Merge branch 'master' of github.com:grpc/grpc into compression-accept-encoding

104 files changed, 1873 insertions, 667 deletions

diff --git a/src/compiler/csharp_generator.cc b/src/compiler/csharp_generator.cc
index 1910e9bd2d..64371047e0 100644
--- a/src/compiler/csharp_generator.cc
+++ b/src/compiler/csharp_generator.cc
@@ -149,7 +149,7 @@ std::string GetMethodRequestParamMaybe(const MethodDescriptor *method) {
 std::string GetMethodReturnTypeClient(const MethodDescriptor *method) {
   switch (GetMethodType(method)) {
     case METHODTYPE_NO_STREAMING:
-      return "Task<" + GetClassName(method->output_type()) + ">";
+      return "AsyncUnaryCall<" + GetClassName(method->output_type()) + ">";
     case METHODTYPE_CLIENT_STREAMING:
       return "AsyncClientStreamingCall<" + GetClassName(method->input_type())
           + ", " + GetClassName(method->output_type()) + ">";
@@ -298,7 +298,7 @@ void GenerateServerInterface(Printer* out, const ServiceDescriptor *service) {
   out->Indent();
   for (int i = 0; i < service->method_count(); i++) {
     const MethodDescriptor *method = service->method(i);
-    out->Print("$returntype$ $methodname$(ServerCallContext context, $request$$response_stream_maybe$);\n",
+    out->Print("$returntype$ $methodname$($request$$response_stream_maybe$, ServerCallContext context);\n",
                "methodname", method->name(), "returntype",
                GetMethodReturnTypeServer(method), "request",
                GetMethodRequestParamServer(method), "response_stream_maybe",
diff --git a/src/compiler/objective_c_generator.cc b/src/compiler/objective_c_generator.cc
index 711d0d5870..69b3805bb1 100644
--- a/src/compiler/objective_c_generator.cc
+++ b/src/compiler/objective_c_generator.cc
@@ -186,9 +186,6 @@ string GetHeader(const ServiceDescriptor *service) {
     grpc::protobuf::io::StringOutputStream output_stream(&output);
     Printer printer(&output_stream, '$');
 
-    printer.Print("@protocol GRXWriteable;\n");
-    printer.Print("@protocol GRXWriter;\n\n");
-
     map<string, string> vars = {{"service_class", ServiceClassName(service)}};
 
     printer.Print(vars, "@protocol $service_class$ <NSObject>\n\n");
diff --git a/src/compiler/objective_c_plugin.cc b/src/compiler/objective_c_plugin.cc
index 2b5ab758fc..10f06ad4df 100644
--- a/src/compiler/objective_c_plugin.cc
+++ b/src/compiler/objective_c_plugin.cc
@@ -63,7 +63,9 @@ class ObjectiveCGrpcGenerator : public grpc::protobuf::compiler::CodeGenerator {
       // Generate .pbrpc.h
 
       string imports = string("#import \"") + file_name + ".pbobjc.h\"\n\n"
-        "#import <ProtoRPC/ProtoService.h>\n";
+        "#import <ProtoRPC/ProtoService.h>\n"
+        "#import <RxLibrary/GRXWriteable.h>\n"
+        "#import <RxLibrary/GRXWriter.h>\n";
 
       // TODO(jcanizales): Instead forward-declare the input and output types
       // and import the files in the .pbrpc.m
@@ -89,7 +91,6 @@ class ObjectiveCGrpcGenerator : public grpc::protobuf::compiler::CodeGenerator {
 
       string imports = string("#import \"") + file_name + ".pbrpc.h\"\n\n"
         "#import <ProtoRPC/ProtoRPC.h>\n"
-        "#import <RxLibrary/GRXWriteable.h>\n"
         "#import <RxLibrary/GRXWriter+Immediate.h>\n";
 
       string definitions;
diff --git a/src/core/channel/client_channel.c b/src/core/channel/client_channel.c
index 10e01ebbb4..c1aa580b2d 100644
--- a/src/core/channel/client_channel.c
+++ b/src/core/channel/client_channel.c
@@ -236,21 +236,6 @@ static void picked_target(void *arg, int iomgr_success) {
   }
 }
 
-static void pick_target(grpc_lb_policy *lb_policy, call_data *calld) {
-  grpc_metadata_batch *initial_metadata;
-  grpc_transport_stream_op *op = &calld->waiting_op;
-
-  GPR_ASSERT(op->bind_pollset);
-  GPR_ASSERT(op->send_ops);
-  GPR_ASSERT(op->send_ops->nops >= 1);
-  GPR_ASSERT(op->send_ops->ops[0].type == GRPC_OP_METADATA);
-  initial_metadata = &op->send_ops->ops[0].data.metadata;
-
-  grpc_iomgr_closure_init(&calld->async_setup_task, picked_target, calld);
-  grpc_lb_policy_pick(lb_policy, op->bind_pollset, initial_metadata,
-                      &calld->picked_channel, &calld->async_setup_task);
-}
-
 static grpc_iomgr_closure *merge_into_waiting_op(
     grpc_call_element *elem, grpc_transport_stream_op *new_op) {
   call_data *calld = elem->call_data;
@@ -358,12 +343,23 @@ static void perform_transport_stream_op(grpc_call_element *elem,
           gpr_mu_lock(&chand->mu_config);
           lb_policy = chand->lb_policy;
           if (lb_policy) {
+            grpc_transport_stream_op *op = &calld->waiting_op;
+            grpc_pollset *bind_pollset = op->bind_pollset;
+            grpc_metadata_batch *initial_metadata = &op->send_ops->ops[0].data.metadata;
             GRPC_LB_POLICY_REF(lb_policy, "pick");
             gpr_mu_unlock(&chand->mu_config);
             calld->state = CALL_WAITING_FOR_PICK;
+
+            GPR_ASSERT(op->bind_pollset);
+            GPR_ASSERT(op->send_ops);
+            GPR_ASSERT(op->send_ops->nops >= 1);
+            GPR_ASSERT(
+                op->send_ops->ops[0].type == GRPC_OP_METADATA);
             gpr_mu_unlock(&calld->mu_state);
 
-            pick_target(lb_policy, calld);
+            grpc_iomgr_closure_init(&calld->async_setup_task, picked_target, calld);
+            grpc_lb_policy_pick(lb_policy, bind_pollset, initial_metadata,
+                                &calld->picked_channel, &calld->async_setup_task);
 
             GRPC_LB_POLICY_UNREF(lb_policy, "pick");
           } else if (chand->resolver != NULL) {
diff --git a/src/core/channel/compress_filter.c b/src/core/channel/compress_filter.c
index 9ff679df18..f656484fac 100644
--- a/src/core/channel/compress_filter.c
+++ b/src/core/channel/compress_filter.c
@@ -208,7 +208,7 @@ static void process_send_ops(grpc_call_element *elem,
             calld->has_compression_algorithm = 1; /* GPR_TRUE */
           }
           /* hint compression algorithm */
-          grpc_metadata_batch_add_head(
+          grpc_metadata_batch_add_tail(
               &(sop->data.metadata), &calld->compression_algorithm_storage,
               GRPC_MDELEM_REF(channeld->mdelem_compression_algorithms
                                   [calld->compression_algorithm]));
diff --git a/src/core/channel/http_client_filter.c b/src/core/channel/http_client_filter.c
index 63e4912397..6e93103a6a 100644
--- a/src/core/channel/http_client_filter.c
+++ b/src/core/channel/http_client_filter.c
@@ -32,13 +32,17 @@
 
 #include "src/core/channel/http_client_filter.h"
 #include <string.h>
+#include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+#include "src/core/support/string.h"
 
 typedef struct call_data {
   grpc_linked_mdelem method;
   grpc_linked_mdelem scheme;
   grpc_linked_mdelem te_trailers;
   grpc_linked_mdelem content_type;
+  grpc_linked_mdelem user_agent;
   int sent_initial_metadata;
 
   int got_initial_metadata;
@@ -58,6 +62,8 @@ typedef struct channel_data {
   grpc_mdelem *scheme;
   grpc_mdelem *content_type;
   grpc_mdelem *status;
+  /** complete user agent mdelem */
+  grpc_mdelem *user_agent;
 } channel_data;
 
 /* used to silence 'variable not used' warnings */
@@ -92,6 +98,18 @@ static void hc_on_recv(void *user_data, int success) {
   calld->on_done_recv->cb(calld->on_done_recv->cb_arg, success);
 }
 
+static grpc_mdelem *client_strip_filter(void *user_data, grpc_mdelem *md) {
+  grpc_call_element *elem = user_data;
+  channel_data *channeld = elem->channel_data;
+  /* eat the things we'd like to set ourselves */
+  if (md->key == channeld->method->key) return NULL;
+  if (md->key == channeld->scheme->key) return NULL;
+  if (md->key == channeld->te_trailers->key) return NULL;
+  if (md->key == channeld->content_type->key) return NULL;
+  if (md->key == channeld->user_agent->key) return NULL;
+  return md;
+}
+
 static void hc_mutate_op(grpc_call_element *elem,
                          grpc_transport_stream_op *op) {
   /* grab pointers to our data from the call element */
@@ -105,6 +123,7 @@ static void hc_mutate_op(grpc_call_element *elem,
       grpc_stream_op *op = &ops[i];
       if (op->type != GRPC_OP_METADATA) continue;
       calld->sent_initial_metadata = 1;
+      grpc_metadata_batch_filter(&op->data.metadata, client_strip_filter, elem);
       /* Send : prefixed headers, which have to be before any application
          layer headers. */
       grpc_metadata_batch_add_head(&op->data.metadata, &calld->method,
@@ -115,6 +134,8 @@ static void hc_mutate_op(grpc_call_element *elem,
                                    GRPC_MDELEM_REF(channeld->te_trailers));
       grpc_metadata_batch_add_tail(&op->data.metadata, &calld->content_type,
                                    GRPC_MDELEM_REF(channeld->content_type));
+      grpc_metadata_batch_add_tail(&op->data.metadata, &calld->user_agent,
+                                   GRPC_MDELEM_REF(channeld->user_agent));
       break;
     }
   }
@@ -169,6 +190,55 @@ static const char *scheme_from_args(const grpc_channel_args *args) {
   return "http";
 }
 
+static grpc_mdstr *user_agent_from_args(grpc_mdctx *mdctx,
+                                        const grpc_channel_args *args) {
+  gpr_strvec v;
+  size_t i;
+  int is_first = 1;
+  char *tmp;
+  grpc_mdstr *result;
+
+  gpr_strvec_init(&v);
+
+  for (i = 0; args && i < args->num_args; i++) {
+    if (0 == strcmp(args->args[i].key, GRPC_ARG_PRIMARY_USER_AGENT_STRING)) {
+      if (args->args[i].type != GRPC_ARG_STRING) {
+        gpr_log(GPR_ERROR, "Channel argument '%s' should be a string",
+                GRPC_ARG_PRIMARY_USER_AGENT_STRING);
+      } else {
+        if (!is_first) gpr_strvec_add(&v, gpr_strdup(" "));
+        is_first = 0;
+        gpr_strvec_add(&v, gpr_strdup(args->args[i].value.string));
+      }
+    }
+  }
+
+  gpr_asprintf(&tmp, "%sgrpc-c/%s (%s)", is_first ? "" : " ",
+               grpc_version_string(), GPR_PLATFORM_STRING);
+  is_first = 0;
+  gpr_strvec_add(&v, tmp);
+
+  for (i = 0; args && i < args->num_args; i++) {
+    if (0 == strcmp(args->args[i].key, GRPC_ARG_SECONDARY_USER_AGENT_STRING)) {
+      if (args->args[i].type != GRPC_ARG_STRING) {
+        gpr_log(GPR_ERROR, "Channel argument '%s' should be a string",
+                GRPC_ARG_SECONDARY_USER_AGENT_STRING);
+      } else {
+        if (!is_first) gpr_strvec_add(&v, gpr_strdup(" "));
+        is_first = 0;
+        gpr_strvec_add(&v, gpr_strdup(args->args[i].value.string));
+      }
+    }
+  }
+
+  tmp = gpr_strvec_flatten(&v, NULL);
+  gpr_strvec_destroy(&v);
+  result = grpc_mdstr_from_string(mdctx, tmp);
+  gpr_free(tmp);
+
+  return result;
+}
+
 /* Constructor for channel_data */
 static void init_channel_elem(grpc_channel_element *elem, grpc_channel *master,
                               const grpc_channel_args *args, grpc_mdctx *mdctx,
@@ -189,6 +259,9 @@ static void init_channel_elem(grpc_channel_element *elem, grpc_channel *master,
   channeld->content_type =
       grpc_mdelem_from_strings(mdctx, "content-type", "application/grpc");
   channeld->status = grpc_mdelem_from_strings(mdctx, ":status", "200");
+  channeld->user_agent = grpc_mdelem_from_metadata_strings(
+      mdctx, grpc_mdstr_from_string(mdctx, "user-agent"),
+      user_agent_from_args(mdctx, args));
 }
 
 /* Destructor for channel data */
@@ -201,6 +274,7 @@ static void destroy_channel_elem(grpc_channel_element *elem) {
   GRPC_MDELEM_UNREF(channeld->scheme);
   GRPC_MDELEM_UNREF(channeld->content_type);
   GRPC_MDELEM_UNREF(channeld->status);
+  GRPC_MDELEM_UNREF(channeld->user_agent);
 }
 
 const grpc_channel_filter grpc_http_client_filter = {
diff --git a/src/core/client_config/subchannel.c b/src/core/client_config/subchannel.c
index 35f172683a..487f5afb35 100644
--- a/src/core/client_config/subchannel.c
+++ b/src/core/client_config/subchannel.c
@@ -300,7 +300,7 @@ static void continue_connect(grpc_subchannel *c) {
 }
 
 static void start_connect(grpc_subchannel *c) {
-  gpr_timespec now = gpr_now(GPR_CLOCK_REALTIME);
+  gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
   c->next_attempt = now;
   c->backoff_delta = gpr_time_from_seconds(1, GPR_TIMESPAN);
 
@@ -585,7 +585,7 @@ static void subchannel_connected(void *arg, int iomgr_success) {
     c->have_alarm = 1;
     c->next_attempt = gpr_time_add(c->next_attempt, c->backoff_delta);
     c->backoff_delta = gpr_time_add(c->backoff_delta, c->backoff_delta);
-    grpc_alarm_init(&c->alarm, c->next_attempt, on_alarm, c, gpr_now(GPR_CLOCK_REALTIME));
+    grpc_alarm_init(&c->alarm, c->next_attempt, on_alarm, c, gpr_now(GPR_CLOCK_MONOTONIC));
     gpr_mu_unlock(&c->mu);
   }
 }
diff --git a/src/core/iomgr/alarm.c b/src/core/iomgr/alarm.c
index 5b9a37e5dd..931f746f75 100644
--- a/src/core/iomgr/alarm.c
+++ b/src/core/iomgr/alarm.c
@@ -36,6 +36,7 @@
 #include "src/core/iomgr/alarm_heap.h"
 #include "src/core/iomgr/alarm_internal.h"
 #include "src/core/iomgr/time_averaged_stats.h"
+#include <grpc/support/log.h>
 #include <grpc/support/sync.h>
 #include <grpc/support/useful.h>
 
@@ -67,6 +68,7 @@ typedef struct {
 static gpr_mu g_mu;
 /* Allow only one run_some_expired_alarms at once */
 static gpr_mu g_checker_mu;
+static gpr_clock_type g_clock_type;
 static shard_type g_shards[NUM_SHARDS];
 /* Protected by g_mu */
 static shard_type *g_shard_queue[NUM_SHARDS];
@@ -85,6 +87,7 @@ void grpc_alarm_list_init(gpr_timespec now) {
 
   gpr_mu_init(&g_mu);
   gpr_mu_init(&g_checker_mu);
+  g_clock_type = now.clock_type;
 
   for (i = 0; i < NUM_SHARDS; i++) {
     shard_type *shard = &g_shards[i];
@@ -102,7 +105,7 @@ void grpc_alarm_list_init(gpr_timespec now) {
 
 void grpc_alarm_list_shutdown(void) {
   int i;
-  while (run_some_expired_alarms(NULL, gpr_inf_future(GPR_CLOCK_REALTIME), NULL,
+  while (run_some_expired_alarms(NULL, gpr_inf_future(g_clock_type), NULL,
                                  0))
     ;
   for (i = 0; i < NUM_SHARDS; i++) {
@@ -175,6 +178,8 @@ void grpc_alarm_init(grpc_alarm *alarm, gpr_timespec deadline,
                      gpr_timespec now) {
   int is_first_alarm = 0;
   shard_type *shard = &g_shards[shard_idx(alarm)];
+  GPR_ASSERT(deadline.clock_type == g_clock_type);
+  GPR_ASSERT(now.clock_type == g_clock_type);
   alarm->cb = alarm_cb;
   alarm->cb_arg = alarm_cb_arg;
   alarm->deadline = deadline;
@@ -355,6 +360,7 @@ static int run_some_expired_alarms(gpr_mu *drop_mu, gpr_timespec now,
 }
 
 int grpc_alarm_check(gpr_mu *drop_mu, gpr_timespec now, gpr_timespec *next) {
+  GPR_ASSERT(now.clock_type == g_clock_type);
   return run_some_expired_alarms(drop_mu, now, next, 1);
 }
 
diff --git a/src/core/iomgr/iomgr.c b/src/core/iomgr/iomgr.c
index 0244f689b1..a18c176b30 100644
--- a/src/core/iomgr/iomgr.c
+++ b/src/core/iomgr/iomgr.c
@@ -57,9 +57,9 @@ static grpc_iomgr_object g_root_object;
 static void background_callback_executor(void *ignored) {
   gpr_mu_lock(&g_mu);
   while (!g_shutdown) {
-    gpr_timespec deadline = gpr_inf_future(GPR_CLOCK_REALTIME);
+    gpr_timespec deadline = gpr_inf_future(GPR_CLOCK_MONOTONIC);
     gpr_timespec short_deadline = gpr_time_add(
-        gpr_now(GPR_CLOCK_REALTIME), gpr_time_from_millis(100, GPR_TIMESPAN));
+        gpr_now(GPR_CLOCK_MONOTONIC), gpr_time_from_millis(100, GPR_TIMESPAN));
     if (g_cbs_head) {
       grpc_iomgr_closure *closure = g_cbs_head;
       g_cbs_head = closure->next;
@@ -67,7 +67,7 @@ static void background_callback_executor(void *ignored) {
       gpr_mu_unlock(&g_mu);
       closure->cb(closure->cb_arg, closure->success);
       gpr_mu_lock(&g_mu);
-    } else if (grpc_alarm_check(&g_mu, gpr_now(GPR_CLOCK_REALTIME),
+    } else if (grpc_alarm_check(&g_mu, gpr_now(GPR_CLOCK_MONOTONIC),
                                 &deadline)) {
     } else {
       gpr_mu_unlock(&g_mu);
@@ -90,7 +90,7 @@ void grpc_iomgr_init(void) {
   gpr_thd_id id;
   gpr_mu_init(&g_mu);
   gpr_cv_init(&g_rcv);
-  grpc_alarm_list_init(gpr_now(GPR_CLOCK_REALTIME));
+  grpc_alarm_list_init(gpr_now(GPR_CLOCK_MONOTONIC));
   g_root_object.next = g_root_object.prev = &g_root_object;
   g_root_object.name = "root";
   grpc_iomgr_platform_init();
@@ -145,7 +145,7 @@ void grpc_iomgr_shutdown(void) {
       } while (g_cbs_head);
       continue;
     }
-    if (grpc_alarm_check(&g_mu, gpr_inf_future(GPR_CLOCK_REALTIME), NULL)) {
+    if (grpc_alarm_check(&g_mu, gpr_inf_future(GPR_CLOCK_MONOTONIC), NULL)) {
       gpr_log(GPR_DEBUG, "got late alarm");
       continue;
     }
diff --git a/src/core/iomgr/pollset_posix.c b/src/core/iomgr/pollset_posix.c
index efb301d81c..c8646af615 100644
--- a/src/core/iomgr/pollset_posix.c
+++ b/src/core/iomgr/pollset_posix.c
@@ -136,7 +136,7 @@ static void finish_shutdown(grpc_pollset *pollset) {
 
 int grpc_pollset_work(grpc_pollset *pollset, gpr_timespec deadline) {
   /* pollset->mu already held */
-  gpr_timespec now = gpr_now(GPR_CLOCK_REALTIME);
+  gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
   if (gpr_time_cmp(now, deadline) > 0) {
     return 0;
   }
@@ -205,7 +205,7 @@ int grpc_poll_deadline_to_millis_timeout(gpr_timespec deadline,
                                          gpr_timespec now) {
   gpr_timespec timeout;
   static const int max_spin_polling_us = 10;
-  if (gpr_time_cmp(deadline, gpr_inf_future(GPR_CLOCK_REALTIME)) == 0) {
+  if (gpr_time_cmp(deadline, gpr_inf_future(deadline.clock_type)) == 0) {
     return -1;
   }
   if (gpr_time_cmp(deadline, gpr_time_add(now, gpr_time_from_micros(
diff --git a/src/core/iomgr/pollset_windows.c b/src/core/iomgr/pollset_windows.c
index 24226cc980..a9c4739c7c 100644
--- a/src/core/iomgr/pollset_windows.c
+++ b/src/core/iomgr/pollset_windows.c
@@ -70,7 +70,7 @@ void grpc_pollset_destroy(grpc_pollset *pollset) {
 
 int grpc_pollset_work(grpc_pollset *pollset, gpr_timespec deadline) {
   gpr_timespec now;
-  now = gpr_now(GPR_CLOCK_REALTIME);
+  now = gpr_now(GPR_CLOCK_MONOTONIC);
   if (gpr_time_cmp(now, deadline) > 0) {
     return 0 /* GPR_FALSE */;
   }
diff --git a/src/core/iomgr/tcp_client_posix.c b/src/core/iomgr/tcp_client_posix.c
index dc0489e64f..41d8b169e0 100644
--- a/src/core/iomgr/tcp_client_posix.c
+++ b/src/core/iomgr/tcp_client_posix.c
@@ -114,6 +114,8 @@ static void on_writable(void *acp, int success) {
   void (*cb)(void *arg, grpc_endpoint *tcp) = ac->cb;
   void *cb_arg = ac->cb_arg;
 
+  grpc_alarm_cancel(&ac->alarm);
+
   gpr_mu_lock(&ac->mu);
   if (success) {
     do {
@@ -178,8 +180,6 @@ finish:
   if (done) {
     gpr_mu_destroy(&ac->mu);
     gpr_free(ac);
-  } else {
-    grpc_alarm_cancel(&ac->alarm);
   }
   cb(cb_arg, ep);
 }
@@ -253,8 +253,8 @@ void grpc_tcp_client_connect(void (*cb)(void *arg, grpc_endpoint *ep),
   ac->write_closure.cb_arg = ac;
 
   gpr_mu_lock(&ac->mu);
-  grpc_alarm_init(&ac->alarm, deadline, on_alarm, ac,
-                  gpr_now(GPR_CLOCK_REALTIME));
+  grpc_alarm_init(&ac->alarm, gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC), 
+                  on_alarm, ac, gpr_now(GPR_CLOCK_MONOTONIC));
   grpc_fd_notify_on_write(ac->fd, &ac->write_closure);
   gpr_mu_unlock(&ac->mu);
 
diff --git a/src/core/iomgr/tcp_client_windows.c b/src/core/iomgr/tcp_client_windows.c
index 16741452b9..39fd43130b 100644
--- a/src/core/iomgr/tcp_client_windows.c
+++ b/src/core/iomgr/tcp_client_windows.c
@@ -216,7 +216,7 @@ void grpc_tcp_client_connect(void (*cb)(void *arg, grpc_endpoint *tcp),
   ac->aborted = 0;
 
   grpc_alarm_init(&ac->alarm, deadline, on_alarm, ac,
-                  gpr_now(GPR_CLOCK_REALTIME));
+                  gpr_now(GPR_CLOCK_MONOTONIC));
   socket->write_info.outstanding = 1;
   grpc_socket_notify_on_write(socket, on_connect, ac);
   return;
diff --git a/src/core/support/sync_posix.c b/src/core/support/sync_posix.c
index 41af8ceb0a..61572b9a8e 100644
--- a/src/core/support/sync_posix.c
+++ b/src/core/support/sync_posix.c
@@ -63,10 +63,11 @@ void gpr_cv_destroy(gpr_cv *cv) { GPR_ASSERT(pthread_cond_destroy(cv) == 0); }
 
 int gpr_cv_wait(gpr_cv *cv, gpr_mu *mu, gpr_timespec abs_deadline) {
   int err = 0;
-  if (gpr_time_cmp(abs_deadline, gpr_inf_future(GPR_CLOCK_REALTIME)) == 0) {
+  if (gpr_time_cmp(abs_deadline, gpr_inf_future(abs_deadline.clock_type)) == 0) {
     err = pthread_cond_wait(cv, mu);
   } else {
     struct timespec abs_deadline_ts;
+    abs_deadline = gpr_convert_clock_type(abs_deadline, GPR_CLOCK_REALTIME);
     abs_deadline_ts.tv_sec = abs_deadline.tv_sec;
     abs_deadline_ts.tv_nsec = abs_deadline.tv_nsec;
     err = pthread_cond_timedwait(cv, mu, &abs_deadline_ts);
diff --git a/src/core/support/sync_win32.c b/src/core/support/sync_win32.c
index 63196d10d3..54f84a46ac 100644
--- a/src/core/support/sync_win32.c
+++ b/src/core/support/sync_win32.c
@@ -83,10 +83,10 @@ int gpr_cv_wait(gpr_cv *cv, gpr_mu *mu, gpr_timespec abs_deadline) {
   int timeout = 0;
   DWORD timeout_max_ms;
   mu->locked = 0;
-  if (gpr_time_cmp(abs_deadline, gpr_inf_future(GPR_CLOCK_REALTIME)) == 0) {
+  if (gpr_time_cmp(abs_deadline, gpr_inf_future(abs_deadline.clock_type)) == 0) {
     SleepConditionVariableCS(cv, &mu->cs, INFINITE);
   } else {
-    gpr_timespec now = gpr_now(GPR_CLOCK_REALTIME);
+    gpr_timespec now = gpr_now(abs_deadline.clock_type);
     gpr_int64 now_ms = now.tv_sec * 1000 + now.tv_nsec / 1000000;
     gpr_int64 deadline_ms =
         abs_deadline.tv_sec * 1000 + abs_deadline.tv_nsec / 1000000;
diff --git a/src/core/support/time.c b/src/core/support/time.c
index 570f195bd1..b523ae01cc 100644
--- a/src/core/support/time.c
+++ b/src/core/support/time.c
@@ -290,3 +290,30 @@ gpr_int32 gpr_time_to_millis(gpr_timespec t) {
 double gpr_timespec_to_micros(gpr_timespec t) {
   return (double)t.tv_sec * GPR_US_PER_SEC + t.tv_nsec * 1e-3;
 }
+
+gpr_timespec gpr_convert_clock_type(gpr_timespec t, gpr_clock_type clock_type) {
+  if (t.clock_type == clock_type) {
+    return t;
+  }
+
+  if (t.tv_nsec == 0) {
+    if (t.tv_sec == TYPE_MAX(time_t)) {
+      t.clock_type = clock_type;
+      return t;
+    }
+    if (t.tv_sec == TYPE_MIN(time_t)) {
+      t.clock_type = clock_type;
+      return t;
+    }
+  }
+
+  if (clock_type == GPR_TIMESPAN) {
+    return gpr_time_sub(t, gpr_now(t.clock_type));
+  }
+
+  if (t.clock_type == GPR_TIMESPAN) {
+    return gpr_time_add(gpr_now(clock_type), t);
+  }
+
+  return gpr_time_add(gpr_now(clock_type), gpr_time_sub(t, gpr_now(t.clock_type)));
+}
diff --git a/src/core/support/time_posix.c b/src/core/support/time_posix.c
index 258b2e640e..841485c4b4 100644
--- a/src/core/support/time_posix.c
+++ b/src/core/support/time_posix.c
@@ -120,7 +120,7 @@ void gpr_sleep_until(gpr_timespec until) {
   for (;;) {
     /* We could simplify by using clock_nanosleep instead, but it might be
      * slightly less portable. */
-    now = gpr_now(GPR_CLOCK_REALTIME);
+    now = gpr_now(until.clock_type);
     if (gpr_time_cmp(until, now) <= 0) {
       return;
     }
diff --git a/src/core/support/time_win32.c b/src/core/support/time_win32.c
index 238cd07ebc..7f64c80e27 100644
--- a/src/core/support/time_win32.c
+++ b/src/core/support/time_win32.c
@@ -80,7 +80,7 @@ void gpr_sleep_until(gpr_timespec until) {
   for (;;) {
     /* We could simplify by using clock_nanosleep instead, but it might be
      * slightly less portable. */
-    now = gpr_now(GPR_CLOCK_REALTIME);
+    now = gpr_now(until.clock_type);
     if (gpr_time_cmp(until, now) <= 0) {
       return;
     }
diff --git a/src/core/surface/call.c b/src/core/surface/call.c
index 54f10261e3..0cdb9e22a5 100644
--- a/src/core/surface/call.c
+++ b/src/core/surface/call.c
@@ -352,7 +352,7 @@ grpc_call *grpc_call_create(grpc_channel *channel, grpc_completion_queue *cq,
   }
   grpc_call_stack_init(channel_stack, server_transport_data, initial_op_ptr,
                        CALL_STACK_FROM_CALL(call));
-  if (gpr_time_cmp(send_deadline, gpr_inf_future(GPR_CLOCK_REALTIME)) != 0) {
+  if (gpr_time_cmp(send_deadline, gpr_inf_future(send_deadline.clock_type)) != 0) {
     set_deadline_alarm(call, send_deadline);
   }
   return call;
@@ -1309,8 +1309,8 @@ static void set_deadline_alarm(grpc_call *call, gpr_timespec deadline) {
   }
   GRPC_CALL_INTERNAL_REF(call, "alarm");
   call->have_alarm = 1;
-  grpc_alarm_init(&call->alarm, deadline, call_alarm, call,
-                  gpr_now(GPR_CLOCK_REALTIME));
+  grpc_alarm_init(&call->alarm, gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC), call_alarm, call,
+                  gpr_now(GPR_CLOCK_MONOTONIC));
 }
 
 /* we offset status by a small amount when storing it into transport metadata
diff --git a/src/core/surface/call.h b/src/core/surface/call.h
index 5736e97b59..49fb4de47a 100644
--- a/src/core/surface/call.h
+++ b/src/core/surface/call.h
@@ -134,6 +134,10 @@ void grpc_server_log_request_call(char *file, int line,
                                   grpc_completion_queue *cq_for_notification,
                                   void *tag);
 
+void grpc_server_log_shutdown(char *file, int line, gpr_log_severity severity,
+                              grpc_server *server, grpc_completion_queue *cq,
+                              void *tag);
+
 /* Set a context pointer.
    No thread safety guarantees are made wrt this value. */
 void grpc_call_context_set(grpc_call *call, grpc_context_index elem,
@@ -151,6 +155,9 @@ void *grpc_call_context_get(grpc_call *call, grpc_context_index elem);
   grpc_server_log_request_call(sev, server, call, details, initial_metadata, \
                                cq_bound_to_call, cq_for_notifications, tag)
 
+#define GRPC_SERVER_LOG_SHUTDOWN(sev, server, cq, tag) \
+  if (grpc_trace_batch) grpc_server_log_shutdown(sev, server, cq, tag)
+
 gpr_uint8 grpc_call_is_client(grpc_call *call);
 
 /** Returns a bitset for the encodings (compression algorithms) supported by \a
diff --git a/src/core/surface/call_log_batch.c b/src/core/surface/call_log_batch.c
index 997046d954..7bf8cafc24 100644
--- a/src/core/surface/call_log_batch.c
+++ b/src/core/surface/call_log_batch.c
@@ -136,3 +136,11 @@ void grpc_server_log_request_call(char *file, int line,
           "tag=%p)", server, call, details, initial_metadata,
           cq_bound_to_call, cq_for_notification, tag);
 }
+
+void grpc_server_log_shutdown(char *file, int line, gpr_log_severity severity,
+                              grpc_server *server, grpc_completion_queue *cq,
+                              void *tag) {
+  gpr_log(file, line, severity,
+          "grpc_server_shutdown_and_notify(server=%p, cq=%p, tag=%p)", server,
+          cq, tag);
+}
diff --git a/src/core/surface/completion_queue.c b/src/core/surface/completion_queue.c
index 8484418247..3f60b0b0ba 100644
--- a/src/core/surface/completion_queue.c
+++ b/src/core/surface/completion_queue.c
@@ -148,6 +148,8 @@ grpc_event grpc_completion_queue_next(grpc_completion_queue *cc,
                                       gpr_timespec deadline) {
   grpc_event ret;
 
+  deadline = gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC);
+
   GRPC_CQ_INTERNAL_REF(cc, "next");
   gpr_mu_lock(GRPC_POLLSET_MU(&cc->pollset));
   for (;;) {
@@ -188,6 +190,8 @@ grpc_event grpc_completion_queue_pluck(grpc_completion_queue *cc, void *tag,
   grpc_cq_completion *c;
   grpc_cq_completion *prev;
 
+  deadline = gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC);
+
   GRPC_CQ_INTERNAL_REF(cc, "pluck");
   gpr_mu_lock(GRPC_POLLSET_MU(&cc->pollset));
   for (;;) {
diff --git a/src/core/surface/server.c b/src/core/surface/server.c
index f2d6b11bc7..439452aea2 100644
--- a/src/core/surface/server.c
+++ b/src/core/surface/server.c
@@ -980,6 +980,8 @@ void grpc_server_shutdown_and_notify(grpc_server *server,
   channel_broadcaster broadcaster;
   request_killer reqkill;
 
+  GRPC_SERVER_LOG_SHUTDOWN(GPR_INFO, server, cq, tag);
+
   /* lock, and gather up some stuff to do */
   gpr_mu_lock(&server->mu_global);
   grpc_cq_begin_op(cq);
diff --git a/src/core/transport/chttp2/parsing.c b/src/core/transport/chttp2/parsing.c
index aa32f2e44a..904b9afce7 100644
--- a/src/core/transport/chttp2/parsing.c
+++ b/src/core/transport/chttp2/parsing.c
@@ -588,7 +588,7 @@ static void on_header(void *tp, grpc_mdelem *md) {
   GPR_ASSERT(stream_parsing);
 
   GRPC_CHTTP2_IF_TRACING(gpr_log(
-      GPR_INFO, "HTTP:%d:HDR: %s: %s", stream_parsing->id,
+      GPR_INFO, "HTTP:%d:HDR:%s: %s: %s", stream_parsing->id,
       transport_parsing->is_client ? "CLI" : "SVR",
       grpc_mdstr_as_c_string(md->key), grpc_mdstr_as_c_string(md->value)));
 
diff --git a/src/core/transport/chttp2/stream_encoder.c b/src/core/transport/chttp2/stream_encoder.c
index d30059abf8..65b31a5afd 100644
--- a/src/core/transport/chttp2/stream_encoder.c
+++ b/src/core/transport/chttp2/stream_encoder.c
@@ -438,7 +438,7 @@ static void deadline_enc(grpc_chttp2_hpack_compressor *c, gpr_timespec deadline,
   char timeout_str[GRPC_CHTTP2_TIMEOUT_ENCODE_MIN_BUFSIZE];
   grpc_mdelem *mdelem;
   grpc_chttp2_encode_timeout(
-      gpr_time_sub(deadline, gpr_now(GPR_CLOCK_REALTIME)), timeout_str);
+      gpr_time_sub(deadline, gpr_now(deadline.clock_type)), timeout_str);
   mdelem = grpc_mdelem_from_metadata_strings(
       c->mdctx, GRPC_MDSTR_REF(c->timeout_key_str),
       grpc_mdstr_from_string(c->mdctx, timeout_str));
@@ -560,6 +560,7 @@ void grpc_chttp2_encode(grpc_stream_op *ops, size_t ops_count, int eof,
   grpc_mdctx *mdctx = compressor->mdctx;
   grpc_linked_mdelem *l;
   int need_unref = 0;
+  gpr_timespec deadline;
 
   GPR_ASSERT(stream_id != 0);
 
@@ -589,9 +590,9 @@ void grpc_chttp2_encode(grpc_stream_op *ops, size_t ops_count, int eof,
           l->md = hpack_enc(compressor, l->md, &st);
           need_unref |= l->md != NULL;
         }
-        if (gpr_time_cmp(op->data.metadata.deadline,
-                         gpr_inf_future(GPR_CLOCK_REALTIME)) != 0) {
-          deadline_enc(compressor, op->data.metadata.deadline, &st);
+        deadline = op->data.metadata.deadline;
+        if (gpr_time_cmp(deadline, gpr_inf_future(deadline.clock_type)) != 0) {
+          deadline_enc(compressor, deadline, &st);
         }
         curop++;
         break;
diff --git a/src/core/transport/transport_op_string.c b/src/core/transport/transport_op_string.c
index 9d127c5472..10d796fc15 100644
--- a/src/core/transport/transport_op_string.c
+++ b/src/core/transport/transport_op_string.c
@@ -61,7 +61,7 @@ static void put_metadata_list(gpr_strvec *b, grpc_metadata_batch md) {
     if (m != md.list.head) gpr_strvec_add(b, gpr_strdup(", "));
     put_metadata(b, m->md);
   }
-  if (gpr_time_cmp(md.deadline, gpr_inf_future(GPR_CLOCK_REALTIME)) != 0) {
+  if (gpr_time_cmp(md.deadline, gpr_inf_future(md.deadline.clock_type)) != 0) {
     char *tmp;
     gpr_asprintf(&tmp, " deadline=%d.%09d", md.deadline.tv_sec,
                  md.deadline.tv_nsec);
diff --git a/src/cpp/client/channel_arguments.cc b/src/cpp/client/channel_arguments.cc
index 92ac5ea6fd..da6602e7af 100644
--- a/src/cpp/client/channel_arguments.cc
+++ b/src/cpp/client/channel_arguments.cc
@@ -33,11 +33,49 @@
 
 #include <grpc++/channel_arguments.h>
 
+#include <grpc/support/log.h>
+
 #include "src/core/channel/channel_args.h"
 
 namespace grpc {
 
-void ChannelArguments::_Experimental_SetCompressionAlgorithm(
+ChannelArguments::ChannelArguments(const ChannelArguments& other)
+    : strings_(other.strings_) {
+  args_.reserve(other.args_.size());
+  auto list_it_dst = strings_.begin();
+  auto list_it_src = other.strings_.begin();
+  for (auto a = other.args_.begin(); a != other.args_.end(); ++a) {
+    grpc_arg ap;
+    ap.type = a->type;
+    GPR_ASSERT(list_it_src->c_str() == a->key);
+    ap.key = const_cast<char*>(list_it_dst->c_str());
+    ++list_it_src;
+    ++list_it_dst;
+    switch (a->type) {
+      case GRPC_ARG_INTEGER:
+        ap.value.integer = a->value.integer;
+        break;
+      case GRPC_ARG_STRING:
+        GPR_ASSERT(list_it_src->c_str() == a->value.string);
+        ap.value.string = const_cast<char*>(list_it_dst->c_str());
+        ++list_it_src;
+        ++list_it_dst;
+        break;
+      case GRPC_ARG_POINTER:
+        ap.value.pointer = a->value.pointer;
+        ap.value.pointer.p = a->value.pointer.copy(ap.value.pointer.p);
+        break;
+    }
+    args_.push_back(ap);
+  }
+}
+
+void ChannelArguments::Swap(ChannelArguments& other) {
+  args_.swap(other.args_);
+  strings_.swap(other.strings_);
+}
+
+void ChannelArguments::SetCompressionAlgorithm(
     grpc_compression_algorithm algorithm) {
   SetInt(GRPC_COMPRESSION_ALGORITHM_ARG, algorithm);
 }
diff --git a/src/cpp/client/client_context.cc b/src/cpp/client/client_context.cc
index 69216d2030..14ab772e50 100644
--- a/src/cpp/client/client_context.cc
+++ b/src/cpp/client/client_context.cc
@@ -79,7 +79,7 @@ void ClientContext::set_call(grpc_call* call,
   }
 }
 
-void ClientContext::_experimental_set_compression_algorithm(
+void ClientContext::set_compression_algorithm(
     grpc_compression_algorithm algorithm) {
   char* algorithm_name = NULL;
   if (!grpc_compression_algorithm_name(algorithm, &algorithm_name)) {
diff --git a/src/cpp/client/create_channel.cc b/src/cpp/client/create_channel.cc
index 510af2bb00..38eeda0dc0 100644
--- a/src/cpp/client/create_channel.cc
+++ b/src/cpp/client/create_channel.cc
@@ -32,9 +32,11 @@
  */
 
 #include <memory>
+#include <sstream>
 
 #include "src/cpp/client/channel.h"
 #include <grpc++/channel_interface.h>
+#include <grpc++/channel_arguments.h>
 #include <grpc++/create_channel.h>
 
 namespace grpc {
@@ -43,7 +45,12 @@ class ChannelArguments;
 std::shared_ptr<ChannelInterface> CreateChannel(
     const grpc::string& target, const std::shared_ptr<Credentials>& creds,
     const ChannelArguments& args) {
-  return creds ? creds->CreateChannel(target, args)
+  ChannelArguments cp_args = args;
+  std::ostringstream user_agent_prefix;
+  user_agent_prefix << "grpc-c++/" << grpc_version_string();
+  cp_args.SetString(GRPC_ARG_PRIMARY_USER_AGENT_STRING,
+                    user_agent_prefix.str());
+  return creds ? creds->CreateChannel(target, cp_args)
                : std::shared_ptr<ChannelInterface>(
                      new Channel(target, grpc_lame_client_channel_create()));
 }
diff --git a/src/csharp/Grpc.Auth/GoogleCredential.cs b/src/csharp/Grpc.Auth/GoogleCredential.cs
index 8d5e543a21..7edf19ed67 100644
--- a/src/csharp/Grpc.Auth/GoogleCredential.cs
+++ b/src/csharp/Grpc.Auth/GoogleCredential.cs
@@ -35,8 +35,11 @@ using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Security.Cryptography;
+using System.Threading;
+using System.Threading.Tasks;
 
 using Google.Apis.Auth.OAuth2;
+using Google.Apis.Auth.OAuth2.Responses;
 using Newtonsoft.Json.Linq;
 using Org.BouncyCastle.Crypto.Parameters;
 using Org.BouncyCastle.Security;
@@ -100,6 +103,19 @@ namespace Grpc.Auth
             return new GoogleCredential(serviceCredential);
         }
 
+        public Task<bool> RequestAccessTokenAsync(CancellationToken taskCancellationToken)
+        {
+            return credential.RequestAccessTokenAsync(taskCancellationToken);
+        }
+
+        public TokenResponse Token
+        {
+            get
+            {
+                return credential.Token;
+            }
+        }
+
         internal ServiceCredential InternalCredential
         {
             get
diff --git a/src/csharp/Grpc.Core.Tests/ClientServerTest.cs b/src/csharp/Grpc.Core.Tests/ClientServerTest.cs
index e797dd82f2..8ba2c8a9a2 100644
--- a/src/csharp/Grpc.Core.Tests/ClientServerTest.cs
+++ b/src/csharp/Grpc.Core.Tests/ClientServerTest.cs
@@ -33,6 +33,7 @@
 
 using System;
 using System.Diagnostics;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Grpc.Core;
@@ -99,17 +100,17 @@ namespace Grpc.Core.Tests
         [Test]
         public void UnaryCall()
         {
-            var call = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
-            Assert.AreEqual("ABC", Calls.BlockingUnaryCall(call, "ABC", CancellationToken.None));
+            var internalCall = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
+            Assert.AreEqual("ABC", Calls.BlockingUnaryCall(internalCall, "ABC", CancellationToken.None));
         }
 
         [Test]
         public void UnaryCall_ServerHandlerThrows()
         {
-            var call = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
+            var internalCall = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
             try
             {
-                Calls.BlockingUnaryCall(call, "THROW", CancellationToken.None);
+                Calls.BlockingUnaryCall(internalCall, "THROW", CancellationToken.None);
                 Assert.Fail();
             }
             catch (RpcException e)
@@ -119,10 +120,40 @@ namespace Grpc.Core.Tests
         }
 
         [Test]
+        public void UnaryCall_ServerHandlerThrowsRpcException()
+        {
+            var internalCall = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
+            try
+            {
+                Calls.BlockingUnaryCall(internalCall, "THROW_UNAUTHENTICATED", CancellationToken.None);
+                Assert.Fail();
+            }
+            catch (RpcException e)
+            {
+                Assert.AreEqual(StatusCode.Unauthenticated, e.Status.StatusCode);
+            }
+        }
+
+        [Test]
+        public void UnaryCall_ServerHandlerSetsStatus()
+        {
+            var internalCall = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
+            try
+            {
+                Calls.BlockingUnaryCall(internalCall, "SET_UNAUTHENTICATED", CancellationToken.None);
+                Assert.Fail();
+            }
+            catch (RpcException e)
+            {
+                Assert.AreEqual(StatusCode.Unauthenticated, e.Status.StatusCode); 
+            }
+        }
+
+        [Test]
         public void AsyncUnaryCall()
         {
-            var call = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
-            var result = Calls.AsyncUnaryCall(call, "ABC", CancellationToken.None).Result;
+            var internalCall = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
+            var result = Calls.AsyncUnaryCall(internalCall, "ABC", CancellationToken.None).ResponseAsync.Result;
             Assert.AreEqual("ABC", result);
         }
 
@@ -131,10 +162,10 @@ namespace Grpc.Core.Tests
         {
             Task.Run(async () =>
             {
-                var call = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
+                var internalCall = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
                 try
                 {
-                    await Calls.AsyncUnaryCall(call, "THROW", CancellationToken.None);
+                    await Calls.AsyncUnaryCall(internalCall, "THROW", CancellationToken.None);
                     Assert.Fail();
                 }
                 catch (RpcException e)
@@ -149,11 +180,11 @@ namespace Grpc.Core.Tests
         {
             Task.Run(async () => 
             {
-                var call = new Call<string, string>(ServiceName, ConcatAndEchoMethod, channel, Metadata.Empty);
-                var callResult = Calls.AsyncClientStreamingCall(call, CancellationToken.None);
+                var internalCall = new Call<string, string>(ServiceName, ConcatAndEchoMethod, channel, Metadata.Empty);
+                var call = Calls.AsyncClientStreamingCall(internalCall, CancellationToken.None);
 
-                await callResult.RequestStream.WriteAll(new string[] { "A", "B", "C" });
-                Assert.AreEqual("ABC", await callResult.Result);
+                await call.RequestStream.WriteAll(new string[] { "A", "B", "C" });
+                Assert.AreEqual("ABC", await call.ResponseAsync);
             }).Wait();
         }
 
@@ -162,10 +193,10 @@ namespace Grpc.Core.Tests
         {
             Task.Run(async () => 
             {
-                var call = new Call<string, string>(ServiceName, ConcatAndEchoMethod, channel, Metadata.Empty);
+                var internalCall = new Call<string, string>(ServiceName, ConcatAndEchoMethod, channel, Metadata.Empty);
 
                 var cts = new CancellationTokenSource();
-                var callResult = Calls.AsyncClientStreamingCall(call, cts.Token);
+                var call = Calls.AsyncClientStreamingCall(internalCall, cts.Token);
 
                 // TODO(jtattermusch): we need this to ensure call has been initiated once we cancel it.
                 await Task.Delay(1000);
@@ -173,7 +204,7 @@ namespace Grpc.Core.Tests
 
                 try
                 {
-                    await callResult.Result;
+                    await call.ResponseAsync;
                 }
                 catch (RpcException e)
                 {
@@ -183,29 +214,53 @@ namespace Grpc.Core.Tests
         }
 
         [Test]
+        public void AsyncUnaryCall_EchoMetadata()
+        {
+            var headers = new Metadata
+            {
+                new Metadata.Entry("asciiHeader", "abcdefg"),
+                new Metadata.Entry("binaryHeader-bin", new byte[] { 1, 2, 3, 0, 0xff }),
+            };
+            var internalCall = new Call<string, string>(ServiceName, EchoMethod, channel, headers);
+            var call = Calls.AsyncUnaryCall(internalCall, "ABC", CancellationToken.None);
+
+            Assert.AreEqual("ABC", call.ResponseAsync.Result);
+
+            Assert.AreEqual(StatusCode.OK, call.GetStatus().StatusCode);
+
+            var trailers = call.GetTrailers();
+            Assert.AreEqual(2, trailers.Count);
+            Assert.AreEqual(headers[0].Key, trailers[0].Key);
+            Assert.AreEqual(headers[0].Value, trailers[0].Value);
+
+            Assert.AreEqual(headers[1].Key, trailers[1].Key);
+            CollectionAssert.AreEqual(headers[1].ValueBytes, trailers[1].ValueBytes);
+        }
+
+        [Test]
         public void UnaryCall_DisposedChannel()
         {
             channel.Dispose();
 
-            var call = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
-            Assert.Throws(typeof(ObjectDisposedException), () => Calls.BlockingUnaryCall(call, "ABC", CancellationToken.None));
+            var internalCall = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
+            Assert.Throws(typeof(ObjectDisposedException), () => Calls.BlockingUnaryCall(internalCall, "ABC", CancellationToken.None));
         }
 
         [Test]
         public void UnaryCallPerformance()
         {
-            var call = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
+            var internalCall = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
             BenchmarkUtil.RunBenchmark(100, 100,
-                                       () => { Calls.BlockingUnaryCall(call, "ABC", default(CancellationToken)); });
+                                       () => { Calls.BlockingUnaryCall(internalCall, "ABC", default(CancellationToken)); });
         }
             
         [Test]
         public void UnknownMethodHandler()
         {
-            var call = new Call<string, string>(ServiceName, NonexistentMethod, channel, Metadata.Empty);
+            var internalCall = new Call<string, string>(ServiceName, NonexistentMethod, channel, Metadata.Empty);
             try
             {
-                Calls.BlockingUnaryCall(call, "ABC", default(CancellationToken));
+                Calls.BlockingUnaryCall(internalCall, "ABC", default(CancellationToken));
                 Assert.Fail();
             }
             catch (RpcException e)
@@ -214,16 +269,48 @@ namespace Grpc.Core.Tests
             }
         }
 
-        private static async Task<string> EchoHandler(ServerCallContext context, string request)
+        [Test]
+        public void UserAgentStringPresent()
         {
+            var internalCall = new Call<string, string>(ServiceName, EchoMethod, channel, Metadata.Empty);
+            string userAgent = Calls.BlockingUnaryCall(internalCall, "RETURN-USER-AGENT", CancellationToken.None);
+            Assert.IsTrue(userAgent.StartsWith("grpc-csharp/"));
+        }
+
+        private static async Task<string> EchoHandler(string request, ServerCallContext context)
+        {
+            foreach (Metadata.Entry metadataEntry in context.RequestHeaders)
+            {
+                if (metadataEntry.Key != "user-agent")
+                {
+                    context.ResponseTrailers.Add(metadataEntry);
+                }
+            }
+
+            if (request == "RETURN-USER-AGENT")
+            {
+                return context.RequestHeaders.Where(entry => entry.Key == "user-agent").Single().Value;
+            }
+
             if (request == "THROW")
             {
                 throw new Exception("This was thrown on purpose by a test");
             }
+
+            if (request == "THROW_UNAUTHENTICATED")
+            {
+                throw new RpcException(new Status(StatusCode.Unauthenticated, ""));
+            }
+
+            if (request == "SET_UNAUTHENTICATED")
+            {
+                context.Status = new Status(StatusCode.Unauthenticated, "");
+            }
+
             return request;
         }
 
-        private static async Task<string> ConcatAndEchoHandler(ServerCallContext context, IAsyncStreamReader<string> requestStream)
+        private static async Task<string> ConcatAndEchoHandler(IAsyncStreamReader<string> requestStream, ServerCallContext context)
         {
             string result = "";
             await requestStream.ForEach(async (request) =>
diff --git a/src/csharp/Grpc.Core.Tests/Internal/MetadataArraySafeHandleTest.cs b/src/csharp/Grpc.Core.Tests/Internal/MetadataArraySafeHandleTest.cs
index 320423b245..46469113c5 100644
--- a/src/csharp/Grpc.Core.Tests/Internal/MetadataArraySafeHandleTest.cs
+++ b/src/csharp/Grpc.Core.Tests/Internal/MetadataArraySafeHandleTest.cs
@@ -51,12 +51,34 @@ namespace Grpc.Core.Internal.Tests
         [Test]
         public void CreateAndDestroy()
         {
-            var metadata = new Metadata {
+            var metadata = new Metadata
+            {
                 new Metadata.Entry("host", "somehost"),
                 new Metadata.Entry("header2", "header value"),
             };
             var nativeMetadata = MetadataArraySafeHandle.Create(metadata);
             nativeMetadata.Dispose();
         }
+
+        [Test]
+        public void ReadMetadataFromPtrUnsafe()
+        {
+            var metadata = new Metadata
+            {
+                new Metadata.Entry("host", "somehost"),
+                new Metadata.Entry("header2", "header value"),
+            };
+            var nativeMetadata = MetadataArraySafeHandle.Create(metadata);
+
+            var copy = MetadataArraySafeHandle.ReadMetadataFromPtrUnsafe(nativeMetadata.Handle);
+            Assert.AreEqual(2, copy.Count);
+
+            Assert.AreEqual("host", copy[0].Key);
+            Assert.AreEqual("somehost", copy[0].Value);
+            Assert.AreEqual("header2", copy[1].Key);
+            Assert.AreEqual("header value", copy[1].Value);
+
+            nativeMetadata.Dispose();
+        }
     }
 }
diff --git a/src/csharp/Grpc.Core.Tests/TimespecTest.cs b/src/csharp/Grpc.Core.Tests/TimespecTest.cs
index 5831121add..a34b407a01 100644
--- a/src/csharp/Grpc.Core.Tests/TimespecTest.cs
+++ b/src/csharp/Grpc.Core.Tests/TimespecTest.cs
@@ -59,6 +59,19 @@ namespace Grpc.Core.Internal.Tests
         }
 
         [Test]
+        public void ToDateTime()
+        {
+            Assert.AreEqual(new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc),
+                new Timespec(IntPtr.Zero, 0).ToDateTime());
+
+            Assert.AreEqual(new DateTime(1970, 1, 1, 0, 0, 10, DateTimeKind.Utc).AddTicks(50),
+                new Timespec(new IntPtr(10), 5000).ToDateTime());
+
+            Assert.AreEqual(new DateTime(2015, 7, 21, 4, 21, 48, DateTimeKind.Utc),
+                new Timespec(new IntPtr(1437452508), 0).ToDateTime());
+        }
+
+        [Test]
         public void Add()
         {
             var t = new Timespec { tv_sec = new IntPtr(12345), tv_nsec = 123456789 };
diff --git a/src/csharp/Grpc.Core/AsyncClientStreamingCall.cs b/src/csharp/Grpc.Core/AsyncClientStreamingCall.cs
index d66b0d4974..bf020cd627 100644
--- a/src/csharp/Grpc.Core/AsyncClientStreamingCall.cs
+++ b/src/csharp/Grpc.Core/AsyncClientStreamingCall.cs
@@ -43,24 +43,28 @@ namespace Grpc.Core
     public sealed class AsyncClientStreamingCall<TRequest, TResponse> : IDisposable
     {
         readonly IClientStreamWriter<TRequest> requestStream;
-        readonly Task<TResponse> result;
+        readonly Task<TResponse> responseAsync;
+        readonly Func<Status> getStatusFunc;
+        readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncClientStreamingCall(IClientStreamWriter<TRequest> requestStream, Task<TResponse> result, Action disposeAction)
+        public AsyncClientStreamingCall(IClientStreamWriter<TRequest> requestStream, Task<TResponse> responseAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.requestStream = requestStream;
-            this.result = result;
+            this.responseAsync = responseAsync;
+            this.getStatusFunc = getStatusFunc;
+            this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
         }
 
         /// <summary>
         /// Asynchronous call result.
         /// </summary>
-        public Task<TResponse> Result
+        public Task<TResponse> ResponseAsync
         {
             get
             {
-                return this.result;
+                return this.responseAsync;
             }
         }
 
@@ -81,11 +85,11 @@ namespace Grpc.Core
         /// <returns></returns>
         public TaskAwaiter<TResponse> GetAwaiter()
         {
-            return result.GetAwaiter();
+            return responseAsync.GetAwaiter();
         }
 
         /// <summary>
-        /// Provides means to provide after the call.
+        /// Provides means to cleanup after the call.
         /// If the call has already finished normally (request stream has been completed and call result has been received), doesn't do anything.
         /// Otherwise, requests cancellation of the call which should terminate all pending async operations associated with the call.
         /// As a result, all resources being used by the call should be released eventually.
diff --git a/src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs b/src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs
index 4c0d5936ac..0979de606f 100644
--- a/src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs
+++ b/src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs
@@ -44,12 +44,16 @@ namespace Grpc.Core
     {
         readonly IClientStreamWriter<TRequest> requestStream;
         readonly IAsyncStreamReader<TResponse> responseStream;
+        readonly Func<Status> getStatusFunc;
+        readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncDuplexStreamingCall(IClientStreamWriter<TRequest> requestStream, IAsyncStreamReader<TResponse> responseStream, Action disposeAction)
+        public AsyncDuplexStreamingCall(IClientStreamWriter<TRequest> requestStream, IAsyncStreamReader<TResponse> responseStream, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.requestStream = requestStream;
             this.responseStream = responseStream;
+            this.getStatusFunc = getStatusFunc;
+            this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
         }
 
@@ -76,6 +80,24 @@ namespace Grpc.Core
         }
 
         /// <summary>
+        /// Gets the call status if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Status GetStatus()
+        {
+            return getStatusFunc();
+        }
+
+        /// <summary>
+        /// Gets the call trailing metadata if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Metadata GetTrailers()
+        {
+            return getTrailersFunc();
+        }
+
+        /// <summary>
         /// Provides means to cleanup after the call.
         /// If the call has already finished normally (request stream has been completed and response stream has been fully read), doesn't do anything.
         /// Otherwise, requests cancellation of the call which should terminate all pending async operations associated with the call.
diff --git a/src/csharp/Grpc.Core/AsyncServerStreamingCall.cs b/src/csharp/Grpc.Core/AsyncServerStreamingCall.cs
index 7a479b9a23..380efcdb0e 100644
--- a/src/csharp/Grpc.Core/AsyncServerStreamingCall.cs
+++ b/src/csharp/Grpc.Core/AsyncServerStreamingCall.cs
@@ -43,11 +43,15 @@ namespace Grpc.Core
     public sealed class AsyncServerStreamingCall<TResponse> : IDisposable
     {
         readonly IAsyncStreamReader<TResponse> responseStream;
+        readonly Func<Status> getStatusFunc;
+        readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncServerStreamingCall(IAsyncStreamReader<TResponse> responseStream, Action disposeAction)
+        public AsyncServerStreamingCall(IAsyncStreamReader<TResponse> responseStream, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.responseStream = responseStream;
+            this.getStatusFunc = getStatusFunc;
+            this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
         }
 
@@ -63,6 +67,24 @@ namespace Grpc.Core
         }
 
         /// <summary>
+        /// Gets the call status if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Status GetStatus()
+        {
+            return getStatusFunc();
+        }
+
+        /// <summary>
+        /// Gets the call trailing metadata if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Metadata GetTrailers()
+        {
+            return getTrailersFunc();
+        }
+
+        /// <summary>
         /// Provides means to cleanup after the call.
         /// If the call has already finished normally (response stream has been fully read), doesn't do anything.
         /// Otherwise, requests cancellation of the call which should terminate all pending async operations associated with the call.
diff --git a/src/csharp/Grpc.Core/AsyncUnaryCall.cs b/src/csharp/Grpc.Core/AsyncUnaryCall.cs
new file mode 100644
index 0000000000..224e343916
--- /dev/null
+++ b/src/csharp/Grpc.Core/AsyncUnaryCall.cs
@@ -0,0 +1,106 @@
+#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;
+using System.Runtime.CompilerServices;
+using System.Threading.Tasks;
+
+namespace Grpc.Core
+{
+    /// <summary>
+    /// Return type for single request - single response call.
+    /// </summary>
+    public sealed class AsyncUnaryCall<TResponse> : IDisposable
+    {
+        readonly Task<TResponse> responseAsync;
+        readonly Func<Status> getStatusFunc;
+        readonly Func<Metadata> getTrailersFunc;
+        readonly Action disposeAction;
+
+        public AsyncUnaryCall(Task<TResponse> responseAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
+        {
+            this.responseAsync = responseAsync;
+            this.getStatusFunc = getStatusFunc;
+            this.getTrailersFunc = getTrailersFunc;
+            this.disposeAction = disposeAction;
+        }
+
+        /// <summary>
+        /// Asynchronous call result.
+        /// </summary>
+        public Task<TResponse> ResponseAsync
+        {
+            get
+            {
+                return this.responseAsync;
+            }
+        }
+
+        /// <summary>
+        /// Allows awaiting this object directly.
+        /// </summary>
+        public TaskAwaiter<TResponse> GetAwaiter()
+        {
+            return responseAsync.GetAwaiter();
+        }
+
+        /// <summary>
+        /// Gets the call status if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Status GetStatus()
+        {
+            return getStatusFunc();
+        }
+
+        /// <summary>
+        /// Gets the call trailing metadata if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Metadata GetTrailers()
+        {
+            return getTrailersFunc();
+        }
+
+        /// <summary>
+        /// Provides means to cleanup after the call.
+        /// If the call has already finished normally (request stream has been completed and call result has been received), doesn't do anything.
+        /// Otherwise, requests cancellation of the call which should terminate all pending async operations associated with the call.
+        /// As a result, all resources being used by the call should be released eventually.
+        /// </summary>
+        public void Dispose()
+        {
+            disposeAction.Invoke();
+        }
+    }
+}
diff --git a/src/csharp/Grpc.Core/Calls.cs b/src/csharp/Grpc.Core/Calls.cs
index 9e95182c72..359fe53741 100644
--- a/src/csharp/Grpc.Core/Calls.cs
+++ b/src/csharp/Grpc.Core/Calls.cs
@@ -53,7 +53,7 @@ namespace Grpc.Core
             return asyncCall.UnaryCall(call.Channel, call.Name, req, call.Headers);
         }
 
-        public static async Task<TResponse> AsyncUnaryCall<TRequest, TResponse>(Call<TRequest, TResponse> call, TRequest req, CancellationToken token)
+        public static AsyncUnaryCall<TResponse> AsyncUnaryCall<TRequest, TResponse>(Call<TRequest, TResponse> call, TRequest req, CancellationToken token)
             where TRequest : class
             where TResponse : class
         {
@@ -61,7 +61,7 @@ namespace Grpc.Core
             asyncCall.Initialize(call.Channel, call.Channel.CompletionQueue, call.Name);
             var asyncResult = asyncCall.UnaryCallAsync(req, call.Headers);
             RegisterCancellationCallback(asyncCall, token);
-            return await asyncResult;
+            return new AsyncUnaryCall<TResponse>(asyncResult, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
 
         public static AsyncServerStreamingCall<TResponse> AsyncServerStreamingCall<TRequest, TResponse>(Call<TRequest, TResponse> call, TRequest req, CancellationToken token)
@@ -73,7 +73,7 @@ namespace Grpc.Core
             asyncCall.StartServerStreamingCall(req, call.Headers);
             RegisterCancellationCallback(asyncCall, token);
             var responseStream = new ClientResponseStream<TRequest, TResponse>(asyncCall);
-            return new AsyncServerStreamingCall<TResponse>(responseStream, asyncCall.Cancel);
+            return new AsyncServerStreamingCall<TResponse>(responseStream, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
 
         public static AsyncClientStreamingCall<TRequest, TResponse> AsyncClientStreamingCall<TRequest, TResponse>(Call<TRequest, TResponse> call, CancellationToken token)
@@ -85,7 +85,7 @@ namespace Grpc.Core
             var resultTask = asyncCall.ClientStreamingCallAsync(call.Headers);
             RegisterCancellationCallback(asyncCall, token);
             var requestStream = new ClientRequestStream<TRequest, TResponse>(asyncCall);
-            return new AsyncClientStreamingCall<TRequest, TResponse>(requestStream, resultTask, asyncCall.Cancel);
+            return new AsyncClientStreamingCall<TRequest, TResponse>(requestStream, resultTask, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
 
         public static AsyncDuplexStreamingCall<TRequest, TResponse> AsyncDuplexStreamingCall<TRequest, TResponse>(Call<TRequest, TResponse> call, CancellationToken token)
@@ -98,7 +98,7 @@ namespace Grpc.Core
             RegisterCancellationCallback(asyncCall, token);
             var requestStream = new ClientRequestStream<TRequest, TResponse>(asyncCall);
             var responseStream = new ClientResponseStream<TRequest, TResponse>(asyncCall);
-            return new AsyncDuplexStreamingCall<TRequest, TResponse>(requestStream, responseStream, asyncCall.Cancel);
+            return new AsyncDuplexStreamingCall<TRequest, TResponse>(requestStream, responseStream, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
 
         private static void RegisterCancellationCallback<TRequest, TResponse>(AsyncCall<TRequest, TResponse> asyncCall, CancellationToken token)
diff --git a/src/csharp/Grpc.Core/Channel.cs b/src/csharp/Grpc.Core/Channel.cs
index 5baf260003..e5c6abd2cb 100644
--- a/src/csharp/Grpc.Core/Channel.cs
+++ b/src/csharp/Grpc.Core/Channel.cs
@@ -28,11 +28,14 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #endregion
+
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Runtime.InteropServices;
 using System.Threading;
 using System.Threading.Tasks;
+
 using Grpc.Core.Internal;
 
 namespace Grpc.Core
@@ -44,6 +47,7 @@ namespace Grpc.Core
     {
         readonly GrpcEnvironment environment;
         readonly ChannelSafeHandle handle;
+        readonly List<ChannelOption> options;
         readonly string target;
         bool disposed;
 
@@ -57,7 +61,10 @@ namespace Grpc.Core
         public Channel(string host, Credentials credentials = null, IEnumerable<ChannelOption> options = null)
         {
             this.environment = GrpcEnvironment.GetInstance();
-            using (ChannelArgsSafeHandle nativeChannelArgs = ChannelOptions.CreateChannelArgs(options))
+            this.options = options != null ? new List<ChannelOption>(options) : new List<ChannelOption>();
+
+            EnsureUserAgentChannelOption(this.options);
+            using (ChannelArgsSafeHandle nativeChannelArgs = ChannelOptions.CreateChannelArgs(this.options))
             {
                 if (credentials != null)
                 {
@@ -71,7 +78,7 @@ namespace Grpc.Core
                     this.handle = ChannelSafeHandle.Create(host, nativeChannelArgs);
                 }
             }
-            this.target = GetOverridenTarget(host, options);
+            this.target = GetOverridenTarget(host, this.options);
         }
 
         /// <summary>
@@ -141,6 +148,20 @@ namespace Grpc.Core
             }
         }
 
+        private static void EnsureUserAgentChannelOption(List<ChannelOption> options)
+        {
+            if (!options.Any((option) => option.Name == ChannelOptions.PrimaryUserAgentString))
+            {
+                options.Add(new ChannelOption(ChannelOptions.PrimaryUserAgentString, GetUserAgentString()));
+            }
+        }
+
+        private static string GetUserAgentString()
+        {
+            // TODO(jtattermusch): it would be useful to also provide .NET/mono version.
+            return string.Format("grpc-csharp/{0}", VersionInfo.CurrentVersion);
+        }
+
         /// <summary>
         /// Look for SslTargetNameOverride option and return its value instead of originalTarget
         /// if found.
diff --git a/src/csharp/Grpc.Core/ChannelOptions.cs b/src/csharp/Grpc.Core/ChannelOptions.cs
index bc23bb59b1..9fe03d2805 100644
--- a/src/csharp/Grpc.Core/ChannelOptions.cs
+++ b/src/csharp/Grpc.Core/ChannelOptions.cs
@@ -115,41 +115,49 @@ namespace Grpc.Core
         }
     }
 
+    /// <summary>
+    /// Defines names of supported channel options.
+    /// </summary>
     public static class ChannelOptions
     {
-        // Override SSL target check. Only to be used for testing.
+        /// <summary>Override SSL target check. Only to be used for testing.</summary>
         public const string SslTargetNameOverride = "grpc.ssl_target_name_override";
 
-        // Enable census for tracing and stats collection
+        /// <summary>Enable census for tracing and stats collection</summary>
         public const string Census = "grpc.census";
 
-        // Maximum number of concurrent incoming streams to allow on a http2 connection
+        /// <summary>Maximum number of concurrent incoming streams to allow on a http2 connection</summary>
         public const string MaxConcurrentStreams = "grpc.max_concurrent_streams";
 
-        // Maximum message length that the channel can receive
+        /// <summary>Maximum message length that the channel can receive</summary>
         public const string MaxMessageLength = "grpc.max_message_length";
 
-        // Initial sequence number for http2 transports
+        /// <summary>Initial sequence number for http2 transports</summary>
         public const string Http2InitialSequenceNumber = "grpc.http2.initial_sequence_number";
 
+        /// <summary>Primary user agent: goes at the start of the user-agent metadata</summary>
+        public const string PrimaryUserAgentString = "grpc.primary_user_agent";
+
+        /// <summary> Secondary user agent: goes at the end of the user-agent metadata</summary>
+        public const string SecondaryUserAgentString = "grpc.secondary_user_agent";
+
         /// <summary>
         /// Creates native object for a collection of channel options.
         /// </summary>
         /// <returns>The native channel arguments.</returns>
-        internal static ChannelArgsSafeHandle CreateChannelArgs(IEnumerable<ChannelOption> options)
+        internal static ChannelArgsSafeHandle CreateChannelArgs(List<ChannelOption> options)
         {
-            if (options == null)
+            if (options == null || options.Count == 0)
             {
                 return ChannelArgsSafeHandle.CreateNull();
             }
-            var optionList = new List<ChannelOption>(options);  // It's better to do defensive copy
             ChannelArgsSafeHandle nativeArgs = null;
             try
             {
-                nativeArgs = ChannelArgsSafeHandle.Create(optionList.Count);
-                for (int i = 0; i < optionList.Count; i++)
+                nativeArgs = ChannelArgsSafeHandle.Create(options.Count);
+                for (int i = 0; i < options.Count; i++)
                 {
-                    var option = optionList[i];
+                    var option = options[i];
                     if (option.Type == ChannelOption.OptionType.Integer)
                     {
                         nativeArgs.SetInteger(i, option.Name, option.IntValue);
diff --git a/src/csharp/Grpc.Core/Grpc.Core.csproj b/src/csharp/Grpc.Core/Grpc.Core.csproj
index a227fe5477..fd68b91851 100644
--- a/src/csharp/Grpc.Core/Grpc.Core.csproj
+++ b/src/csharp/Grpc.Core/Grpc.Core.csproj
@@ -33,13 +33,12 @@
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
-    <Reference Include="System.Collections.Immutable, Version=1.1.36.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
-      <HintPath>..\packages\System.Collections.Immutable.1.1.36\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
-    </Reference>
     <Reference Include="System.Interactive.Async">
       <HintPath>..\packages\Ix-Async.1.2.3\lib\net45\System.Interactive.Async.dll</HintPath>
     </Reference>
+    <Reference Include="System.Collections.Immutable">
+      <HintPath>..\packages\System.Collections.Immutable.1.1.36\lib\portable-net45+win8+wp8+wpa81\System.Collections.Immutable.dll</HintPath>
+    </Reference>
   </ItemGroup>
   <ItemGroup>
     <Compile Include="AsyncDuplexStreamingCall.cs" />
@@ -102,6 +101,8 @@
     <Compile Include="Internal\CompletionRegistry.cs" />
     <Compile Include="Internal\BatchContextSafeHandle.cs" />
     <Compile Include="ChannelOptions.cs" />
+    <Compile Include="AsyncUnaryCall.cs" />
+    <Compile Include="VersionInfo.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="Grpc.Core.nuspec" />
diff --git a/src/csharp/Grpc.Core/Internal/AsyncCall.cs b/src/csharp/Grpc.Core/Internal/AsyncCall.cs
index 24b75d1668..f983dbb759 100644
--- a/src/csharp/Grpc.Core/Internal/AsyncCall.cs
+++ b/src/csharp/Grpc.Core/Internal/AsyncCall.cs
@@ -52,8 +52,8 @@ namespace Grpc.Core.Internal
         // Completion of a pending unary response if not null.
         TaskCompletionSource<TResponse> unaryResponseTcs;
 
-        // Set after status is received. Only used for streaming response calls.
-        Status? finishedStatus;
+        // Set after status is received. Used for both unary and streaming response calls.
+        ClientSideStatus? finishedStatus;
 
         bool readObserverCompleted;  // True if readObserver has already been completed.
 
@@ -249,6 +249,32 @@ namespace Grpc.Core.Internal
         }
 
         /// <summary>
+        /// Gets the resulting status if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Status GetStatus()
+        {
+            lock (myLock)
+            {
+                Preconditions.CheckState(finishedStatus.HasValue, "Status can only be accessed once the call has finished.");
+                return finishedStatus.Value.Status;
+            }
+        }
+
+        /// <summary>
+        /// Gets the trailing metadata if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Metadata GetTrailers()
+        {
+            lock (myLock)
+            {
+                Preconditions.CheckState(finishedStatus.HasValue, "Trailers can only be accessed once the call has finished.");
+                return finishedStatus.Value.Trailers;
+            }
+        }
+
+        /// <summary>
         /// On client-side, we only fire readCompletionDelegate once all messages have been read 
         /// and status has been received.
         /// </summary>
@@ -265,7 +291,7 @@ namespace Grpc.Core.Internal
 
                 if (shouldComplete)
                 {
-                    var status = finishedStatus.Value;
+                    var status = finishedStatus.Value.Status;
                     if (status.StatusCode != StatusCode.OK)
                     {
                         FireCompletion(completionDelegate, default(TResponse), new RpcException(status));
@@ -288,9 +314,13 @@ namespace Grpc.Core.Internal
         /// </summary>
         private void HandleUnaryResponse(bool success, BatchContextSafeHandle ctx)
         {
+            var fullStatus = ctx.GetReceivedStatusOnClient();
+
             lock (myLock)
             {
                 finished = true;
+                finishedStatus = fullStatus;
+
                 halfclosed = true;
 
                 ReleaseResourcesIfPossible();
@@ -302,7 +332,8 @@ namespace Grpc.Core.Internal
                 return;
             }
 
-            var status = ctx.GetReceivedStatus();
+            var status = fullStatus.Status;
+
             if (status.StatusCode != StatusCode.OK)
             {
                 unaryResponseTcs.SetException(new RpcException(status));
@@ -321,13 +352,13 @@ namespace Grpc.Core.Internal
         /// </summary>
         private void HandleFinished(bool success, BatchContextSafeHandle ctx)
         {
-            var status = ctx.GetReceivedStatus();
+            var fullStatus = ctx.GetReceivedStatusOnClient();
 
             AsyncCompletionDelegate<TResponse> origReadCompletionDelegate = null;
             lock (myLock)
             {
                 finished = true;
-                finishedStatus = status;
+                finishedStatus = fullStatus;
 
                 origReadCompletionDelegate = readCompletionDelegate;
 
diff --git a/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs b/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs
index 309067ea9d..f809f4a84c 100644
--- a/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs
+++ b/src/csharp/Grpc.Core/Internal/AsyncCallServer.cs
@@ -101,14 +101,17 @@ namespace Grpc.Core.Internal
         /// Only one pending send action is allowed at any given time.
         /// completionDelegate is called when the operation finishes.
         /// </summary>
-        public void StartSendStatusFromServer(Status status, AsyncCompletionDelegate<object> completionDelegate)
+        public void StartSendStatusFromServer(Status status, Metadata trailers, AsyncCompletionDelegate<object> completionDelegate)
         {
             lock (myLock)
             {
                 Preconditions.CheckNotNull(completionDelegate, "Completion delegate cannot be null");
                 CheckSendingAllowed();
 
-                call.StartSendStatusFromServer(status, HandleHalfclosed);
+                using (var metadataArray = MetadataArraySafeHandle.Create(trailers))
+                {
+                    call.StartSendStatusFromServer(status, HandleHalfclosed, metadataArray);
+                }
                 halfcloseRequested = true;
                 readingDone = true;
                 sendCompletionDelegate = completionDelegate;
diff --git a/src/csharp/Grpc.Core/Internal/BatchContextSafeHandle.cs b/src/csharp/Grpc.Core/Internal/BatchContextSafeHandle.cs
index 861cbbe4c6..6a2add54db 100644
--- a/src/csharp/Grpc.Core/Internal/BatchContextSafeHandle.cs
+++ b/src/csharp/Grpc.Core/Internal/BatchContextSafeHandle.cs
@@ -38,7 +38,6 @@ using Grpc.Core;
 namespace Grpc.Core.Internal
 {
     /// <summary>
-    /// Not owned version of 
     /// grpcsharp_batch_context
     /// </summary>
     internal class BatchContextSafeHandle : SafeHandleZeroIsInvalid
@@ -47,6 +46,9 @@ namespace Grpc.Core.Internal
         static extern BatchContextSafeHandle grpcsharp_batch_context_create();
 
         [DllImport("grpc_csharp_ext.dll")]
+        static extern IntPtr grpcsharp_batch_context_recv_initial_metadata(BatchContextSafeHandle ctx);
+
+        [DllImport("grpc_csharp_ext.dll")]
         static extern IntPtr grpcsharp_batch_context_recv_message_length(BatchContextSafeHandle ctx);
 
         [DllImport("grpc_csharp_ext.dll")]
@@ -59,12 +61,24 @@ namespace Grpc.Core.Internal
         static extern IntPtr grpcsharp_batch_context_recv_status_on_client_details(BatchContextSafeHandle ctx);  // returns const char*
 
         [DllImport("grpc_csharp_ext.dll")]
+        static extern IntPtr grpcsharp_batch_context_recv_status_on_client_trailing_metadata(BatchContextSafeHandle ctx);
+
+        [DllImport("grpc_csharp_ext.dll")]
         static extern CallSafeHandle grpcsharp_batch_context_server_rpc_new_call(BatchContextSafeHandle ctx);
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern IntPtr grpcsharp_batch_context_server_rpc_new_method(BatchContextSafeHandle ctx);  // returns const char*
 
         [DllImport("grpc_csharp_ext.dll")]
+        static extern IntPtr grpcsharp_batch_context_server_rpc_new_host(BatchContextSafeHandle ctx);  // returns const char*
+
+        [DllImport("grpc_csharp_ext.dll")]
+        static extern Timespec grpcsharp_batch_context_server_rpc_new_deadline(BatchContextSafeHandle ctx);
+
+        [DllImport("grpc_csharp_ext.dll")]
+        static extern IntPtr grpcsharp_batch_context_server_rpc_new_request_metadata(BatchContextSafeHandle ctx);
+
+        [DllImport("grpc_csharp_ext.dll")]
         static extern int grpcsharp_batch_context_recv_close_on_server_cancelled(BatchContextSafeHandle ctx);
 
         [DllImport("grpc_csharp_ext.dll")]
@@ -87,13 +101,26 @@ namespace Grpc.Core.Internal
             }
         }
 
-        public Status GetReceivedStatus()
+        // Gets data of recv_initial_metadata completion.
+        public Metadata GetReceivedInitialMetadata()
+        {
+            IntPtr metadataArrayPtr = grpcsharp_batch_context_recv_initial_metadata(this);
+            return MetadataArraySafeHandle.ReadMetadataFromPtrUnsafe(metadataArrayPtr);
+        }
+            
+        // Gets data of recv_status_on_client completion.
+        public ClientSideStatus GetReceivedStatusOnClient()
         {
-            // TODO: can the native method return string directly?
             string details = Marshal.PtrToStringAnsi(grpcsharp_batch_context_recv_status_on_client_details(this));
-            return new Status(grpcsharp_batch_context_recv_status_on_client_status(this), details);
+            var status = new Status(grpcsharp_batch_context_recv_status_on_client_status(this), details);
+
+            IntPtr metadataArrayPtr = grpcsharp_batch_context_recv_status_on_client_trailing_metadata(this);
+            var metadata = MetadataArraySafeHandle.ReadMetadataFromPtrUnsafe(metadataArrayPtr);
+
+            return new ClientSideStatus(status, metadata);
         }
 
+        // Gets data of recv_message completion.
         public byte[] GetReceivedMessage()
         {
             IntPtr len = grpcsharp_batch_context_recv_message_length(this);
@@ -106,16 +133,22 @@ namespace Grpc.Core.Internal
             return data;
         }
 
-        public CallSafeHandle GetServerRpcNewCall()
+        // Gets data of server_rpc_new completion.
+        public ServerRpcNew GetServerRpcNew()
         {
-            return grpcsharp_batch_context_server_rpc_new_call(this);
-        }
+            var call = grpcsharp_batch_context_server_rpc_new_call(this);
 
-        public string GetServerRpcNewMethod()
-        {
-            return Marshal.PtrToStringAnsi(grpcsharp_batch_context_server_rpc_new_method(this));
+            var method = Marshal.PtrToStringAnsi(grpcsharp_batch_context_server_rpc_new_method(this));
+            var host = Marshal.PtrToStringAnsi(grpcsharp_batch_context_server_rpc_new_host(this));
+            var deadline = grpcsharp_batch_context_server_rpc_new_deadline(this);
+
+            IntPtr metadataArrayPtr = grpcsharp_batch_context_server_rpc_new_request_metadata(this);
+            var metadata = MetadataArraySafeHandle.ReadMetadataFromPtrUnsafe(metadataArrayPtr);
+
+            return new ServerRpcNew(call, method, host, deadline, metadata);
         }
 
+        // Gets data of receive_close_on_server completion.
         public bool GetReceivedCloseOnServerCancelled()
         {
             return grpcsharp_batch_context_recv_close_on_server_cancelled(this) != 0;
@@ -127,4 +160,97 @@ namespace Grpc.Core.Internal
             return true;
         }
     }
+
+    /// <summary>
+    /// Status + metadata received on client side when call finishes.
+    /// (when receive_status_on_client operation finishes).
+    /// </summary>
+    internal struct ClientSideStatus
+    {
+        readonly Status status;
+        readonly Metadata trailers;
+
+        public ClientSideStatus(Status status, Metadata trailers)
+        {
+            this.status = status;
+            this.trailers = trailers;
+        }
+
+        public Status Status
+        {
+            get
+            {
+                return this.status;
+            }    
+        }
+
+        public Metadata Trailers
+        {
+            get
+            {
+                return this.trailers;
+            }
+        }
+    }
+
+    /// <summary>
+    /// Details of a newly received RPC.
+    /// </summary>
+    internal struct ServerRpcNew
+    {
+        readonly CallSafeHandle call;
+        readonly string method;
+        readonly string host;
+        readonly Timespec deadline;
+        readonly Metadata requestMetadata;
+
+        public ServerRpcNew(CallSafeHandle call, string method, string host, Timespec deadline, Metadata requestMetadata)
+        {
+            this.call = call;
+            this.method = method;
+            this.host = host;
+            this.deadline = deadline;
+            this.requestMetadata = requestMetadata;
+        }
+
+        public CallSafeHandle Call
+        {
+            get
+            {
+                return this.call;
+            }
+        }
+
+        public string Method
+        {
+            get
+            {
+                return this.method;
+            }
+        }
+
+        public string Host
+        {
+            get
+            {
+                return this.host;
+            }
+        }
+
+        public Timespec Deadline
+        {
+            get
+            {
+                return this.deadline;
+            }
+        }
+
+        public Metadata RequestMetadata
+        {
+            get
+            {
+                return this.requestMetadata;
+            }
+        }
+    }
 }
\ No newline at end of file
diff --git a/src/csharp/Grpc.Core/Internal/CallSafeHandle.cs b/src/csharp/Grpc.Core/Internal/CallSafeHandle.cs
index 3b246ac01b..19dbb83f24 100644
--- a/src/csharp/Grpc.Core/Internal/CallSafeHandle.cs
+++ b/src/csharp/Grpc.Core/Internal/CallSafeHandle.cs
@@ -81,7 +81,7 @@ namespace Grpc.Core.Internal
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern GRPCCallError grpcsharp_call_send_status_from_server(CallSafeHandle call, 
-            BatchContextSafeHandle ctx, StatusCode statusCode, string statusMessage);
+            BatchContextSafeHandle ctx, StatusCode statusCode, string statusMessage, MetadataArraySafeHandle metadataArray);
 
         [DllImport("grpc_csharp_ext.dll")]
         static extern GRPCCallError grpcsharp_call_recv_message(CallSafeHandle call,
@@ -159,11 +159,11 @@ namespace Grpc.Core.Internal
             grpcsharp_call_send_close_from_client(this, ctx).CheckOk();
         }
 
-        public void StartSendStatusFromServer(Status status, BatchCompletionDelegate callback)
+        public void StartSendStatusFromServer(Status status, BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
         {
             var ctx = BatchContextSafeHandle.Create();
             completionRegistry.RegisterBatchCompletion(ctx, callback);
-            grpcsharp_call_send_status_from_server(this, ctx, status.StatusCode, status.Detail).CheckOk();
+            grpcsharp_call_send_status_from_server(this, ctx, status.StatusCode, status.Detail, metadataArray).CheckOk();
         }
 
         public void StartReceiveMessage(BatchCompletionDelegate callback)
diff --git a/src/csharp/Grpc.Core/Internal/MetadataArraySafeHandle.cs b/src/csharp/Grpc.Core/Internal/MetadataArraySafeHandle.cs
index 80aa7f5603..427c16fac6 100644
--- a/src/csharp/Grpc.Core/Internal/MetadataArraySafeHandle.cs
+++ b/src/csharp/Grpc.Core/Internal/MetadataArraySafeHandle.cs
@@ -46,12 +46,24 @@ namespace Grpc.Core.Internal
         static extern void grpcsharp_metadata_array_add(MetadataArraySafeHandle array, string key, byte[] value, UIntPtr valueLength);
 
         [DllImport("grpc_csharp_ext.dll")]
+        static extern UIntPtr grpcsharp_metadata_array_count(IntPtr metadataArray);
+
+        [DllImport("grpc_csharp_ext.dll")]
+        static extern IntPtr grpcsharp_metadata_array_get_key(IntPtr metadataArray, UIntPtr index);
+
+        [DllImport("grpc_csharp_ext.dll")]
+        static extern IntPtr grpcsharp_metadata_array_get_value(IntPtr metadataArray, UIntPtr index);
+
+        [DllImport("grpc_csharp_ext.dll")]
+        static extern UIntPtr grpcsharp_metadata_array_get_value_length(IntPtr metadataArray, UIntPtr index);
+
+        [DllImport("grpc_csharp_ext.dll")]
         static extern void grpcsharp_metadata_array_destroy_full(IntPtr array);
 
         private MetadataArraySafeHandle()
         {
         }
-
+            
         public static MetadataArraySafeHandle Create(Metadata metadata)
         {
             // TODO(jtattermusch): we might wanna check that the metadata is readonly 
@@ -63,6 +75,38 @@ namespace Grpc.Core.Internal
             return metadataArray;
         }
 
+        /// <summary>
+        /// Reads metadata from pointer to grpc_metadata_array
+        /// </summary>
+        public static Metadata ReadMetadataFromPtrUnsafe(IntPtr metadataArray)
+        {
+            if (metadataArray == IntPtr.Zero)
+            {
+                return null;
+            }
+
+            ulong count = grpcsharp_metadata_array_count(metadataArray).ToUInt64();
+
+            var metadata = new Metadata();
+            for (ulong i = 0; i < count; i++)
+            {
+                var index = new UIntPtr(i);
+                string key = Marshal.PtrToStringAnsi(grpcsharp_metadata_array_get_key(metadataArray, index));
+                var bytes = new byte[grpcsharp_metadata_array_get_value_length(metadataArray, index).ToUInt64()];
+                Marshal.Copy(grpcsharp_metadata_array_get_value(metadataArray, index), bytes, 0, bytes.Length);
+                metadata.Add(new Metadata.Entry(key, bytes));
+            }
+            return metadata;
+        }
+
+        internal IntPtr Handle
+        {
+            get
+            {
+                return handle;
+            }
+        }
+
         protected override bool ReleaseHandle()
         {
             grpcsharp_metadata_array_destroy_full(handle);
diff --git a/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs b/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
index 594e46b159..3680b1e791 100644
--- a/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
+++ b/src/csharp/Grpc.Core/Internal/ServerCallHandler.cs
@@ -34,6 +34,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading;
 using System.Threading.Tasks;
 using Grpc.Core.Internal;
 using Grpc.Core.Utils;
@@ -42,7 +43,7 @@ namespace Grpc.Core.Internal
 {
     internal interface IServerCallHandler
     {
-        Task HandleCall(string methodName, CallSafeHandle call, GrpcEnvironment environment);
+        Task HandleCall(ServerRpcNew newRpc, GrpcEnvironment environment);
     }
 
     internal class UnaryServerCallHandler<TRequest, TResponse> : IServerCallHandler
@@ -58,27 +59,28 @@ namespace Grpc.Core.Internal
             this.handler = handler;
         }
 
-        public async Task HandleCall(string methodName, CallSafeHandle call, GrpcEnvironment environment)
+        public async Task HandleCall(ServerRpcNew newRpc, GrpcEnvironment environment)
         {
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
                 method.RequestMarshaller.Deserializer,
                 environment);
 
-            asyncCall.Initialize(call);
+            asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
             var requestStream = new ServerRequestStream<TRequest, TResponse>(asyncCall);
             var responseStream = new ServerResponseStream<TRequest, TResponse>(asyncCall);
 
-            Status status = Status.DefaultSuccess;
+            Status status;
+            var context = HandlerUtils.NewContext(newRpc);
             try
             {
                 Preconditions.CheckArgument(await requestStream.MoveNext());
                 var request = requestStream.Current;
                 // TODO(jtattermusch): we need to read the full stream so that native callhandle gets deallocated.
                 Preconditions.CheckArgument(!await requestStream.MoveNext());
-                var context = new ServerCallContext();  // TODO(jtattermusch): initialize the context
-                var result = await handler(context, request);
+                var result = await handler(request, context);
+                status = context.Status;
                 await responseStream.WriteAsync(result);
             } 
             catch (Exception e)
@@ -88,7 +90,7 @@ namespace Grpc.Core.Internal
             }
             try
             {
-                await responseStream.WriteStatusAsync(status);
+                await responseStream.WriteStatusAsync(status, context.ResponseTrailers);
             }
             catch (OperationCanceledException)
             {
@@ -111,28 +113,28 @@ namespace Grpc.Core.Internal
             this.handler = handler;
         }
 
-        public async Task HandleCall(string methodName, CallSafeHandle call, GrpcEnvironment environment)
+        public async Task HandleCall(ServerRpcNew newRpc, GrpcEnvironment environment)
         {
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
                 method.RequestMarshaller.Deserializer,
                 environment);
 
-            asyncCall.Initialize(call);
+            asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
             var requestStream = new ServerRequestStream<TRequest, TResponse>(asyncCall);
             var responseStream = new ServerResponseStream<TRequest, TResponse>(asyncCall);
 
-            Status status = Status.DefaultSuccess;
+            Status status;
+            var context = HandlerUtils.NewContext(newRpc);
             try
             {
                 Preconditions.CheckArgument(await requestStream.MoveNext());
                 var request = requestStream.Current;
                 // TODO(jtattermusch): we need to read the full stream so that native callhandle gets deallocated.
                 Preconditions.CheckArgument(!await requestStream.MoveNext());
-
-                var context = new ServerCallContext();  // TODO(jtattermusch): initialize the context
-                await handler(context, request, responseStream);
+                await handler(request, responseStream, context);
+                status = context.Status;
             }
             catch (Exception e)
             {
@@ -142,7 +144,7 @@ namespace Grpc.Core.Internal
 
             try
             {
-                await responseStream.WriteStatusAsync(status);
+                await responseStream.WriteStatusAsync(status, context.ResponseTrailers);
             }
             catch (OperationCanceledException)
             {
@@ -165,23 +167,24 @@ namespace Grpc.Core.Internal
             this.handler = handler;
         }
 
-        public async Task HandleCall(string methodName, CallSafeHandle call, GrpcEnvironment environment)
+        public async Task HandleCall(ServerRpcNew newRpc, GrpcEnvironment environment)
         {
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
                 method.RequestMarshaller.Deserializer,
                 environment);
 
-            asyncCall.Initialize(call);
+            asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
             var requestStream = new ServerRequestStream<TRequest, TResponse>(asyncCall);
             var responseStream = new ServerResponseStream<TRequest, TResponse>(asyncCall);
-            var context = new ServerCallContext();  // TODO(jtattermusch): initialize the context
 
-            Status status = Status.DefaultSuccess;
+            Status status;
+            var context = HandlerUtils.NewContext(newRpc);
             try
             {
-                var result = await handler(context, requestStream);
+                var result = await handler(requestStream, context);
+                status = context.Status;
                 try
                 {
                     await responseStream.WriteAsync(result);
@@ -199,7 +202,7 @@ namespace Grpc.Core.Internal
 
             try
             {
-                await responseStream.WriteStatusAsync(status);
+                await responseStream.WriteStatusAsync(status, context.ResponseTrailers);
             }
             catch (OperationCanceledException)
             {
@@ -222,23 +225,24 @@ namespace Grpc.Core.Internal
             this.handler = handler;
         }
 
-        public async Task HandleCall(string methodName, CallSafeHandle call, GrpcEnvironment environment)
+        public async Task HandleCall(ServerRpcNew newRpc, GrpcEnvironment environment)
         {
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
                 method.RequestMarshaller.Deserializer,
                 environment);
 
-            asyncCall.Initialize(call);
+            asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
             var requestStream = new ServerRequestStream<TRequest, TResponse>(asyncCall);
             var responseStream = new ServerResponseStream<TRequest, TResponse>(asyncCall);
-            var context = new ServerCallContext();  // TODO(jtattermusch): initialize the context
 
-            Status status = Status.DefaultSuccess;
+            Status status;
+            var context = HandlerUtils.NewContext(newRpc);
             try
             {
-                await handler(context, requestStream, responseStream);
+                await handler(requestStream, responseStream, context);
+                status = context.Status;
             }
             catch (Exception e)
             {
@@ -247,7 +251,7 @@ namespace Grpc.Core.Internal
             }
             try
             {
-                await responseStream.WriteStatusAsync(status);
+                await responseStream.WriteStatusAsync(status, context.ResponseTrailers);
             }
             catch (OperationCanceledException)
             {
@@ -259,18 +263,19 @@ namespace Grpc.Core.Internal
 
     internal class NoSuchMethodCallHandler : IServerCallHandler
     {
-        public async Task HandleCall(string methodName, CallSafeHandle call, GrpcEnvironment environment)
+        public static readonly NoSuchMethodCallHandler Instance = new NoSuchMethodCallHandler();
+
+        public async Task HandleCall(ServerRpcNew newRpc, GrpcEnvironment environment)
         {
             // We don't care about the payload type here.
             var asyncCall = new AsyncCallServer<byte[], byte[]>(
                 (payload) => payload, (payload) => payload, environment);
             
-            asyncCall.Initialize(call);
+            asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
-            var requestStream = new ServerRequestStream<byte[], byte[]>(asyncCall);
             var responseStream = new ServerResponseStream<byte[], byte[]>(asyncCall);
 
-            await responseStream.WriteStatusAsync(new Status(StatusCode.Unimplemented, "No such method."));
+            await responseStream.WriteStatusAsync(new Status(StatusCode.Unimplemented, "No such method."), Metadata.Empty);
             await finishedTask;
         }
     }
@@ -279,8 +284,22 @@ namespace Grpc.Core.Internal
     {
         public static Status StatusFromException(Exception e)
         {
+            var rpcException = e as RpcException;
+            if (rpcException != null)
+            {
+                // use the status thrown by handler.
+                return rpcException.Status;
+            }
+
             // TODO(jtattermusch): what is the right status code here?
             return new Status(StatusCode.Unknown, "Exception was thrown by handler.");
         }
+
+        public static ServerCallContext NewContext(ServerRpcNew newRpc)
+        {
+            return new ServerCallContext(
+                newRpc.Method, newRpc.Host, newRpc.Deadline.ToDateTime(),
+                newRpc.RequestMetadata, CancellationToken.None);
+        }
     }
 }
diff --git a/src/csharp/Grpc.Core/Internal/ServerResponseStream.cs b/src/csharp/Grpc.Core/Internal/ServerResponseStream.cs
index a2d77dd5b7..756dcee87f 100644
--- a/src/csharp/Grpc.Core/Internal/ServerResponseStream.cs
+++ b/src/csharp/Grpc.Core/Internal/ServerResponseStream.cs
@@ -56,10 +56,10 @@ namespace Grpc.Core.Internal
             return taskSource.Task;
         }
 
-        public Task WriteStatusAsync(Status status)
+        public Task WriteStatusAsync(Status status, Metadata trailers)
         {
             var taskSource = new AsyncCompletionTaskSource<object>();
-            call.StartSendStatusFromServer(status, taskSource.CompletionDelegate);
+            call.StartSendStatusFromServer(status, trailers, taskSource.CompletionDelegate);
             return taskSource.Task;
         }
     }
diff --git a/src/csharp/Grpc.Core/Internal/Timespec.cs b/src/csharp/Grpc.Core/Internal/Timespec.cs
index de783f5a4b..da2819f14d 100644
--- a/src/csharp/Grpc.Core/Internal/Timespec.cs
+++ b/src/csharp/Grpc.Core/Internal/Timespec.cs
@@ -43,6 +43,8 @@ namespace Grpc.Core.Internal
         const int NanosPerSecond = 1000 * 1000 * 1000;
         const int NanosPerTick = 100;
 
+        static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
+
         [DllImport("grpc_csharp_ext.dll")]
         static extern Timespec gprsharp_now();
 
@@ -52,6 +54,13 @@ namespace Grpc.Core.Internal
         [DllImport("grpc_csharp_ext.dll")]
         static extern int gprsharp_sizeof_timespec();
 
+        public Timespec(IntPtr tv_sec, int tv_nsec)
+        {
+            this.tv_sec = tv_sec;
+            this.tv_nsec = tv_nsec;
+            this.clock_type = GPRClockType.Realtime;
+        }
+
         // NOTE: on linux 64bit  sizeof(gpr_timespec) = 16, on windows 32bit sizeof(gpr_timespec) = 8
         // so IntPtr seems to have the right size to work on both.
         public System.IntPtr tv_sec;
@@ -76,6 +85,11 @@ namespace Grpc.Core.Internal
                 return gprsharp_now();
             }
         }
+            
+        public DateTime ToDateTime()
+        {
+            return UnixEpoch.AddTicks(tv_sec.ToInt64() * (NanosPerSecond / NanosPerTick) + tv_nsec / NanosPerTick);
+        }
 
         internal static int NativeSize
         {
diff --git a/src/csharp/Grpc.Core/Metadata.cs b/src/csharp/Grpc.Core/Metadata.cs
index 4552d39d88..2f308cbb11 100644
--- a/src/csharp/Grpc.Core/Metadata.cs
+++ b/src/csharp/Grpc.Core/Metadata.cs
@@ -220,6 +220,11 @@ namespace Grpc.Core
                     return value;
                 }
             }
+                
+            public override string ToString()
+            {
+                return string.Format("[Entry: key={0}, value={1}]", Key, Value);
+            }
         }
     }
 }
diff --git a/src/csharp/Grpc.Core/Server.cs b/src/csharp/Grpc.Core/Server.cs
index cbf77196cf..fd30735359 100644
--- a/src/csharp/Grpc.Core/Server.cs
+++ b/src/csharp/Grpc.Core/Server.cs
@@ -53,6 +53,7 @@ namespace Grpc.Core
         public const int PickUnusedPort = 0;
 
         readonly GrpcEnvironment environment;
+        readonly List<ChannelOption> options;
         readonly ServerSafeHandle handle;
         readonly object myLock = new object();
 
@@ -69,7 +70,8 @@ namespace Grpc.Core
         public Server(IEnumerable<ChannelOption> options = null)
         {
             this.environment = GrpcEnvironment.GetInstance();
-            using (var channelArgs = ChannelOptions.CreateChannelArgs(options))
+            this.options = options != null ? new List<ChannelOption>(options) : new List<ChannelOption>();
+            using (var channelArgs = ChannelOptions.CreateChannelArgs(this.options))
             {
                 this.handle = ServerSafeHandle.NewServer(environment.CompletionQueue, channelArgs);
             }
@@ -218,16 +220,16 @@ namespace Grpc.Core
         /// <summary>
         /// Selects corresponding handler for given call and handles the call.
         /// </summary>
-        private async Task InvokeCallHandler(CallSafeHandle call, string method)
+        private async Task HandleCallAsync(ServerRpcNew newRpc)
         {
             try
             {
                 IServerCallHandler callHandler;
-                if (!callHandlers.TryGetValue(method, out callHandler))
+                if (!callHandlers.TryGetValue(newRpc.Method, out callHandler))
                 {
-                    callHandler = new NoSuchMethodCallHandler();
+                    callHandler = NoSuchMethodCallHandler.Instance;
                 }
-                await callHandler.HandleCall(method, call, environment);
+                await callHandler.HandleCall(newRpc, environment);
             }
             catch (Exception e)
             {
@@ -240,15 +242,15 @@ namespace Grpc.Core
         /// </summary>
         private void HandleNewServerRpc(bool success, BatchContextSafeHandle ctx)
         {
-            // TODO: handle error
-
-            CallSafeHandle call = ctx.GetServerRpcNewCall();
-            string method = ctx.GetServerRpcNewMethod();
-
-            // after server shutdown, the callback returns with null call
-            if (!call.IsInvalid)
+            if (success)
             {
-                Task.Run(async () => await InvokeCallHandler(call, method));
+                ServerRpcNew newRpc = ctx.GetServerRpcNew();
+
+                // after server shutdown, the callback returns with null call
+                if (!newRpc.Call.IsInvalid)
+                {
+                    Task.Run(async () => await HandleCallAsync(newRpc));
+                }
             }
 
             AllowOneRpc();
diff --git a/src/csharp/Grpc.Core/ServerCallContext.cs b/src/csharp/Grpc.Core/ServerCallContext.cs
index bc9a499c51..17a2eefd07 100644
--- a/src/csharp/Grpc.Core/ServerCallContext.cs
+++ b/src/csharp/Grpc.Core/ServerCallContext.cs
@@ -33,6 +33,7 @@
 
 using System;
 using System.Runtime.CompilerServices;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace Grpc.Core
@@ -42,14 +43,93 @@ namespace Grpc.Core
     /// </summary>
     public sealed class ServerCallContext
     {
-        // TODO(jtattermusch): add cancellationToken
+        // TODO(jtattermusch): expose method to send initial metadata back to client
 
-        // TODO(jtattermusch): add deadline info
+        private readonly string method;
+        private readonly string host;
+        private readonly DateTime deadline;
+        private readonly Metadata requestHeaders;
+        private readonly CancellationToken cancellationToken;
+        private readonly Metadata responseTrailers = new Metadata();
 
-        // TODO(jtattermusch): expose initial metadata sent by client for reading
+        private Status status = Status.DefaultSuccess;
 
-        // TODO(jtattermusch): expose method to send initial metadata back to client
+        public ServerCallContext(string method, string host, DateTime deadline, Metadata requestHeaders, CancellationToken cancellationToken)
+        {
+            this.method = method;
+            this.host = host;
+            this.deadline = deadline;
+            this.requestHeaders = requestHeaders;
+            this.cancellationToken = cancellationToken;
+        }
+            
+        /// <summary> Name of method called in this RPC. </summary>
+        public string Method
+        {
+            get
+            {
+                return this.method;
+            }
+        }
+
+        /// <summary> Name of host called in this RPC. </summary>
+        public string Host
+        {
+            get
+            {
+                return this.host;
+            }
+        }
+
+        /// <summary> Deadline for this RPC. </summary>
+        public DateTime Deadline
+        {
+            get
+            {
+                return this.deadline;
+            }
+        }
+
+        /// <summary> Initial metadata sent by client. </summary>
+        public Metadata RequestHeaders
+        {
+            get
+            {
+                return this.requestHeaders;
+            }
+        }
+
+        // TODO(jtattermusch): support signalling cancellation.
+        /// <summary> Cancellation token signals when call is cancelled. </summary>
+        public CancellationToken CancellationToken
+        {
+            get
+            {
+                return this.cancellationToken;
+            }
+        }
+
+        /// <summary> Trailers to send back to client after RPC finishes.</summary>
+        public Metadata ResponseTrailers
+        {
+            get
+            {
+                return this.responseTrailers;
+            }
+        }
+
+        /// <summary> Status to send back to client after RPC finishes.</summary>
+        public Status Status
+        {
+            get
+            {
+                return this.status;
+            }
 
-        // TODO(jtattermusch): allow setting status and trailing metadata to send after handler completes.
+            set
+            {
+                status = value;
+            }
+        }
     }
 }
diff --git a/src/csharp/Grpc.Core/ServerMethods.cs b/src/csharp/Grpc.Core/ServerMethods.cs
index 377b78eb30..d457770203 100644
--- a/src/csharp/Grpc.Core/ServerMethods.cs
+++ b/src/csharp/Grpc.Core/ServerMethods.cs
@@ -42,28 +42,28 @@ namespace Grpc.Core
     /// <summary>
     /// Server-side handler for unary call.
     /// </summary>
-    public delegate Task<TResponse> UnaryServerMethod<TRequest, TResponse>(ServerCallContext context, TRequest request)
+    public delegate Task<TResponse> UnaryServerMethod<TRequest, TResponse>(TRequest request, ServerCallContext context)
         where TRequest : class
         where TResponse : class;
 
     /// <summary>
     /// Server-side handler for client streaming call.
     /// </summary>
-    public delegate Task<TResponse> ClientStreamingServerMethod<TRequest, TResponse>(ServerCallContext context, IAsyncStreamReader<TRequest> requestStream)
+    public delegate Task<TResponse> ClientStreamingServerMethod<TRequest, TResponse>(IAsyncStreamReader<TRequest> requestStream, ServerCallContext context)
         where TRequest : class
         where TResponse : class;
 
     /// <summary>
     /// Server-side handler for server streaming call.
     /// </summary>
-    public delegate Task ServerStreamingServerMethod<TRequest, TResponse>(ServerCallContext context, TRequest request, IServerStreamWriter<TResponse> responseStream)
+    public delegate Task ServerStreamingServerMethod<TRequest, TResponse>(TRequest request, IServerStreamWriter<TResponse> responseStream, ServerCallContext context)
         where TRequest : class
         where TResponse : class;
 
     /// <summary>
     /// Server-side handler for bidi streaming call.
     /// </summary>
-    public delegate Task DuplexStreamingServerMethod<TRequest, TResponse>(ServerCallContext context, IAsyncStreamReader<TRequest> requestStream, IServerStreamWriter<TResponse> responseStream)
+    public delegate Task DuplexStreamingServerMethod<TRequest, TResponse>(IAsyncStreamReader<TRequest> requestStream, IServerStreamWriter<TResponse> responseStream, ServerCallContext context)
         where TRequest : class
         where TResponse : class;
 }
diff --git a/src/csharp/Grpc.Core/Version.cs b/src/csharp/Grpc.Core/Version.cs
index f1db1f6157..b5cb652945 100644
--- a/src/csharp/Grpc.Core/Version.cs
+++ b/src/csharp/Grpc.Core/Version.cs
@@ -2,4 +2,4 @@ using System.Reflection;
 using System.Runtime.CompilerServices;
 
 // The current version of gRPC C#.
-[assembly: AssemblyVersion("0.6.0.*")]
+[assembly: AssemblyVersion(Grpc.Core.VersionInfo.CurrentVersion + ".*")]
diff --git a/src/csharp/Grpc.Core/VersionInfo.cs b/src/csharp/Grpc.Core/VersionInfo.cs
new file mode 100644
index 0000000000..656a3d47bb
--- /dev/null
+++ b/src/csharp/Grpc.Core/VersionInfo.cs
@@ -0,0 +1,13 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+
+namespace Grpc.Core
+{
+    public static class VersionInfo
+    {
+        /// <summary>
+        /// Current version of gRPC
+        /// </summary>
+        public const string CurrentVersion = "0.6.0";
+    }
+}
diff --git a/src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs b/src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs
index e7c4b33120..7a957c5b6f 100644
--- a/src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs
+++ b/src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs
@@ -144,7 +144,7 @@ namespace math.Tests
                              n => Num.CreateBuilder().SetNum_(n).Build());
 
                     await call.RequestStream.WriteAll(numbers);
-                    var result = await call.Result;
+                    var result = await call.ResponseAsync;
                     Assert.AreEqual(60, result.Num_);
                 }
             }).Wait();
diff --git a/src/csharp/Grpc.Examples/MathExamples.cs b/src/csharp/Grpc.Examples/MathExamples.cs
index 7deb651689..06d81a4d83 100644
--- a/src/csharp/Grpc.Examples/MathExamples.cs
+++ b/src/csharp/Grpc.Examples/MathExamples.cs
@@ -46,8 +46,7 @@ namespace math
 
         public static async Task DivAsyncExample(Math.IMathClient client)
         {
-            Task<DivReply> resultTask = client.DivAsync(new DivArgs.Builder { Dividend = 4, Divisor = 5 }.Build());
-            DivReply result = await resultTask;
+            DivReply result = await client.DivAsync(new DivArgs.Builder { Dividend = 4, Divisor = 5 }.Build());
             Console.WriteLine("DivAsync Result: " + result);
         }
 
@@ -72,7 +71,7 @@ namespace math
             using (var call = client.Sum())
             {
                 await call.RequestStream.WriteAll(numbers);
-                Console.WriteLine("Sum Result: " + await call.Result);
+                Console.WriteLine("Sum Result: " + await call.ResponseAsync);
             }
         }
 
@@ -104,7 +103,7 @@ namespace math
             using (var sumCall = client.Sum())
             {
                 await sumCall.RequestStream.WriteAll(numbers);
-                sum = await sumCall.Result;
+                sum = await sumCall.ResponseAsync;
             }
 
             DivReply result = await client.DivAsync(new DivArgs.Builder { Dividend = sum.Num_, Divisor = numbers.Count }.Build());
diff --git a/src/csharp/Grpc.Examples/MathGrpc.cs b/src/csharp/Grpc.Examples/MathGrpc.cs
index 1805972ce3..ef787cf1d8 100644
--- a/src/csharp/Grpc.Examples/MathGrpc.cs
+++ b/src/csharp/Grpc.Examples/MathGrpc.cs
@@ -45,7 +45,7 @@ namespace math {
     public interface IMathClient
     {
       global::math.DivReply Div(global::math.DivArgs request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
-      Task<global::math.DivReply> DivAsync(global::math.DivArgs request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
+      AsyncUnaryCall<global::math.DivReply> DivAsync(global::math.DivArgs request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
       AsyncDuplexStreamingCall<global::math.DivArgs, global::math.DivReply> DivMany(Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
       AsyncServerStreamingCall<global::math.Num> Fib(global::math.FibArgs request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
       AsyncClientStreamingCall<global::math.Num, global::math.Num> Sum(Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
@@ -54,10 +54,10 @@ namespace math {
     // server-side interface
     public interface IMath
     {
-      Task<global::math.DivReply> Div(ServerCallContext context, global::math.DivArgs request);
-      Task DivMany(ServerCallContext context, IAsyncStreamReader<global::math.DivArgs> requestStream, IServerStreamWriter<global::math.DivReply> responseStream);
-      Task Fib(ServerCallContext context, global::math.FibArgs request, IServerStreamWriter<global::math.Num> responseStream);
-      Task<global::math.Num> Sum(ServerCallContext context, IAsyncStreamReader<global::math.Num> requestStream);
+      Task<global::math.DivReply> Div(global::math.DivArgs request, ServerCallContext context);
+      Task DivMany(IAsyncStreamReader<global::math.DivArgs> requestStream, IServerStreamWriter<global::math.DivReply> responseStream, ServerCallContext context);
+      Task Fib(global::math.FibArgs request, IServerStreamWriter<global::math.Num> responseStream, ServerCallContext context);
+      Task<global::math.Num> Sum(IAsyncStreamReader<global::math.Num> requestStream, ServerCallContext context);
     }
 
     // client stub
@@ -71,7 +71,7 @@ namespace math {
         var call = CreateCall(__ServiceName, __Method_Div, headers);
         return Calls.BlockingUnaryCall(call, request, cancellationToken);
       }
-      public Task<global::math.DivReply> DivAsync(global::math.DivArgs request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken))
+      public AsyncUnaryCall<global::math.DivReply> DivAsync(global::math.DivArgs request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         var call = CreateCall(__ServiceName, __Method_Div, headers);
         return Calls.AsyncUnaryCall(call, request, cancellationToken);
diff --git a/src/csharp/Grpc.Examples/MathServiceImpl.cs b/src/csharp/Grpc.Examples/MathServiceImpl.cs
index e247ac9d73..3dd0f53a0d 100644
--- a/src/csharp/Grpc.Examples/MathServiceImpl.cs
+++ b/src/csharp/Grpc.Examples/MathServiceImpl.cs
@@ -45,12 +45,12 @@ namespace math
     /// </summary>
     public class MathServiceImpl : Math.IMath
     {
-        public Task<DivReply> Div(ServerCallContext context, DivArgs request)
+        public Task<DivReply> Div(DivArgs request, ServerCallContext context)
         {
             return Task.FromResult(DivInternal(request));
         }
 
-        public async Task Fib(ServerCallContext context, FibArgs request, IServerStreamWriter<Num> responseStream)
+        public async Task Fib(FibArgs request, IServerStreamWriter<Num> responseStream, ServerCallContext context)
         {
             if (request.Limit <= 0)
             {
@@ -67,7 +67,7 @@ namespace math
             }
         }
 
-        public async Task<Num> Sum(ServerCallContext context, IAsyncStreamReader<Num> requestStream)
+        public async Task<Num> Sum(IAsyncStreamReader<Num> requestStream, ServerCallContext context)
         {
             long sum = 0;
             await requestStream.ForEach(async num =>
@@ -77,7 +77,7 @@ namespace math
             return Num.CreateBuilder().SetNum_(sum).Build();
         }
 
-        public async Task DivMany(ServerCallContext context, IAsyncStreamReader<DivArgs> requestStream, IServerStreamWriter<DivReply> responseStream)
+        public async Task DivMany(IAsyncStreamReader<DivArgs> requestStream, IServerStreamWriter<DivReply> responseStream, ServerCallContext context)
         {
             await requestStream.ForEach(async divArgs =>
             {
diff --git a/src/csharp/Grpc.HealthCheck.Tests/HealthClientServerTest.cs b/src/csharp/Grpc.HealthCheck.Tests/HealthClientServerTest.cs
index 73ff0e74b5..bc14a0a62f 100644
--- a/src/csharp/Grpc.HealthCheck.Tests/HealthClientServerTest.cs
+++ b/src/csharp/Grpc.HealthCheck.Tests/HealthClientServerTest.cs
@@ -87,9 +87,7 @@ namespace Grpc.HealthCheck.Tests
         [Test]
         public void ServiceDoesntExist()
         {
-            // TODO(jtattermusch): currently, this returns wrong status code, because we don't enable sending arbitrary status code from
-            // server handlers yet.
-            Assert.Throws(typeof(RpcException), () => client.Check(HealthCheckRequest.CreateBuilder().SetHost("").SetService("nonexistent.service").Build()));
+            Assert.Throws(Is.TypeOf(typeof(RpcException)).And.Property("Status").Property("StatusCode").EqualTo(StatusCode.NotFound), () => client.Check(HealthCheckRequest.CreateBuilder().SetHost("").SetService("nonexistent.service").Build()));
         }
 
         // TODO(jtattermusch): add test with timeout once timeouts are supported
diff --git a/src/csharp/Grpc.HealthCheck.Tests/HealthServiceImplTest.cs b/src/csharp/Grpc.HealthCheck.Tests/HealthServiceImplTest.cs
index 9b7c4f2140..7184415655 100644
--- a/src/csharp/Grpc.HealthCheck.Tests/HealthServiceImplTest.cs
+++ b/src/csharp/Grpc.HealthCheck.Tests/HealthServiceImplTest.cs
@@ -101,7 +101,7 @@ namespace Grpc.HealthCheck.Tests
 
         private static HealthCheckResponse.Types.ServingStatus GetStatusHelper(HealthServiceImpl impl, string host, string service)
         {
-            return impl.Check(null, HealthCheckRequest.CreateBuilder().SetHost(host).SetService(service).Build()).Result.Status;
+            return impl.Check(HealthCheckRequest.CreateBuilder().SetHost(host).SetService(service).Build(), null).Result.Status;
         }
     }
 }
diff --git a/src/csharp/Grpc.HealthCheck/HealthGrpc.cs b/src/csharp/Grpc.HealthCheck/HealthGrpc.cs
index 3aebdcb557..217127eca7 100644
--- a/src/csharp/Grpc.HealthCheck/HealthGrpc.cs
+++ b/src/csharp/Grpc.HealthCheck/HealthGrpc.cs
@@ -25,13 +25,13 @@ namespace Grpc.Health.V1Alpha {
     public interface IHealthClient
     {
       global::Grpc.Health.V1Alpha.HealthCheckResponse Check(global::Grpc.Health.V1Alpha.HealthCheckRequest request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
-      Task<global::Grpc.Health.V1Alpha.HealthCheckResponse> CheckAsync(global::Grpc.Health.V1Alpha.HealthCheckRequest request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
+      AsyncUnaryCall<global::Grpc.Health.V1Alpha.HealthCheckResponse> CheckAsync(global::Grpc.Health.V1Alpha.HealthCheckRequest request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
     }
 
     // server-side interface
     public interface IHealth
     {
-      Task<global::Grpc.Health.V1Alpha.HealthCheckResponse> Check(ServerCallContext context, global::Grpc.Health.V1Alpha.HealthCheckRequest request);
+      Task<global::Grpc.Health.V1Alpha.HealthCheckResponse> Check(global::Grpc.Health.V1Alpha.HealthCheckRequest request, ServerCallContext context);
     }
 
     // client stub
@@ -45,7 +45,7 @@ namespace Grpc.Health.V1Alpha {
         var call = CreateCall(__ServiceName, __Method_Check, headers);
         return Calls.BlockingUnaryCall(call, request, cancellationToken);
       }
-      public Task<global::Grpc.Health.V1Alpha.HealthCheckResponse> CheckAsync(global::Grpc.Health.V1Alpha.HealthCheckRequest request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken))
+      public AsyncUnaryCall<global::Grpc.Health.V1Alpha.HealthCheckResponse> CheckAsync(global::Grpc.Health.V1Alpha.HealthCheckRequest request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         var call = CreateCall(__ServiceName, __Method_Check, headers);
         return Calls.AsyncUnaryCall(call, request, cancellationToken);
diff --git a/src/csharp/Grpc.HealthCheck/HealthServiceImpl.cs b/src/csharp/Grpc.HealthCheck/HealthServiceImpl.cs
index db3a2a0942..3c3b9c35f1 100644
--- a/src/csharp/Grpc.HealthCheck/HealthServiceImpl.cs
+++ b/src/csharp/Grpc.HealthCheck/HealthServiceImpl.cs
@@ -95,7 +95,7 @@ namespace Grpc.HealthCheck
             }
         }
 
-        public Task<HealthCheckResponse> Check(ServerCallContext context, HealthCheckRequest request)
+        public Task<HealthCheckResponse> Check(HealthCheckRequest request, ServerCallContext context)
         {
             lock (myLock)
             {
diff --git a/src/csharp/Grpc.HealthCheck/Settings.StyleCop b/src/csharp/Grpc.HealthCheck/Settings.StyleCop
new file mode 100644
index 0000000000..2942add962
--- /dev/null
+++ b/src/csharp/Grpc.HealthCheck/Settings.StyleCop
@@ -0,0 +1,10 @@
+<StyleCopSettings Version="105">
+  <SourceFileList>
+    <SourceFile>Health.cs</SourceFile>
+    <Settings>
+    <GlobalSettings>
+      <BooleanProperty Name="RulesEnabledByDefault">False</BooleanProperty>
+    </GlobalSettings>
+    </Settings>
+  </SourceFileList>
+</StyleCopSettings>
diff --git a/src/csharp/Grpc.IntegrationTesting.Client/Grpc.IntegrationTesting.Client.csproj b/src/csharp/Grpc.IntegrationTesting.Client/Grpc.IntegrationTesting.Client.csproj
index 328acb5b47..dc1d0a44c0 100644
--- a/src/csharp/Grpc.IntegrationTesting.Client/Grpc.IntegrationTesting.Client.csproj
+++ b/src/csharp/Grpc.IntegrationTesting.Client/Grpc.IntegrationTesting.Client.csproj
@@ -3,8 +3,6 @@
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">x86</Platform>
-    <ProductVersion>10.0.0</ProductVersion>
-    <SchemaVersion>2.0</SchemaVersion>
     <ProjectGuid>{3D166931-BA2D-416E-95A3-D36E8F6E90B9}</ProjectGuid>
     <OutputType>Exe</OutputType>
     <RootNamespace>Grpc.IntegrationTesting.Client</RootNamespace>
@@ -48,6 +46,10 @@
       <Project>{C61154BA-DD4A-4838-8420-0162A28925E0}</Project>
       <Name>Grpc.IntegrationTesting</Name>
     </ProjectReference>
+    <ProjectReference Include="..\Grpc.Core\Grpc.Core.csproj">
+      <Project>{CCC4440E-49F7-4790-B0AF-FEABB0837AE7}</Project>
+      <Name>Grpc.Core</Name>
+    </ProjectReference>
   </ItemGroup>
   <ItemGroup>
     <None Include="app.config" />
diff --git a/src/csharp/Grpc.IntegrationTesting.Server/Grpc.IntegrationTesting.Server.csproj b/src/csharp/Grpc.IntegrationTesting.Server/Grpc.IntegrationTesting.Server.csproj
index ae184c1dc7..f03c8f3ce3 100644
--- a/src/csharp/Grpc.IntegrationTesting.Server/Grpc.IntegrationTesting.Server.csproj
+++ b/src/csharp/Grpc.IntegrationTesting.Server/Grpc.IntegrationTesting.Server.csproj
@@ -3,8 +3,6 @@
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">x86</Platform>
-    <ProductVersion>10.0.0</ProductVersion>
-    <SchemaVersion>2.0</SchemaVersion>
     <ProjectGuid>{A654F3B8-E859-4E6A-B30D-227527DBEF0D}</ProjectGuid>
     <OutputType>Exe</OutputType>
     <RootNamespace>Grpc.IntegrationTesting.Server</RootNamespace>
@@ -48,6 +46,10 @@
       <Project>{C61154BA-DD4A-4838-8420-0162A28925E0}</Project>
       <Name>Grpc.IntegrationTesting</Name>
     </ProjectReference>
+    <ProjectReference Include="..\Grpc.Core\Grpc.Core.csproj">
+      <Project>{CCC4440E-49F7-4790-B0AF-FEABB0837AE7}</Project>
+      <Name>Grpc.Core</Name>
+    </ProjectReference>
   </ItemGroup>
   <ItemGroup>
     <None Include="app.config" />
diff --git a/src/csharp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj b/src/csharp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj
index af4a75a034..d3c69ab9eb 100644
--- a/src/csharp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj
+++ b/src/csharp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj
@@ -32,21 +32,34 @@
     <PlatformTarget>x86</PlatformTarget>
   </PropertyGroup>
   <ItemGroup>
-    <Reference Include="Google.Apis.Auth.PlatformServices">
+    <Reference Include="Google.Apis.Auth, Version=1.9.1.12395, Culture=neutral, processorArchitecture=MSIL">
+      <SpecificVersion>False</SpecificVersion>
+      <HintPath>..\packages\Google.Apis.Auth.1.9.1\lib\net40\Google.Apis.Auth.dll</HintPath>
+    </Reference>
+    <Reference Include="Google.Apis.Auth.PlatformServices, Version=1.9.1.12399, Culture=neutral, processorArchitecture=MSIL">
+      <SpecificVersion>False</SpecificVersion>
       <HintPath>..\packages\Google.Apis.Auth.1.9.1\lib\net40\Google.Apis.Auth.PlatformServices.dll</HintPath>
     </Reference>
-    <Reference Include="Google.Apis.Core">
+    <Reference Include="Google.Apis.Core, Version=1.9.1.12394, Culture=neutral, processorArchitecture=MSIL">
+      <SpecificVersion>False</SpecificVersion>
       <HintPath>..\packages\Google.Apis.Core.1.9.1\lib\portable-net40+sl50+win+wpa81+wp80\Google.Apis.Core.dll</HintPath>
     </Reference>
-    <Reference Include="Microsoft.Threading.Tasks">
+    <Reference Include="Microsoft.Threading.Tasks, Version=1.0.12.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
+      <SpecificVersion>False</SpecificVersion>
       <HintPath>..\packages\Microsoft.Bcl.Async.1.0.168\lib\net40\Microsoft.Threading.Tasks.dll</HintPath>
     </Reference>
-    <Reference Include="Microsoft.Threading.Tasks.Extensions">
+    <Reference Include="Microsoft.Threading.Tasks.Extensions, Version=1.0.12.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
+      <SpecificVersion>False</SpecificVersion>
       <HintPath>..\packages\Microsoft.Bcl.Async.1.0.168\lib\net40\Microsoft.Threading.Tasks.Extensions.dll</HintPath>
     </Reference>
-    <Reference Include="Microsoft.Threading.Tasks.Extensions.Desktop">
+    <Reference Include="Microsoft.Threading.Tasks.Extensions.Desktop, Version=1.0.168.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
+      <SpecificVersion>False</SpecificVersion>
       <HintPath>..\packages\Microsoft.Bcl.Async.1.0.168\lib\net40\Microsoft.Threading.Tasks.Extensions.Desktop.dll</HintPath>
     </Reference>
+    <Reference Include="Newtonsoft.Json, Version=6.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed, processorArchitecture=MSIL">
+      <SpecificVersion>False</SpecificVersion>
+      <HintPath>..\packages\Newtonsoft.Json.6.0.6\lib\net45\Newtonsoft.Json.dll</HintPath>
+    </Reference>
     <Reference Include="nunit.framework">
       <HintPath>..\packages\NUnit.2.6.4\lib\nunit.framework.dll</HintPath>
     </Reference>
@@ -63,16 +76,15 @@
     </Reference>
     <Reference Include="System.Net" />
     <Reference Include="System.Net.Http" />
-    <Reference Include="System.Net.Http.Extensions">
+    <Reference Include="System.Net.Http.Extensions, Version=2.2.28.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
+      <SpecificVersion>False</SpecificVersion>
       <HintPath>..\packages\Microsoft.Net.Http.2.2.28\lib\net45\System.Net.Http.Extensions.dll</HintPath>
     </Reference>
-    <Reference Include="System.Net.Http.Primitives">
+    <Reference Include="System.Net.Http.Primitives, Version=4.2.28.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
+      <SpecificVersion>False</SpecificVersion>
       <HintPath>..\packages\Microsoft.Net.Http.2.2.28\lib\net45\System.Net.Http.Primitives.dll</HintPath>
     </Reference>
     <Reference Include="System.Net.Http.WebRequest" />
-    <Reference Include="Newtonsoft.Json">
-      <HintPath>..\packages\Newtonsoft.Json.6.0.6\lib\net45\Newtonsoft.Json.dll</HintPath>
-    </Reference>
   </ItemGroup>
   <ItemGroup>
     <Compile Include="..\Grpc.Core\Version.cs">
diff --git a/src/csharp/Grpc.IntegrationTesting/InteropClient.cs b/src/csharp/Grpc.IntegrationTesting/InteropClient.cs
index 05e732dbd4..ce255f9423 100644
--- a/src/csharp/Grpc.IntegrationTesting/InteropClient.cs
+++ b/src/csharp/Grpc.IntegrationTesting/InteropClient.cs
@@ -135,7 +135,7 @@ namespace Grpc.IntegrationTesting
             GrpcEnvironment.Shutdown();
         }
 
-        private void RunTestCase(string testCase, TestService.ITestServiceClient client)
+        private void RunTestCase(string testCase, TestService.TestServiceClient client)
         {
             switch (testCase)
             {
@@ -163,6 +163,12 @@ namespace Grpc.IntegrationTesting
                 case "compute_engine_creds":
                     RunComputeEngineCreds(client);
                     break;
+                case "oauth2_auth_token":
+                    RunOAuth2AuthToken(client);
+                    break;
+                case "per_rpc_creds":
+                    RunPerRpcCreds(client);
+                    break;
                 case "cancel_after_begin":
                     RunCancelAfterBegin(client);
                     break;
@@ -213,7 +219,7 @@ namespace Grpc.IntegrationTesting
                 {
                     await call.RequestStream.WriteAll(bodySizes);
 
-                    var response = await call.Result;
+                    var response = await call.ResponseAsync;
                     Assert.AreEqual(74922, response.AggregatedPayloadSize);
                 }
                 Console.WriteLine("Passed!");
@@ -355,6 +361,51 @@ namespace Grpc.IntegrationTesting
             Console.WriteLine("Passed!");
         }
 
+        public static void RunOAuth2AuthToken(TestService.TestServiceClient client)
+        {
+            Console.WriteLine("running oauth2_auth_token");
+            var credential = GoogleCredential.GetApplicationDefault().CreateScoped(new[] { AuthScope });
+            Assert.IsTrue(credential.RequestAccessTokenAsync(CancellationToken.None).Result);
+            string oauth2Token = credential.Token.AccessToken;
+
+            // Intercept calls with an OAuth2 token obtained out-of-band.
+            client.HeaderInterceptor = new MetadataInterceptorDelegate((metadata) =>
+            {
+                metadata.Add(new Metadata.Entry("Authorization", "Bearer " + oauth2Token));
+            });
+
+            var request = SimpleRequest.CreateBuilder()
+                .SetFillUsername(true)
+                .SetFillOauthScope(true)
+                .Build();
+
+            var response = client.UnaryCall(request);
+
+            Assert.AreEqual(AuthScopeResponse, response.OauthScope);
+            Assert.AreEqual(ServiceAccountUser, response.Username);
+            Console.WriteLine("Passed!");
+        }
+
+        public static void RunPerRpcCreds(TestService.TestServiceClient client)
+        {
+            Console.WriteLine("running per_rpc_creds");
+
+            var credential = GoogleCredential.GetApplicationDefault().CreateScoped(new[] { AuthScope });
+            Assert.IsTrue(credential.RequestAccessTokenAsync(CancellationToken.None).Result);
+            string oauth2Token = credential.Token.AccessToken;
+
+            var request = SimpleRequest.CreateBuilder()
+                .SetFillUsername(true)
+                .SetFillOauthScope(true)
+                .Build();
+
+            var response = client.UnaryCall(request, headers: new Metadata { new Metadata.Entry("Authorization", "Bearer " + oauth2Token) });
+
+            Assert.AreEqual(AuthScopeResponse, response.OauthScope);
+            Assert.AreEqual(ServiceAccountUser, response.Username);
+            Console.WriteLine("Passed!");
+        }
+
         public static void RunCancelAfterBegin(TestService.ITestServiceClient client)
         {
             Task.Run(async () =>
@@ -370,7 +421,7 @@ namespace Grpc.IntegrationTesting
 
                     try
                     {
-                        var response = await call.Result;
+                        var response = await call.ResponseAsync;
                         Assert.Fail();
                     }
                     catch (RpcException e)
diff --git a/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs b/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs
index 96d9b23717..de2fa07441 100644
--- a/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs
@@ -60,9 +60,9 @@ namespace grpc.testing {
     public interface ITestServiceClient
     {
       global::grpc.testing.Empty EmptyCall(global::grpc.testing.Empty request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
-      Task<global::grpc.testing.Empty> EmptyCallAsync(global::grpc.testing.Empty request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
+      AsyncUnaryCall<global::grpc.testing.Empty> EmptyCallAsync(global::grpc.testing.Empty request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
       global::grpc.testing.SimpleResponse UnaryCall(global::grpc.testing.SimpleRequest request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
-      Task<global::grpc.testing.SimpleResponse> UnaryCallAsync(global::grpc.testing.SimpleRequest request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
+      AsyncUnaryCall<global::grpc.testing.SimpleResponse> UnaryCallAsync(global::grpc.testing.SimpleRequest request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
       AsyncServerStreamingCall<global::grpc.testing.StreamingOutputCallResponse> StreamingOutputCall(global::grpc.testing.StreamingOutputCallRequest request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
       AsyncClientStreamingCall<global::grpc.testing.StreamingInputCallRequest, global::grpc.testing.StreamingInputCallResponse> StreamingInputCall(Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
       AsyncDuplexStreamingCall<global::grpc.testing.StreamingOutputCallRequest, global::grpc.testing.StreamingOutputCallResponse> FullDuplexCall(Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken));
@@ -72,12 +72,12 @@ namespace grpc.testing {
     // server-side interface
     public interface ITestService
     {
-      Task<global::grpc.testing.Empty> EmptyCall(ServerCallContext context, global::grpc.testing.Empty request);
-      Task<global::grpc.testing.SimpleResponse> UnaryCall(ServerCallContext context, global::grpc.testing.SimpleRequest request);
-      Task StreamingOutputCall(ServerCallContext context, global::grpc.testing.StreamingOutputCallRequest request, IServerStreamWriter<global::grpc.testing.StreamingOutputCallResponse> responseStream);
-      Task<global::grpc.testing.StreamingInputCallResponse> StreamingInputCall(ServerCallContext context, IAsyncStreamReader<global::grpc.testing.StreamingInputCallRequest> requestStream);
-      Task FullDuplexCall(ServerCallContext context, IAsyncStreamReader<global::grpc.testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::grpc.testing.StreamingOutputCallResponse> responseStream);
-      Task HalfDuplexCall(ServerCallContext context, IAsyncStreamReader<global::grpc.testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::grpc.testing.StreamingOutputCallResponse> responseStream);
+      Task<global::grpc.testing.Empty> EmptyCall(global::grpc.testing.Empty request, ServerCallContext context);
+      Task<global::grpc.testing.SimpleResponse> UnaryCall(global::grpc.testing.SimpleRequest request, ServerCallContext context);
+      Task StreamingOutputCall(global::grpc.testing.StreamingOutputCallRequest request, IServerStreamWriter<global::grpc.testing.StreamingOutputCallResponse> responseStream, ServerCallContext context);
+      Task<global::grpc.testing.StreamingInputCallResponse> StreamingInputCall(IAsyncStreamReader<global::grpc.testing.StreamingInputCallRequest> requestStream, ServerCallContext context);
+      Task FullDuplexCall(IAsyncStreamReader<global::grpc.testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::grpc.testing.StreamingOutputCallResponse> responseStream, ServerCallContext context);
+      Task HalfDuplexCall(IAsyncStreamReader<global::grpc.testing.StreamingOutputCallRequest> requestStream, IServerStreamWriter<global::grpc.testing.StreamingOutputCallResponse> responseStream, ServerCallContext context);
     }
 
     // client stub
@@ -91,7 +91,7 @@ namespace grpc.testing {
         var call = CreateCall(__ServiceName, __Method_EmptyCall, headers);
         return Calls.BlockingUnaryCall(call, request, cancellationToken);
       }
-      public Task<global::grpc.testing.Empty> EmptyCallAsync(global::grpc.testing.Empty request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken))
+      public AsyncUnaryCall<global::grpc.testing.Empty> EmptyCallAsync(global::grpc.testing.Empty request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         var call = CreateCall(__ServiceName, __Method_EmptyCall, headers);
         return Calls.AsyncUnaryCall(call, request, cancellationToken);
@@ -101,7 +101,7 @@ namespace grpc.testing {
         var call = CreateCall(__ServiceName, __Method_UnaryCall, headers);
         return Calls.BlockingUnaryCall(call, request, cancellationToken);
       }
-      public Task<global::grpc.testing.SimpleResponse> UnaryCallAsync(global::grpc.testing.SimpleRequest request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken))
+      public AsyncUnaryCall<global::grpc.testing.SimpleResponse> UnaryCallAsync(global::grpc.testing.SimpleRequest request, Metadata headers = null, CancellationToken cancellationToken = default(CancellationToken))
       {
         var call = CreateCall(__ServiceName, __Method_UnaryCall, headers);
         return Calls.AsyncUnaryCall(call, request, cancellationToken);
diff --git a/src/csharp/Grpc.IntegrationTesting/TestServiceImpl.cs b/src/csharp/Grpc.IntegrationTesting/TestServiceImpl.cs
index 6bd997d1f4..ccf9fe6ced 100644
--- a/src/csharp/Grpc.IntegrationTesting/TestServiceImpl.cs
+++ b/src/csharp/Grpc.IntegrationTesting/TestServiceImpl.cs
@@ -46,19 +46,19 @@ namespace grpc.testing
     /// </summary>
     public class TestServiceImpl : TestService.ITestService
     {
-        public Task<Empty> EmptyCall(ServerCallContext context, Empty request)
+        public Task<Empty> EmptyCall(Empty request, ServerCallContext context)
         {
             return Task.FromResult(Empty.DefaultInstance);
         }
 
-        public Task<SimpleResponse> UnaryCall(ServerCallContext context, SimpleRequest request)
+        public Task<SimpleResponse> UnaryCall(SimpleRequest request, ServerCallContext context)
         {
             var response = SimpleResponse.CreateBuilder()
                 .SetPayload(CreateZerosPayload(request.ResponseSize)).Build();
             return Task.FromResult(response);
         }
 
-        public async Task StreamingOutputCall(ServerCallContext context, StreamingOutputCallRequest request, IServerStreamWriter<StreamingOutputCallResponse> responseStream)
+        public async Task StreamingOutputCall(StreamingOutputCallRequest request, IServerStreamWriter<StreamingOutputCallResponse> responseStream, ServerCallContext context)
         {
             foreach (var responseParam in request.ResponseParametersList)
             {
@@ -68,7 +68,7 @@ namespace grpc.testing
             }
         }
 
-        public async Task<StreamingInputCallResponse> StreamingInputCall(ServerCallContext context, IAsyncStreamReader<StreamingInputCallRequest> requestStream)
+        public async Task<StreamingInputCallResponse> StreamingInputCall(IAsyncStreamReader<StreamingInputCallRequest> requestStream, ServerCallContext context)
         {
             int sum = 0;
             await requestStream.ForEach(async request =>
@@ -78,7 +78,7 @@ namespace grpc.testing
             return StreamingInputCallResponse.CreateBuilder().SetAggregatedPayloadSize(sum).Build();
         }
 
-        public async Task FullDuplexCall(ServerCallContext context, IAsyncStreamReader<StreamingOutputCallRequest> requestStream, IServerStreamWriter<StreamingOutputCallResponse> responseStream)
+        public async Task FullDuplexCall(IAsyncStreamReader<StreamingOutputCallRequest> requestStream, IServerStreamWriter<StreamingOutputCallResponse> responseStream, ServerCallContext context)
         {
             await requestStream.ForEach(async request =>
             {
@@ -91,7 +91,7 @@ namespace grpc.testing
             });
         }
 
-        public async Task HalfDuplexCall(ServerCallContext context, IAsyncStreamReader<StreamingOutputCallRequest> requestStream, IServerStreamWriter<StreamingOutputCallResponse> responseStream)
+        public async Task HalfDuplexCall(IAsyncStreamReader<StreamingOutputCallRequest> requestStream, IServerStreamWriter<StreamingOutputCallResponse> responseStream, ServerCallContext context)
         {
             throw new NotImplementedException();
         }
diff --git a/src/csharp/ext/grpc_csharp_ext.c b/src/csharp/ext/grpc_csharp_ext.c
index 7dd1959a5f..682521446f 100644
--- a/src/csharp/ext/grpc_csharp_ext.c
+++ b/src/csharp/ext/grpc_csharp_ext.c
@@ -167,6 +167,29 @@ grpcsharp_metadata_array_add(grpc_metadata_array *array, const char *key,
   array->count++;
 }
 
+GPR_EXPORT gpr_intptr GPR_CALLTYPE
+grpcsharp_metadata_array_count(grpc_metadata_array *array) {
+  return (gpr_intptr) array->count;
+}
+
+GPR_EXPORT const char *GPR_CALLTYPE
+grpcsharp_metadata_array_get_key(grpc_metadata_array *array, size_t index) {
+  GPR_ASSERT(index < array->count);
+  return array->metadata[index].key;
+}
+
+GPR_EXPORT const char *GPR_CALLTYPE
+grpcsharp_metadata_array_get_value(grpc_metadata_array *array, size_t index) {
+  GPR_ASSERT(index < array->count);
+  return array->metadata[index].value;
+}
+
+GPR_EXPORT gpr_intptr GPR_CALLTYPE
+grpcsharp_metadata_array_get_value_length(grpc_metadata_array *array, size_t index) {
+  GPR_ASSERT(index < array->count);
+  return (gpr_intptr) array->metadata[index].value_length;
+}
+
 /* Move contents of metadata array */
 void grpcsharp_metadata_array_move(grpc_metadata_array *dest,
                                    grpc_metadata_array *src) {
@@ -218,6 +241,12 @@ GPR_EXPORT void GPR_CALLTYPE grpcsharp_batch_context_destroy(grpcsharp_batch_con
   gpr_free(ctx);
 }
 
+GPR_EXPORT const grpc_metadata_array *GPR_CALLTYPE
+grpcsharp_batch_context_recv_initial_metadata(
+    const grpcsharp_batch_context *ctx) {
+  return &(ctx->recv_initial_metadata);
+}
+
 GPR_EXPORT gpr_intptr GPR_CALLTYPE grpcsharp_batch_context_recv_message_length(
     const grpcsharp_batch_context *ctx) {
   if (!ctx->recv_message) {
@@ -260,6 +289,12 @@ grpcsharp_batch_context_recv_status_on_client_details(
   return ctx->recv_status_on_client.status_details;
 }
 
+GPR_EXPORT const grpc_metadata_array *GPR_CALLTYPE
+grpcsharp_batch_context_recv_status_on_client_trailing_metadata(
+    const grpcsharp_batch_context *ctx) {
+  return &(ctx->recv_status_on_client.trailing_metadata);
+}
+
 GPR_EXPORT grpc_call *GPR_CALLTYPE grpcsharp_batch_context_server_rpc_new_call(
     const grpcsharp_batch_context *ctx) {
   return ctx->server_rpc_new.call;
@@ -271,6 +306,24 @@ grpcsharp_batch_context_server_rpc_new_method(
   return ctx->server_rpc_new.call_details.method;
 }
 
+GPR_EXPORT const char *GPR_CALLTYPE
+grpcsharp_batch_context_server_rpc_new_host(
+    const grpcsharp_batch_context *ctx) {
+  return ctx->server_rpc_new.call_details.host;
+}
+
+GPR_EXPORT gpr_timespec GPR_CALLTYPE
+grpcsharp_batch_context_server_rpc_new_deadline(
+    const grpcsharp_batch_context *ctx) {
+  return ctx->server_rpc_new.call_details.deadline;
+}
+
+GPR_EXPORT const grpc_metadata_array *GPR_CALLTYPE
+grpcsharp_batch_context_server_rpc_new_request_metadata(
+    const grpcsharp_batch_context *ctx) {
+  return &(ctx->server_rpc_new.request_metadata);
+}
+
 GPR_EXPORT gpr_int32 GPR_CALLTYPE
 grpcsharp_batch_context_recv_close_on_server_cancelled(
     const grpcsharp_batch_context *ctx) {
@@ -589,15 +642,20 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE
 grpcsharp_call_send_status_from_server(grpc_call *call,
                                        grpcsharp_batch_context *ctx,
                                        grpc_status_code status_code,
-                                       const char *status_details) {
+                                       const char *status_details,
+                                       grpc_metadata_array *trailing_metadata) {
   /* TODO: don't use magic number */
   grpc_op ops[1];
   ops[0].op = GRPC_OP_SEND_STATUS_FROM_SERVER;
   ops[0].data.send_status_from_server.status = status_code;
   ops[0].data.send_status_from_server.status_details =
       gpr_strdup(status_details);
-  ops[0].data.send_status_from_server.trailing_metadata = NULL;
-  ops[0].data.send_status_from_server.trailing_metadata_count = 0;
+  grpcsharp_metadata_array_move(&(ctx->send_status_from_server.trailing_metadata),
+                                  trailing_metadata);
+  ops[0].data.send_status_from_server.trailing_metadata_count =
+      ctx->send_status_from_server.trailing_metadata.count;
+  ops[0].data.send_status_from_server.trailing_metadata =
+      ctx->send_status_from_server.trailing_metadata.metadata;
   ops[0].flags = 0;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx);
diff --git a/src/node/README.md b/src/node/README.md
index 2f4c49096d..78781dab14 100644
--- a/src/node/README.md
+++ b/src/node/README.md
@@ -54,10 +54,10 @@ function loadObject(reflectionObject)
 Returns the same structure that `load` returns, but takes a reflection object from `ProtoBuf.js` instead of a file name.
 
 ```javascript
-function buildServer(serviceArray)
+function Server([serverOpions])
 ```
 
-Takes an array of service objects and returns a constructor for a server that handles requests to all of those services.
+Constructs a server to which service/implementation pairs can be added.
 
 
 ```javascript
diff --git a/src/node/examples/math_server.js b/src/node/examples/math_server.js
index 0a86e7eaff..b1f8a6323f 100644
--- a/src/node/examples/math_server.js
+++ b/src/node/examples/math_server.js
@@ -36,8 +36,6 @@
 var grpc = require('..');
 var math = grpc.load(__dirname + '/math.proto').math;
 
-var Server = grpc.buildServer([math.Math.service]);
-
 /**
  * Server function for division. Provides the /Math/DivMany and /Math/Div
  * functions (Div is just DivMany with only one stream element). For each
@@ -108,19 +106,17 @@ function mathDivMany(stream) {
     stream.end();
   });
 }
-
-var server = new Server({
-  'math.Math' : {
-    div: mathDiv,
-    fib: mathFib,
-    sum: mathSum,
-    divMany: mathDivMany
-  }
+var server = new grpc.Server();
+server.addProtoService(math.Math.service, {
+  div: mathDiv,
+  fib: mathFib,
+  sum: mathSum,
+  divMany: mathDivMany
 });
 
 if (require.main === module) {
   server.bind('0.0.0.0:50051');
-  server.listen();
+  server.start();
 }
 
 /**
diff --git a/src/node/examples/route_guide_server.js b/src/node/examples/route_guide_server.js
index c777eab7bc..70044a322c 100644
--- a/src/node/examples/route_guide_server.js
+++ b/src/node/examples/route_guide_server.js
@@ -40,8 +40,6 @@ var _ = require('lodash');
 var grpc = require('..');
 var examples = grpc.load(__dirname + '/route_guide.proto').examples;
 
-var Server = grpc.buildServer([examples.RouteGuide.service]);
-
 var COORD_FACTOR = 1e7;
 
 /**
@@ -228,14 +226,14 @@ function routeChat(call) {
  * @return {Server} The new server object
  */
 function getServer() {
-  return new Server({
-    'examples.RouteGuide' : {
-      getFeature: getFeature,
-      listFeatures: listFeatures,
-      recordRoute: recordRoute,
-      routeChat: routeChat
-    }
+  var server = new grpc.Server();
+  server.addProtoService(examples.RouteGuide.service, {
+    getFeature: getFeature,
+    listFeatures: listFeatures,
+    recordRoute: recordRoute,
+    routeChat: routeChat
   });
+  return server;
 }
 
 if (require.main === module) {
diff --git a/src/node/examples/stock_server.js b/src/node/examples/stock_server.js
index caaf9f99ba..f2eb6ad4ab 100644
--- a/src/node/examples/stock_server.js
+++ b/src/node/examples/stock_server.js
@@ -37,8 +37,6 @@ var _ = require('lodash');
 var grpc = require('..');
 var examples = grpc.load(__dirname + '/stock.proto').examples;
 
-var StockServer = grpc.buildServer([examples.Stock.service]);
-
 function getLastTradePrice(call, callback) {
   callback(null, {symbol: call.request.symbol, price: 88});
 }
@@ -73,13 +71,12 @@ function getLastTradePriceMultiple(call) {
   });
 }
 
-var stockServer = new StockServer({
-  'examples.Stock' : {
-    getLastTradePrice: getLastTradePrice,
-    getLastTradePriceMultiple: getLastTradePriceMultiple,
-    watchFutureTrades: watchFutureTrades,
-    getHighestTradePrice: getHighestTradePrice
-  }
+var stockServer = new grpc.Server();
+stockServer.addProtoService(examples.Stock.service, {
+  getLastTradePrice: getLastTradePrice,
+  getLastTradePriceMultiple: getLastTradePriceMultiple,
+  watchFutureTrades: watchFutureTrades,
+  getHighestTradePrice: getHighestTradePrice
 });
 
 if (require.main === module) {
diff --git a/src/node/index.js b/src/node/index.js
index b6a4e2d0ee..d81e780443 100644
--- a/src/node/index.js
+++ b/src/node/index.js
@@ -133,9 +133,9 @@ exports.loadObject = loadObject;
 exports.load = load;
 
 /**
- * See docs for server.makeServerConstructor
+ * See docs for Server
  */
-exports.buildServer = server.makeProtobufServerConstructor;
+exports.Server = server.Server;
 
 /**
  * Status name to code number mapping
@@ -159,5 +159,3 @@ exports.ServerCredentials = grpc.ServerCredentials;
 exports.getGoogleAuthDelegate = getGoogleAuthDelegate;
 
 exports.makeGenericClientConstructor = client.makeClientConstructor;
-
-exports.makeGenericServerConstructor = server.makeServerConstructor;
diff --git a/src/node/interop/interop_client.js b/src/node/interop/interop_client.js
index b61b0b63c0..e810e68e45 100644
--- a/src/node/interop/interop_client.js
+++ b/src/node/interop/interop_client.js
@@ -318,6 +318,51 @@ function authTest(expected_user, scope, client, done) {
   });
 }
 
+function oauth2Test(expected_user, scope, per_rpc, client, done) {
+  (new GoogleAuth()).getApplicationDefault(function(err, credential) {
+    assert.ifError(err);
+    var arg = {
+      fill_username: true,
+      fill_oauth_scope: true
+    };
+    credential = credential.createScoped(scope);
+    credential.getAccessToken(function(err, token) {
+      assert.ifError(err);
+      var updateMetadata = function(authURI, metadata, callback) {
+        metadata = _.clone(metadata);
+        if (metadata.Authorization) {
+          metadata.Authorization = _.clone(metadata.Authorization);
+        } else {
+          metadata.Authorization = [];
+        }
+        metadata.Authorization.push('Bearer ' + token);
+        callback(null, metadata);
+      };
+      var makeTestCall = function(error, client_metadata) {
+        assert.ifError(error);
+        var call = client.unaryCall(arg, function(err, resp) {
+          assert.ifError(err);
+          assert.strictEqual(resp.username, expected_user);
+          assert.strictEqual(resp.oauth_scope, AUTH_SCOPE_RESPONSE);
+        });
+        call.on('status', function(status) {
+          assert.strictEqual(status.code, grpc.status.OK);
+          if (done) {
+            done();
+          }
+        });
+      };
+      if (per_rpc) {
+        updateMetadata('', {}, makeTestCall);
+      } else {
+        client.updateMetadata = updateMetadata;
+        makeTestCall(null, {});
+      }
+
+    });
+  });
+}
+
 /**
  * Map from test case names to test functions
  */
@@ -333,7 +378,9 @@ var test_cases = {
   timeout_on_sleeping_server: timeoutOnSleepingServer,
   compute_engine_creds: _.partial(authTest, COMPUTE_ENGINE_USER, null),
   service_account_creds: _.partial(authTest, AUTH_USER, AUTH_SCOPE),
-  jwt_token_creds: _.partial(authTest, AUTH_USER, null)
+  jwt_token_creds: _.partial(authTest, AUTH_USER, null),
+  oauth2_auth_token: _.partial(oauth2Test, AUTH_USER, AUTH_SCOPE, false),
+  per_rpc_creds: _.partial(oauth2Test, AUTH_USER, AUTH_SCOPE, true)
 };
 
 /**
diff --git a/src/node/interop/interop_server.js b/src/node/interop/interop_server.js
index 0baa78a094..505c6bb537 100644
--- a/src/node/interop/interop_server.js
+++ b/src/node/interop/interop_server.js
@@ -38,7 +38,6 @@ var path = require('path');
 var _ = require('lodash');
 var grpc = require('..');
 var testProto = grpc.load(__dirname + '/test.proto').grpc.testing;
-var Server = grpc.buildServer([testProto.TestService.service]);
 
 /**
  * Create a buffer filled with size zeroes
@@ -173,16 +172,15 @@ function getServer(port, tls) {
                                                     key_data,
                                                     pem_data);
   }
-  var server = new Server({
-    'grpc.testing.TestService' : {
-      emptyCall: handleEmpty,
-      unaryCall: handleUnary,
-      streamingOutputCall: handleStreamingOutput,
-      streamingInputCall: handleStreamingInput,
-      fullDuplexCall: handleFullDuplex,
-      halfDuplexCall: handleHalfDuplex
-    }
-  }, null, options);
+  var server = new grpc.Server(options);
+  server.addProtoService(testProto.TestService.service, {
+    emptyCall: handleEmpty,
+    unaryCall: handleUnary,
+    streamingOutputCall: handleStreamingOutput,
+    streamingInputCall: handleStreamingInput,
+    fullDuplexCall: handleFullDuplex,
+    halfDuplexCall: handleHalfDuplex
+  });
   var port_num = server.bind('0.0.0.0:' + port, server_creds);
   return {server: server, port: port_num};
 }
diff --git a/src/node/src/client.js b/src/node/src/client.js
index b7bad949d4..da6327b432 100644
--- a/src/node/src/client.js
+++ b/src/node/src/client.js
@@ -47,6 +47,7 @@ var Readable = stream.Readable;
 var Writable = stream.Writable;
 var Duplex = stream.Duplex;
 var util = require('util');
+var version = require('../package.json').version;
 
 util.inherits(ClientWritableStream, Writable);
 
@@ -517,9 +518,12 @@ function makeClientConstructor(methods, serviceName) {
         callback(null, metadata);
       };
     }
-
-    this.server_address = address.replace(/\/$/, '');
+    if (!options) {
+      options = {};
+    }
+    options['grpc.primary_user_agent'] = 'grpc-node/' + version;
     this.channel = new grpc.Channel(address, options);
+    this.server_address = address.replace(/\/$/, '');
     this.auth_uri = this.server_address + '/' + serviceName;
     this.updateMetadata = updateMetadata;
   }
diff --git a/src/node/src/server.js b/src/node/src/server.js
index 00be400e61..0a3a0031bd 100644
--- a/src/node/src/server.js
+++ b/src/node/src/server.js
@@ -72,6 +72,9 @@ function handleError(call, error) {
     status.metadata = error.metadata;
   }
   var error_batch = {};
+  if (!call.metadataSent) {
+    error_batch[grpc.opType.SEND_INITIAL_METADATA] = {};
+  }
   error_batch[grpc.opType.SEND_STATUS_FROM_SERVER] = status;
   call.startBatch(error_batch, function(){});
 }
@@ -115,6 +118,10 @@ function sendUnaryResponse(call, value, serialize, metadata) {
   if (metadata) {
     status.metadata = metadata;
   }
+  if (!call.metadataSent) {
+    end_batch[grpc.opType.SEND_INITIAL_METADATA] = {};
+    call.metadataSent = true;
+  }
   end_batch[grpc.opType.SEND_MESSAGE] = serialize(value);
   end_batch[grpc.opType.SEND_STATUS_FROM_SERVER] = status;
   call.startBatch(end_batch, function (){});
@@ -136,6 +143,10 @@ function setUpWritable(stream, serialize) {
   stream.serialize = common.wrapIgnoreNull(serialize);
   function sendStatus() {
     var batch = {};
+    if (!stream.call.metadataSent) {
+      stream.call.metadataSent = true;
+      batch[grpc.opType.SEND_INITIAL_METADATA] = {};
+    }
     batch[grpc.opType.SEND_STATUS_FROM_SERVER] = stream.status;
     stream.call.startBatch(batch, function(){});
   }
@@ -239,6 +250,10 @@ function ServerWritableStream(call, serialize) {
 function _write(chunk, encoding, callback) {
   /* jshint validthis: true */
   var batch = {};
+  if (!this.call.metadataSent) {
+    batch[grpc.opType.SEND_INITIAL_METADATA] = {};
+    this.call.metadataSent = true;
+  }
   batch[grpc.opType.SEND_MESSAGE] = this.serialize(chunk);
   this.call.startBatch(batch, function(err, value) {
     if (err) {
@@ -251,6 +266,23 @@ function _write(chunk, encoding, callback) {
 
 ServerWritableStream.prototype._write = _write;
 
+function sendMetadata(responseMetadata) {
+  /* jshint validthis: true */
+  if (!this.call.metadataSent) {
+    this.call.metadataSent = true;
+    var batch = [];
+    batch[grpc.opType.SEND_INITIAL_METADATA] = responseMetadata;
+    this.call.startBatch(batch, function(err) {
+      if (err) {
+        this.emit('error', err);
+        return;
+      }
+    });
+  }
+}
+
+ServerWritableStream.prototype.sendMetadata = sendMetadata;
+
 util.inherits(ServerReadableStream, Readable);
 
 /**
@@ -339,6 +371,7 @@ function ServerDuplexStream(call, serialize, deserialize) {
 
 ServerDuplexStream.prototype._read = _read;
 ServerDuplexStream.prototype._write = _write;
+ServerDuplexStream.prototype.sendMetadata = sendMetadata;
 
 /**
  * Fully handle a unary call
@@ -348,12 +381,20 @@ ServerDuplexStream.prototype._write = _write;
  */
 function handleUnary(call, handler, metadata) {
   var emitter = new EventEmitter();
+  emitter.sendMetadata = function(responseMetadata) {
+    if (!call.metadataSent) {
+      call.metadataSent = true;
+      var batch = {};
+      batch[grpc.opType.SEND_INITIAL_METADATA] = responseMetadata;
+      call.startBatch(batch, function() {});
+    }
+  };
   emitter.on('error', function(error) {
     handleError(call, error);
   });
+  emitter.metadata = metadata;
   waitForCancel(call, emitter);
   var batch = {};
-  batch[grpc.opType.SEND_INITIAL_METADATA] = metadata;
   batch[grpc.opType.RECV_MESSAGE] = true;
   call.startBatch(batch, function(err, result) {
     if (err) {
@@ -392,8 +433,8 @@ function handleUnary(call, handler, metadata) {
 function handleServerStreaming(call, handler, metadata) {
   var stream = new ServerWritableStream(call, handler.serialize);
   waitForCancel(call, stream);
+  stream.metadata = metadata;
   var batch = {};
-  batch[grpc.opType.SEND_INITIAL_METADATA] = metadata;
   batch[grpc.opType.RECV_MESSAGE] = true;
   call.startBatch(batch, function(err, result) {
     if (err) {
@@ -419,13 +460,19 @@ function handleServerStreaming(call, handler, metadata) {
  */
 function handleClientStreaming(call, handler, metadata) {
   var stream = new ServerReadableStream(call, handler.deserialize);
+  stream.sendMetadata = function(responseMetadata) {
+    if (!call.metadataSent) {
+      call.metadataSent = true;
+      var batch = {};
+      batch[grpc.opType.SEND_INITIAL_METADATA] = responseMetadata;
+      call.startBatch(batch, function() {});
+    }
+  };
   stream.on('error', function(error) {
     handleError(call, error);
   });
   waitForCancel(call, stream);
-  var metadata_batch = {};
-  metadata_batch[grpc.opType.SEND_INITIAL_METADATA] = metadata;
-  call.startBatch(metadata_batch, function() {});
+  stream.metadata = metadata;
   handler.func(stream, function(err, value, trailer) {
     stream.terminate();
     if (err) {
@@ -449,9 +496,7 @@ function handleBidiStreaming(call, handler, metadata) {
   var stream = new ServerDuplexStream(call, handler.serialize,
                                       handler.deserialize);
   waitForCancel(call, stream);
-  var metadata_batch = {};
-  metadata_batch[grpc.opType.SEND_INITIAL_METADATA] = metadata;
-  call.startBatch(metadata_batch, function() {});
+  stream.metadata = metadata;
   handler.func(stream);
 }
 
@@ -466,29 +511,28 @@ var streamHandlers = {
  * Constructs a server object that stores request handlers and delegates
  * incoming requests to those handlers
  * @constructor
- * @param {function(string, Object<string, Array<Buffer>>):
-           Object<string, Array<Buffer|string>>=} getMetadata Callback that gets
- *     metatada for a given method
  * @param {Object=} options Options that should be passed to the internal server
  *     implementation
  */
-function Server(getMetadata, options) {
+function Server(options) {
   this.handlers = {};
   var handlers = this.handlers;
   var server = new grpc.Server(options);
   this._server = server;
+  this.started = false;
   /**
    * Start the server and begin handling requests
    * @this Server
    */
-  this.listen = function() {
+  this.start = function() {
+    if (this.started) {
+      throw new Error('Server is already running');
+    }
+    this.started = true;
     console.log('Server starting');
     _.each(handlers, function(handler, handler_name) {
       console.log('Serving', handler_name);
     });
-    if (this.started) {
-      throw 'Server is already running';
-    }
     server.start();
     /**
      * Handles the SERVER_RPC_NEW event. If there is a handler associated with
@@ -523,11 +567,7 @@ function Server(getMetadata, options) {
         call.startBatch(batch, function() {});
         return;
       }
-      var response_metadata = {};
-      if (getMetadata) {
-        response_metadata = getMetadata(method, metadata);
-      }
-      streamHandlers[handler.type](call, handler, response_metadata);
+      streamHandlers[handler.type](call, handler, metadata);
     }
     server.requestCall(handleNewCall);
   };
@@ -565,6 +605,47 @@ Server.prototype.register = function(name, handler, serialize, deserialize,
   return true;
 };
 
+Server.prototype.addService = function(service, implementation) {
+  if (this.started) {
+    throw new Error('Can\'t add a service to a started server.');
+  }
+  var self = this;
+  _.each(service, function(attrs, name) {
+    var method_type;
+    if (attrs.requestStream) {
+      if (attrs.responseStream) {
+        method_type = 'bidi';
+      } else {
+        method_type = 'client_stream';
+      }
+    } else {
+      if (attrs.responseStream) {
+        method_type = 'server_stream';
+      } else {
+        method_type = 'unary';
+      }
+    }
+    if (implementation[name] === undefined) {
+      throw new Error('Method handler for ' + attrs.path +
+          ' not provided.');
+    }
+    var serialize = attrs.responseSerialize;
+    var deserialize = attrs.requestDeserialize;
+    var register_success = self.register(attrs.path,
+                                         _.bind(implementation[name],
+                                                implementation),
+                                         serialize, deserialize, method_type);
+    if (!register_success) {
+      throw new Error('Method handler for ' + attrs.path +
+          ' already provided.');
+    }
+  });
+};
+
+Server.prototype.addProtoService = function(service, implementation) {
+  this.addService(common.getProtobufServiceAttrs(service), implementation);
+};
+
 /**
  * Binds the server to the given port, with SSL enabled if creds is given
  * @param {string} port The port that the server should bind on, in the format
@@ -573,6 +654,9 @@ Server.prototype.register = function(name, handler, serialize, deserialize,
  *     nothing for an insecure port
  */
 Server.prototype.bind = function(port, creds) {
+  if (this.started) {
+    throw new Error('Can\'t bind an already running server to an address');
+  }
   if (creds) {
     return this._server.addSecureHttp2Port(port, creds);
   } else {
@@ -581,131 +665,6 @@ Server.prototype.bind = function(port, creds) {
 };
 
 /**
- * Create a constructor for servers with services defined by service_attr_map.
- * That is an object that maps (namespaced) service names to objects that in
- * turn map method names to objects with the following keys:
- * path: The path on the server for accessing the method. For example, for
- *     protocol buffers, we use "/service_name/method_name"
- * requestStream: bool indicating whether the client sends a stream
- * resonseStream: bool indicating whether the server sends a stream
- * requestDeserialize: function to deserialize request objects
- * responseSerialize: function to serialize response objects
- * @param {Object} service_attr_map An object mapping service names to method
- *     attribute map objects
- * @return {function(Object, function, Object=)} New server constructor
- */
-function makeServerConstructor(service_attr_map) {
-  /**
-   * Create a server with the given handlers for all of the methods.
-   * @constructor
-   * @param {Object} service_handlers Map from service names to map from method
-   *     names to handlers
-   * @param {function(string, Object<string, Array<Buffer>>):
-             Object<string, Array<Buffer|string>>=} getMetadata Callback that
-   *     gets metatada for a given method
-   * @param {Object=} options Options to pass to the underlying server
-   */
-  function SurfaceServer(service_handlers, getMetadata, options) {
-    var server = new Server(getMetadata, options);
-    this.inner_server = server;
-    _.each(service_attr_map, function(service_attrs, service_name) {
-      if (service_handlers[service_name] === undefined) {
-        throw new Error('Handlers for service ' +
-            service_name + ' not provided.');
-      }
-      _.each(service_attrs, function(attrs, name) {
-        var method_type;
-        if (attrs.requestStream) {
-          if (attrs.responseStream) {
-            method_type = 'bidi';
-          } else {
-            method_type = 'client_stream';
-          }
-        } else {
-          if (attrs.responseStream) {
-            method_type = 'server_stream';
-          } else {
-            method_type = 'unary';
-          }
-        }
-        if (service_handlers[service_name][name] === undefined) {
-          throw new Error('Method handler for ' + attrs.path +
-              ' not provided.');
-        }
-        var serialize = attrs.responseSerialize;
-        var deserialize = attrs.requestDeserialize;
-        server.register(attrs.path, _.bind(service_handlers[service_name][name],
-                                           service_handlers[service_name]),
-                        serialize, deserialize, method_type);
-      });
-    }, this);
-  }
-
-  /**
-   * Binds the server to the given port, with SSL enabled if creds is supplied
-   * @param {string} port The port that the server should bind on, in the format
-   *     "address:port"
-   * @param {boolean=} creds Credentials to use for SSL
-   * @return {SurfaceServer} this
-   */
-  SurfaceServer.prototype.bind = function(port, creds) {
-    return this.inner_server.bind(port, creds);
-  };
-
-  /**
-   * Starts the server listening on any bound ports
-   * @return {SurfaceServer} this
-   */
-  SurfaceServer.prototype.listen = function() {
-    this.inner_server.listen();
-    return this;
-  };
-
-  /**
-   * Shuts the server down; tells it to stop listening for new requests and to
-   * kill old requests.
-   */
-  SurfaceServer.prototype.shutdown = function() {
-    this.inner_server.shutdown();
-  };
-
-  return SurfaceServer;
-}
-
-/**
- * Create a constructor for servers that serve the given services.
- * @param {Array<ProtoBuf.Reflect.Service>} services The services that the
- *     servers will serve
- * @return {function(Object, function, Object=)} New server constructor
- */
-function makeProtobufServerConstructor(services) {
-  var qual_names = [];
-  var service_attr_map = {};
-  _.each(services, function(service) {
-    var service_name = common.fullyQualifiedName(service);
-    _.each(service.children, function(method) {
-      var name = common.fullyQualifiedName(method);
-      if (_.indexOf(qual_names, name) !== -1) {
-        throw new Error('Method ' + name + ' exposed by more than one service');
-      }
-      qual_names.push(name);
-    });
-    var method_attrs = common.getProtobufServiceAttrs(service);
-    if (!service_attr_map.hasOwnProperty(service_name)) {
-      service_attr_map[service_name] = {};
-    }
-    service_attr_map[service_name] = _.extend(service_attr_map[service_name],
-                                              method_attrs);
-  });
-  return makeServerConstructor(service_attr_map);
-}
-
-/**
- * See documentation for makeServerConstructor
- */
-exports.makeServerConstructor = makeServerConstructor;
-
-/**
- * See documentation for makeProtobufServerConstructor
+ * See documentation for Server
  */
-exports.makeProtobufServerConstructor = makeProtobufServerConstructor;
+exports.Server = Server;
diff --git a/src/node/test/health_test.js b/src/node/test/health_test.js
index 4d1a5082e0..bb700cc46c 100644
--- a/src/node/test/health_test.js
+++ b/src/node/test/health_test.js
@@ -49,14 +49,13 @@ describe('Health Checking', function() {
       'grpc.test.TestService': 'SERVING'
     }
   };
-  var HealthServer = grpc.buildServer([health.service]);
-  var healthServer = new HealthServer({
-    'grpc.health.v1alpha.Health': new health.Implementation(statusMap)
-  });
+  var healthServer = new grpc.Server();
+  healthServer.addProtoService(health.service,
+                               new health.Implementation(statusMap));
   var healthClient;
   before(function() {
     var port_num = healthServer.bind('0.0.0.0:0');
-    healthServer.listen();
+    healthServer.start();
     healthClient = new health.Client('localhost:' + port_num);
   });
   after(function() {
diff --git a/src/node/test/interop_sanity_test.js b/src/node/test/interop_sanity_test.js
index fcd8eb6403..0a5eb29c0c 100644
--- a/src/node/test/interop_sanity_test.js
+++ b/src/node/test/interop_sanity_test.js
@@ -46,7 +46,7 @@ describe('Interop tests', function() {
   before(function(done) {
     var server_obj = interop_server.getServer(0, true);
     server = server_obj.server;
-    server.listen();
+    server.start();
     port = 'localhost:' + server_obj.port;
     done();
   });
diff --git a/src/node/test/math_client_test.js b/src/node/test/math_client_test.js
index 3461922e66..f2751857ff 100644
--- a/src/node/test/math_client_test.js
+++ b/src/node/test/math_client_test.js
@@ -52,7 +52,7 @@ var server = require('../examples/math_server.js');
 describe('Math client', function() {
   before(function(done) {
     var port_num = server.bind('0.0.0.0:0');
-    server.listen();
+    server.start();
     math_client = new math.Math('localhost:' + port_num);
     done();
   });
diff --git a/src/node/test/surface_test.js b/src/node/test/surface_test.js
index 125957277f..3cb68f8cd8 100644
--- a/src/node/test/surface_test.js
+++ b/src/node/test/surface_test.js
@@ -69,34 +69,45 @@ describe('File loader', function() {
     });
   });
 });
-describe('Surface server constructor', function() {
-  it('Should fail with conflicting method names', function() {
-    assert.throws(function() {
-      grpc.buildServer([mathService, mathService]);
-    });
+describe('Server.prototype.addProtoService', function() {
+  var server;
+  var dummyImpls = {
+    'div': function() {},
+    'divMany': function() {},
+    'fib': function() {},
+    'sum': function() {}
+  };
+  beforeEach(function() {
+    server = new grpc.Server();
+  });
+  afterEach(function() {
+    server.shutdown();
   });
   it('Should succeed with a single service', function() {
     assert.doesNotThrow(function() {
-      grpc.buildServer([mathService]);
+      server.addProtoService(mathService, dummyImpls);
+    });
+  });
+  it('Should fail with conflicting method names', function() {
+    server.addProtoService(mathService, dummyImpls);
+    assert.throws(function() {
+      server.addProtoService(mathService, dummyImpls);
     });
   });
   it('Should fail with missing handlers', function() {
-    var Server = grpc.buildServer([mathService]);
     assert.throws(function() {
-      new Server({
-        'math.Math': {
-          'div': function() {},
-          'divMany': function() {},
-          'fib': function() {}
-        }
+      server.addProtoService(mathService, {
+        'div': function() {},
+        'divMany': function() {},
+        'fib': function() {}
       });
     }, /math.Math.Sum/);
   });
-  it('Should fail with no handlers for the service', function() {
-    var Server = grpc.buildServer([mathService]);
+  it('Should fail if the server has been started', function() {
+    server.start();
     assert.throws(function() {
-      new Server({});
-    }, /math.Math/);
+      server.addProtoService(mathService, dummyImpls);
+    });
   });
 });
 describe('Echo service', function() {
@@ -105,18 +116,16 @@ describe('Echo service', function() {
   before(function() {
     var test_proto = ProtoBuf.loadProtoFile(__dirname + '/echo_service.proto');
     var echo_service = test_proto.lookup('EchoService');
-    var Server = grpc.buildServer([echo_service]);
-    server = new Server({
-      'EchoService': {
-        echo: function(call, callback) {
-          callback(null, call.request);
-        }
+    server = new grpc.Server();
+    server.addProtoService(echo_service, {
+      echo: function(call, callback) {
+        callback(null, call.request);
       }
     });
     var port = server.bind('localhost:0');
     var Client = surface_client.makeProtobufClientConstructor(echo_service);
     client = new Client('localhost:' + port);
-    server.listen();
+    server.start();
   });
   after(function() {
     server.shutdown();
@@ -151,18 +160,14 @@ describe('Generic client and server', function() {
     var client;
     var server;
     before(function() {
-      var Server = grpc.makeGenericServerConstructor({
-        string: string_service_attrs
-      });
-      server = new Server({
-        string: {
-          capitalize: function(call, callback) {
-            callback(null, _.capitalize(call.request));
-          }
+      server = new grpc.Server();
+      server.addService(string_service_attrs, {
+        capitalize: function(call, callback) {
+          callback(null, _.capitalize(call.request));
         }
       });
       var port = server.bind('localhost:0');
-      server.listen();
+      server.start();
       var Client = grpc.makeGenericClientConstructor(string_service_attrs);
       client = new Client('localhost:' + port);
     });
@@ -178,6 +183,92 @@ describe('Generic client and server', function() {
     });
   });
 });
+describe('Echo metadata', function() {
+  var client;
+  var server;
+  before(function() {
+    var test_proto = ProtoBuf.loadProtoFile(__dirname + '/test_service.proto');
+    var test_service = test_proto.lookup('TestService');
+    server = new grpc.Server();
+    server.addProtoService(test_service, {
+      unary: function(call, cb) {
+        call.sendMetadata(call.metadata);
+        cb(null, {});
+      },
+      clientStream: function(stream, cb){
+        stream.on('data', function(data) {});
+        stream.on('end', function() {
+          stream.sendMetadata(stream.metadata);
+          cb(null, {});
+        });
+      },
+      serverStream: function(stream) {
+        stream.sendMetadata(stream.metadata);
+        stream.end();
+      },
+      bidiStream: function(stream) {
+        stream.on('data', function(data) {});
+        stream.on('end', function() {
+          stream.sendMetadata(stream.metadata);
+          stream.end();
+        });
+      }
+    });
+    var port = server.bind('localhost:0');
+    var Client = surface_client.makeProtobufClientConstructor(test_service);
+    client = new Client('localhost:' + port);
+    server.start();
+  });
+  after(function() {
+    server.shutdown();
+  });
+  it('with unary call', function(done) {
+    var call = client.unary({}, function(err, data) {
+      assert.ifError(err);
+    }, {key: ['value']});
+    call.on('metadata', function(metadata) {
+      assert.deepEqual(metadata.key, ['value']);
+      done();
+    });
+  });
+  it('with client stream call', function(done) {
+    var call = client.clientStream(function(err, data) {
+      assert.ifError(err);
+    }, {key: ['value']});
+    call.on('metadata', function(metadata) {
+      assert.deepEqual(metadata.key, ['value']);
+      done();
+    });
+    call.end();
+  });
+  it('with server stream call', function(done) {
+    var call = client.serverStream({}, {key: ['value']});
+    call.on('data', function() {});
+    call.on('metadata', function(metadata) {
+      assert.deepEqual(metadata.key, ['value']);
+      done();
+    });
+  });
+  it('with bidi stream call', function(done) {
+    var call = client.bidiStream({key: ['value']});
+    call.on('data', function() {});
+    call.on('metadata', function(metadata) {
+      assert.deepEqual(metadata.key, ['value']);
+      done();
+    });
+    call.end();
+  });
+  it('shows the correct user-agent string', function(done) {
+    var version = require('../package.json').version;
+    var call = client.unary({}, function(err, data) {
+      assert.ifError(err);
+    }, {key: ['value']});
+    call.on('metadata', function(metadata) {
+      assert(_.startsWith(metadata['user-agent'], 'grpc-node/' + version));
+      done();
+    });
+  });
+});
 describe('Other conditions', function() {
   var client;
   var server;
@@ -185,72 +276,70 @@ describe('Other conditions', function() {
   before(function() {
     var test_proto = ProtoBuf.loadProtoFile(__dirname + '/test_service.proto');
     var test_service = test_proto.lookup('TestService');
-    var Server = grpc.buildServer([test_service]);
-    server = new Server({
-      TestService: {
-        unary: function(call, cb) {
-          var req = call.request;
-          if (req.error) {
-            cb(new Error('Requested error'), null, {metadata: ['yes']});
+    server = new grpc.Server();
+    server.addProtoService(test_service, {
+      unary: function(call, cb) {
+        var req = call.request;
+        if (req.error) {
+          cb(new Error('Requested error'), null, {trailer_present: ['yes']});
+        } else {
+          cb(null, {count: 1}, {trailer_present: ['yes']});
+        }
+      },
+      clientStream: function(stream, cb){
+        var count = 0;
+        var errored;
+        stream.on('data', function(data) {
+          if (data.error) {
+            errored = true;
+            cb(new Error('Requested error'), null, {trailer_present: ['yes']});
           } else {
-            cb(null, {count: 1}, {metadata: ['yes']});
+            count += 1;
           }
-        },
-        clientStream: function(stream, cb){
-          var count = 0;
-          var errored;
-          stream.on('data', function(data) {
-            if (data.error) {
-              errored = true;
-              cb(new Error('Requested error'), null, {metadata: ['yes']});
-            } else {
-              count += 1;
-            }
-          });
-          stream.on('end', function() {
-            if (!errored) {
-              cb(null, {count: count}, {metadata: ['yes']});
-            }
-          });
-        },
-        serverStream: function(stream) {
-          var req = stream.request;
-          if (req.error) {
+        });
+        stream.on('end', function() {
+          if (!errored) {
+            cb(null, {count: count}, {trailer_present: ['yes']});
+          }
+        });
+      },
+      serverStream: function(stream) {
+        var req = stream.request;
+        if (req.error) {
+          var err = new Error('Requested error');
+          err.metadata = {trailer_present: ['yes']};
+          stream.emit('error', err);
+        } else {
+          for (var i = 0; i < 5; i++) {
+            stream.write({count: i});
+          }
+          stream.end({trailer_present: ['yes']});
+        }
+      },
+      bidiStream: function(stream) {
+        var count = 0;
+        stream.on('data', function(data) {
+          if (data.error) {
             var err = new Error('Requested error');
-            err.metadata = {metadata: ['yes']};
+            err.metadata = {
+              trailer_present: ['yes'],
+              count: ['' + count]
+            };
             stream.emit('error', err);
           } else {
-            for (var i = 0; i < 5; i++) {
-              stream.write({count: i});
-            }
-            stream.end({metadata: ['yes']});
+            stream.write({count: count});
+            count += 1;
           }
-        },
-        bidiStream: function(stream) {
-          var count = 0;
-          stream.on('data', function(data) {
-            if (data.error) {
-              var err = new Error('Requested error');
-              err.metadata = {
-                metadata: ['yes'],
-                count: ['' + count]
-              };
-              stream.emit('error', err);
-            } else {
-              stream.write({count: count});
-              count += 1;
-            }
-          });
-          stream.on('end', function() {
-            stream.end({metadata: ['yes']});
-          });
-        }
+        });
+        stream.on('end', function() {
+          stream.end({trailer_present: ['yes']});
+        });
       }
     });
     port = server.bind('localhost:0');
     var Client = surface_client.makeProtobufClientConstructor(test_service);
     client = new Client('localhost:' + port);
-    server.listen();
+    server.start();
   });
   after(function() {
     server.shutdown();
@@ -340,7 +429,7 @@ describe('Other conditions', function() {
         assert.ifError(err);
       });
       call.on('status', function(status) {
-        assert.deepEqual(status.metadata.metadata, ['yes']);
+        assert.deepEqual(status.metadata.trailer_present, ['yes']);
         done();
       });
     });
@@ -349,7 +438,7 @@ describe('Other conditions', function() {
         assert(err);
       });
       call.on('status', function(status) {
-        assert.deepEqual(status.metadata.metadata, ['yes']);
+        assert.deepEqual(status.metadata.trailer_present, ['yes']);
         done();
       });
     });
@@ -361,7 +450,7 @@ describe('Other conditions', function() {
       call.write({error: false});
       call.end();
       call.on('status', function(status) {
-        assert.deepEqual(status.metadata.metadata, ['yes']);
+        assert.deepEqual(status.metadata.trailer_present, ['yes']);
         done();
       });
     });
@@ -373,7 +462,7 @@ describe('Other conditions', function() {
       call.write({error: true});
       call.end();
       call.on('status', function(status) {
-        assert.deepEqual(status.metadata.metadata, ['yes']);
+        assert.deepEqual(status.metadata.trailer_present, ['yes']);
         done();
       });
     });
@@ -382,7 +471,7 @@ describe('Other conditions', function() {
       call.on('data', function(){});
       call.on('status', function(status) {
         assert.strictEqual(status.code, grpc.status.OK);
-        assert.deepEqual(status.metadata.metadata, ['yes']);
+        assert.deepEqual(status.metadata.trailer_present, ['yes']);
         done();
       });
     });
@@ -390,7 +479,7 @@ describe('Other conditions', function() {
       var call = client.serverStream({error: true});
       call.on('data', function(){});
       call.on('error', function(error) {
-        assert.deepEqual(error.metadata.metadata, ['yes']);
+        assert.deepEqual(error.metadata.trailer_present, ['yes']);
         done();
       });
     });
@@ -402,7 +491,7 @@ describe('Other conditions', function() {
       call.on('data', function(){});
       call.on('status', function(status) {
         assert.strictEqual(status.code, grpc.status.OK);
-        assert.deepEqual(status.metadata.metadata, ['yes']);
+        assert.deepEqual(status.metadata.trailer_present, ['yes']);
         done();
       });
     });
@@ -413,7 +502,7 @@ describe('Other conditions', function() {
       call.end();
       call.on('data', function(){});
       call.on('error', function(error) {
-        assert.deepEqual(error.metadata.metadata, ['yes']);
+        assert.deepEqual(error.metadata.trailer_present, ['yes']);
         done();
       });
     });
@@ -465,18 +554,17 @@ describe('Cancelling surface client', function() {
   var client;
   var server;
   before(function() {
-    var Server = grpc.buildServer([mathService]);
-    server = new Server({
-      'math.Math': {
-        'div': function(stream) {},
-        'divMany': function(stream) {},
-        'fib': function(stream) {},
-        'sum': function(stream) {}
-      }
+    server = new grpc.Server();
+    server.addProtoService(mathService, {
+      'div': function(stream) {},
+      'divMany': function(stream) {},
+      'fib': function(stream) {},
+      'sum': function(stream) {}
     });
     var port = server.bind('localhost:0');
     var Client = surface_client.makeProtobufClientConstructor(mathService);
     client = new Client('localhost:' + port);
+    server.start();
   });
   after(function() {
     server.shutdown();
diff --git a/src/objective-c/GRPCClient/GRPCCall.m b/src/objective-c/GRPCClient/GRPCCall.m
index 53e5abe177..9435bf2b35 100644
--- a/src/objective-c/GRPCClient/GRPCCall.m
+++ b/src/objective-c/GRPCClient/GRPCCall.m
@@ -35,10 +35,10 @@
 
 #include <grpc/grpc.h>
 #include <grpc/support/time.h>
+#import <RxLibrary/GRXConcurrentWriteable.h>
 
 #import "private/GRPCChannel.h"
 #import "private/GRPCCompletionQueue.h"
-#import "private/GRPCDelegateWrapper.h"
 #import "private/GRPCWrappedCall.h"
 #import "private/NSData+GRPC.h"
 #import "private/NSDictionary+GRPC.h"
@@ -78,9 +78,13 @@ NSString * const kGRPCStatusMetadataKey = @"io.grpc.StatusMetadataKey";
   // do. Particularly, in the face of errors, there's no ordering guarantee at
   // all. This wrapper over our actual writeable ensures thread-safety and
   // correct ordering.
-  GRPCDelegateWrapper *_responseWriteable;
+  GRXConcurrentWriteable *_responseWriteable;
   GRXWriter *_requestWriter;
 
+  // To create a retain cycle when a call is started, up until it finishes. See
+  // |startWithWriteable:| and |finishWithError:|.
+  GRPCCall *_self;
+
   NSMutableDictionary *_requestMetadata;
   NSMutableDictionary *_responseMetadata;
 }
@@ -143,8 +147,13 @@ NSString * const kGRPCStatusMetadataKey = @"io.grpc.StatusMetadataKey";
 #pragma mark Finish
 
 - (void)finishWithError:(NSError *)errorOrNil {
+  // If the call isn't retained anywhere else, it can be deallocated now.
+  _self = nil;
+
+  // If there were still request messages coming, stop them.
   _requestWriter.state = GRXWriterStateFinished;
   _requestWriter = nil;
+
   if (errorOrNil) {
     [_responseWriteable cancelWithError:errorOrNil];
   } else {
@@ -191,7 +200,7 @@ NSString * const kGRPCStatusMetadataKey = @"io.grpc.StatusMetadataKey";
     return;
   }
   __weak GRPCCall *weakSelf = self;
-  __weak GRPCDelegateWrapper *weakWriteable = _responseWriteable;
+  __weak GRXConcurrentWriteable *weakWriteable = _responseWriteable;
 
   dispatch_async(_callQueue, ^{
     [weakSelf startReadWithHandler:^(grpc_byte_buffer *message) {
@@ -216,7 +225,7 @@ NSString * const kGRPCStatusMetadataKey = @"io.grpc.StatusMetadataKey";
         [weakSelf cancelCall];
         return;
       }
-      [weakWriteable enqueueMessage:data completionHandler:^{
+      [weakWriteable enqueueValue:data completionHandler:^{
         [weakSelf startNextRead];
       }];
     }];
@@ -276,6 +285,7 @@ NSString * const kGRPCStatusMetadataKey = @"io.grpc.StatusMetadataKey";
 }
 
 - (void)writesFinishedWithError:(NSError *)errorOrNil {
+  _requestWriter = nil;
   if (errorOrNil) {
     [self cancel];
   } else {
@@ -335,12 +345,14 @@ NSString * const kGRPCStatusMetadataKey = @"io.grpc.StatusMetadataKey";
 #pragma mark GRXWriter implementation
 
 - (void)startWithWriteable:(id<GRXWriteable>)writeable {
-  // The following produces a retain cycle self:_responseWriteable:self, which is only
-  // broken when writesFinishedWithError: is sent to the wrapped writeable.
-  // Care is taken not to retain self strongly in any of the blocks used in
-  // the implementation of GRPCCall, so that the life of the instance is
-  // determined by this retain cycle.
-  _responseWriteable = [[GRPCDelegateWrapper alloc] initWithWriteable:writeable writer:self];
+  // Create a retain cycle so that this instance lives until the RPC finishes (or is cancelled).
+  // This makes RPCs in which the call isn't externally retained possible (as long as it is started
+  // before being autoreleased).
+  // Care is taken not to retain self strongly in any of the blocks used in this implementation, so
+  // that the life of the instance is determined by this retain cycle.
+  _self = self;
+
+  _responseWriteable = [[GRXConcurrentWriteable alloc] initWithWriteable:writeable];
   [self sendHeaders:_requestMetadata];
   [self invokeCall];
 }
diff --git a/src/objective-c/GRPCClient/private/GRPCCompletionQueue.m b/src/objective-c/GRPCClient/private/GRPCCompletionQueue.m
index 40aade4f9a..12535c9616 100644
--- a/src/objective-c/GRPCClient/private/GRPCCompletionQueue.m
+++ b/src/objective-c/GRPCClient/private/GRPCCompletionQueue.m
@@ -65,7 +65,8 @@
     dispatch_async(gDefaultConcurrentQueue, ^{
       while (YES) {
         // The following call blocks until an event is available.
-        grpc_event event = grpc_completion_queue_next(unmanagedQueue, gpr_inf_future);
+        grpc_event event = grpc_completion_queue_next(unmanagedQueue,
+                                                      gpr_inf_future(GPR_CLOCK_REALTIME));
         GRPCQueueCompletionHandler handler;
         switch (event.type) {
           case GRPC_OP_COMPLETE:
diff --git a/src/objective-c/GRPCClient/private/GRPCWrappedCall.m b/src/objective-c/GRPCClient/private/GRPCWrappedCall.m
index 45f10f5d63..1db63df77f 100644
--- a/src/objective-c/GRPCClient/private/GRPCWrappedCall.m
+++ b/src/objective-c/GRPCClient/private/GRPCWrappedCall.m
@@ -246,8 +246,11 @@
     if (!_queue) {
       return nil;
     }
-    _call = grpc_channel_create_call(channel.unmanagedChannel, _queue.unmanagedQueue,
-                                     path.UTF8String, host.UTF8String, gpr_inf_future);
+    _call = grpc_channel_create_call(channel.unmanagedChannel,
+                                     _queue.unmanagedQueue,
+                                     path.UTF8String,
+                                     host.UTF8String,
+                                     gpr_inf_future(GPR_CLOCK_REALTIME));
     if (_call == NULL) {
       return nil;
     }
diff --git a/src/objective-c/GRPCClient/private/GRPCDelegateWrapper.h b/src/objective-c/RxLibrary/GRXConcurrentWriteable.h
index 9a30a2f966..1080001905 100644
--- a/src/objective-c/GRPCClient/private/GRPCDelegateWrapper.h
+++ b/src/objective-c/RxLibrary/GRXConcurrentWriteable.h
@@ -33,49 +33,39 @@
 
 #import <Foundation/Foundation.h>
 
-#import <RxLibrary/GRXWriter.h>
+#import "GRXWriter.h"
+#import "GRXWriteable.h"
 
-@protocol GRXWriteable;
-
-// This is a thread-safe wrapper over a GRXWriteable instance. It lets one
-// enqueue calls to a GRXWriteable instance for the main thread, guaranteeing
-// that writesFinishedWithError: is the last message sent to it (no matter what
-// messages are sent to the wrapper, in what order, nor from which thread). It
-// also guarantees that, if cancelWithError: is called from the main thread
-// (e.g. by the app cancelling the writes), no further messages are sent to the
-// writeable except writesFinishedWithError:.
+// This is a thread-safe wrapper over a GRXWriteable instance. It lets one enqueue calls to a
+// GRXWriteable instance for the main thread, guaranteeing that writesFinishedWithError: is the last
+// message sent to it (no matter what messages are sent to the wrapper, in what order, nor from
+// which thread). It also guarantees that, if cancelWithError: is called from the main thread (e.g.
+// by the app cancelling the writes), no further messages are sent to the writeable except
+// writesFinishedWithError:.
 //
-// TODO(jcanizales): Let the user specify another queue for the writeable
-// callbacks.
-// TODO(jcanizales): Rename to GRXWriteableWrapper and move to the Rx library.
-@interface GRPCDelegateWrapper : NSObject
+// TODO(jcanizales): Let the user specify another queue for the writeable callbacks.
+@interface GRXConcurrentWriteable : NSObject
 
 // The GRXWriteable passed is the wrapped writeable.
-// Both the GRXWriter instance and the GRXWriteable instance are retained until
-// writesFinishedWithError: is sent to the writeable, and released after that.
-// This is used to create a retain cycle that keeps both objects alive until the
-// writing is explicitly finished.
-- (instancetype)initWithWriteable:(id<GRXWriteable>)writeable writer:(GRXWriter *)writer
-    NS_DESIGNATED_INITIALIZER;
+// The GRXWriteable instance is retained until writesFinishedWithError: is sent to it, and released
+// after that.
+- (instancetype)initWithWriteable:(id<GRXWriteable>)writeable NS_DESIGNATED_INITIALIZER;
 
 // Enqueues writeValue: to be sent to the writeable in the main thread.
 // The passed handler is invoked from the main thread after writeValue: returns.
-- (void)enqueueMessage:(NSData *)message completionHandler:(void (^)())handler;
+- (void)enqueueValue:(id)value completionHandler:(void (^)())handler;
 
-// Enqueues writesFinishedWithError:nil to be sent to the writeable in the main
-// thread. After that message is sent to the writeable, all other methods of
-// this object are effectively noops.
+// Enqueues writesFinishedWithError:nil to be sent to the writeable in the main thread. After that
+// message is sent to the writeable, all other methods of this object are effectively noops.
 - (void)enqueueSuccessfulCompletion;
 
-// If the writeable has not yet received a writesFinishedWithError: message, this
-// will enqueue one to be sent to it in the main thread, and cancel all other
-// pending messages to the writeable enqueued by this object (both past and
-// future).
+// If the writeable has not yet received a writesFinishedWithError: message, this will enqueue one
+// to be sent to it in the main thread, and cancel all other pending messages to the writeable
+// enqueued by this object (both past and future).
 // The error argument cannot be nil.
 - (void)cancelWithError:(NSError *)error;
 
-// Cancels all pending messages to the writeable enqueued by this object (both
-// past and future). Because the writeable won't receive writesFinishedWithError:,
-// this also releases the writeable and the writer.
+// Cancels all pending messages to the writeable enqueued by this object (both past and future).
+// Because the writeable won't receive writesFinishedWithError:, this also releases the writeable.
 - (void)cancelSilently;
 @end
diff --git a/src/objective-c/GRPCClient/private/GRPCDelegateWrapper.m b/src/objective-c/RxLibrary/GRXConcurrentWriteable.m
index 294cfb7e23..08bd079aea 100644
--- a/src/objective-c/GRPCClient/private/GRPCDelegateWrapper.m
+++ b/src/objective-c/RxLibrary/GRXConcurrentWriteable.m
@@ -31,45 +31,42 @@
  *
  */
 
-#import "GRPCDelegateWrapper.h"
+#import "GRXConcurrentWriteable.h"
 
 #import <RxLibrary/GRXWriteable.h>
 
-@interface GRPCDelegateWrapper ()
-// These are atomic so that cancellation can nillify them from any thread.
+@interface GRXConcurrentWriteable ()
+// This is atomic so that cancellation can nillify it from any thread.
 @property(atomic, strong) id<GRXWriteable> writeable;
-@property(atomic, strong) GRXWriter *writer;
 @end
 
-@implementation GRPCDelegateWrapper {
+@implementation GRXConcurrentWriteable {
   dispatch_queue_t _writeableQueue;
   // This ensures that writesFinishedWithError: is only sent once to the writeable.
   dispatch_once_t _alreadyFinished;
 }
 
 - (instancetype)init {
-  return [self initWithWriteable:nil writer:nil];
+  return [self initWithWriteable:nil];
 }
 
 // Designated initializer
-- (instancetype)initWithWriteable:(id<GRXWriteable>)writeable writer:(GRXWriter *)writer {
+- (instancetype)initWithWriteable:(id<GRXWriteable>)writeable {
   if (self = [super init]) {
     _writeableQueue = dispatch_get_main_queue();
     _writeable = writeable;
-    _writer = writer;
   }
   return self;
 }
 
-- (void)enqueueMessage:(NSData *)message completionHandler:(void (^)())handler {
+- (void)enqueueValue:(id)value completionHandler:(void (^)())handler {
   dispatch_async(_writeableQueue, ^{
-    // We're racing a possible cancellation performed by another thread. To turn
-    // all already-enqueued messages into noops, cancellation nillifies the
-    // writeable property. If we get it before it's nil, we won
-    // the race.
+    // We're racing a possible cancellation performed by another thread. To turn all already-
+    // enqueued messages into noops, cancellation nillifies the writeable property. If we get it
+    // before it's nil, we won the race.
     id<GRXWriteable> writeable = self.writeable;
     if (writeable) {
-      [writeable writeValue:message];
+      [writeable writeValue:value];
       handler();
     }
   });
@@ -78,13 +75,11 @@
 - (void)enqueueSuccessfulCompletion {
   dispatch_async(_writeableQueue, ^{
     dispatch_once(&_alreadyFinished, ^{
-      // Cancellation is now impossible. None of the other three blocks can run
-      // concurrently with this one.
+      // Cancellation is now impossible. None of the other three blocks can run concurrently with
+      // this one.
       [self.writeable writesFinishedWithError:nil];
-      // Break the retain cycle with writer, and skip any possible message to the
-      // wrapped writeable enqueued after this one.
+      // Skip any possible message to the wrapped writeable enqueued after this one.
       self.writeable = nil;
-      self.writer = nil;
     });
   });
 }
@@ -92,29 +87,24 @@
 - (void)cancelWithError:(NSError *)error {
   NSAssert(error, @"For a successful completion, use enqueueSuccessfulCompletion.");
   dispatch_once(&_alreadyFinished, ^{
-    // Skip any of the still-enqueued messages to the wrapped writeable. We use
-    // the atomic setter to nillify writer and writeable because we might be
-    // running concurrently with the blocks in _writeableQueue, and assignment
-    // with ARC isn't atomic.
+    // Skip any of the still-enqueued messages to the wrapped writeable. We use the atomic setter to
+    // nillify writeable because we might be running concurrently with the blocks in
+    // _writeableQueue, and assignment with ARC isn't atomic.
     id<GRXWriteable> writeable = self.writeable;
     self.writeable = nil;
 
     dispatch_async(_writeableQueue, ^{
       [writeable writesFinishedWithError:error];
-      // Break the retain cycle with writer.
-      self.writer = nil;
     });
   });
 }
 
 - (void)cancelSilently {
   dispatch_once(&_alreadyFinished, ^{
-    // Skip any of the still-enqueued messages to the wrapped writeable. We use
-    // the atomic setter to nillify writer and writeable because we might be
-    // running concurrently with the blocks in _writeableQueue, and assignment
-    // with ARC isn't atomic.
+    // Skip any of the still-enqueued messages to the wrapped writeable. We use the atomic setter to
+    // nillify writeable because we might be running concurrently with the blocks in
+    // _writeableQueue, and assignment with ARC isn't atomic.
     self.writeable = nil;
-    self.writer = nil;
   });
 }
 @end
diff --git a/src/objective-c/RxLibrary/GRXImmediateWriter.m b/src/objective-c/RxLibrary/GRXImmediateWriter.m
index b6d2b2cac0..3edae788ab 100644
--- a/src/objective-c/RxLibrary/GRXImmediateWriter.m
+++ b/src/objective-c/RxLibrary/GRXImmediateWriter.m
@@ -76,28 +76,15 @@
 }
 
 + (GRXWriter *)writerWithValue:(id)value {
-  if (value) {
-    return [self writerWithEnumerator:[NSEnumerator grx_enumeratorWithSingleValue:value]];
-  } else {
-    return [self emptyWriter];
-  }
+  return [self writerWithEnumerator:[NSEnumerator grx_enumeratorWithSingleValue:value]];
 }
 
 + (GRXWriter *)writerWithError:(NSError *)error {
-  if (error) {
-    return [self writerWithEnumerator:nil error:error];
-  } else {
-    return [self emptyWriter];
-  }
+  return [self writerWithEnumerator:nil error:error];
 }
 
 + (GRXWriter *)emptyWriter {
-  static GRXImmediateWriter *emptyWriter;
-  static dispatch_once_t onceToken;
-  dispatch_once(&onceToken, ^{
-    emptyWriter = [self writerWithEnumerator:nil error:nil];
-  });
-  return emptyWriter;
+  return [self writerWithEnumerator:nil error:nil];
 }
 
 #pragma mark Conformance with GRXWriter
diff --git a/src/objective-c/RxLibrary/private/GRXNSFastEnumerator.m b/src/objective-c/RxLibrary/private/GRXNSFastEnumerator.m
index 2050fa98ec..0387c9954e 100644
--- a/src/objective-c/RxLibrary/private/GRXNSFastEnumerator.m
+++ b/src/objective-c/RxLibrary/private/GRXNSFastEnumerator.m
@@ -59,7 +59,6 @@
 
 // Designated initializer.
 - (instancetype)initWithContainer:(id<NSFastEnumeration>)container {
-  NSAssert(container, @"container can't be nil");
   if ((self = [super init])) {
     _container = container;
   }
diff --git a/src/objective-c/generated_libraries/RemoteTestClient/RemoteTest.podspec b/src/objective-c/generated_libraries/RemoteTestClient/RemoteTest.podspec
index dd0dab352d..7cc9a040fe 100644
--- a/src/objective-c/generated_libraries/RemoteTestClient/RemoteTest.podspec
+++ b/src/objective-c/generated_libraries/RemoteTestClient/RemoteTest.podspec
@@ -7,7 +7,13 @@ Pod::Spec.new do |s|
   s.osx.deployment_target = "10.8"
 
   # Run protoc with the Objective-C and gRPC plugins to generate protocol messages and gRPC clients.
-  s.prepare_command = "protoc --objc_out=. --objcgrpc_out=. *.proto"
+  s.prepare_command = <<-CMD
+    cd ../../../..
+    # TODO(jcanizales): Make only Objective-C plugin.
+    make plugins
+    cd -
+    protoc --plugin=protoc-gen-grpc=../../../../bins/opt/grpc_objective_c_plugin --objc_out=. --grpc_out=. *.proto
+  CMD
 
   s.subspec "Messages" do |ms|
     ms.source_files = "*.pbobjc.{h,m}"
diff --git a/src/objective-c/generated_libraries/RouteGuideClient/RouteGuide.podspec b/src/objective-c/generated_libraries/RouteGuideClient/RouteGuide.podspec
index e26e62f5bb..0e8dacd1c4 100644
--- a/src/objective-c/generated_libraries/RouteGuideClient/RouteGuide.podspec
+++ b/src/objective-c/generated_libraries/RouteGuideClient/RouteGuide.podspec
@@ -7,7 +7,13 @@ Pod::Spec.new do |s|
   s.osx.deployment_target = "10.8"
 
   # Run protoc with the Objective-C and gRPC plugins to generate protocol messages and gRPC clients.
-  s.prepare_command = "protoc --objc_out=. --objcgrpc_out=. *.proto"
+  s.prepare_command = <<-CMD
+    cd ../../../..
+    # TODO(jcanizales): Make only Objective-C plugin.
+    make plugins
+    cd -
+    protoc --plugin=protoc-gen-grpc=../../../../bins/opt/grpc_objective_c_plugin --objc_out=. --grpc_out=. *.proto
+  CMD
 
   s.subspec "Messages" do |ms|
     ms.source_files = "*.pbobjc.{h,m}"
diff --git a/src/objective-c/tests/Tests.xcodeproj/project.pbxproj b/src/objective-c/tests/Tests.xcodeproj/project.pbxproj
index 34be705db2..f13fb8288b 100644
--- a/src/objective-c/tests/Tests.xcodeproj/project.pbxproj
+++ b/src/objective-c/tests/Tests.xcodeproj/project.pbxproj
@@ -391,7 +391,6 @@
 		635697DC1B14FC11007A7283 /* Debug */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
-				OTHER_LDFLAGS = "-ObjC";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
 			};
@@ -400,7 +399,6 @@
 		635697DD1B14FC11007A7283 /* Release */ = {
 			isa = XCBuildConfiguration;
 			buildSettings = {
-				OTHER_LDFLAGS = "-ObjC";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
 			};
diff --git a/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/AllTests.xcscheme b/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/AllTests.xcscheme
new file mode 100644
index 0000000000..3a6e2c3591
--- /dev/null
+++ b/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/AllTests.xcscheme
@@ -0,0 +1,104 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "0630"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "NO"
+            buildForArchiving = "NO"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "63423F431B150A5F006CF63C"
+               BuildableName = "AllTests.xctest"
+               BlueprintName = "AllTests"
+               ReferencedContainer = "container:Tests.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      buildConfiguration = "Debug">
+      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "63423F431B150A5F006CF63C"
+               BuildableName = "AllTests.xctest"
+               BlueprintName = "AllTests"
+               ReferencedContainer = "container:Tests.xcodeproj">
+            </BuildableReference>
+            <SkippedTests>
+               <Test
+                  Identifier = "LocalClearTextTests">
+               </Test>
+               <Test
+                  Identifier = "LocalClearTextTests/testConnectionToLocalServer">
+               </Test>
+            </SkippedTests>
+         </TestableReference>
+      </Testables>
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "63423F431B150A5F006CF63C"
+            BuildableName = "AllTests.xctest"
+            BlueprintName = "AllTests"
+            ReferencedContainer = "container:Tests.xcodeproj">
+         </BuildableReference>
+      </MacroExpansion>
+   </TestAction>
+   <LaunchAction
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      buildConfiguration = "Debug"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      allowLocationSimulation = "YES">
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "63423F431B150A5F006CF63C"
+            BuildableName = "AllTests.xctest"
+            BlueprintName = "AllTests"
+            ReferencedContainer = "container:Tests.xcodeproj">
+         </BuildableReference>
+      </MacroExpansion>
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </LaunchAction>
+   <ProfileAction
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      buildConfiguration = "Release"
+      debugDocumentVersioning = "YES">
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "63423F431B150A5F006CF63C"
+            BuildableName = "AllTests.xctest"
+            BlueprintName = "AllTests"
+            ReferencedContainer = "container:Tests.xcodeproj">
+         </BuildableReference>
+      </MacroExpansion>
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>
diff --git a/src/objective-c/tests/run_tests.sh b/src/objective-c/tests/run_tests.sh
new file mode 100755
index 0000000000..37fced3a62
--- /dev/null
+++ b/src/objective-c/tests/run_tests.sh
@@ -0,0 +1,49 @@
+#!/bin/bash
+# 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.
+
+set -e
+
+cd $(dirname $0)
+
+# TODO(jcanizales): Remove when Cocoapods issue #3823 is resolved.
+export COCOAPODS_DISABLE_DETERMINISTIC_UUIDS=YES
+pod install
+
+# xcodebuild is very verbose. We filter its output and tell Bash to fail if any
+# element of the pipe fails.
+# TODO(jcanizales): Use xctool instead? Issue #2540.
+set -o pipefail
+XCODEBUILD_FILTER='(^===|^\*\*|\bfatal\b|\berror\b|\bwarning\b|\bfail)'
+xcodebuild \
+    -workspace Tests.xcworkspace \
+    -scheme AllTests \
+    -destination name="iPhone 6" \
+    test \
+    | egrep "$XCODEBUILD_FILTER" -
diff --git a/src/php/ext/grpc/server.c b/src/php/ext/grpc/server.c
index c319526e42..8b8d5b2f47 100644
--- a/src/php/ext/grpc/server.c
+++ b/src/php/ext/grpc/server.c
@@ -64,6 +64,7 @@ void free_wrapped_grpc_server(void *object TSRMLS_DC) {
   wrapped_grpc_server *server = (wrapped_grpc_server *)object;
   if (server->wrapped != NULL) {
     grpc_server_shutdown_and_notify(server->wrapped, completion_queue, NULL);
+    grpc_server_cancel_all_calls(server->wrapped);
     grpc_completion_queue_pluck(completion_queue, NULL,
                                 gpr_inf_future(GPR_CLOCK_REALTIME));
     grpc_server_destroy(server->wrapped);
diff --git a/src/php/tests/unit_tests/EndToEndTest.php b/src/php/tests/unit_tests/EndToEndTest.php
index 296873fa8f..2980dca4a7 100755
--- a/src/php/tests/unit_tests/EndToEndTest.php
+++ b/src/php/tests/unit_tests/EndToEndTest.php
@@ -61,7 +61,6 @@ class EndToEndTest extends PHPUnit_Framework_TestCase{
 
     $event = $this->server->requestCall();
     $this->assertSame('dummy_method', $event->method);
-    $this->assertSame([], $event->metadata);
     $server_call = $event->call;
 
     $event = $server_call->startBatch([
@@ -83,7 +82,6 @@ class EndToEndTest extends PHPUnit_Framework_TestCase{
         Grpc\OP_RECV_STATUS_ON_CLIENT => true
                                  ]);
 
-    $this->assertSame([], $event->metadata);
     $status = $event->status;
     $this->assertSame([], $status->metadata);
     $this->assertSame(Grpc\STATUS_OK, $status->code);
diff --git a/src/php/tests/unit_tests/SecureEndToEndTest.php b/src/php/tests/unit_tests/SecureEndToEndTest.php
index 0c18cd3e91..f91c006da5 100755
--- a/src/php/tests/unit_tests/SecureEndToEndTest.php
+++ b/src/php/tests/unit_tests/SecureEndToEndTest.php
@@ -73,7 +73,6 @@ class SecureEndToEndTest extends PHPUnit_Framework_TestCase{
 
     $event = $this->server->requestCall();
     $this->assertSame('dummy_method', $event->method);
-    $this->assertSame([], $event->metadata);
     $server_call = $event->call;
 
     $event = $server_call->startBatch([
diff --git a/src/python/src/grpc/_adapter/_c/utility.c b/src/python/src/grpc/_adapter/_c/utility.c
index 000c8d0c38..d9f911a41a 100644
--- a/src/python/src/grpc/_adapter/_c/utility.c
+++ b/src/python/src/grpc/_adapter/_c/utility.c
@@ -489,10 +489,10 @@ PyObject *pygrpc_cast_metadata_array_to_pyseq(grpc_metadata_array metadata) {
 void pygrpc_byte_buffer_to_bytes(
     grpc_byte_buffer *buffer, char **result, size_t *result_size) {
   grpc_byte_buffer_reader reader;
-  grpc_byte_buffer_reader_init(&reader, buffer);
   gpr_slice slice;
   char *read_result = NULL;
   size_t size = 0;
+  grpc_byte_buffer_reader_init(&reader, buffer);
   while (grpc_byte_buffer_reader_next(&reader, &slice)) {
     read_result = gpr_realloc(read_result, size + GPR_SLICE_LENGTH(slice));
     memcpy(read_result + size, GPR_SLICE_START_PTR(slice),
diff --git a/src/python/src/grpc/_adapter/_low_test.py b/src/python/src/grpc/_adapter/_low_test.py
index 268e5fe765..a49cd007bf 100644
--- a/src/python/src/grpc/_adapter/_low_test.py
+++ b/src/python/src/grpc/_adapter/_low_test.py
@@ -129,7 +129,10 @@ class InsecureServerInsecureClient(unittest.TestCase):
     self.assertIsInstance(request_event.call, _low.Call)
     self.assertIs(server_request_tag, request_event.tag)
     self.assertEquals(1, len(request_event.results))
-    self.assertEquals(dict(client_initial_metadata), dict(request_event.results[0].initial_metadata))
+    got_initial_metadata = dict(request_event.results[0].initial_metadata)
+    self.assertEquals(
+        dict(client_initial_metadata),
+        dict((x, got_initial_metadata[x]) for x in zip(*client_initial_metadata)[0]))
     self.assertEquals(METHOD, request_event.call_details.method)
     self.assertEquals(HOST, request_event.call_details.host)
     self.assertLess(abs(DEADLINE - request_event.call_details.deadline), DEADLINE_TOLERANCE)
diff --git a/src/python/src/grpc/_links/_transmission_test.py b/src/python/src/grpc/_links/_transmission_test.py
index c5ef1edb25..3eeec03f46 100644
--- a/src/python/src/grpc/_links/_transmission_test.py
+++ b/src/python/src/grpc/_links/_transmission_test.py
@@ -93,8 +93,13 @@ class TransmissionTest(test_cases.TransmissionTest, unittest.TestCase):
   def create_service_completion(self):
     return _intermediary_low.Code.OK, 'An exuberant test "details" message!'
 
-  def assertMetadataEqual(self, original_metadata, transmitted_metadata):
-    self.assertSequenceEqual(original_metadata, transmitted_metadata)
+  def assertMetadataTransmitted(self, original_metadata, transmitted_metadata):
+    # we need to filter out any additional metadata added in transmitted_metadata
+    # since implementations are allowed to add to what is sent (in any position)
+    keys, _ = zip(*original_metadata)
+    self.assertSequenceEqual(
+        original_metadata,
+        [x for x in transmitted_metadata if x[0] in keys])
 
 
 class RoundTripTest(unittest.TestCase):
diff --git a/src/python/src/grpc/framework/interfaces/links/test_cases.py b/src/python/src/grpc/framework/interfaces/links/test_cases.py
index 3ac212ebdf..bf1f09d99d 100644
--- a/src/python/src/grpc/framework/interfaces/links/test_cases.py
+++ b/src/python/src/grpc/framework/interfaces/links/test_cases.py
@@ -161,8 +161,8 @@ class TransmissionTest(object):
     raise NotImplementedError()
 
   @abc.abstractmethod
-  def assertMetadataEqual(self, original_metadata, transmitted_metadata):
-    """Asserts that two metadata objects are equal.
+  def assertMetadataTransmitted(self, original_metadata, transmitted_metadata):
+    """Asserts that transmitted_metadata contains original_metadata.
 
     Args:
       original_metadata: A metadata object used in this test.
@@ -170,7 +170,8 @@ class TransmissionTest(object):
         through the system under test.
 
     Raises:
-      AssertionError: if the two metadata objects are not equal.
+      AssertionError: if the transmitted_metadata object does not contain
+        original_metadata.
     """
     raise NotImplementedError()
 
@@ -239,7 +240,7 @@ class TransmissionTest(object):
         self.assertFalse(initial_metadata_seen)
         self.assertFalse(seen_payloads)
         self.assertFalse(terminal_metadata_seen)
-        self.assertMetadataEqual(initial_metadata, ticket.initial_metadata)
+        self.assertMetadataTransmitted(initial_metadata, ticket.initial_metadata)
         initial_metadata_seen = True
 
       if ticket.payload is not None:
@@ -248,7 +249,7 @@ class TransmissionTest(object):
 
       if ticket.terminal_metadata is not None:
         self.assertFalse(terminal_metadata_seen)
-        self.assertMetadataEqual(terminal_metadata, ticket.terminal_metadata)
+        self.assertMetadataTransmitted(terminal_metadata, ticket.terminal_metadata)
         terminal_metadata_seen = True
     self.assertSequenceEqual(payloads, seen_payloads)
 
diff --git a/src/ruby/spec/generic/rpc_server_spec.rb b/src/ruby/spec/generic/rpc_server_spec.rb
index f2403de77c..0326f6e894 100644
--- a/src/ruby/spec/generic/rpc_server_spec.rb
+++ b/src/ruby/spec/generic/rpc_server_spec.rb
@@ -35,6 +35,14 @@ def load_test_certs
   files.map { |f| File.open(File.join(test_root, f)).read }
 end
 
+def check_md(wanted_md, received_md)
+  wanted_md.zip(received_md).each do |w, r|
+    w.each do |key, value|
+      expect(r[key]).to eq(value)
+    end
+  end
+end
+
 # A test message
 class EchoMsg
   def self.marshal(_o)
@@ -376,7 +384,7 @@ describe GRPC::RpcServer do
         stub = EchoStub.new(@host, **client_opts)
         expect(stub.an_rpc(req, k1: 'v1', k2: 'v2')).to be_a(EchoMsg)
         wanted_md = [{ 'k1' => 'v1', 'k2' => 'v2' }]
-        expect(service.received_md).to eq(wanted_md)
+        check_md(wanted_md, service.received_md)
         @srv.stop
         t.join
       end
@@ -391,7 +399,7 @@ describe GRPC::RpcServer do
         deadline = service.delay + 1.0 # wait for long enough
         expect(stub.an_rpc(req, deadline, k1: 'v1', k2: 'v2')).to be_a(EchoMsg)
         wanted_md = [{ 'k1' => 'v1', 'k2' => 'v2' }]
-        expect(service.received_md).to eq(wanted_md)
+        check_md(wanted_md, service.received_md)
         @srv.stop
         t.join
       end
@@ -443,7 +451,7 @@ describe GRPC::RpcServer do
         expect(stub.an_rpc(req, k1: 'v1', k2: 'v2')).to be_a(EchoMsg)
         wanted_md = [{ 'k1' => 'updated-v1', 'k2' => 'v2',
                        'jwt_aud_uri' => "https://#{@host}/EchoService" }]
-        expect(service.received_md).to eq(wanted_md)
+        check_md(wanted_md, service.received_md)
         @srv.stop
         t.join
       end
@@ -535,7 +543,9 @@ describe GRPC::RpcServer do
           'method' => '/EchoService/an_rpc',
           'connect_k1' => 'connect_v1'
         }
-        expect(op.metadata).to eq(wanted_md)
+        wanted_md.each do |key, value|
+          expect(op.metadata[key]).to eq(value)
+        end
         @srv.stop
         t.join
       end