grpc_proto_library")
+
+grpc_proto_library(
+    name = "echo_duplicate_proto",
+    srcs = ["echo_duplicate.proto"],
+    deps = ["//src/proto/grpc/testing:echo_messages_proto"],
+)
diff --git a/src/python/grpcio/commands.py b/src/python/grpcio/commands.py
index ea3b6f3391..701c6af017 100644
--- a/src/python/grpcio/commands.py
+++ b/src/python/grpcio/commands.py
@@ -62,6 +62,7 @@ napoleon_numpy_docstring = True
 napoleon_include_special_with_doc = True
 
 html_theme = 'sphinx_rtd_theme'
+copyright = "2016, The gRPC Authors"
 """
 
 API_GLOSSARY = """
diff --git a/src/python/grpcio/grpc/__init__.py b/src/python/grpcio/grpc/__init__.py
index 6087276d51..e3c10156d0 100644
--- a/src/python/grpcio/grpc/__init__.py
+++ b/src/python/grpcio/grpc/__init__.py
@@ -31,6 +31,7 @@
 
 import abc
 import enum
+import sys
 
 import six
 
@@ -767,8 +768,8 @@ class ServicerContext(six.with_metaclass(abc.ABCMeta, RpcContext)):
     gRPC runtime to determine the status code of the RPC.
 
     Args:
-      code: The integer status code of the RPC to be transmitted to the
-        invocation side of the RPC.
+      code: A StatusCode value to be transmitted to the invocation side of the
+        RPC as the status code of the RPC.
     """
     raise NotImplementedError()
 
@@ -780,8 +781,8 @@ class ServicerContext(six.with_metaclass(abc.ABCMeta, RpcContext)):
     details to transmit.
 
     Args:
-      details: The details string of the RPC to be transmitted to
-        the invocation side of the RPC.
+      details: A string to be transmitted to the invocation side of the RPC as
+        the status details of the RPC.
     """
     raise NotImplementedError()
 
@@ -849,6 +850,26 @@ class GenericRpcHandler(six.with_metaclass(abc.ABCMeta)):
     raise NotImplementedError()
 
 
+class ServiceRpcHandler(six.with_metaclass(abc.ABCMeta, GenericRpcHandler)):
+  """An implementation of RPC methods belonging to a service.
+
+  A service handles RPC methods with structured names of the form
+  '/Service.Name/Service.MethodX', where 'Service.Name' is the value
+  returned by service_name(), and 'Service.MethodX' is the service method
+  name.  A service can have multiple service methods names, but only a single
+  service name.
+  """
+
+  @abc.abstractmethod
+  def service_name(self):
+    """Returns this services name.
+
+    Returns:
+      The service name.
+    """
+    raise NotImplementedError()
+
+
 #############################  Server Interface  ###############################
 
 
@@ -905,21 +926,6 @@ class Server(six.with_metaclass(abc.ABCMeta)):
     raise NotImplementedError()
 
   @abc.abstractmethod
-  def add_shutdown_handler(self, shutdown_handler):
-    """Adds a handler to be called on server shutdown.
-
-    Shutdown handlers are run on server stop() or in the event that a running
-    server is destroyed unexpectedly.  The handlers are run in series before
-    the stop grace period.
-
-    Args:
-      shutdown_handler:  A function taking a single arg, a time in seconds
-      within which the handler should complete.  None indicates the handler can
-      run for any duration.
-    """
-    raise NotImplementedError()
-
-  @abc.abstractmethod
   def start(self):
     """Starts this Server's service of RPCs.
 
@@ -929,7 +935,7 @@ class Server(six.with_metaclass(abc.ABCMeta)):
     raise NotImplementedError()
 
   @abc.abstractmethod
-  def stop(self, grace, shutdown_handler_grace=None):
+  def stop(self, grace):
     """Stops this Server's service of RPCs.
 
     All calls to this method immediately stop service of new RPCs. When existing
@@ -952,8 +958,6 @@ class Server(six.with_metaclass(abc.ABCMeta)):
         aborted by this Server's stopping. If None, all RPCs will be aborted
         immediately and this method will block until this Server is completely
         stopped.
-      shutdown_handler_grace:  A duration of time in seconds or None.  This
-        value is passed to all shutdown handlers.
 
     Returns:
       A threading.Event that will be set when this Server has completely
@@ -1248,8 +1252,7 @@ def secure_channel(target, credentials, options=None):
                           credentials._credentials)
 
 
-def server(thread_pool, handlers=None, options=None, exit_grace=None,
-           exit_shutdown_handler_grace=None):
+def server(thread_pool, handlers=None, options=None):
   """Creates a Server with which RPCs can be serviced.
 
   Args:
@@ -1262,19 +1265,13 @@ def server(thread_pool, handlers=None, options=None, exit_grace=None,
       returned Server is started.
     options: A sequence of string-value pairs according to which to configure
       the created server.
-    exit_grace:  The grace period to use when terminating
-      running servers at interpreter exit.  None indicates unspecified.
-    exit_shutdown_handler_grace:  The shutdown handler grace to use when
-      terminating running servers at interpreter exit.  None indicates
-      unspecified.
 
   Returns:
     A Server with which RPCs can be serviced.
   """
   from grpc import _server
   return _server.Server(thread_pool, () if handlers is None else handlers,
-                        () if options is None else options, exit_grace,
-                        exit_shutdown_handler_grace)
+                        () if options is None else options)
 
 
 ###################################  __all__  #################################
@@ -1304,6 +1301,7 @@ __all__ = (
     'RpcMethodHandler',
     'HandlerCallDetails',
     'GenericRpcHandler',
+    'ServiceRpcHandler',
     'Server',
     'unary_unary_rpc_method_handler',
     'unary_stream_rpc_method_handler',
@@ -1321,3 +1319,24 @@ __all__ = (
     'secure_channel',
     'server',
 )
+
+
+############################### Extension Shims ################################
+
+
+# Here to maintain backwards compatibility; avoid using these in new code!
+try:
+  import grpc_tools
+  sys.modules.update({'grpc.tools': grpc_tools})
+except ImportError:
+  pass
+try:
+  import grpc_health
+  sys.modules.update({'grpc.health': grpc_health})
+except ImportError:
+  pass
+try:
+  import grpc_reflection
+  sys.modules.update({'grpc.reflection': grpc_reflection})
+except ImportError:
+  pass
diff --git a/src/python/grpcio/grpc/_channel.py b/src/python/grpcio/grpc/_channel.py
index 53a26727ab..e8c6a99cb1 100644
--- a/src/python/grpcio/grpc/_channel.py
+++ b/src/python/grpcio/grpc/_channel.py
@@ -32,12 +32,13 @@
 import sys
 import threading
 import time
+import logging
 
 import grpc
 from grpc import _common
 from grpc import _grpcio_metadata
-from grpc.framework.foundation import callable_util
 from grpc._cython import cygrpc
+from grpc.framework.foundation import callable_util
 
 _USER_AGENT = 'Python-gRPC-{}'.format(_grpcio_metadata.__version__)
 
@@ -99,6 +100,22 @@ def _wait_once_until(condition, until):
     else:
       condition.wait(timeout=remaining)
 
+_INTERNAL_CALL_ERROR_MESSAGE_FORMAT = (
+    'Internal gRPC call error %d. ' +
+    'Please report to https://github.com/grpc/grpc/issues')
+
+def _check_call_error(call_error, metadata):
+  if call_error == cygrpc.CallError.invalid_metadata:
+    raise ValueError('metadata was invalid: %s' % metadata)
+  elif call_error != cygrpc.CallError.ok:
+    raise ValueError(_INTERNAL_CALL_ERROR_MESSAGE_FORMAT % call_error)
+
+def _call_error_set_RPCstate(state, call_error, metadata):
+  if call_error == cygrpc.CallError.invalid_metadata:
+    _abort(state, grpc.StatusCode.INTERNAL, 'metadata was invalid: %s' % metadata)
+  else:
+    _abort(state, grpc.StatusCode.INTERNAL, 
+        _INTERNAL_CALL_ERROR_MESSAGE_FORMAT % call_error)
 
 class _RPCState(object):
 
@@ -181,7 +198,16 @@ def _consume_request_iterator(
   event_handler = _event_handler(state, call, None)
 
   def consume_request_iterator():
-    for request in request_iterator:
+    while True:
+      try:
+        request = next(request_iterator)
+      except StopIteration:
+        break
+      except Exception as e:
+        logging.exception("Exception iterating requests!")
+        call.cancel()
+        _abort(state, grpc.StatusCode.UNKNOWN, "Exception iterating requests!")
+        return
       serialized_request = _common.serialize(request, request_serializer)
       with state.condition:
         if state.code is None and not state.cancelled:
@@ -358,7 +384,7 @@ class _Rendezvous(grpc.RpcError, grpc.Future, grpc.Call):
       if self._state.callbacks is None:
         return False
       else:
-        self._state.callbacks.append(lambda: callback())
+        self._state.callbacks.append(callback)
         return True
 
   def initial_metadata(self):
@@ -435,10 +461,10 @@ def _end_unary_response_blocking(state, with_call, deadline):
 class _UnaryUnaryMultiCallable(grpc.UnaryUnaryMultiCallable):
 
   def __init__(
-      self, channel, create_managed_call, method, request_serializer,
+      self, channel, managed_call, method, request_serializer,
       response_deserializer):
     self._channel = channel
-    self._create_managed_call = create_managed_call
+    self._managed_call = managed_call
     self._method = method
     self._request_serializer = request_serializer
     self._response_deserializer = response_deserializer
@@ -472,7 +498,8 @@ class _UnaryUnaryMultiCallable(grpc.UnaryUnaryMultiCallable):
           None, 0, completion_queue, self._method, None, deadline_timespec)
       if credentials is not None:
         call.set_credentials(credentials._credentials)
-      call.start_client_batch(cygrpc.Operations(operations), None)
+      call_error = call.start_client_batch(cygrpc.Operations(operations), None)
+      _check_call_error(call_error, metadata)
       _handle_event(completion_queue.poll(), state, self._response_deserializer)
       return state, deadline
 
@@ -490,23 +517,28 @@ class _UnaryUnaryMultiCallable(grpc.UnaryUnaryMultiCallable):
     if rendezvous:
       return rendezvous
     else:
-      call = self._create_managed_call(
+      call, drive_call = self._managed_call(
           None, 0, self._method, None, deadline_timespec)
       if credentials is not None:
         call.set_credentials(credentials._credentials)
       event_handler = _event_handler(state, call, self._response_deserializer)
       with state.condition:
-        call.start_client_batch(cygrpc.Operations(operations), event_handler)
+        call_error = call.start_client_batch(cygrpc.Operations(operations),
+            event_handler)
+        if call_error != cygrpc.CallError.ok:
+          _call_error_set_RPCstate(state, call_error, metadata)
+          return _Rendezvous(state, None, None, deadline)
+        drive_call()
       return _Rendezvous(state, call, self._response_deserializer, deadline)
 
 
 class _UnaryStreamMultiCallable(grpc.UnaryStreamMultiCallable):
 
   def __init__(
-      self, channel, create_managed_call, method, request_serializer,
+      self, channel, managed_call, method, request_serializer,
       response_deserializer):
     self._channel = channel
-    self._create_managed_call = create_managed_call
+    self._managed_call = managed_call
     self._method = method
     self._request_serializer = request_serializer
     self._response_deserializer = response_deserializer
@@ -518,7 +550,7 @@ class _UnaryStreamMultiCallable(grpc.UnaryStreamMultiCallable):
       raise rendezvous
     else:
       state = _RPCState(_UNARY_STREAM_INITIAL_DUE, None, None, None, None)
-      call = self._create_managed_call(
+      call, drive_call = self._managed_call(
           None, 0, self._method, None, deadline_timespec)
       if credentials is not None:
         call.set_credentials(credentials._credentials)
@@ -535,17 +567,22 @@ class _UnaryStreamMultiCallable(grpc.UnaryStreamMultiCallable):
             cygrpc.operation_send_close_from_client(_EMPTY_FLAGS),
             cygrpc.operation_receive_status_on_client(_EMPTY_FLAGS),
         )
-        call.start_client_batch(cygrpc.Operations(operations), event_handler)
+        call_error = call.start_client_batch(cygrpc.Operations(operations),
+            event_handler)
+        if call_error != cygrpc.CallError.ok:
+          _call_error_set_RPCstate(state, call_error, metadata)
+          return _Rendezvous(state, None, None, deadline)
+        drive_call()
       return _Rendezvous(state, call, self._response_deserializer, deadline)
 
 
 class _StreamUnaryMultiCallable(grpc.StreamUnaryMultiCallable):
 
   def __init__(
-      self, channel, create_managed_call, method, request_serializer,
+      self, channel, managed_call, method, request_serializer,
       response_deserializer):
     self._channel = channel
-    self._create_managed_call = create_managed_call
+    self._managed_call = managed_call
     self._method = method
     self._request_serializer = request_serializer
     self._response_deserializer = response_deserializer
@@ -569,7 +606,8 @@ class _StreamUnaryMultiCallable(grpc.StreamUnaryMultiCallable):
           cygrpc.operation_receive_message(_EMPTY_FLAGS),
           cygrpc.operation_receive_status_on_client(_EMPTY_FLAGS),
       )
-      call.start_client_batch(cygrpc.Operations(operations), None)
+      call_error = call.start_client_batch(cygrpc.Operations(operations), None)
+      _check_call_error(call_error, metadata)
       _consume_request_iterator(
           request_iterator, state, call, self._request_serializer)
     while True:
@@ -597,7 +635,7 @@ class _StreamUnaryMultiCallable(grpc.StreamUnaryMultiCallable):
       self, request_iterator, timeout=None, metadata=None, credentials=None):
     deadline, deadline_timespec = _deadline(timeout)
     state = _RPCState(_STREAM_UNARY_INITIAL_DUE, None, None, None, None)
-    call = self._create_managed_call(
+    call, drive_call = self._managed_call(
         None, 0, self._method, None, deadline_timespec)
     if credentials is not None:
       call.set_credentials(credentials._credentials)
@@ -613,7 +651,12 @@ class _StreamUnaryMultiCallable(grpc.StreamUnaryMultiCallable):
           cygrpc.operation_receive_message(_EMPTY_FLAGS),
           cygrpc.operation_receive_status_on_client(_EMPTY_FLAGS),
       )
-      call.start_client_batch(cygrpc.Operations(operations), event_handler)
+      call_error = call.start_client_batch(cygrpc.Operations(operations),
+          event_handler)
+      if call_error != cygrpc.CallError.ok:
+        _call_error_set_RPCstate(state, call_error, metadata)
+        return _Rendezvous(state, None, None, deadline)
+      drive_call()
       _consume_request_iterator(
           request_iterator, state, call, self._request_serializer)
     return _Rendezvous(state, call, self._response_deserializer, deadline)
@@ -622,10 +665,10 @@ class _StreamUnaryMultiCallable(grpc.StreamUnaryMultiCallable):
 class _StreamStreamMultiCallable(grpc.StreamStreamMultiCallable):
 
   def __init__(
-      self, channel, create_managed_call, method, request_serializer,
+      self, channel, managed_call, method, request_serializer,
       response_deserializer):
     self._channel = channel
-    self._create_managed_call = create_managed_call
+    self._managed_call = managed_call
     self._method = method
     self._request_serializer = request_serializer
     self._response_deserializer = response_deserializer
@@ -634,7 +677,7 @@ class _StreamStreamMultiCallable(grpc.StreamStreamMultiCallable):
       self, request_iterator, timeout=None, metadata=None, credentials=None):
     deadline, deadline_timespec = _deadline(timeout)
     state = _RPCState(_STREAM_STREAM_INITIAL_DUE, None, None, None, None)
-    call = self._create_managed_call(
+    call, drive_call = self._managed_call(
         None, 0, self._method, None, deadline_timespec)
     if credentials is not None:
       call.set_credentials(credentials._credentials)
@@ -649,7 +692,12 @@ class _StreamStreamMultiCallable(grpc.StreamStreamMultiCallable):
               _common.cygrpc_metadata(metadata), _EMPTY_FLAGS),
           cygrpc.operation_receive_status_on_client(_EMPTY_FLAGS),
       )
-      call.start_client_batch(cygrpc.Operations(operations), event_handler)
+      call_error = call.start_client_batch(cygrpc.Operations(operations),
+          event_handler)
+      if call_error != cygrpc.CallError.ok:
+        _call_error_set_RPCstate(state, call_error, metadata)
+        return _Rendezvous(state, None, None, deadline)
+      drive_call()
       _consume_request_iterator(
           request_iterator, state, call, self._request_serializer)
     return _Rendezvous(state, call, self._response_deserializer, deadline)
@@ -687,16 +735,13 @@ def _run_channel_spin_thread(state):
   channel_spin_thread.start()
 
 
-def _create_channel_managed_call(state):
-  def create_channel_managed_call(parent, flags, method, host, deadline):
-    """Creates a managed cygrpc.Call.
+def _channel_managed_call_management(state):
+  def create(parent, flags, method, host, deadline):
+    """Creates a managed cygrpc.Call and a function to call to drive it.
 
-    Callers of this function must conduct at least one operation on the returned
-    call. The tags associated with operations conducted on the returned call
-    must be no-argument callables that return None to indicate that this channel
-    should continue polling for events associated with the call and return the
-    call itself to indicate that no more events associated with the call will be
-    generated.
+    If operations are successfully added to the returned cygrpc.Call, the
+    returned function must be called. If operations are not successfully added
+    to the returned cygrpc.Call, the returned function must not be called.
 
     Args:
       parent: A cygrpc.Call to be used as the parent of the created call.
@@ -706,18 +751,22 @@ def _create_channel_managed_call(state):
       deadline: A cygrpc.Timespec to be the deadline of the created call.
 
     Returns:
-      A cygrpc.Call with which to conduct an RPC.
+      A cygrpc.Call with which to conduct an RPC and a function to call if
+        operations are successfully started on the call.
     """
-    with state.lock:
-      call = state.channel.create_call(
-          parent, flags, state.completion_queue, method, host, deadline)
-      if state.managed_calls is None:
-        state.managed_calls = set((call,))
-        _run_channel_spin_thread(state)
-      else:
-        state.managed_calls.add(call)
-      return call
-  return create_channel_managed_call
+    call = state.channel.create_call(
+        parent, flags, state.completion_queue, method, host, deadline)
+
+    def drive():
+      with state.lock:
+        if state.managed_calls is None:
+          state.managed_calls = set((call,))
+          _run_channel_spin_thread(state)
+        else:
+          state.managed_calls.add(call)
+
+    return call, drive
+  return create
 
 
 class _ChannelConnectivityState(object):
@@ -847,6 +896,7 @@ def _options(options):
 
 
 class Channel(grpc.Channel):
+  """A cygrpc.Channel-backed implementation of grpc.Channel."""
 
   def __init__(self, target, options, credentials):
     """Constructor.
@@ -871,25 +921,25 @@ class Channel(grpc.Channel):
   def unary_unary(
       self, method, request_serializer=None, response_deserializer=None):
     return _UnaryUnaryMultiCallable(
-        self._channel, _create_channel_managed_call(self._call_state),
+        self._channel, _channel_managed_call_management(self._call_state),
         _common.encode(method), request_serializer, response_deserializer)
 
   def unary_stream(
       self, method, request_serializer=None, response_deserializer=None):
     return _UnaryStreamMultiCallable(
-        self._channel, _create_channel_managed_call(self._call_state),
+        self._channel, _channel_managed_call_management(self._call_state),
         _common.encode(method), request_serializer, response_deserializer)
 
   def stream_unary(
       self, method, request_serializer=None, response_deserializer=None):
     return _StreamUnaryMultiCallable(
-        self._channel, _create_channel_managed_call(self._call_state),
+        self._channel, _channel_managed_call_management(self._call_state),
         _common.encode(method), request_serializer, response_deserializer)
 
   def stream_stream(
       self, method, request_serializer=None, response_deserializer=None):
     return _StreamStreamMultiCallable(
-        self._channel, _create_channel_managed_call(self._call_state),
+        self._channel, _channel_managed_call_management(self._call_state),
         _common.encode(method), request_serializer, response_deserializer)
 
   def __del__(self):
diff --git a/src/python/grpcio/grpc/_server.py b/src/python/grpcio/grpc/_server.py
index d83a2e6ded..5223712dfa 100644
--- a/src/python/grpcio/grpc/_server.py
+++ b/src/python/grpcio/grpc/_server.py
@@ -60,8 +60,7 @@ _CANCELLED = 'cancelled'
 _EMPTY_FLAGS = 0
 _EMPTY_METADATA = cygrpc.Metadata(())
 
-_DEFAULT_EXIT_GRACE = 1.0
-_DEFAULT_EXIT_SHUTDOWN_HANDLER_GRACE = 5.0
+_UNEXPECTED_EXIT_SERVER_GRACE = 1.0
 
 
 def _serialized_request(request_event):
@@ -596,18 +595,14 @@ class _ServerStage(enum.Enum):
 
 class _ServerState(object):
 
-  def __init__(self, completion_queue, server, generic_handlers, thread_pool,
-               exit_grace, exit_shutdown_handler_grace):
+  def __init__(self, completion_queue, server, generic_handlers, thread_pool):
     self.lock = threading.Lock()
     self.completion_queue = completion_queue
     self.server = server
     self.generic_handlers = list(generic_handlers)
     self.thread_pool = thread_pool
-    self.exit_grace = exit_grace
-    self.exit_shutdown_handler_grace = exit_shutdown_handler_grace
     self.stage = _ServerStage.STOPPED
     self.shutdown_events = None
-    self.shutdown_handlers = []
 
     # TODO(https://github.com/grpc/grpc/issues/6597): eliminate these fields.
     self.rpc_states = set()
@@ -677,45 +672,41 @@ def _serve(state):
             return
 
 
-def _stop(state, grace, shutdown_handler_grace):
-  shutdown_event = threading.Event()
-
-  def cancel_all_calls_after_grace():
-    with state.lock:
-      if state.stage is _ServerStage.STOPPED:
-        shutdown_event.set()
-        return
-      elif state.stage is _ServerStage.STARTED:
-        do_shutdown = True
-        state.stage = _ServerStage.GRACE
-        state.shutdown_events = []
-      else:
-        do_shutdown = False
-      state.shutdown_events.append(shutdown_event)
-
-    if do_shutdown:
-      # Run Shutdown Handlers without the lock
-      for handler in state.shutdown_handlers:
-        handler(shutdown_handler_grace)
-      with state.lock:
+def _stop(state, grace):
+  with state.lock:
+    if state.stage is _ServerStage.STOPPED:
+      shutdown_event = threading.Event()
+      shutdown_event.set()
+      return shutdown_event
+    else:
+      if state.stage is _ServerStage.STARTED:
         state.server.shutdown(state.completion_queue, _SHUTDOWN_TAG)
         state.stage = _ServerStage.GRACE
+        state.shutdown_events = []
         state.due.add(_SHUTDOWN_TAG)
-
-    if not shutdown_event.wait(timeout=grace):
-      with state.lock:
+      shutdown_event = threading.Event()
+      state.shutdown_events.append(shutdown_event)
+      if grace is None:
         state.server.cancel_all_calls()
         # TODO(https://github.com/grpc/grpc/issues/6597): delete this loop.
         for rpc_state in state.rpc_states:
           with rpc_state.condition:
             rpc_state.client = _CANCELLED
             rpc_state.condition.notify_all()
-
-  if grace is None:
-    cancel_all_calls_after_grace()
-  else:
-    threading.Thread(target=cancel_all_calls_after_grace).start()
-
+      else:
+        def cancel_all_calls_after_grace():
+          shutdown_event.wait(timeout=grace)
+          with state.lock:
+            state.server.cancel_all_calls()
+            # TODO(https://github.com/grpc/grpc/issues/6597): delete this loop.
+            for rpc_state in state.rpc_states:
+              with rpc_state.condition:
+                rpc_state.client = _CANCELLED
+                rpc_state.condition.notify_all()
+        thread = threading.Thread(target=cancel_all_calls_after_grace)
+        thread.start()
+        return shutdown_event
+  shutdown_event.wait()
   return shutdown_event
 
 
@@ -725,12 +716,12 @@ def _start(state):
       raise ValueError('Cannot start already-started server!')
     state.server.start()
     state.stage = _ServerStage.STARTED
-    _request_call(state)
+    _request_call(state)    
     def cleanup_server(timeout):
       if timeout is None:
-        _stop(state, state.exit_grace, state.exit_shutdown_handler_grace).wait()
+        _stop(state, _UNEXPECTED_EXIT_SERVER_GRACE).wait()
       else:
-        _stop(state, timeout, 0).wait()
+        _stop(state, timeout).wait()
 
     thread = _common.CleanupThread(
         cleanup_server, target=_serve, args=(state,))
@@ -738,16 +729,12 @@ def _start(state):
 
 class Server(grpc.Server):
 
-  def __init__(self, thread_pool, generic_handlers, options, exit_grace,
-               exit_shutdown_handler_grace):
+  def __init__(self, thread_pool, generic_handlers, options):
     completion_queue = cygrpc.CompletionQueue()
     server = cygrpc.Server(_common.channel_args(options))
     server.register_completion_queue(completion_queue)
     self._state = _ServerState(
-        completion_queue, server, generic_handlers, thread_pool,
-        _DEFAULT_EXIT_GRACE if exit_grace is None else exit_grace,
-        _DEFAULT_EXIT_SHUTDOWN_HANDLER_GRACE if exit_shutdown_handler_grace
-        is None else exit_shutdown_handler_grace)
+        completion_queue, server, generic_handlers, thread_pool)
 
   def add_generic_rpc_handlers(self, generic_rpc_handlers):
     _add_generic_handlers(self._state, generic_rpc_handlers)
@@ -758,14 +745,11 @@ class Server(grpc.Server):
   def add_secure_port(self, address, server_credentials):
     return _add_secure_port(self._state, _common.encode(address), server_credentials)
 
-  def add_shutdown_handler(self, handler):
-    self._state.shutdown_handlers.append(handler)
-
   def start(self):
     _start(self._state)
 
-  def stop(self, grace, shutdown_handler_grace=None):
-    return _stop(self._state, grace, shutdown_handler_grace)
+  def stop(self, grace):
+    return _stop(self._state, grace)
 
   def __del__(self):
-    _stop(self._state, None, None)
+    _stop(self._state, None)
diff --git a/src/python/grpcio/grpc/_utilities.py b/src/python/grpcio/grpc/_utilities.py
index 4850967fbc..a375896e6e 100644
--- a/src/python/grpcio/grpc/_utilities.py
+++ b/src/python/grpcio/grpc/_utilities.py
@@ -53,13 +53,17 @@ class RpcMethodHandler(
   pass
 
 
-class DictionaryGenericHandler(grpc.GenericRpcHandler):
+class DictionaryGenericHandler(grpc.ServiceRpcHandler):
 
   def __init__(self, service, method_handlers):
+    self._name = service
     self._method_handlers = {
         _common.fully_qualified_method(service, method): method_handler
         for method, method_handler in six.iteritems(method_handlers)}
 
+  def service_name(self):
+    return self._name
+
   def service(self, handler_call_details):
     return self._method_handlers.get(handler_call_details.method)
 
diff --git a/src/python/grpcio/grpc_core_dependencies.py b/src/python/grpcio/grpc_core_dependencies.py
index bfd706a78b..e27e9e181d 100644
--- a/src/python/grpcio/grpc_core_dependencies.py
+++ b/src/python/grpcio/grpc_core_dependencies.py
@@ -82,6 +82,8 @@ CORE_SOURCE_FILES = [
   'src/core/lib/channel/connected_channel.c',
   'src/core/lib/channel/deadline_filter.c',
   'src/core/lib/channel/handshaker.c',
+  'src/core/lib/channel/handshaker_factory.c',
+  'src/core/lib/channel/handshaker_registry.c',
   'src/core/lib/channel/http_client_filter.c',
   'src/core/lib/channel/http_server_filter.c',
   'src/core/lib/channel/message_size_filter.c',
@@ -226,9 +228,9 @@ CORE_SOURCE_FILES = [
   'src/core/lib/security/credentials/plugin/plugin_credentials.c',
   'src/core/lib/security/credentials/ssl/ssl_credentials.c',
   'src/core/lib/security/transport/client_auth_filter.c',
-  'src/core/lib/security/transport/handshake.c',
   'src/core/lib/security/transport/secure_endpoint.c',
   'src/core/lib/security/transport/security_connector.c',
+  'src/core/lib/security/transport/security_handshaker.c',
   'src/core/lib/security/transport/server_auth_filter.c',
   'src/core/lib/security/transport/tsi_error.c',
   'src/core/lib/security/util/b64.c',
@@ -237,6 +239,7 @@ CORE_SOURCE_FILES = [
   'src/core/lib/tsi/fake_transport_security.c',
   'src/core/lib/tsi/ssl_transport_security.c',
   'src/core/lib/tsi/transport_security.c',
+  'src/core/ext/transport/chttp2/server/chttp2_server.c',
   'src/core/ext/transport/chttp2/client/secure/secure_channel_create.c',
   'src/core/ext/client_channel/channel_connectivity.c',
   'src/core/ext/client_channel/client_channel.c',
@@ -256,6 +259,7 @@ CORE_SOURCE_FILES = [
   'src/core/ext/client_channel/subchannel.c',
   'src/core/ext/client_channel/subchannel_index.c',
   'src/core/ext/client_channel/uri_parser.c',
+  'src/core/ext/transport/chttp2/client/chttp2_connector.c',
   'src/core/ext/transport/chttp2/server/insecure/server_chttp2.c',
   'src/core/ext/transport/chttp2/server/insecure/server_chttp2_posix.c',
   'src/core/ext/transport/chttp2/client/insecure/channel_create.c',
diff --git a/src/python/grpcio/support.py b/src/python/grpcio/support.py
index f363f5fdc5..b226e690fd 100644
--- a/src/python/grpcio/support.py
+++ b/src/python/grpcio/support.py
@@ -100,9 +100,15 @@ def diagnose_compile_error(build_ext, error):
             .format(source)
           )
 
+def diagnose_attribute_error(build_ext, error):
+  if any('_needs_stub' in arg for arg in error.args):
+    raise commands.CommandError(
+        "We expect a missing `_needs_stub` attribute from older versions of "
+        "setuptools. Consider upgrading setuptools.")
 
 _ERROR_DIAGNOSES = {
-    errors.CompileError: diagnose_compile_error
+    errors.CompileError: diagnose_compile_error,
+    AttributeError: diagnose_attribute_error
 }
 
 def diagnose_build_ext_error(build_ext, error, formatted):
diff --git a/src/python/grpcio_health_checking/MANIFEST.in b/src/python/grpcio_health_checking/MANIFEST.in
index 7407f646d1..5255e4c403 100644
--- a/src/python/grpcio_health_checking/MANIFEST.in
+++ b/src/python/grpcio_health_checking/MANIFEST.in
@@ -1,4 +1,4 @@
 include grpc_version.py
 include health_commands.py
-graft grpc
+graft grpc_health
 global-exclude *.pyc
diff --git a/src/python/grpcio_health_checking/grpc/health/__init__.py b/src/python/grpcio_health_checking/grpc_health/__init__.py
index 7086519106..7086519106 100644
--- a/src/python/grpcio_health_checking/grpc/health/__init__.py
+++ b/src/python/grpcio_health_checking/grpc_health/__init__.py
diff --git a/src/python/grpcio_health_checking/grpc/health/v1/__init__.py b/src/python/grpcio_health_checking/grpc_health/v1/__init__.py
index 7086519106..7086519106 100644
--- a/src/python/grpcio_health_checking/grpc/health/v1/__init__.py
+++ b/src/python/grpcio_health_checking/grpc_health/v1/__init__.py
diff --git a/src/python/grpcio_health_checking/grpc/health/v1/health.py b/src/python/grpcio_health_checking/grpc_health/v1/health.py
index 8108ac1096..0df679b0e2 100644
--- a/src/python/grpcio_health_checking/grpc/health/v1/health.py
+++ b/src/python/grpcio_health_checking/grpc_health/v1/health.py
@@ -33,7 +33,7 @@ import threading
 
 import grpc
 
-from grpc.health.v1 import health_pb2
+from grpc_health.v1 import health_pb2
 
 
 class HealthServicer(health_pb2.HealthServicer):
diff --git a/src/python/grpcio_health_checking/health_commands.py b/src/python/grpcio_health_checking/health_commands.py
index 66df25da63..0c420a655f 100644
--- a/src/python/grpcio_health_checking/health_commands.py
+++ b/src/python/grpcio_health_checking/health_commands.py
@@ -54,7 +54,7 @@ class CopyProtoModules(setuptools.Command):
     if os.path.isfile(HEALTH_PROTO):
       shutil.copyfile(
           HEALTH_PROTO,
-          os.path.join(ROOT_DIR, 'grpc/health/v1/health.proto'))
+          os.path.join(ROOT_DIR, 'grpc_health/v1/health.proto'))
 
 
 class BuildPackageProtos(setuptools.Command):
@@ -74,5 +74,5 @@ class BuildPackageProtos(setuptools.Command):
     # directory is provided as an 'include' directory. We assume it's the '' key
     # to `self.distribution.package_dir` (and get a key error if it's not
     # there).
-    from grpc.tools import command
+    from grpc_tools import command
     command.build_package_protos(self.distribution.package_dir[''])
diff --git a/src/python/grpcio_health_checking/setup.py b/src/python/grpcio_health_checking/setup.py
index 8c92ee16a9..e88f389ba8 100644
--- a/src/python/grpcio_health_checking/setup.py
+++ b/src/python/grpcio_health_checking/setup.py
@@ -66,7 +66,6 @@ setuptools.setup(
     license='3-clause BSD',
     package_dir=PACKAGE_DIRECTORIES,
     packages=setuptools.find_packages('.'),
-    namespace_packages=['grpc'],
     install_requires=INSTALL_REQUIRES,
     setup_requires=SETUP_REQUIRES,
     cmdclass=COMMAND_CLASS
diff --git a/src/python/grpcio_reflection/grpc/__init__.py b/src/python/grpcio_reflection/grpc/__init__.py
deleted file mode 100644
index 70ac5edd48..0000000000
--- a/src/python/grpcio_reflection/grpc/__init__.py
+++ /dev/null
@@ -1,30 +0,0 @@
-# Copyright 2016, Google Inc.
-# All rights reserved.
-#
-# Redistribution and use in source and binary forms, with or without
-# modification, are permitted provided that the following conditions are
-# met:
-#
-#     * Redistributions of source code must retain the above copyright
-# notice, this list of conditions and the following disclaimer.
-#     * Redistributions in binary form must reproduce the above
-# copyright notice, this list of conditions and the following disclaimer
-# in the documentation and/or other materials provided with the
-# distribution.
-#     * Neither the name of Google Inc. nor the names of its
-# contributors may be used to endorse or promote products derived from
-# this software without specific prior written permission.
-#
-# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-__import__('pkg_resources').declare_namespace(__name__)
diff --git a/src/python/grpcio_reflection/grpc/reflection/__init__.py b/src/python/grpcio_reflection/grpc_reflection/__init__.py
index d5ad73a74a..d5ad73a74a 100644
--- a/src/python/grpcio_reflection/grpc/reflection/__init__.py
+++ b/src/python/grpcio_reflection/grpc_reflection/__init__.py
diff --git a/src/python/grpcio_reflection/grpc/reflection/v1alpha/__init__.py b/src/python/grpcio_reflection/grpc_reflection/v1alpha/__init__.py
index d5ad73a74a..d5ad73a74a 100644
--- a/src/python/grpcio_reflection/grpc/reflection/v1alpha/__init__.py
+++ b/src/python/grpcio_reflection/grpc_reflection/v1alpha/__init__.py
diff --git a/src/python/grpcio_reflection/grpc/reflection/v1alpha/reflection.py b/src/python/grpcio_reflection/grpc_reflection/v1alpha/reflection.py
index 3c399b0d79..bfcbce8e04 100644
--- a/src/python/grpcio_reflection/grpc/reflection/v1alpha/reflection.py
+++ b/src/python/grpcio_reflection/grpc_reflection/v1alpha/reflection.py
@@ -35,7 +35,7 @@ import grpc
 from google.protobuf import descriptor_pb2
 from google.protobuf import descriptor_pool
 
-from grpc.reflection.v1alpha import reflection_pb2
+from grpc_reflection.v1alpha import reflection_pb2
 
 _POOL = descriptor_pool.Default()
 
diff --git a/src/python/grpcio_reflection/reflection_commands.py b/src/python/grpcio_reflection/reflection_commands.py
index d189aee577..dee5491e0a 100644
--- a/src/python/grpcio_reflection/reflection_commands.py
+++ b/src/python/grpcio_reflection/reflection_commands.py
@@ -54,7 +54,7 @@ class CopyProtoModules(setuptools.Command):
     if os.path.isfile(HEALTH_PROTO):
       shutil.copyfile(
           HEALTH_PROTO,
-          os.path.join(ROOT_DIR, 'grpc/reflection/v1alpha/reflection.proto'))
+          os.path.join(ROOT_DIR, 'grpc_reflection/v1alpha/reflection.proto'))
 
 
 class BuildPackageProtos(setuptools.Command):
@@ -74,5 +74,5 @@ class BuildPackageProtos(setuptools.Command):
     # directory is provided as an 'include' directory. We assume it's the '' key
     # to `self.distribution.package_dir` (and get a key error if it's not
     # there).
-    from grpc.tools import command
+    from grpc_tools import command
     command.build_package_protos(self.distribution.package_dir[''])
diff --git a/src/python/grpcio_reflection/setup.py b/src/python/grpcio_reflection/setup.py
index df95af4de1..cfc41f4fe7 100644
--- a/src/python/grpcio_reflection/setup.py
+++ b/src/python/grpcio_reflection/setup.py
@@ -66,7 +66,6 @@ setuptools.setup(
     license='3-clause BSD',
     package_dir=PACKAGE_DIRECTORIES,
     packages=setuptools.find_packages('.'),
-    namespace_packages=['grpc'],
     install_requires=INSTALL_REQUIRES,
     setup_requires=SETUP_REQUIRES,
     cmdclass=COMMAND_CLASS
diff --git a/src/python/grpcio_tests/commands.py b/src/python/grpcio_tests/commands.py
index 5ee551cfe1..e822971fe0 100644
--- a/src/python/grpcio_tests/commands.py
+++ b/src/python/grpcio_tests/commands.py
@@ -100,7 +100,7 @@ class BuildProtoModules(setuptools.Command):
     pass
 
   def run(self):
-    import grpc.tools.protoc as protoc
+    import grpc_tools.protoc as protoc
 
     include_regex = re.compile(self.include)
     exclude_regex = re.compile(self.exclude) if self.exclude else None
@@ -116,7 +116,7 @@ class BuildProtoModules(setuptools.Command):
     # but we currently have name conflicts in src/proto
     for path in paths:
       command = [
-          'grpc.tools.protoc',
+          'grpc_tools.protoc',
           '-I {}'.format(PROTO_STEM),
           '--python_out={}'.format(PROTO_STEM),
           '--grpc_python_out={}'.format(PROTO_STEM),
diff --git a/src/python/grpcio_tests/setup.py b/src/python/grpcio_tests/setup.py
index 01d5fa875b..375fbd6c77 100644
--- a/src/python/grpcio_tests/setup.py
+++ b/src/python/grpcio_tests/setup.py
@@ -35,7 +35,7 @@ import sys
 
 import setuptools
 
-import grpc.tools.command
+import grpc_tools.command
 
 PY3 = sys.version_info.major == 3
 
@@ -68,7 +68,7 @@ COMMAND_CLASS = {
     # Run `preprocess` *before* doing any packaging!
     'preprocess': commands.GatherProto,
 
-    'build_package_protos': grpc.tools.command.BuildPackageProtos,
+    'build_package_protos': grpc_tools.command.BuildPackageProtos,
     'build_py': commands.BuildPy,
     'run_interop': commands.RunInterop,
     'test_lite': commands.TestLite
diff --git a/src/python/grpcio_tests/tests/health_check/_health_servicer_test.py b/src/python/grpcio_tests/tests/health_check/_health_servicer_test.py
index 80300d13df..5dde72b169 100644
--- a/src/python/grpcio_tests/tests/health_check/_health_servicer_test.py
+++ b/src/python/grpcio_tests/tests/health_check/_health_servicer_test.py
@@ -27,14 +27,14 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-"""Tests of grpc.health.v1.health."""
+"""Tests of grpc_health.v1.health."""
 
 import unittest
 
 import grpc
 from grpc.framework.foundation import logging_pool
-from grpc.health.v1 import health
-from grpc.health.v1 import health_pb2
+from grpc_health.v1 import health
+from grpc_health.v1 import health_pb2
 
 from tests.unit.framework.common import test_constants
 
diff --git a/src/python/grpcio_tests/tests/http2/_negative_http2_client.py b/src/python/grpcio_tests/tests/http2/_negative_http2_client.py
new file mode 100644
index 0000000000..f8604683b3
--- /dev/null
+++ b/src/python/grpcio_tests/tests/http2/_negative_http2_client.py
@@ -0,0 +1,153 @@
+# Copyright 2016, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""The Python client used to test negative http2 conditions."""
+
+import argparse
+
+import grpc
+from src.proto.grpc.testing import test_pb2
+from src.proto.grpc.testing import messages_pb2
+
+def _validate_payload_type_and_length(response, expected_type, expected_length):
+  if response.payload.type is not expected_type:
+    raise ValueError(
+      'expected payload type %s, got %s' %
+          (expected_type, type(response.payload.type)))
+  elif len(response.payload.body) != expected_length:
+    raise ValueError(
+      'expected payload body size %d, got %d' %
+          (expected_length, len(response.payload.body)))
+
+def _expect_status_code(call, expected_code):
+  if call.code() != expected_code:
+    raise ValueError(
+      'expected code %s, got %s' % (expected_code, call.code()))
+
+def _expect_status_details(call, expected_details):
+  if call.details() != expected_details:
+    raise ValueError(
+      'expected message %s, got %s' % (expected_details, call.details()))
+
+def _validate_status_code_and_details(call, expected_code, expected_details):
+  _expect_status_code(call, expected_code)
+  _expect_status_details(call, expected_details)
+
+# common requests
+_REQUEST_SIZE = 314159
+_RESPONSE_SIZE = 271828
+
+_SIMPLE_REQUEST = messages_pb2.SimpleRequest(
+    response_type=messages_pb2.COMPRESSABLE,
+    response_size=_RESPONSE_SIZE,
+    payload=messages_pb2.Payload(body=b'\x00' * _REQUEST_SIZE))
+
+def _goaway(stub):
+  first_response = stub.UnaryCall(_SIMPLE_REQUEST)
+  _validate_payload_type_and_length(first_response, 
+      messages_pb2.COMPRESSABLE, _RESPONSE_SIZE)
+  second_response = stub.UnaryCall(_SIMPLE_REQUEST)
+  _validate_payload_type_and_length(second_response, 
+      messages_pb2.COMPRESSABLE, _RESPONSE_SIZE)
+
+def _rst_after_header(stub):
+  resp_future = stub.UnaryCall.future(_SIMPLE_REQUEST)
+  _validate_status_code_and_details(resp_future, grpc.StatusCode.UNAVAILABLE, "")
+
+def _rst_during_data(stub):
+  resp_future = stub.UnaryCall.future(_SIMPLE_REQUEST)
+  _validate_status_code_and_details(resp_future, grpc.StatusCode.UNKNOWN, "")
+
+def _rst_after_data(stub):
+  resp_future = stub.UnaryCall.future(_SIMPLE_REQUEST)
+  _validate_payload_type_and_length(next(resp_future),
+      messages_pb2.COMPRESSABLE, _RESPONSE_SIZE)
+  _validate_status_code_and_details(resp_future, grpc.StatusCode.UNKNOWN, "")
+
+def _ping(stub):
+  response = stub.UnaryCall(_SIMPLE_REQUEST)
+  _validate_payload_type_and_length(response, 
+      messages_pb2.COMPRESSABLE, _RESPONSE_SIZE)
+
+def _max_streams(stub):
+  # send one req to ensure server sets MAX_STREAMS
+  response = stub.UnaryCall(_SIMPLE_REQUEST)
+  _validate_payload_type_and_length(response, 
+      messages_pb2.COMPRESSABLE, _RESPONSE_SIZE)
+
+  # give the streams a workout
+  futures = []
+  for _ in range(15):
+    futures.append(stub.UnaryCall.future(_SIMPLE_REQUEST))
+  for future in futures:
+    _validate_payload_type_and_length(future.result(),
+        messages_pb2.COMPRESSABLE, _RESPONSE_SIZE)
+
+def _run_test_case(test_case, stub):
+  if test_case == 'goaway':
+    _goaway(stub)
+  elif test_case == 'rst_after_header':
+    _rst_after_header(stub)
+  elif test_case == 'rst_during_data':
+    _rst_during_data(stub)
+  elif test_case == 'rst_after_data':
+    _rst_after_data(stub)
+  elif test_case =='ping':
+    _ping(stub)
+  elif test_case == 'max_streams':
+    _max_streams(stub)
+  else:
+    raise ValueError("Invalid test case: %s" % test_case)
+
+def _args():
+  parser = argparse.ArgumentParser()
+  parser.add_argument(
+      '--server_host', help='the host to which to connect', type=str,
+      default="127.0.0.1")
+  parser.add_argument(
+      '--server_port', help='the port to which to connect', type=int,
+      default="8080")
+  parser.add_argument(
+      '--test_case', help='the test case to execute', type=str,
+      default="goaway")
+  return parser.parse_args()
+
+def _stub(server_host, server_port):
+  target = '{}:{}'.format(server_host, server_port)
+  channel = grpc.insecure_channel(target)
+  return test_pb2.TestServiceStub(channel)
+
+def main():
+  args = _args()
+  stub = _stub(args.server_host, args.server_port)
+  _run_test_case(args.test_case, stub)
+
+
+if __name__ == '__main__':
+  main()
diff --git a/src/python/grpcio_tests/tests/interop/_insecure_interop_test.py b/src/python/grpcio_tests/tests/interop/_insecure_intraop_test.py
index 936c895bd2..4fb22b4d9d 100644
--- a/src/python/grpcio_tests/tests/interop/_insecure_interop_test.py
+++ b/src/python/grpcio_tests/tests/interop/_insecure_intraop_test.py
@@ -35,13 +35,13 @@ import unittest
 import grpc
 from src.proto.grpc.testing import test_pb2
 
-from tests.interop import _interop_test_case
+from tests.interop import _intraop_test_case
 from tests.interop import methods
 from tests.interop import server
 
 
-class InsecureInteropTest(
-    _interop_test_case.InteropTestCase,
+class InsecureIntraopTest(
+    _intraop_test_case.IntraopTestCase,
     unittest.TestCase):
 
   def setUp(self):
diff --git a/src/python/grpcio_tests/tests/interop/_interop_test_case.py b/src/python/grpcio_tests/tests/interop/_intraop_test_case.py
index ccea17a66d..fe1c173992 100644
--- a/src/python/grpcio_tests/tests/interop/_interop_test_case.py
+++ b/src/python/grpcio_tests/tests/interop/_intraop_test_case.py
@@ -32,7 +32,7 @@
 from tests.interop import methods
 
 
-class InteropTestCase(object):
+class IntraopTestCase(object):
   """Unit test methods.
 
   This class must be mixed in with unittest.TestCase and a class that defines
diff --git a/src/python/grpcio_tests/tests/interop/_secure_interop_test.py b/src/python/grpcio_tests/tests/interop/_secure_intraop_test.py
index eaca553e1b..3665c69726 100644
--- a/src/python/grpcio_tests/tests/interop/_secure_interop_test.py
+++ b/src/python/grpcio_tests/tests/interop/_secure_intraop_test.py
@@ -35,15 +35,15 @@ import unittest
 import grpc
 from src.proto.grpc.testing import test_pb2
 
-from tests.interop import _interop_test_case
+from tests.interop import _intraop_test_case
 from tests.interop import methods
 from tests.interop import resources
 
 _SERVER_HOST_OVERRIDE = 'foo.test.google.fr'
 
 
-class SecureInteropTest(
-    _interop_test_case.InteropTestCase,
+class SecureIntraopTest(
+    _intraop_test_case.IntraopTestCase,
     unittest.TestCase):
 
   def setUp(self):
diff --git a/src/python/grpcio_tests/tests/interop/methods.py b/src/python/grpcio_tests/tests/interop/methods.py
index 52e56f3502..9038ae5751 100644
--- a/src/python/grpcio_tests/tests/interop/methods.py
+++ b/src/python/grpcio_tests/tests/interop/methods.py
@@ -33,7 +33,6 @@ import enum
 import json
 import os
 import threading
-import time
 
 from oauth2client import client as oauth2client_client
 
@@ -196,16 +195,6 @@ def _server_streaming(stub):
         response, messages_pb2.COMPRESSABLE, sizes[index])
 
 
-def _cancel_after_begin(stub):
-  sizes = (27182, 8, 1828, 45904,)
-  payloads = (messages_pb2.Payload(body=b'\x00' * size) for size in sizes)
-  requests = (messages_pb2.StreamingInputCallRequest(payload=payload)
-              for payload in payloads)
-  response_future = stub.StreamingInputCall.future(requests)
-  response_future.cancel()
-  if not response_future.cancelled():
-    raise ValueError('expected call to be cancelled')
-
 
 class _Pipe(object):
 
@@ -265,6 +254,16 @@ def _ping_pong(stub):
           response, messages_pb2.COMPRESSABLE, response_size)
 
 
+def _cancel_after_begin(stub):
+  with _Pipe() as pipe:
+    response_future = stub.StreamingInputCall.future(pipe)
+    response_future.cancel()
+    if not response_future.cancelled():
+      raise ValueError('expected cancelled method to return True')
+    if response_future.code() is not grpc.StatusCode.CANCELLED:
+      raise ValueError('expected status code CANCELLED')
+
+
 def _cancel_after_first_response(stub):
   request_response_sizes = (31415, 9, 2653, 58979,)
   request_payload_sizes = (27182, 8, 1828, 45904,)
@@ -302,7 +301,6 @@ def _timeout_on_sleeping_server(stub):
         response_type=messages_pb2.COMPRESSABLE,
         payload=messages_pb2.Payload(body=b'\x00' * request_payload_size))
     pipe.add(request)
-    time.sleep(0.1)
     try:
       next(response_iterator)
     except grpc.RpcError as rpc_error:
diff --git a/src/python/grpcio_tests/tests/protoc_plugin/_split_definitions_test.py b/src/python/grpcio_tests/tests/protoc_plugin/_split_definitions_test.py
index 089366a8c7..f8ae05bb7a 100644
--- a/src/python/grpcio_tests/tests/protoc_plugin/_split_definitions_test.py
+++ b/src/python/grpcio_tests/tests/protoc_plugin/_split_definitions_test.py
@@ -44,7 +44,7 @@ import threading
 import unittest
 
 import grpc
-from grpc.tools import protoc
+from grpc_tools import protoc
 from tests.unit.framework.common import test_constants
 
 _MESSAGES_IMPORT = b'import "messages.proto";'
@@ -167,7 +167,7 @@ class SameSeparateTest(unittest.TestCase, SeparateTestMixin):
         '',
         '--proto_path={}'.format(self.proto_directory),
         '--python_out={}'.format(self.python_out_directory),
-        '--grpc_python_out={}'.format(self.grpc_python_out_directory),
+        '--grpc_python_out=grpc_2_0:{}'.format(self.grpc_python_out_directory),
         same_proto_file,
     ])
     if protoc_result != 0:
@@ -241,7 +241,7 @@ class SplitCommonTest(unittest.TestCase, CommonTestMixin):
         '',
         '--proto_path={}'.format(self.proto_directory),
         '--python_out={}'.format(self.python_out_directory),
-        '--grpc_python_out={}'.format(self.python_out_directory),
+        '--grpc_python_out={}'.format(self.grpc_python_out_directory),
         services_proto_file,
         messages_proto_file,
     ])
@@ -285,7 +285,7 @@ class SplitSeparateTest(unittest.TestCase, SeparateTestMixin):
         '',
         '--proto_path={}'.format(self.proto_directory),
         '--python_out={}'.format(self.python_out_directory),
-        '--grpc_python_out={}'.format(self.grpc_python_out_directory),
+        '--grpc_python_out=grpc_2_0:{}'.format(self.grpc_python_out_directory),
         services_proto_file,
         messages_proto_file,
     ])
diff --git a/src/python/grpcio_tests/tests/qps/benchmark_client.py b/src/python/grpcio_tests/tests/qps/benchmark_client.py
index 83b46c914e..650e4756e7 100644
--- a/src/python/grpcio_tests/tests/qps/benchmark_client.py
+++ b/src/python/grpcio_tests/tests/qps/benchmark_client.py
@@ -68,12 +68,8 @@ class BenchmarkClient:
     else:
       channel = grpc.insecure_channel(server)
 
-    connected_event = threading.Event()
-    def wait_for_ready(connectivity):
-      if connectivity == grpc.ChannelConnectivity.READY:
-        connected_event.set()
-    channel.subscribe(wait_for_ready, try_to_connect=True)
-    connected_event.wait()
+    # waits for the channel to be ready before we start sending messages
+    grpc.channel_ready_future(channel).result()
 
     if config.payload_config.WhichOneof('payload') == 'simple_params':
       self._generic = False
diff --git a/src/python/grpcio_tests/tests/reflection/_reflection_servicer_test.py b/src/python/grpcio_tests/tests/reflection/_reflection_servicer_test.py
index 87264cf9ba..43d6c971b5 100644
--- a/src/python/grpcio_tests/tests/reflection/_reflection_servicer_test.py
+++ b/src/python/grpcio_tests/tests/reflection/_reflection_servicer_test.py
@@ -27,14 +27,14 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-"""Tests of grpc.reflection.v1alpha.reflection."""
+"""Tests of grpc_reflection.v1alpha.reflection."""
 
 import unittest
 
 import grpc
 from grpc.framework.foundation import logging_pool
-from grpc.reflection.v1alpha import reflection
-from grpc.reflection.v1alpha import reflection_pb2
+from grpc_reflection.v1alpha import reflection
+from grpc_reflection.v1alpha import reflection_pb2
 
 from google.protobuf import descriptor_pool
 from google.protobuf import descriptor_pb2
@@ -75,7 +75,7 @@ class ReflectionServicerTest(unittest.TestCase):
         file_by_filename='i-donut-exist'
       ),
     )
-    responses = tuple(self._stub.ServerReflectionInfo(requests))
+    responses = tuple(self._stub.ServerReflectionInfo(iter(requests)))
     expected_responses = (
       reflection_pb2.ServerReflectionResponse(
         valid_host='',
@@ -93,7 +93,7 @@ class ReflectionServicerTest(unittest.TestCase):
         )
       ),
     )
-    self.assertEqual(expected_responses, responses)
+    self.assertSequenceEqual(expected_responses, responses)
 
   def testFileBySymbol(self):
     requests = (
@@ -104,7 +104,7 @@ class ReflectionServicerTest(unittest.TestCase):
         file_containing_symbol='i.donut.exist.co.uk.org.net.me.name.foo'
       ),
     )
-    responses = tuple(self._stub.ServerReflectionInfo(requests))
+    responses = tuple(self._stub.ServerReflectionInfo(iter(requests)))
     expected_responses = (
       reflection_pb2.ServerReflectionResponse(
         valid_host='',
@@ -122,7 +122,7 @@ class ReflectionServicerTest(unittest.TestCase):
         )
       ),
     )
-    self.assertEqual(expected_responses, responses)
+    self.assertSequenceEqual(expected_responses, responses)
 
   @unittest.skip('TODO(atash): implement file-containing-extension reflection '
                  '(see https://github.com/google/protobuf/issues/2248)')
@@ -141,7 +141,7 @@ class ReflectionServicerTest(unittest.TestCase):
         ),
       ),
     )
-    responses = tuple(self._stub.ServerReflectionInfo(requests))
+    responses = tuple(self._stub.ServerReflectionInfo(iter(requests)))
     expected_responses = (
       reflection_pb2.ServerReflectionResponse(
         valid_host='',
@@ -159,7 +159,7 @@ class ReflectionServicerTest(unittest.TestCase):
         )
       ),
     )
-    self.assertEqual(expected_responses, responses)
+    self.assertSequenceEqual(expected_responses, responses)
 
   def testListServices(self):
     requests = (
@@ -167,7 +167,7 @@ class ReflectionServicerTest(unittest.TestCase):
         list_services='',
       ),
     )
-    responses = tuple(self._stub.ServerReflectionInfo(requests))
+    responses = tuple(self._stub.ServerReflectionInfo(iter(requests)))
     expected_responses = (
       reflection_pb2.ServerReflectionResponse(
         valid_host='',
@@ -179,7 +179,7 @@ class ReflectionServicerTest(unittest.TestCase):
         )
       ),
     )
-    self.assertEqual(expected_responses, responses)
+    self.assertSequenceEqual(expected_responses, responses)
 
 if __name__ == '__main__':
   unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/stress/client.py b/src/python/grpcio_tests/tests/stress/client.py
index 390ea13021..b8116729b5 100644
--- a/src/python/grpcio_tests/tests/stress/client.py
+++ b/src/python/grpcio_tests/tests/stress/client.py
@@ -110,10 +110,13 @@ def _get_channel(target, args):
     channel_credentials = grpc.ssl_channel_credentials(
         root_certificates=root_certificates)
     options = (('grpc.ssl_target_name_override', args.server_host_override,),)
-    return grpc.secure_channel(
-        target, channel_credentials, options=options)
+    channel = grpc.secure_channel(target, channel_credentials, options=options)
   else:
-    return grpc.insecure_channel(target)
+    channel = grpc.insecure_channel(target)
+
+  # waits for the channel to be ready before we start sending messages
+  grpc.channel_ready_future(channel).result()
+  return channel
 
 def run_test(args):
   test_cases = _parse_weighted_test_cases(args.test_cases)
diff --git a/src/python/grpcio_tests/tests/tests.json b/src/python/grpcio_tests/tests/tests.json
index 04a2e44178..70d965d3ca 100644
--- a/src/python/grpcio_tests/tests/tests.json
+++ b/src/python/grpcio_tests/tests/tests.json
@@ -1,7 +1,7 @@
 [
   "health_check._health_servicer_test.HealthServicerTest",
-  "interop._insecure_interop_test.InsecureInteropTest",
-  "interop._secure_interop_test.SecureInteropTest",
+  "interop._insecure_intraop_test.InsecureIntraopTest",
+  "interop._secure_intraop_test.SecureIntraopTest",
   "protoc_plugin._python_plugin_test.PythonPluginTest",
   "protoc_plugin._split_definitions_test.SameCommonTest",
   "protoc_plugin._split_definitions_test.SameSeparateTest",
@@ -27,7 +27,8 @@
   "unit._cython.cygrpc_test.TypeSmokeTest",
   "unit._empty_message_test.EmptyMessageTest",
   "unit._exit_test.ExitTest",
-  "unit._exit_test.ShutdownHandlerTest",
+  "unit._invalid_metadata_test.InvalidMetadataTest",
+  "unit._invocation_defects_test.InvocationDefectsTest",
   "unit._metadata_code_details_test.MetadataCodeDetailsTest",
   "unit._metadata_test.MetadataTest",
   "unit._rpc_test.RPCTest",
diff --git a/src/python/grpcio_tests/tests/unit/_api_test.py b/src/python/grpcio_tests/tests/unit/_api_test.py
index 2fe89499f5..51dc425420 100644
--- a/src/python/grpcio_tests/tests/unit/_api_test.py
+++ b/src/python/grpcio_tests/tests/unit/_api_test.py
@@ -65,6 +65,7 @@ class AllTest(unittest.TestCase):
         'RpcMethodHandler',
         'HandlerCallDetails',
         'GenericRpcHandler',
+        'ServiceRpcHandler',
         'Server',
         'unary_unary_rpc_method_handler',
         'unary_stream_rpc_method_handler',
diff --git a/src/python/grpcio_tests/tests/unit/_channel_ready_future_test.py b/src/python/grpcio_tests/tests/unit/_channel_ready_future_test.py
index e0a7d15aa7..46a964db8c 100644
--- a/src/python/grpcio_tests/tests/unit/_channel_ready_future_test.py
+++ b/src/python/grpcio_tests/tests/unit/_channel_ready_future_test.py
@@ -64,7 +64,7 @@ class ChannelReadyFutureTest(unittest.TestCase):
     ready_future = grpc.channel_ready_future(channel)
     ready_future.add_done_callback(callback.accept_value)
     with self.assertRaises(grpc.FutureTimeoutError):
-      ready_future.result(test_constants.SHORT_TIMEOUT)
+      ready_future.result(timeout=test_constants.SHORT_TIMEOUT)
     self.assertFalse(ready_future.cancelled())
     self.assertFalse(ready_future.done())
     self.assertTrue(ready_future.running())
@@ -85,7 +85,7 @@ class ChannelReadyFutureTest(unittest.TestCase):
 
     ready_future = grpc.channel_ready_future(channel)
     ready_future.add_done_callback(callback.accept_value)
-    self.assertIsNone(ready_future.result(test_constants.SHORT_TIMEOUT))
+    self.assertIsNone(ready_future.result(timeout=test_constants.LONG_TIMEOUT))
     value_passed_to_callback = callback.block_until_called()
     self.assertIs(ready_future, value_passed_to_callback)
     self.assertFalse(ready_future.cancelled())
diff --git a/src/python/grpcio_tests/tests/unit/_compression_test.py b/src/python/grpcio_tests/tests/unit/_compression_test.py
index 83b9109466..4d3f02e917 100644
--- a/src/python/grpcio_tests/tests/unit/_compression_test.py
+++ b/src/python/grpcio_tests/tests/unit/_compression_test.py
@@ -125,7 +125,7 @@ class CompressionTest(unittest.TestCase):
     compressed_channel = grpc.insecure_channel('localhost:%d' % self._port,
         options=[('grpc.default_compression_algorithm', 1)])
     multi_callable = compressed_channel.stream_stream(_STREAM_STREAM)
-    call = multi_callable([request] * test_constants.STREAM_LENGTH)
+    call = multi_callable(iter([request] * test_constants.STREAM_LENGTH))
     for response in call:
       self.assertEqual(request, response)
 
diff --git a/src/python/grpcio_tests/tests/unit/_empty_message_test.py b/src/python/grpcio_tests/tests/unit/_empty_message_test.py
index 131f6e9452..69f4689279 100644
--- a/src/python/grpcio_tests/tests/unit/_empty_message_test.py
+++ b/src/python/grpcio_tests/tests/unit/_empty_message_test.py
@@ -123,12 +123,12 @@ class EmptyMessageTest(unittest.TestCase):
 
   def testStreamUnary(self):
     response = self._channel.stream_unary(_STREAM_UNARY)(
-        [_REQUEST] * test_constants.STREAM_LENGTH)
+        iter([_REQUEST] * test_constants.STREAM_LENGTH))
     self.assertEqual(_RESPONSE, response)
 
   def testStreamStream(self):
     response_iterator = self._channel.stream_stream(_STREAM_STREAM)(
-        [_REQUEST] * test_constants.STREAM_LENGTH)
+        iter([_REQUEST] * test_constants.STREAM_LENGTH))
     self.assertSequenceEqual(
         [_RESPONSE] * test_constants.STREAM_LENGTH, list(response_iterator))
 
diff --git a/src/python/grpcio_tests/tests/unit/_exit_scenarios.py b/src/python/grpcio_tests/tests/unit/_exit_scenarios.py
index b33802bf57..777527137f 100644
--- a/src/python/grpcio_tests/tests/unit/_exit_scenarios.py
+++ b/src/python/grpcio_tests/tests/unit/_exit_scenarios.py
@@ -240,7 +240,7 @@ if __name__ == '__main__':
       multi_callable = channel.stream_unary(method)
       future = multi_callable.future(infinite_request_iterator())
       result, call = multi_callable.with_call(
-          [REQUEST] * test_constants.STREAM_LENGTH)
+          iter([REQUEST] * test_constants.STREAM_LENGTH))
     elif (args.scenario == IN_FLIGHT_STREAM_STREAM_CALL or
           args.scenario == IN_FLIGHT_PARTIAL_STREAM_STREAM_CALL):
       multi_callable = channel.stream_stream(method)
diff --git a/src/python/grpcio_tests/tests/unit/_exit_test.py b/src/python/grpcio_tests/tests/unit/_exit_test.py
index 342f5fcc10..5a4a32887c 100644
--- a/src/python/grpcio_tests/tests/unit/_exit_test.py
+++ b/src/python/grpcio_tests/tests/unit/_exit_test.py
@@ -43,8 +43,6 @@ import threading
 import time
 import unittest
 
-import grpc
-from grpc.framework.foundation import logging_pool
 from tests.unit import _exit_scenarios
 
 SCENARIO_FILE = os.path.abspath(os.path.join(
@@ -54,7 +52,7 @@ BASE_COMMAND = [INTERPRETER, SCENARIO_FILE]
 BASE_SIGTERM_COMMAND = BASE_COMMAND + ['--wait_for_interrupt']
 
 INIT_TIME = 1.0
-SHUTDOWN_GRACE = 5.0
+
 
 processes = []
 process_lock = threading.Lock()
@@ -184,24 +182,5 @@ class ExitTest(unittest.TestCase):
     interrupt_and_wait(process)
 
 
-class _ShutDownHandler(object):
-
-  def __init__(self):
-    self.seen_handler_grace = None
-
-  def shutdown_handler(self, handler_grace):
-    self.seen_handler_grace = handler_grace
-
-  
-class ShutdownHandlerTest(unittest.TestCase):
-
-  def test_shutdown_handler(self):
-    server = grpc.server(logging_pool.pool(1))
-    handler = _ShutDownHandler()
-    server.add_shutdown_handler(handler.shutdown_handler)
-    server.start()
-    server.stop(0, shutdown_handler_grace=SHUTDOWN_GRACE).wait()
-    self.assertEqual(SHUTDOWN_GRACE, handler.seen_handler_grace)
-
 if __name__ == '__main__':
   unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/_invalid_metadata_test.py b/src/python/grpcio_tests/tests/unit/_invalid_metadata_test.py
new file mode 100644
index 0000000000..2dc225de29
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_invalid_metadata_test.py
@@ -0,0 +1,175 @@
+# Copyright 2016, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Test of RPCs made against gRPC Python's application-layer API."""
+
+import unittest
+
+import grpc
+
+from tests.unit.framework.common import test_constants
+
+_SERIALIZE_REQUEST = lambda bytestring: bytestring * 2
+_DESERIALIZE_REQUEST = lambda bytestring: bytestring[len(bytestring) // 2:]
+_SERIALIZE_RESPONSE = lambda bytestring: bytestring * 3
+_DESERIALIZE_RESPONSE = lambda bytestring: bytestring[:len(bytestring) // 3]
+
+_UNARY_UNARY = '/test/UnaryUnary'
+_UNARY_STREAM = '/test/UnaryStream'
+_STREAM_UNARY = '/test/StreamUnary'
+_STREAM_STREAM = '/test/StreamStream'
+
+
+def _unary_unary_multi_callable(channel):
+  return channel.unary_unary(_UNARY_UNARY)
+
+
+def _unary_stream_multi_callable(channel):
+  return channel.unary_stream(
+      _UNARY_STREAM,
+      request_serializer=_SERIALIZE_REQUEST,
+      response_deserializer=_DESERIALIZE_RESPONSE)
+
+
+def _stream_unary_multi_callable(channel):
+  return channel.stream_unary(
+      _STREAM_UNARY,
+      request_serializer=_SERIALIZE_REQUEST,
+      response_deserializer=_DESERIALIZE_RESPONSE)
+
+
+def _stream_stream_multi_callable(channel):
+  return channel.stream_stream(_STREAM_STREAM)
+
+
+class InvalidMetadataTest(unittest.TestCase):
+
+  def setUp(self):
+    self._channel = grpc.insecure_channel('localhost:8080')
+    self._unary_unary = _unary_unary_multi_callable(self._channel)
+    self._unary_stream = _unary_stream_multi_callable(self._channel)
+    self._stream_unary = _stream_unary_multi_callable(self._channel)
+    self._stream_stream = _stream_stream_multi_callable(self._channel)
+
+  def testUnaryRequestBlockingUnaryResponse(self):
+    request = b'\x07\x08'
+    metadata = (('InVaLiD', 'UnaryRequestBlockingUnaryResponse'),)
+    expected_error_details = "metadata was invalid: %s" % metadata
+    with self.assertRaises(ValueError) as exception_context:
+      self._unary_unary(request, metadata=metadata)
+    self.assertIn(expected_error_details, str(exception_context.exception))
+
+  def testUnaryRequestBlockingUnaryResponseWithCall(self):
+    request = b'\x07\x08'
+    metadata = (('InVaLiD', 'UnaryRequestBlockingUnaryResponseWithCall'),)
+    expected_error_details = "metadata was invalid: %s" % metadata
+    with self.assertRaises(ValueError) as exception_context:
+      self._unary_unary.with_call(request, metadata=metadata)
+    self.assertIn(expected_error_details, str(exception_context.exception))
+
+  def testUnaryRequestFutureUnaryResponse(self):
+    request = b'\x07\x08'
+    metadata = (('InVaLiD', 'UnaryRequestFutureUnaryResponse'),)
+    expected_error_details = "metadata was invalid: %s" % metadata
+    response_future = self._unary_unary.future(request, metadata=metadata)
+    with self.assertRaises(grpc.RpcError) as exception_context:
+      response_future.result()
+    self.assertEqual(
+        exception_context.exception.details(), expected_error_details)
+    self.assertEqual(
+        exception_context.exception.code(), grpc.StatusCode.INTERNAL)
+    self.assertEqual(response_future.details(), expected_error_details)
+    self.assertEqual(response_future.code(), grpc.StatusCode.INTERNAL)
+
+  def testUnaryRequestStreamResponse(self):
+    request = b'\x37\x58'
+    metadata = (('InVaLiD', 'UnaryRequestStreamResponse'),)
+    expected_error_details = "metadata was invalid: %s" % metadata
+    response_iterator = self._unary_stream(request, metadata=metadata)
+    with self.assertRaises(grpc.RpcError) as exception_context:
+      next(response_iterator)
+    self.assertEqual(
+        exception_context.exception.details(), expected_error_details)
+    self.assertEqual(
+        exception_context.exception.code(), grpc.StatusCode.INTERNAL)
+    self.assertEqual(response_iterator.details(), expected_error_details)
+    self.assertEqual(response_iterator.code(), grpc.StatusCode.INTERNAL)
+
+  def testStreamRequestBlockingUnaryResponse(self):
+    request_iterator = (b'\x07\x08' for _ in range(test_constants.STREAM_LENGTH))
+    metadata = (('InVaLiD', 'StreamRequestBlockingUnaryResponse'),)
+    expected_error_details = "metadata was invalid: %s" % metadata
+    with self.assertRaises(ValueError) as exception_context:
+      self._stream_unary(request_iterator, metadata=metadata)
+    self.assertIn(expected_error_details, str(exception_context.exception))
+
+  def testStreamRequestBlockingUnaryResponseWithCall(self):
+    request_iterator = (
+        b'\x07\x08' for _ in range(test_constants.STREAM_LENGTH))
+    metadata = (('InVaLiD', 'StreamRequestBlockingUnaryResponseWithCall'),)
+    expected_error_details = "metadata was invalid: %s" % metadata
+    multi_callable = _stream_unary_multi_callable(self._channel)
+    with self.assertRaises(ValueError) as exception_context:
+      multi_callable.with_call(request_iterator, metadata=metadata)
+    self.assertIn(expected_error_details, str(exception_context.exception))
+
+  def testStreamRequestFutureUnaryResponse(self):
+    request_iterator = (
+        b'\x07\x08' for _ in range(test_constants.STREAM_LENGTH))
+    metadata = (('InVaLiD', 'StreamRequestFutureUnaryResponse'),)
+    expected_error_details = "metadata was invalid: %s" % metadata
+    response_future = self._stream_unary.future(
+        request_iterator, metadata=metadata)
+    with self.assertRaises(grpc.RpcError) as exception_context:
+      response_future.result()
+    self.assertEqual(
+        exception_context.exception.details(), expected_error_details)
+    self.assertEqual(
+        exception_context.exception.code(), grpc.StatusCode.INTERNAL)
+    self.assertEqual(response_future.details(), expected_error_details)
+    self.assertEqual(response_future.code(), grpc.StatusCode.INTERNAL)
+
+  def testStreamRequestStreamResponse(self):
+    request_iterator = (
+        b'\x07\x08' for _ in range(test_constants.STREAM_LENGTH))
+    metadata = (('InVaLiD', 'StreamRequestStreamResponse'),)
+    expected_error_details = "metadata was invalid: %s" % metadata
+    response_iterator = self._stream_stream(request_iterator, metadata=metadata)
+    with self.assertRaises(grpc.RpcError) as exception_context:
+      next(response_iterator)
+    self.assertEqual(
+        exception_context.exception.details(), expected_error_details)
+    self.assertEqual(
+        exception_context.exception.code(), grpc.StatusCode.INTERNAL)
+    self.assertEqual(response_iterator.details(), expected_error_details)
+    self.assertEqual(response_iterator.code(), grpc.StatusCode.INTERNAL)
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/_invocation_defects_test.py b/src/python/grpcio_tests/tests/unit/_invocation_defects_test.py
new file mode 100644
index 0000000000..4312679bb9
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_invocation_defects_test.py
@@ -0,0 +1,247 @@
+# Copyright 2016, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+import itertools
+import threading
+import unittest
+from concurrent import futures
+
+import grpc
+from grpc.framework.foundation import logging_pool
+
+from tests.unit.framework.common import test_constants
+from tests.unit.framework.common import test_control
+
+_SERIALIZE_REQUEST = lambda bytestring: bytestring * 2
+_DESERIALIZE_REQUEST = lambda bytestring: bytestring[len(bytestring) // 2:]
+_SERIALIZE_RESPONSE = lambda bytestring: bytestring * 3
+_DESERIALIZE_RESPONSE = lambda bytestring: bytestring[:len(bytestring) // 3]
+
+_UNARY_UNARY = '/test/UnaryUnary'
+_UNARY_STREAM = '/test/UnaryStream'
+_STREAM_UNARY = '/test/StreamUnary'
+_STREAM_STREAM = '/test/StreamStream'
+
+
+class _Callback(object):
+  def __init__(self):
+    self._condition = threading.Condition()
+    self._value = None
+    self._called = False
+
+  def __call__(self, value):
+    with self._condition:
+      self._value = value
+      self._called = True
+      self._condition.notify_all()
+
+  def value(self):
+    with self._condition:
+      while not self._called:
+        self._condition.wait()
+      return self._value
+
+
+class _Handler(object):
+  def __init__(self, control):
+    self._control = control
+
+  def handle_unary_unary(self, request, servicer_context):
+    self._control.control()
+    if servicer_context is not None:
+      servicer_context.set_trailing_metadata((('testkey', 'testvalue',),))
+    return request
+
+  def handle_unary_stream(self, request, servicer_context):
+    for _ in range(test_constants.STREAM_LENGTH):
+      self._control.control()
+      yield request
+    self._control.control()
+    if servicer_context is not None:
+      servicer_context.set_trailing_metadata((('testkey', 'testvalue',),))
+
+  def handle_stream_unary(self, request_iterator, servicer_context):
+    if servicer_context is not None:
+      servicer_context.invocation_metadata()
+    self._control.control()
+    response_elements = []
+    for request in request_iterator:
+      self._control.control()
+      response_elements.append(request)
+    self._control.control()
+    if servicer_context is not None:
+      servicer_context.set_trailing_metadata((('testkey', 'testvalue',),))
+    return b''.join(response_elements)
+
+  def handle_stream_stream(self, request_iterator, servicer_context):
+    self._control.control()
+    if servicer_context is not None:
+      servicer_context.set_trailing_metadata((('testkey', 'testvalue',),))
+    for request in request_iterator:
+      self._control.control()
+      yield request
+    self._control.control()
+
+
+class _MethodHandler(grpc.RpcMethodHandler):
+  def __init__(
+    self, request_streaming, response_streaming, request_deserializer,
+    response_serializer, unary_unary, unary_stream, stream_unary,
+    stream_stream):
+    self.request_streaming = request_streaming
+    self.response_streaming = response_streaming
+    self.request_deserializer = request_deserializer
+    self.response_serializer = response_serializer
+    self.unary_unary = unary_unary
+    self.unary_stream = unary_stream
+    self.stream_unary = stream_unary
+    self.stream_stream = stream_stream
+
+
+class _GenericHandler(grpc.GenericRpcHandler):
+  def __init__(self, handler):
+    self._handler = handler
+
+  def service(self, handler_call_details):
+    if handler_call_details.method == _UNARY_UNARY:
+      return _MethodHandler(
+        False, False, None, None, self._handler.handle_unary_unary, None,
+        None, None)
+    elif handler_call_details.method == _UNARY_STREAM:
+      return _MethodHandler(
+        False, True, _DESERIALIZE_REQUEST, _SERIALIZE_RESPONSE, None,
+        self._handler.handle_unary_stream, None, None)
+    elif handler_call_details.method == _STREAM_UNARY:
+      return _MethodHandler(
+        True, False, _DESERIALIZE_REQUEST, _SERIALIZE_RESPONSE, None, None,
+        self._handler.handle_stream_unary, None)
+    elif handler_call_details.method == _STREAM_STREAM:
+      return _MethodHandler(
+        True, True, None, None, None, None, None,
+        self._handler.handle_stream_stream)
+    else:
+      return None
+
+
+class FailAfterFewIterationsCounter(object):
+    def __init__(self, high, bytestring):
+        self._current = 0
+        self._high = high
+        self._bytestring = bytestring
+
+    def __iter__(self):
+        return self
+
+    def __next__(self):
+        if self._current >= self._high:
+            raise Exception("This is a deliberate failure in a unit test.")
+        else:
+            self._current += 1
+            return self._bytestring
+
+
+def _unary_unary_multi_callable(channel):
+  return channel.unary_unary(_UNARY_UNARY)
+
+
+def _unary_stream_multi_callable(channel):
+  return channel.unary_stream(
+    _UNARY_STREAM,
+    request_serializer=_SERIALIZE_REQUEST,
+    response_deserializer=_DESERIALIZE_RESPONSE)
+
+
+def _stream_unary_multi_callable(channel):
+  return channel.stream_unary(
+    _STREAM_UNARY,
+    request_serializer=_SERIALIZE_REQUEST,
+    response_deserializer=_DESERIALIZE_RESPONSE)
+
+
+def _stream_stream_multi_callable(channel):
+  return channel.stream_stream(_STREAM_STREAM)
+
+
+class InvocationDefectsTest(unittest.TestCase):
+  def setUp(self):
+    self._control = test_control.PauseFailControl()
+    self._handler = _Handler(self._control)
+    self._server_pool = logging_pool.pool(test_constants.THREAD_CONCURRENCY)
+
+    self._server = grpc.server(self._server_pool)
+    port = self._server.add_insecure_port('[::]:0')
+    self._server.add_generic_rpc_handlers((_GenericHandler(self._handler),))
+    self._server.start()
+
+    self._channel = grpc.insecure_channel('localhost:%d' % port)
+
+  def tearDown(self):
+    self._server.stop(0)
+
+  def testIterableStreamRequestBlockingUnaryResponse(self):
+    requests = [b'\x07\x08' for _ in range(test_constants.STREAM_LENGTH)]
+    multi_callable = _stream_unary_multi_callable(self._channel)
+
+    with self.assertRaises(grpc.RpcError):
+      response = multi_callable(
+        requests,
+        metadata=(('test', 'IterableStreamRequestBlockingUnaryResponse'),))
+
+  def testIterableStreamRequestFutureUnaryResponse(self):
+    requests = [b'\x07\x08' for _ in range(test_constants.STREAM_LENGTH)]
+    multi_callable = _stream_unary_multi_callable(self._channel)
+    response_future = multi_callable.future(
+      requests,
+      metadata=(
+        ('test', 'IterableStreamRequestFutureUnaryResponse'),))
+
+    with self.assertRaises(grpc.RpcError):
+      response = response_future.result()
+
+  def testIterableStreamRequestStreamResponse(self):
+    requests = [b'\x77\x58' for _ in range(test_constants.STREAM_LENGTH)]
+    multi_callable = _stream_stream_multi_callable(self._channel)
+    response_iterator = multi_callable(
+      requests,
+      metadata=(('test', 'IterableStreamRequestStreamResponse'),))
+
+    with self.assertRaises(grpc.RpcError):
+      next(response_iterator)
+
+  def testIteratorStreamRequestStreamResponse(self):
+    requests_iterator = FailAfterFewIterationsCounter(
+      test_constants.STREAM_LENGTH // 2, b'\x07\x08')
+    multi_callable = _stream_stream_multi_callable(self._channel)
+    response_iterator = multi_callable(
+      requests_iterator,
+      metadata=(('test', 'IteratorStreamRequestStreamResponse'),))
+
+    with self.assertRaises(grpc.RpcError):
+      for _ in range(test_constants.STREAM_LENGTH // 2 + 1):
+        next(response_iterator)
diff --git a/src/python/grpcio_tests/tests/unit/_metadata_test.py b/src/python/grpcio_tests/tests/unit/_metadata_test.py
index da73476929..caba53ffcc 100644
--- a/src/python/grpcio_tests/tests/unit/_metadata_test.py
+++ b/src/python/grpcio_tests/tests/unit/_metadata_test.py
@@ -193,7 +193,7 @@ class MetadataTest(unittest.TestCase):
   def testStreamUnary(self):
     multi_callable = self._channel.stream_unary(_STREAM_UNARY)
     unused_response, call = multi_callable.with_call(
-        [_REQUEST] * test_constants.STREAM_LENGTH,
+        iter([_REQUEST] * test_constants.STREAM_LENGTH),
         metadata=_CLIENT_METADATA)
     self.assertTrue(test_common.metadata_transmitted(
         _SERVER_INITIAL_METADATA, call.initial_metadata()))
@@ -202,7 +202,7 @@ class MetadataTest(unittest.TestCase):
 
   def testStreamStream(self):
     multi_callable = self._channel.stream_stream(_STREAM_STREAM)
-    call = multi_callable([_REQUEST] * test_constants.STREAM_LENGTH,
+    call = multi_callable(iter([_REQUEST] * test_constants.STREAM_LENGTH),
                           metadata=_CLIENT_METADATA)
     self.assertTrue(test_common.metadata_transmitted(
         _SERVER_INITIAL_METADATA, call.initial_metadata()))
diff --git a/src/python/grpcio_tests/tests/unit/beta/_utilities_test.py b/src/python/grpcio_tests/tests/unit/beta/_utilities_test.py
index 90fe10c77c..9cce96cc85 100644
--- a/src/python/grpcio_tests/tests/unit/beta/_utilities_test.py
+++ b/src/python/grpcio_tests/tests/unit/beta/_utilities_test.py
@@ -66,7 +66,7 @@ class ChannelConnectivityTest(unittest.TestCase):
     ready_future = utilities.channel_ready_future(channel)
     ready_future.add_done_callback(callback.accept_value)
     with self.assertRaises(future.TimeoutError):
-      ready_future.result(test_constants.SHORT_TIMEOUT)
+      ready_future.result(timeout=test_constants.SHORT_TIMEOUT)
     self.assertFalse(ready_future.cancelled())
     self.assertFalse(ready_future.done())
     self.assertTrue(ready_future.running())
@@ -88,7 +88,7 @@ class ChannelConnectivityTest(unittest.TestCase):
       ready_future = utilities.channel_ready_future(channel)
       ready_future.add_done_callback(callback.accept_value)
       self.assertIsNone(
-          ready_future.result(test_constants.SHORT_TIMEOUT))
+          ready_future.result(timeout=test_constants.LONG_TIMEOUT))
       value_passed_to_callback = callback.block_until_called()
       self.assertIs(ready_future, value_passed_to_callback)
       self.assertFalse(ready_future.cancelled())
diff --git a/src/ruby/ext/grpc/rb_byte_buffer.c b/src/ruby/ext/grpc/rb_byte_buffer.c
index f97890e4a2..47fd6d9120 100644
--- a/src/ruby/ext/grpc/rb_byte_buffer.c
+++ b/src/ruby/ext/grpc/rb_byte_buffer.c
@@ -65,5 +65,6 @@ VALUE grpc_rb_byte_buffer_to_s(grpc_byte_buffer *buffer) {
                GRPC_SLICE_LENGTH(next));
     grpc_slice_unref(next);
   }
+  grpc_byte_buffer_reader_destroy(&reader);
   return rb_string;
 }
diff --git a/src/ruby/ext/grpc/rb_server.c b/src/ruby/ext/grpc/rb_server.c
index 2a6a246e67..c7b112c94b 100644
--- a/src/ruby/ext/grpc/rb_server.c
+++ b/src/ruby/ext/grpc/rb_server.c
@@ -37,6 +37,7 @@
 #include "rb_server.h"
 
 #include <grpc/grpc.h>
+#include <grpc/support/atm.h>
 #include <grpc/grpc_security.h>
 #include <grpc/support/log.h>
 #include "rb_call.h"
@@ -59,22 +60,26 @@ typedef struct grpc_rb_server {
   /* The actual server */
   grpc_server *wrapped;
   grpc_completion_queue *queue;
+  gpr_atm shutdown_started;
 } grpc_rb_server;
 
 static void destroy_server(grpc_rb_server *server, gpr_timespec deadline) {
   grpc_event ev;
-  if (server->wrapped != NULL) {
-    grpc_server_shutdown_and_notify(server->wrapped, server->queue, NULL);
-    ev = rb_completion_queue_pluck(server->queue, NULL, deadline, NULL);
-    if (ev.type == GRPC_QUEUE_TIMEOUT) {
-      grpc_server_cancel_all_calls(server->wrapped);
-      rb_completion_queue_pluck(server->queue, NULL,
-                                gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
+  // This can be started by app or implicitly by GC. Avoid a race between these.
+  if (gpr_atm_full_fetch_add(&server->shutdown_started, (gpr_atm)1) == 0) {
+    if (server->wrapped != NULL) {
+      grpc_server_shutdown_and_notify(server->wrapped, server->queue, NULL);
+      ev = rb_completion_queue_pluck(server->queue, NULL, deadline, NULL);
+      if (ev.type == GRPC_QUEUE_TIMEOUT) {
+        grpc_server_cancel_all_calls(server->wrapped);
+        rb_completion_queue_pluck(server->queue, NULL,
+                                  gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
+      }
+      grpc_server_destroy(server->wrapped);
+      grpc_rb_completion_queue_destroy(server->queue);
+      server->wrapped = NULL;
+      server->queue = NULL;
     }
-    grpc_server_destroy(server->wrapped);
-    grpc_rb_completion_queue_destroy(server->queue);
-    server->wrapped = NULL;
-    server->queue = NULL;
   }
 }
 
@@ -115,6 +120,7 @@ static const rb_data_type_t grpc_rb_server_data_type = {
 static VALUE grpc_rb_server_alloc(VALUE cls) {
   grpc_rb_server *wrapper = ALLOC(grpc_rb_server);
   wrapper->wrapped = NULL;
+  wrapper->shutdown_started = (gpr_atm)0;
   return TypedData_Wrap_Struct(cls, &grpc_rb_server_data_type, wrapper);
 }
 
diff --git a/src/ruby/lib/grpc/errors.rb b/src/ruby/lib/grpc/errors.rb
index 23b2bb7e12..f6998e17c4 100644
--- a/src/ruby/lib/grpc/errors.rb
+++ b/src/ruby/lib/grpc/errors.rb
@@ -35,9 +35,18 @@ module GRPC
   # either end of a GRPC connection.  When raised, it indicates that a status
   # error should be returned to the other end of a GRPC connection; when
   # caught it means that this end received a status error.
+  #
+  # There is also subclass of BadStatus in this module for each GRPC status.
+  # E.g., the GRPC::Cancelled class corresponds to status CANCELLED.
+  #
+  # See
+  # https://github.com/grpc/grpc/blob/master/include/grpc/impl/codegen/status.h
+  # for detailed descriptions of each status code.
   class BadStatus < StandardError
     attr_reader :code, :details, :metadata
 
+    include GRPC::Core::StatusCodes
+
     # @param code [Numeric] the status code
     # @param details [String] the details of the exception
     # @param metadata [Hash] the error's metadata
@@ -55,9 +64,152 @@ module GRPC
     def to_status
       Struct::Status.new(code, details, @metadata)
     end
+
+    def self.new_status_exception(code, details = 'unkown cause', metadata = {})
+      codes = {}
+      codes[OK] = Ok
+      codes[CANCELLED] = Cancelled
+      codes[UNKNOWN] = Unknown
+      codes[INVALID_ARGUMENT] = InvalidArgument
+      codes[DEADLINE_EXCEEDED] = DeadlineExceeded
+      codes[NOT_FOUND] = NotFound
+      codes[ALREADY_EXISTS] = AlreadyExists
+      codes[PERMISSION_DENIED] =  PermissionDenied
+      codes[UNAUTHENTICATED] = Unauthenticated
+      codes[RESOURCE_EXHAUSTED] = ResourceExhausted
+      codes[FAILED_PRECONDITION] = FailedPrecondition
+      codes[ABORTED] = Aborted
+      codes[OUT_OF_RANGE] = OutOfRange
+      codes[UNIMPLEMENTED] =  Unimplemented
+      codes[INTERNAL] = Internal
+      codes[UNIMPLEMENTED] =  Unimplemented
+      codes[UNAVAILABLE] =  Unavailable
+      codes[DATA_LOSS] = DataLoss
+
+      if codes[code].nil?
+        BadStatus.new(code, details, metadata)
+      else
+        codes[code].new(details, metadata)
+      end
+    end
+  end
+
+  # GRPC status code corresponding to status OK
+  class Ok < BadStatus
+    def initialize(details = 'unknown cause', metadata = {})
+      super(Core::StatusCodes::OK, details, metadata)
+    end
   end
 
-  # Cancelled is an exception class that indicates that an rpc was cancelled.
-  class Cancelled < StandardError
+  # GRPC status code corresponding to status CANCELLED
+  class Cancelled < BadStatus
+    def initialize(details = 'unknown cause', metadata = {})
+      super(Core::StatusCodes::CANCELLED, details, metadata)
+    end
+  end
+
+  # GRPC status code corresponding to status UNKNOWN
+  class Unknown < BadStatus
+    def initialize(details = 'unknown cause', metadata = {})
+      super(Core::StatusCodes::UNKNOWN, details, metadata)
+    end
+  end
+
+  # GRPC status code corresponding to status INVALID_ARGUMENT
+  class InvalidArgument < BadStatus
+    def initialize(details = 'unknown cause', metadata = {})
+      super(Core::StatusCodes::INVALID_ARGUMENT, details, metadata)
+    end
+  end
+
+  # GRPC status code corresponding to status DEADLINE_EXCEEDED
+  class DeadlineExceeded < BadStatus
+    def initialize(details = 'unknown cause', metadata = {})
+      super(Core::StatusCodes::DEADLINE_EXCEEDED, details, metadata)
+    end
+  end
+
+  # GRPC status code corresponding to status NOT_FOUND
+  class NotFound < BadStatus
+    def initialize(details = 'unknown cause', metadata = {})
+      super(Core::StatusCodes::NOT_FOUND, details, metadata)
+    end
+  end
+
+  # GRPC status code corresponding to status ALREADY_EXISTS
+  class AlreadyExists < BadStatus
+    def initialize(details = 'unknown cause', metadata = {})
+      super(Core::StatusCodes::ALREADY_EXISTS, details, metadata)
+    end
+  end
+
+  # GRPC status code corresponding to status PERMISSION_DENIED
+  class PermissionDenied < BadStatus
+    def initialize(details = 'unknown cause', metadata = {})
+      super(Core::StatusCodes::PERMISSION_DENIED, details, metadata)
+    end
+  end
+
+  # GRPC status code corresponding to status UNAUTHENTICATED
+  class Unauthenticated < BadStatus
+    def initialize(details = 'unknown cause', metadata = {})
+      super(Core::StatusCodes::UNAUTHENTICATED, details, metadata)
+    end
+  end
+
+  # GRPC status code corresponding to status RESOURCE_EXHAUSTED
+  class ResourceExhausted < BadStatus
+    def initialize(details = 'unknown cause', metadata = {})
+      super(Core::StatusCodes::RESOURCE_EXHAUSTED, details, metadata)
+    end
+  end
+
+  # GRPC status code corresponding to status FAILED_PRECONDITION
+  class FailedPrecondition < BadStatus
+    def initialize(details = 'unknown cause', metadata = {})
+      super(Core::StatusCodes::FAILED_PRECONDITION, details, metadata)
+    end
+  end
+
+  # GRPC status code corresponding to status ABORTED
+  class Aborted < BadStatus
+    def initialize(details = 'unknown cause', metadata = {})
+      super(Core::StatusCodes::ABORTED, details, metadata)
+    end
+  end
+
+  # GRPC status code corresponding to status OUT_OF_RANGE
+  class OutOfRange < BadStatus
+    def initialize(details = 'unknown cause', metadata = {})
+      super(Core::StatusCodes::OUT_OF_RANGE, details, metadata)
+    end
+  end
+
+  # GRPC status code corresponding to status UNIMPLEMENTED
+  class Unimplemented < BadStatus
+    def initialize(details = 'unknown cause', metadata = {})
+      super(Core::StatusCodes::UNIMPLEMENTED, details, metadata)
+    end
+  end
+
+  # GRPC status code corresponding to status INTERNAL
+  class Internal < BadStatus
+    def initialize(details = 'unknown cause', metadata = {})
+      super(Core::StatusCodes::INTERNAL, details, metadata)
+    end
+  end
+
+  # GRPC status code corresponding to status UNAVAILABLE
+  class Unavailable < BadStatus
+    def initialize(details = 'unknown cause', metadata = {})
+      super(Core::StatusCodes::UNAVAILABLE, details, metadata)
+    end
+  end
+
+  # GRPC status code corresponding to status DATA_LOSS
+  class DataLoss < BadStatus
+    def initialize(details = 'unknown cause', metadata = {})
+      super(Core::StatusCodes::DATA_LOSS, details, metadata)
+    end
   end
 end
diff --git a/src/ruby/lib/grpc/generic/active_call.rb b/src/ruby/lib/grpc/generic/active_call.rb
index f5c426ebfc..3b31f77ec0 100644
--- a/src/ruby/lib/grpc/generic/active_call.rb
+++ b/src/ruby/lib/grpc/generic/active_call.rb
@@ -43,8 +43,8 @@ class Struct
         GRPC.logger.debug("Failing with status #{status}")
         # raise BadStatus, propagating the metadata if present.
         md = status.metadata
-        fail GRPC::BadStatus.new(status.code, status.details, md),
-             "status code: #{status.code}, details: #{status.details}"
+        fail GRPC::BadStatus.new_status_exception(
+          status.code, status.details, md)
       end
       status
     end
diff --git a/src/ruby/lib/grpc/generic/bidi_call.rb b/src/ruby/lib/grpc/generic/bidi_call.rb
index d7cd9e6df2..adc77bbf5d 100644
--- a/src/ruby/lib/grpc/generic/bidi_call.rb
+++ b/src/ruby/lib/grpc/generic/bidi_call.rb
@@ -200,6 +200,7 @@ module GRPC
             if is_client
               batch_result = @call.run_batch(RECV_STATUS_ON_CLIENT => nil)
               @call.status = batch_result.status
+              @call.trailing_metadata = @call.status.metadata if @call.status
               batch_result.check_status
               GRPC.logger.debug("bidi-read-loop: done status #{@call.status}")
             end
@@ -219,6 +220,10 @@ module GRPC
       GRPC.logger.debug('bidi-read-loop: finished')
       @reads_complete = true
       finished
+      # Make sure that the write loop is done done before finishing the call.
+      # Note that blocking is ok at this point because we've already received
+      # a status
+      @enq_th.join if is_client
     end
   end
 end
diff --git a/src/ruby/lib/grpc/generic/rpc_desc.rb b/src/ruby/lib/grpc/generic/rpc_desc.rb
index cd17aed8e7..d46c4a1b5c 100644
--- a/src/ruby/lib/grpc/generic/rpc_desc.rb
+++ b/src/ruby/lib/grpc/generic/rpc_desc.rb
@@ -119,7 +119,7 @@ module GRPC
       # Send back a UNKNOWN status to the client
       GRPC.logger.warn("failed handler: #{active_call}; sending status:UNKNOWN")
       GRPC.logger.warn(e)
-      send_status(active_call, UNKNOWN, 'unkown error handling call on server')
+      send_status(active_call, UNKNOWN, "#{e.class}: #{e.message}")
     end
 
     def assert_arity_matches(mth)
diff --git a/src/ruby/lib/grpc/generic/service.rb b/src/ruby/lib/grpc/generic/service.rb
index 7cb9f1cc99..f5a6b49eb4 100644
--- a/src/ruby/lib/grpc/generic/service.rb
+++ b/src/ruby/lib/grpc/generic/service.rb
@@ -110,8 +110,9 @@ module GRPC
         rpc_descs[name] = RpcDesc.new(name, input, output,
                                       marshal_class_method,
                                       unmarshal_class_method)
-        define_method(name) do
-          fail GRPC::BadStatus, GRPC::Core::StatusCodes::UNIMPLEMENTED
+        define_method(GenericService.underscore(name.to_s).to_sym) do |_, _|
+          fail GRPC::BadStatus.new_status_exception(
+            GRPC::Core::StatusCodes::UNIMPLEMENTED)
         end
       end
 
diff --git a/src/ruby/pb/grpc/health/checker.rb b/src/ruby/pb/grpc/health/checker.rb
index 4bce1744c4..6b2d852ebf 100644
--- a/src/ruby/pb/grpc/health/checker.rb
+++ b/src/ruby/pb/grpc/health/checker.rb
@@ -52,7 +52,9 @@ module Grpc
         @status_mutex.synchronize do
           status = @statuses["#{req.service}"]
         end
-        fail GRPC::BadStatus, StatusCodes::NOT_FOUND if status.nil?
+	if status.nil?
+          fail GRPC::BadStatus.new_status_exception(StatusCodes::NOT_FOUND)
+	end
         HealthCheckResponse.new(status: status)
       end
 
diff --git a/src/ruby/pb/src/proto/grpc/testing/test_services_pb.rb b/src/ruby/pb/src/proto/grpc/testing/test_services_pb.rb
index fde328e4c5..7d1072e512 100644
--- a/src/ruby/pb/src/proto/grpc/testing/test_services_pb.rb
+++ b/src/ruby/pb/src/proto/grpc/testing/test_services_pb.rb
@@ -54,6 +54,10 @@ module Grpc
         rpc :EmptyCall, Empty, Empty
         # One request followed by one response.
         rpc :UnaryCall, SimpleRequest, SimpleResponse
+        # One request followed by one response. Response has cache control
+        # headers set such that a caching HTTP proxy (such as GFE) can
+        # satisfy subsequent requests.
+        rpc :CacheableUnaryCall, SimpleRequest, SimpleResponse
         # One request followed by a sequence of responses (streamed download).
         # The server returns the payload with client desired type and sizes.
         rpc :StreamingOutputCall, StreamingOutputCallRequest, stream(StreamingOutputCallResponse)
@@ -69,6 +73,9 @@ module Grpc
         # stream of responses are returned to the client when the server starts with
         # first request.
         rpc :HalfDuplexCall, stream(StreamingOutputCallRequest), stream(StreamingOutputCallResponse)
+        # The test server will not implement this method. It will be used
+        # to test the behavior when clients call unimplemented methods.
+        rpc :UnimplementedCall, Empty, Empty
       end
 
       Stub = Service.rpc_stub_class
diff --git a/src/ruby/pb/test/client.rb b/src/ruby/pb/test/client.rb
index 1e3ae65630..9c4ee9c6f2 100755
--- a/src/ruby/pb/test/client.rb
+++ b/src/ruby/pb/test/client.rb
@@ -158,14 +158,26 @@ def create_stub(opts)
 
     GRPC.logger.info("... connecting securely to #{address}")
     stub_opts[:channel_args].merge!(compression_channel_args)
-    Grpc::Testing::TestService::Stub.new(address, creds, **stub_opts)
+    if opts.test_case == "unimplemented_service"
+      Grpc::Testing::UnimplementedService::Stub.new(address, creds, **stub_opts)
+    else
+      Grpc::Testing::TestService::Stub.new(address, creds, **stub_opts)
+    end
   else
     GRPC.logger.info("... connecting insecurely to #{address}")
-    Grpc::Testing::TestService::Stub.new(
-      address,
-      :this_channel_is_insecure,
-      channel_args: compression_channel_args
-    )
+    if opts.test_case == "unimplemented_service"
+      Grpc::Testing::UnimplementedService::Stub.new(
+        address,
+        :this_channel_is_insecure,
+        channel_args: compression_channel_args
+      )
+    else
+      Grpc::Testing::TestService::Stub.new(
+        address,
+        :this_channel_is_insecure,
+        channel_args: compression_channel_args
+      )
+    end
   end
 end
 
@@ -459,11 +471,8 @@ class NamedTests
     deadline = GRPC::Core::TimeConsts::from_relative_time(1)
     resps = @stub.full_duplex_call(enum.each_item, deadline: deadline)
     resps.each { } # wait to receive each request (or timeout)
-    fail 'Should have raised GRPC::BadStatus(DEADLINE_EXCEEDED)'
-  rescue GRPC::BadStatus => e
-    assert("#{__callee__}: status was wrong") do
-      e.code == GRPC::Core::StatusCodes::DEADLINE_EXCEEDED
-    end
+    fail 'Should have raised GRPC::DeadlineExceeded'
+  rescue GRPC::DeadlineExceeded
   end
 
   def empty_stream
@@ -505,6 +514,153 @@ class NamedTests
     op.wait
   end
 
+  def unimplemented_method
+    begin
+      resp = @stub.unimplemented_call(Empty.new)
+    rescue GRPC::Unimplemented => e
+      return
+    rescue Exception => e
+      fail AssertionError, "Expected BadStatus. Received: #{e.inspect}"
+    end
+    fail AssertionError, "GRPC::Unimplemented should have been raised. Was not."
+  end
+
+  def unimplemented_service
+    begin
+      resp = @stub.unimplemented_call(Empty.new)
+    rescue GRPC::Unimplemented => e
+      return
+    rescue Exception => e
+      fail AssertionError, "Expected BadStatus. Received: #{e.inspect}"
+    end
+    fail AssertionError, "GRPC::Unimplemented should have been raised. Was not."
+  end
+
+  def status_code_and_message
+
+    # Function wide constants.
+    message = "test status method"
+    code = GRPC::Core::StatusCodes::UNKNOWN
+
+    # Testing with UnaryCall.
+    payload = Payload.new(type: :COMPRESSABLE, body: nulls(1))
+    echo_status = EchoStatus.new(code: code, message: message)
+    req = SimpleRequest.new(response_type: :COMPRESSABLE,
+			    response_size: 1,
+			    payload: payload,
+			    response_status: echo_status)
+    seen_correct_exception = false
+    begin
+      resp = @stub.unary_call(req)
+    rescue GRPC::Unknown => e
+      if e.details != message
+	      fail AssertionError,
+	        "Expected message #{message}. Received: #{e.details}"
+      end
+      seen_correct_exception = true
+    rescue Exception => e
+      fail AssertionError, "Expected BadStatus. Received: #{e.inspect}"
+    end
+
+    if not seen_correct_exception
+      fail AssertionError, "Did not see expected status from UnaryCall"
+    end
+
+    # testing with FullDuplex
+    req_cls, p_cls = StreamingOutputCallRequest, ResponseParameters
+    duplex_req = req_cls.new(payload: Payload.new(body: nulls(1)),
+                  response_type: :COMPRESSABLE,
+                  response_parameters: [p_cls.new(size: 1)],
+                  response_status: echo_status)
+    seen_correct_exception = false
+    begin
+      resp = @stub.full_duplex_call([duplex_req])
+      resp.each { |r| }
+    rescue GRPC::Unknown => e
+      if e.details != message
+        fail AssertionError,
+          "Expected message #{message}. Received: #{e.details}"
+      end
+      seen_correct_exception = true
+    rescue Exception => e
+      fail AssertionError, "Expected BadStatus. Received: #{e.inspect}"
+    end
+
+    if not seen_correct_exception
+      fail AssertionError, "Did not see expected status from FullDuplexCall"
+    end
+
+  end
+
+
+  def custom_metadata
+
+    # Function wide constants
+    req_size, wanted_response_size = 271_828, 314_159
+    initial_metadata_key = "x-grpc-test-echo-initial"
+    initial_metadata_value = "test_initial_metadata_value"
+    trailing_metadata_key = "x-grpc-test-echo-trailing-bin"
+    trailing_metadata_value = "\x0a\x0b\x0a\x0b\x0a\x0b"
+
+    metadata = {
+      initial_metadata_key => initial_metadata_value,
+      trailing_metadata_key => trailing_metadata_value
+    }
+
+    # Testing with UnaryCall
+    payload = Payload.new(type: :COMPRESSABLE, body: nulls(req_size))
+    req = SimpleRequest.new(response_type: :COMPRESSABLE,
+			    response_size: wanted_response_size,
+			    payload: payload)
+
+    op = @stub.unary_call(req, metadata: metadata, return_op: true)
+    op.execute
+    if not op.metadata.has_key?(initial_metadata_key)
+      fail AssertionError, "Expected initial metadata. None received"
+    elsif op.metadata[initial_metadata_key] != metadata[initial_metadata_key]
+      fail AssertionError, 
+             "Expected initial metadata: #{metadata[initial_metadata_key]}. "\
+             "Received: #{op.metadata[initial_metadata_key]}"
+    end
+    if not op.trailing_metadata.has_key?(trailing_metadata_key)
+      fail AssertionError, "Expected trailing metadata. None received"
+    elsif op.trailing_metadata[trailing_metadata_key] !=
+          metadata[trailing_metadata_key]
+      fail AssertionError, 
+            "Expected trailing metadata: #{metadata[trailing_metadata_key]}. "\
+            "Received: #{op.trailing_metadata[trailing_metadata_key]}"
+    end
+
+    # Testing with FullDuplex
+    req_cls, p_cls = StreamingOutputCallRequest, ResponseParameters
+    duplex_req = req_cls.new(payload: Payload.new(body: nulls(req_size)),
+                  response_type: :COMPRESSABLE,
+                  response_parameters: [p_cls.new(size: wanted_response_size)])
+
+    duplex_op = @stub.full_duplex_call([duplex_req], metadata: metadata,
+                                        return_op: true)
+    resp = duplex_op.execute
+    resp.each { |r| } # ensures that the server sends trailing data
+    duplex_op.wait
+    if not duplex_op.metadata.has_key?(initial_metadata_key)
+      fail AssertionError, "Expected initial metadata. None received"
+    elsif duplex_op.metadata[initial_metadata_key] !=
+          metadata[initial_metadata_key]
+      fail AssertionError,
+             "Expected initial metadata: #{metadata[initial_metadata_key]}. "\
+             "Received: #{duplex_op.metadata[initial_metadata_key]}"
+    end
+    if not duplex_op.trailing_metadata[trailing_metadata_key]
+      fail AssertionError, "Expected trailing metadata. None received"
+    elsif duplex_op.trailing_metadata[trailing_metadata_key] !=
+          metadata[trailing_metadata_key]
+      fail AssertionError, 
+          "Expected trailing metadata: #{metadata[trailing_metadata_key]}. "\
+          "Received: #{duplex_op.trailing_metadata[trailing_metadata_key]}"
+    end
+
+  end
+
   def all
     all_methods = NamedTests.instance_methods(false).map(&:to_s)
     all_methods.each do |m|
diff --git a/src/ruby/pb/test/server.rb b/src/ruby/pb/test/server.rb
index 3f1e0a1ccf..cc9b872648 100755
--- a/src/ruby/pb/test/server.rb
+++ b/src/ruby/pb/test/server.rb
@@ -129,6 +129,27 @@ def nulls(l)
   [].pack('x' * l).force_encoding('ascii-8bit')
 end
 
+def maybe_echo_metadata(_call)
+  
+  # these are consistent for all interop tests
+  initial_metadata_key = "x-grpc-test-echo-initial"
+  trailing_metadata_key = "x-grpc-test-echo-trailing-bin"
+
+  if _call.metadata.has_key?(initial_metadata_key)
+    _call.metadata_to_send[initial_metadata_key] = _call.metadata[initial_metadata_key]
+  end
+  if _call.metadata.has_key?(trailing_metadata_key)
+    _call.output_metadata[trailing_metadata_key] = _call.metadata[trailing_metadata_key]
+  end
+end
+
+def maybe_echo_status_and_message(req)
+  unless req.response_status.nil?
+    fail GRPC::BadStatus.new_status_exception(
+        req.response_status.code, req.response_status.message)
+  end
+end
+
 # A FullDuplexEnumerator passes requests to a block and yields generated responses
 class FullDuplexEnumerator
   include Grpc::Testing
@@ -143,6 +164,7 @@ class FullDuplexEnumerator
     begin
       cls = StreamingOutputCallResponse
       @requests.each do |req|
+        maybe_echo_status_and_message(req)
         req.response_parameters.each do |params|
           resp_size = params.size
           GRPC.logger.info("read a req, response size is #{resp_size}")
@@ -170,6 +192,8 @@ class TestTarget < Grpc::Testing::TestService::Service
   end
 
   def unary_call(simple_req, _call)
+    maybe_echo_metadata(_call)
+    maybe_echo_status_and_message(simple_req)
     req_size = simple_req.response_size
     SimpleResponse.new(payload: Payload.new(type: :COMPRESSABLE,
                                             body: nulls(req_size)))
@@ -189,7 +213,8 @@ class TestTarget < Grpc::Testing::TestService::Service
     end
   end
 
-  def full_duplex_call(reqs)
+  def full_duplex_call(reqs, _call)
+    maybe_echo_metadata(_call)
     # reqs is a lazy Enumerator of the requests sent by the client.
     FullDuplexEnumerator.new(reqs).each_item
   end
diff --git a/src/ruby/qps/client.rb b/src/ruby/qps/client.rb
index 8aed866da5..817192626b 100644
--- a/src/ruby/qps/client.rb
+++ b/src/ruby/qps/client.rb
@@ -134,6 +134,7 @@ class BenchmarkClient
     resp = stub.streaming_call(q.each_item)
     start = Time.now
     q.push(req)
+    pushed_sentinal = false
     resp.each do |r|
       @histogram.add((Time.now-start)*1e9)
       if !@done
@@ -141,8 +142,9 @@ class BenchmarkClient
         start = Time.now
         q.push(req)
       else
-        q.push(self)
-        break
+        q.push(self) unless pushed_sentinal
+	# Continue polling on the responses to consume and release resources
+        pushed_sentinal = true
       end
     end
   end
diff --git a/src/python/grpcio_health_checking/grpc/__init__.py b/src/ruby/spec/error_sanity_spec.rb
index fcc7048815..77e94a8816 100644
--- a/src/python/grpcio_health_checking/grpc/__init__.py
+++ b/src/ruby/spec/error_sanity_spec.rb
@@ -27,4 +27,38 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-__import__('pkg_resources').declare_namespace(__name__)
+require 'grpc'
+
+StatusCodes = GRPC::Core::StatusCodes
+
+describe StatusCodes do
+  # convert upper snake-case to camel case.
+  # e.g., DEADLINE_EXCEEDED -> DeadlineExceeded
+  def upper_snake_to_camel(name)
+    name.to_s.split('_').map(&:downcase).map(&:capitalize).join('')
+  end
+
+  StatusCodes.constants.each do |status_name|
+    it 'there is a subclass of BadStatus corresponding to StatusCode: ' \
+      "#{status_name} that has code: #{StatusCodes.const_get(status_name)}" do
+      camel_case = upper_snake_to_camel(status_name)
+      error_class = GRPC.const_get(camel_case)
+      # expect the error class to be a subclass of BadStatus
+      expect(error_class < GRPC::BadStatus)
+
+      error_object = error_class.new
+      # check that the code matches the int value of the error's constant
+      status_code = StatusCodes.const_get(status_name)
+      expect(error_object.code).to eq(status_code)
+
+      # check default parameters
+      expect(error_object.details).to eq('unknown cause')
+      expect(error_object.metadata).to eq({})
+
+      # check that the BadStatus factory for creates the correct
+      # exception too
+      from_factory = GRPC::BadStatus.new_status_exception(status_code)
+      expect(from_factory.is_a?(error_class)).to be(true)
+    end
+  end
+end
diff --git a/src/ruby/spec/generic/client_stub_spec.rb b/src/ruby/spec/generic/client_stub_spec.rb
index 607a4a3c5d..b51b291cbd 100644
--- a/src/ruby/spec/generic/client_stub_spec.rb
+++ b/src/ruby/spec/generic/client_stub_spec.rb
@@ -190,15 +190,14 @@ describe 'ClientStub' do
         end
         creds = GRPC::Core::CallCredentials.new(failing_auth)
 
-        error_occured = false
+        unauth_error_occured = false
         begin
           get_response(stub, credentials: creds)
-        rescue GRPC::BadStatus => e
-          error_occured = true
-          expect(e.code).to eq(GRPC::Core::StatusCodes::UNAUTHENTICATED)
+        rescue GRPC::Unauthenticated => e
+          unauth_error_occured = true
           expect(e.details.include?(error_message)).to be true
         end
-        expect(error_occured).to eq(true)
+        expect(unauth_error_occured).to eq(true)
 
         # Kill the server thread so tests can complete
         th.kill
diff --git a/src/ruby/spec/generic/rpc_desc_spec.rb b/src/ruby/spec/generic/rpc_desc_spec.rb
index a3f0efa603..1ace7211e9 100644
--- a/src/ruby/spec/generic/rpc_desc_spec.rb
+++ b/src/ruby/spec/generic/rpc_desc_spec.rb
@@ -48,7 +48,6 @@ describe GRPC::RpcDesc do
     @bidi_streamer = RpcDesc.new('ss', Stream.new(Object.new),
                                  Stream.new(Object.new), 'encode', 'decode')
     @bs_code = INTERNAL
-    @no_reason = 'unkown error handling call on server'
     @ok_response = Object.new
   end
 
@@ -62,8 +61,9 @@ describe GRPC::RpcDesc do
 
     it 'sends status UNKNOWN if other StandardErrors are raised' do
       expect(@call).to receive(:remote_read).once.and_return(Object.new)
-      expect(@call).to receive(:send_status) .once.with(UNKNOWN, @no_reason,
-                                                        false, metadata: {})
+      expect(@call).to receive(:send_status).once.with(UNKNOWN,
+                                                       arg_error_msg,
+                                                       false, metadata: {})
       this_desc.run_server_method(@call, method(:other_error))
     end
 
@@ -112,7 +112,7 @@ describe GRPC::RpcDesc do
       end
 
       it 'sends status UNKNOWN if other StandardErrors are raised' do
-        expect(@call).to receive(:send_status).once.with(UNKNOWN, @no_reason,
+        expect(@call).to receive(:send_status).once.with(UNKNOWN, arg_error_msg,
                                                          false, metadata: {})
         @client_streamer.run_server_method(@call, method(:other_error_alt))
       end
@@ -174,8 +174,9 @@ describe GRPC::RpcDesc do
       end
 
       it 'sends status UNKNOWN if other StandardErrors are raised' do
+        error_msg = arg_error_msg(StandardError.new)
         expect(@call).to receive(:run_server_bidi).and_raise(StandardError)
-        expect(@call).to receive(:send_status).once.with(UNKNOWN, @no_reason,
+        expect(@call).to receive(:send_status).once.with(UNKNOWN, error_msg,
                                                          false, metadata: {})
         @bidi_streamer.run_server_method(@call, method(:other_error_alt))
       end
@@ -342,4 +343,9 @@ describe GRPC::RpcDesc do
   def other_error_alt(_call)
     fail(ArgumentError, 'other error')
   end
+
+  def arg_error_msg(error = nil)
+    error ||= ArgumentError.new('other error')
+    "#{error.class}: #{error.message}"
+  end
 end
diff --git a/src/ruby/spec/generic/rpc_server_pool_spec.rb b/src/ruby/spec/generic/rpc_server_pool_spec.rb
index 48ccaee510..69e8222cb9 100644
--- a/src/ruby/spec/generic/rpc_server_pool_spec.rb
+++ b/src/ruby/spec/generic/rpc_server_pool_spec.rb
@@ -94,18 +94,6 @@ describe GRPC::Pool do
       expect(q.pop).to be(o)
       p.stop
     end
-
-    it 'it throws an error if all of the workers have tasks to do' do
-      p = Pool.new(5)
-      p.start
-      job = proc {}
-      5.times do
-        expect(p.ready_for_work?).to be(true)
-        p.schedule(&job)
-      end
-      expect { p.schedule(&job) }.to raise_error
-      expect { p.schedule(&job) }.to raise_error
-    end
   end
 
   describe '#stop' do
diff --git a/src/ruby/spec/generic/rpc_server_spec.rb b/src/ruby/spec/generic/rpc_server_spec.rb
index c5694790fd..806ea8ce9f 100644
--- a/src/ruby/spec/generic/rpc_server_spec.rb
+++ b/src/ruby/spec/generic/rpc_server_spec.rb
@@ -408,21 +408,21 @@ describe GRPC::RpcServer do
         req = EchoMsg.new
         n = 20 # arbitrary, use as many to ensure the server pool is exceeded
         threads = []
-        bad_status_code = nil
+        one_failed_as_unavailable = false
         n.times do
           threads << Thread.new do
             stub = SlowStub.new(alt_host, :this_channel_is_insecure)
             begin
               stub.an_rpc(req)
-            rescue GRPC::BadStatus => e
-              bad_status_code = e.code
+            rescue GRPC::ResourceExhausted
+              one_failed_as_unavailable = true
             end
           end
         end
         threads.each(&:join)
         alt_srv.stop
         t.join
-        expect(bad_status_code).to be(StatusCodes::RESOURCE_EXHAUSTED)
+        expect(one_failed_as_unavailable).to be(true)
       end
     end
 
diff --git a/src/ruby/spec/pb/health/checker_spec.rb b/src/ruby/spec/pb/health/checker_spec.rb
index 4711e09e88..719510001c 100644
--- a/src/ruby/spec/pb/health/checker_spec.rb
+++ b/src/ruby/spec/pb/health/checker_spec.rb
@@ -122,7 +122,7 @@ describe Grpc::Health::Checker do
           checker.check(HCReq.new(service: t[:service]), nil)
         end
         expected_msg = /#{StatusCodes::NOT_FOUND}/
-        expect(&blk).to raise_error GRPC::BadStatus, expected_msg
+        expect(&blk).to raise_error GRPC::NotFound, expected_msg
       end
     end
   end
@@ -141,7 +141,7 @@ describe Grpc::Health::Checker do
           checker.check(HCReq.new(service: t[:service]), nil)
         end
         expected_msg = /#{StatusCodes::NOT_FOUND}/
-        expect(&blk).to raise_error GRPC::BadStatus, expected_msg
+        expect(&blk).to raise_error GRPC::NotFound, expected_msg
       end
     end
   end
@@ -163,7 +163,7 @@ describe Grpc::Health::Checker do
           checker.check(HCReq.new(service: t[:service]), nil)
         end
         expected_msg = /#{StatusCodes::NOT_FOUND}/
-        expect(&blk).to raise_error GRPC::BadStatus, expected_msg
+        expect(&blk).to raise_error GRPC::NotFound, expected_msg
       end
     end
   end
@@ -214,7 +214,7 @@ describe Grpc::Health::Checker do
         stub.check(HCReq.new(service: 'unknown'))
       end
       expected_msg = /#{StatusCodes::NOT_FOUND}/
-      expect(&blk).to raise_error GRPC::BadStatus, expected_msg
+      expect(&blk).to raise_error GRPC::NotFound, expected_msg
       @srv.stop
       t.join
     end
diff --git a/src/ruby/spec/spec_helper.rb b/src/ruby/spec/spec_helper.rb
index c891c1bf5e..c2be0afa72 100644
--- a/src/ruby/spec/spec_helper.rb
+++ b/src/ruby/spec/spec_helper.rb
@@ -67,3 +67,5 @@ RSpec.configure do |config|
 end
 
 RSpec::Expectations.configuration.warn_about_potential_false_positives = false
+
+Thread.abort_on_exception = true