Merge branch 'count-the-things' into we-dont-need-no-backup

Conflicts:
	Makefile
	src/core/iomgr/pollset_posix.c
	src/core/surface/call.c
	src/core/surface/channel.c
	src/core/surface/server.c
	src/python/src/grpc/_adapter/_low_test.py
	tools/doxygen/Doxyfile.core.internal

58 files changed, 3459 insertions, 2912 deletions

diff --git a/src/python/src/grpc/_adapter/_call.h b/src/core/census/README.md
index b4cf9d7ec9..fb615a2194 100644
--- a/src/python/src/grpc/_adapter/_call.h
+++ b/src/core/census/README.md
@@ -1,5 +1,4 @@
-/*
- *
+<!---
  * Copyright 2015, Google Inc.
  * All rights reserved.
  *
@@ -28,50 +27,50 @@
  * 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.
- *
- */
+-->
+
+# Census - a resource measurement and tracing system
 
-#ifndef _ADAPTER__CALL_H_
-#define _ADAPTER__CALL_H_
+This directory contains code for Census, which will ultimately provide the
+following features for any gRPC-using system:
+* A [dapper](http://research.google.com/pubs/pub36356.html)-like tracing
+  system, enabling tracing across a distributed infrastructure.
+* RPC statistics and measurements for key metrics, such as latency, bytes
+  transferred, number of errors etc.
+* Resource measurement framework which can be used for measuring custom
+  metrics. Through the use of [tags](#Tags), these can be broken down across
+  the entire distributed stack.
+* Easy integration of the above with
+  [Google Cloud Trace](https://cloud.google.com/tools/cloud-trace) and
+  [Google Cloud Monitoring](https://cloud.google.com/monitoring/).
 
-#include <Python.h>
-#include <grpc/grpc.h>
+## Concepts
 
-#include "grpc/_adapter/_completion_queue.h"
-#include "grpc/_adapter/_channel.h"
-#include "grpc/_adapter/_server.h"
+### Context
 
-typedef struct {
-  PyObject_HEAD
+### Operations
 
-  CompletionQueue *completion_queue;
-  Channel *channel;
-  Server *server;
+### Tags
 
-  /* Legacy state. */
-  grpc_call_details call_details;
-  grpc_metadata_array recv_metadata;
-  grpc_metadata_array recv_trailing_metadata;
-  grpc_metadata *send_metadata;
-  size_t send_metadata_count;
-  grpc_metadata *send_trailing_metadata;
-  size_t send_trailing_metadata_count;
-  int adding_to_trailing;
+### Metrics
 
-  grpc_byte_buffer *send_message;
-  grpc_byte_buffer *recv_message;
+## API
 
-  grpc_status_code status;
-  char *status_details;
-  size_t status_details_capacity;
+### Internal/RPC API
 
-  int cancelled;
+### External/Client API
 
-  grpc_call *c_call;
-} Call;
+### RPC API
 
-extern PyTypeObject pygrpc_CallType;
+## Files in this directory
 
-int pygrpc_add_call(PyObject *module);
+Note that files and functions in this directory can be split into two
+categories:
+* Files that define core census library functions. Functions etc. in these
+  files are named census\_\*, and constitute the core census library
+  functionality. At some time in the future, these will become a standalone
+  library.
+* Files that define functions etc. that provide a convenient interface between
+  grpc and the core census functionality. These files are all named
+  grpc\_\*.{c,h}, and define function names beginning with grpc\_census\_\*.
 
-#endif /* _ADAPTER__CALL_H_ */
diff --git a/src/python/src/grpc/_adapter/_client_credentials.h b/src/core/census/context.c
index fe04016d20..1358c5127b 100644
--- a/src/python/src/grpc/_adapter/_client_credentials.h
+++ b/src/core/census/context.c
@@ -31,19 +31,29 @@
  *
  */
 
-#ifndef _ADAPTER__CLIENT_CREDENTIALS_H_
-#define _ADAPTER__CLIENT_CREDENTIALS_H_
+#include "context.h"
 
-#include <Python.h>
-#include <grpc/grpc_security.h>
+#include <string.h>
+#include <grpc/census.h>
+#include <grpc/support/alloc.h>
 
-typedef struct {
-  PyObject_HEAD
-  grpc_credentials *c_client_credentials;
-} ClientCredentials;
+/* Placeholder implementation only. */
 
-extern PyTypeObject pygrpc_ClientCredentialsType;
+size_t census_context_serialize(const census_context *context, char *buffer,
+                                size_t buf_size) {
+  /* TODO(aveitch): implement serialization */
+  return 0;
+}
 
-int pygrpc_add_client_credentials(PyObject *module);
+int census_context_deserialize(const char *buffer, census_context **context) {
+  int ret = 0;
+  if (buffer != NULL) {
+    /* TODO(aveitch): implement deserialization. */
+    ret = 1;
+  }
+  *context = gpr_malloc(sizeof(census_context));
+  memset(*context, 0, sizeof(census_context));
+  return ret;
+}
 
-#endif /* _ADAPTER__CLIENT_CREDENTIALS_H_ */
+void census_context_destroy(census_context *context) { gpr_free(context); }
diff --git a/src/python/src/grpc/_adapter/_completion_queue.h b/src/core/census/context.h
index 516694daa1..d43a69f7e5 100644
--- a/src/python/src/grpc/_adapter/_completion_queue.h
+++ b/src/core/census/context.h
@@ -31,19 +31,19 @@
  *
  */
 
-#ifndef _ADAPTER__COMPLETION_QUEUE_H_
-#define _ADAPTER__COMPLETION_QUEUE_H_
+#ifndef GRPC_INTERNAL_CORE_CENSUS_CONTEXT_H
+#define GRPC_INTERNAL_CORE_CENSUS_CONTEXT_H
 
-#include <Python.h>
-#include <grpc/grpc.h>
+#include <grpc/census.h>
 
-typedef struct {
-  PyObject_HEAD
-  grpc_completion_queue *c_completion_queue;
-} CompletionQueue;
+/* census_context is the in-memory representation of information needed to
+ * maintain tracing, RPC statistics and resource usage information. */
+struct census_context {
+  gpr_uint64 op_id;    /* Operation identifier - unique per-context */
+  gpr_uint64 trace_id; /* Globally unique trace identifier */
+  /* TODO(aveitch) Add census tags:
+  const census_tag_set *tags;
+  */
+};
 
-extern PyTypeObject pygrpc_CompletionQueueType;
-
-int pygrpc_add_completion_queue(PyObject *module);
-
-#endif /* _ADAPTER__COMPLETION_QUEUE_H_ */
+#endif /* GRPC_INTERNAL_CORE_CENSUS_CONTEXT_H */
diff --git a/src/python/src/grpc/_adapter/_channel.h b/src/core/census/grpc_context.c
index 65894939a2..cf2353199f 100644
--- a/src/python/src/grpc/_adapter/_channel.h
+++ b/src/core/census/grpc_context.c
@@ -31,19 +31,15 @@
  *
  */
 
-#ifndef _ADAPTER__CHANNEL_H_
-#define _ADAPTER__CHANNEL_H_
+#include <grpc/census.h>
+#include "src/core/census/grpc_context.h"
 
-#include <Python.h>
-#include <grpc/grpc.h>
+void *grpc_census_context_create() {
+  census_context *context;
+  census_context_deserialize(NULL, &context);
+  return (void *)context;
+}
 
-typedef struct {
-  PyObject_HEAD
-  grpc_channel *c_channel;
-} Channel;
-
-extern PyTypeObject pygrpc_ChannelType;
-
-int pygrpc_add_channel(PyObject *module);
-
-#endif /* _ADAPTER__CHANNEL_H_ */
+void grpc_census_context_destroy(void *context) {
+  census_context_destroy((census_context *)context);
+}
diff --git a/src/python/src/grpc/_adapter/_error.h b/src/core/census/grpc_context.h
index 6988b1c95e..f610f6ce21 100644
--- a/src/python/src/grpc/_adapter/_error.h
+++ b/src/core/census/grpc_context.h
@@ -31,12 +31,12 @@
  *
  */
 
-#ifndef _ADAPTER__ERROR_H_
-#define _ADAPTER__ERROR_H_
+/* GRPC <--> CENSUS context interface */
 
-#include <Python.h>
-#include <grpc/grpc.h>
+#ifndef CENSUS_GRPC_CONTEXT_H
+#define CENSUS_GRPC_CONTEXT_H
 
-const PyObject *pygrpc_translate_call_error(grpc_call_error call_error);
+void *grpc_census_context_create();
+void grpc_census_context_destroy(void *context);
 
-#endif /* _ADAPTER__ERROR_H_ */
+#endif /* CENSUS_GRPC_CONTEXT_H */
diff --git a/src/python/src/grpc/_adapter/_server.h b/src/core/census/initialize.c
index d31d4e678b..057ac78ee7 100644
--- a/src/python/src/grpc/_adapter/_server.h
+++ b/src/core/census/initialize.c
@@ -31,21 +31,20 @@
  *
  */
 
-#ifndef _ADAPTER__SERVER_H_
-#define _ADAPTER__SERVER_H_
+#include <grpc/census.h>
 
-#include <Python.h>
-#include <grpc/grpc.h>
+static int census_fns_enabled = CENSUS_NONE;
 
-#include "grpc/_adapter/_completion_queue.h"
+int census_initialize(int functions) {
+  if (census_fns_enabled != CENSUS_NONE) {
+    return 1;
+  }
+  if (functions != CENSUS_NONE) {
+    return 1;
+  } else {
+    census_fns_enabled = functions;
+    return 0;
+  }
+}
 
-typedef struct {
-  PyObject_HEAD
-
-  CompletionQueue *completion_queue;
-  grpc_server *c_server;
-} Server;
-
-int pygrpc_add_server(PyObject *module);
-
-#endif /* _ADAPTER__SERVER_H_ */
+void census_shutdown() { census_fns_enabled = CENSUS_NONE; }
diff --git a/src/core/channel/child_channel.c b/src/core/channel/child_channel.c
index bdd4147117..cdc1c11681 100644
--- a/src/core/channel/child_channel.c
+++ b/src/core/channel/child_channel.c
@@ -58,6 +58,9 @@ typedef struct {
   gpr_uint8 sending_farewell;
   /* have we sent farewell (goaway + disconnect) */
   gpr_uint8 sent_farewell;
+
+  grpc_iomgr_closure finally_destroy_channel_closure;
+  grpc_iomgr_closure send_farewells_closure;
 } lb_channel_data;
 
 typedef struct { grpc_child_channel *channel; } lb_call_data;
@@ -222,12 +225,16 @@ static void maybe_destroy_channel(grpc_child_channel *channel) {
   lb_channel_data *chand = LINK_BACK_ELEM_FROM_CHANNEL(channel)->channel_data;
   if (chand->destroyed && chand->disconnected && chand->active_calls == 0 &&
       !chand->sending_farewell && !chand->calling_back) {
-    grpc_iomgr_add_callback(finally_destroy_channel, channel);
+    chand->finally_destroy_channel_closure.cb = finally_destroy_channel;
+    chand->finally_destroy_channel_closure.cb_arg = channel;
+    grpc_iomgr_add_callback(&chand->finally_destroy_channel_closure);
   } else if (chand->destroyed && !chand->disconnected &&
              chand->active_calls == 0 && !chand->sending_farewell &&
              !chand->sent_farewell) {
     chand->sending_farewell = 1;
-    grpc_iomgr_add_callback(send_farewells, channel);
+    chand->send_farewells_closure.cb = send_farewells;
+    chand->send_farewells_closure.cb_arg = channel;
+    grpc_iomgr_add_callback(&chand->send_farewells_closure);
   }
 }
 
diff --git a/src/core/iomgr/fd_posix.c b/src/core/iomgr/fd_posix.c
index 4a55049b0b..a43e3ed278 100644
--- a/src/core/iomgr/fd_posix.c
+++ b/src/core/iomgr/fd_posix.c
@@ -90,6 +90,7 @@ static grpc_fd *alloc_fd(int fd) {
     gpr_mu_init(&r->set_state_mu);
     gpr_mu_init(&r->watcher_mu);
   }
+
   gpr_atm_rel_store(&r->refst, 1);
   gpr_atm_rel_store(&r->readst, NOT_READY);
   gpr_atm_rel_store(&r->writest, NOT_READY);
@@ -133,8 +134,7 @@ static void unref_by(grpc_fd *fd, int n) {
 #endif
   old = gpr_atm_full_fetch_add(&fd->refst, -n);
   if (old == n) {
-    close(fd->fd);
-    grpc_iomgr_add_callback(fd->on_done, fd->on_done_user_data);
+    grpc_iomgr_add_callback(&fd->on_done_closure);
     freelist_fd(fd);
     grpc_iomgr_unregister_object(&fd->iomgr_object);
   } else {
@@ -196,8 +196,8 @@ static void wake_all_watchers_locked(grpc_fd *fd) {
 }
 
 void grpc_fd_orphan(grpc_fd *fd, grpc_iomgr_cb_func on_done, void *user_data) {
-  fd->on_done = on_done ? on_done : do_nothing;
-  fd->on_done_user_data = user_data;
+  grpc_iomgr_closure_init(&fd->on_done_closure, on_done ? on_done : do_nothing,
+                          user_data);
   shutdown(fd->fd, SHUT_RDWR);
   REF_BY(fd, 1, "orphan"); /* remove active status, but keep referenced */
   gpr_mu_lock(&fd->watcher_mu);
@@ -225,21 +225,20 @@ void grpc_fd_unref(grpc_fd *fd) {
 }
 #endif
 
-static void make_callback(grpc_iomgr_cb_func cb, void *arg, int success,
+static void process_callback(grpc_iomgr_closure *closure, int success,
                           int allow_synchronous_callback) {
   if (allow_synchronous_callback) {
-    cb(arg, success);
+    closure->cb(closure->cb_arg, success);
   } else {
-    grpc_iomgr_add_delayed_callback(cb, arg, success);
+    grpc_iomgr_add_delayed_callback(closure, success);
   }
 }
 
-static void make_callbacks(grpc_iomgr_closure *callbacks, size_t n, int success,
-                           int allow_synchronous_callback) {
+static void process_callbacks(grpc_iomgr_closure *callbacks, size_t n,
+                              int success, int allow_synchronous_callback) {
   size_t i;
   for (i = 0; i < n; i++) {
-    make_callback(callbacks[i].cb, callbacks[i].cb_arg, success,
-                  allow_synchronous_callback);
+    process_callback(callbacks + i, success, allow_synchronous_callback);
   }
 }
 
@@ -264,10 +263,9 @@ static void notify_on(grpc_fd *fd, gpr_atm *st, grpc_iomgr_closure *closure,
     /* swap was unsuccessful due to an intervening set_ready call.
        Fall through to the READY code below */
     case READY:
-      assert(gpr_atm_no_barrier_load(st) == READY);
+      GPR_ASSERT(gpr_atm_no_barrier_load(st) == READY);
       gpr_atm_rel_store(st, NOT_READY);
-      make_callback(closure->cb, closure->cb_arg,
-                    !gpr_atm_acq_load(&fd->shutdown),
+      process_callback(closure, !gpr_atm_acq_load(&fd->shutdown),
                     allow_synchronous_callback);
       return;
     default: /* WAITING */
@@ -281,7 +279,7 @@ static void notify_on(grpc_fd *fd, gpr_atm *st, grpc_iomgr_closure *closure,
   abort();
 }
 
-static void set_ready_locked(gpr_atm *st, grpc_iomgr_closure *callbacks,
+static void set_ready_locked(gpr_atm *st, grpc_iomgr_closure **callbacks,
                              size_t *ncallbacks) {
   gpr_intptr state = gpr_atm_acq_load(st);
 
@@ -299,9 +297,9 @@ static void set_ready_locked(gpr_atm *st, grpc_iomgr_closure *callbacks,
          Fall through to the WAITING code below */
       state = gpr_atm_acq_load(st);
     default: /* waiting */
-      assert(gpr_atm_no_barrier_load(st) != READY &&
-             gpr_atm_no_barrier_load(st) != NOT_READY);
-      callbacks[(*ncallbacks)++] = *(grpc_iomgr_closure *)state;
+      GPR_ASSERT(gpr_atm_no_barrier_load(st) != READY &&
+                 gpr_atm_no_barrier_load(st) != NOT_READY);
+      callbacks[(*ncallbacks)++] = (grpc_iomgr_closure *)state;
       gpr_atm_rel_store(st, NOT_READY);
       return;
   }
@@ -312,25 +310,30 @@ static void set_ready(grpc_fd *fd, gpr_atm *st,
   /* only one set_ready can be active at once (but there may be a racing
      notify_on) */
   int success;
-  grpc_iomgr_closure cb;
+  grpc_iomgr_closure* closure;
   size_t ncb = 0;
+
   gpr_mu_lock(&fd->set_state_mu);
-  set_ready_locked(st, &cb, &ncb);
+  set_ready_locked(st, &closure, &ncb);
   gpr_mu_unlock(&fd->set_state_mu);
   success = !gpr_atm_acq_load(&fd->shutdown);
-  make_callbacks(&cb, ncb, success, allow_synchronous_callback);
+  GPR_ASSERT(ncb <= 1);
+  if (ncb > 0) {
+    process_callbacks(closure, ncb, success, allow_synchronous_callback);
+  }
 }
 
 void grpc_fd_shutdown(grpc_fd *fd) {
-  grpc_iomgr_closure cb[2];
   size_t ncb = 0;
   gpr_mu_lock(&fd->set_state_mu);
   GPR_ASSERT(!gpr_atm_no_barrier_load(&fd->shutdown));
   gpr_atm_rel_store(&fd->shutdown, 1);
-  set_ready_locked(&fd->readst, cb, &ncb);
-  set_ready_locked(&fd->writest, cb, &ncb);
+  set_ready_locked(&fd->readst, &fd->shutdown_closures[0], &ncb);
+  set_ready_locked(&fd->writest, &fd->shutdown_closures[0], &ncb);
   gpr_mu_unlock(&fd->set_state_mu);
-  make_callbacks(cb, ncb, 0, 0);
+  GPR_ASSERT(ncb <= 2);
+  process_callbacks(fd->shutdown_closures[0], ncb, 0 /* GPR_FALSE */,
+                    0 /* GPR_FALSE */);
 }
 
 void grpc_fd_notify_on_read(grpc_fd *fd, grpc_iomgr_closure *closure) {
diff --git a/src/core/iomgr/fd_posix.h b/src/core/iomgr/fd_posix.h
index d1d6c8fe1f..70992aead5 100644
--- a/src/core/iomgr/fd_posix.h
+++ b/src/core/iomgr/fd_posix.h
@@ -40,11 +40,6 @@
 #include <grpc/support/sync.h>
 #include <grpc/support/time.h>
 
-typedef struct {
-  grpc_iomgr_cb_func cb;
-  void *cb_arg;
-} grpc_iomgr_closure;
-
 typedef struct grpc_fd grpc_fd;
 
 typedef struct grpc_fd_watcher {
@@ -96,10 +91,11 @@ struct grpc_fd {
   gpr_atm readst;
   gpr_atm writest;
 
-  grpc_iomgr_cb_func on_done;
-  void *on_done_user_data;
   struct grpc_fd *freelist_next;
 
+  grpc_iomgr_closure on_done_closure;
+  grpc_iomgr_closure *shutdown_closures[2];
+
   grpc_iomgr_object iomgr_object;
 };
 
diff --git a/src/core/iomgr/iomgr.c b/src/core/iomgr/iomgr.c
index 8266b9247e..c6c44658df 100644
--- a/src/core/iomgr/iomgr.c
+++ b/src/core/iomgr/iomgr.c
@@ -43,17 +43,10 @@
 #include <grpc/support/thd.h>
 #include <grpc/support/sync.h>
 
-typedef struct delayed_callback {
-  grpc_iomgr_cb_func cb;
-  void *cb_arg;
-  int success;
-  struct delayed_callback *next;
-} delayed_callback;
-
 static gpr_mu g_mu;
 static gpr_cv g_rcv;
-static delayed_callback *g_cbs_head = NULL;
-static delayed_callback *g_cbs_tail = NULL;
+static grpc_iomgr_closure *g_cbs_head = NULL;
+static grpc_iomgr_closure *g_cbs_tail = NULL;
 static int g_shutdown;
 static gpr_event g_background_callback_executor_done;
 static grpc_iomgr_object g_root_object;
@@ -67,12 +60,11 @@ static void background_callback_executor(void *ignored) {
     gpr_timespec short_deadline =
         gpr_time_add(gpr_now(), gpr_time_from_millis(100));
     if (g_cbs_head) {
-      delayed_callback *cb = g_cbs_head;
-      g_cbs_head = cb->next;
+      grpc_iomgr_closure *closure = g_cbs_head;
+      g_cbs_head = closure->next;
       if (!g_cbs_head) g_cbs_tail = NULL;
       gpr_mu_unlock(&g_mu);
-      cb->cb(cb->cb_arg, cb->success);
-      gpr_free(cb);
+      closure->cb(closure->cb_arg, closure->success);
       gpr_mu_lock(&g_mu);
     } else if (grpc_alarm_check(&g_mu, gpr_now(), &deadline)) {
     } else {
@@ -114,8 +106,8 @@ static size_t count_objects(void) {
 }
 
 void grpc_iomgr_shutdown(void) {
-  delayed_callback *cb;
   grpc_iomgr_object *obj;
+  grpc_iomgr_closure *closure;
   gpr_timespec shutdown_deadline =
       gpr_time_add(gpr_now(), gpr_time_from_seconds(10));
 
@@ -135,13 +127,12 @@ void grpc_iomgr_shutdown(void) {
     }
     if (g_cbs_head) {
       do {
-        cb = g_cbs_head;
-        g_cbs_head = cb->next;
+        closure = g_cbs_head;
+        g_cbs_head = closure->next;
         if (!g_cbs_head) g_cbs_tail = NULL;
         gpr_mu_unlock(&g_mu);
 
-        cb->cb(cb->cb_arg, 0);
-        gpr_free(cb);
+        closure->cb(closure->cb_arg, 0);
         gpr_mu_lock(&g_mu);
       } while (g_cbs_head);
       continue;
@@ -202,19 +193,23 @@ void grpc_iomgr_unregister_object(grpc_iomgr_object *obj) {
   gpr_mu_unlock(&g_mu);
 }
 
-void grpc_iomgr_add_delayed_callback(grpc_iomgr_cb_func cb, void *cb_arg,
-                                     int success) {
-  delayed_callback *dcb = gpr_malloc(sizeof(delayed_callback));
-  dcb->cb = cb;
-  dcb->cb_arg = cb_arg;
-  dcb->success = success;
+
+void grpc_iomgr_closure_init(grpc_iomgr_closure *closure, grpc_iomgr_cb_func cb,
+                             void *cb_arg) {
+  closure->cb = cb;
+  closure->cb_arg = cb_arg;
+  closure->next = NULL;
+}
+
+void grpc_iomgr_add_delayed_callback(grpc_iomgr_closure *closure, int success) {
+  closure->success = success;
   gpr_mu_lock(&g_mu);
-  dcb->next = NULL;
+  closure->next = NULL;
   if (!g_cbs_tail) {
-    g_cbs_head = g_cbs_tail = dcb;
+    g_cbs_head = g_cbs_tail = closure;
   } else {
-    g_cbs_tail->next = dcb;
-    g_cbs_tail = dcb;
+    g_cbs_tail->next = closure;
+    g_cbs_tail = closure;
   }
   if (g_shutdown) {
     gpr_cv_signal(&g_rcv);
@@ -222,25 +217,27 @@ void grpc_iomgr_add_delayed_callback(grpc_iomgr_cb_func cb, void *cb_arg,
   gpr_mu_unlock(&g_mu);
 }
 
-void grpc_iomgr_add_callback(grpc_iomgr_cb_func cb, void *cb_arg) {
-  grpc_iomgr_add_delayed_callback(cb, cb_arg, 1);
+
+void grpc_iomgr_add_callback(grpc_iomgr_closure *closure) {
+  grpc_iomgr_add_delayed_callback(closure, 1 /* GPR_TRUE */);
 }
 
+
 int grpc_maybe_call_delayed_callbacks(gpr_mu *drop_mu, int success) {
   int n = 0;
   gpr_mu *retake_mu = NULL;
-  delayed_callback *cb;
+  grpc_iomgr_closure *closure;
   for (;;) {
     /* check for new work */
     if (!gpr_mu_trylock(&g_mu)) {
       break;
     }
-    cb = g_cbs_head;
-    if (!cb) {
+    closure = g_cbs_head;
+    if (!closure) {
       gpr_mu_unlock(&g_mu);
       break;
     }
-    g_cbs_head = cb->next;
+    g_cbs_head = closure->next;
     if (!g_cbs_head) g_cbs_tail = NULL;
     gpr_mu_unlock(&g_mu);
     /* if we have a mutex to drop, do so before executing work */
@@ -249,8 +246,7 @@ int grpc_maybe_call_delayed_callbacks(gpr_mu *drop_mu, int success) {
       retake_mu = drop_mu;
       drop_mu = NULL;
     }
-    cb->cb(cb->cb_arg, success && cb->success);
-    gpr_free(cb);
+    closure->cb(closure->cb_arg, success && closure->success);
     n++;
   }
   if (retake_mu) {
diff --git a/src/core/iomgr/iomgr.h b/src/core/iomgr/iomgr.h
index 1f5d23fdda..a10e481e48 100644
--- a/src/core/iomgr/iomgr.h
+++ b/src/core/iomgr/iomgr.h
@@ -34,14 +34,43 @@
 #ifndef GRPC_INTERNAL_CORE_IOMGR_IOMGR_H
 #define GRPC_INTERNAL_CORE_IOMGR_IOMGR_H
 
-/* gRPC Callback definition */
+/** gRPC Callback definition.
+ *
+ * \param arg Arbitrary input.
+ * \param success An indication on the state of the iomgr. On false, cleanup
+ * actions should be taken (eg, shutdown). */
 typedef void (*grpc_iomgr_cb_func)(void *arg, int success);
 
+/** A closure over a grpc_iomgr_cb_func. */
+typedef struct grpc_iomgr_closure {
+  /** Bound callback. */
+  grpc_iomgr_cb_func cb;
+
+  /** Arguments to be passed to "cb". */
+  void *cb_arg;
+
+  /** Internal. A boolean indication to "cb" on the state of the iomgr.
+   * For instance, closures created during a shutdown would have this field set
+   * to false. */
+  int success;
+
+  /**< Internal. Do not touch */
+  struct grpc_iomgr_closure *next;
+} grpc_iomgr_closure;
+
+/** Initializes \a closure with \a cb and \a cb_arg. */
+void grpc_iomgr_closure_init(grpc_iomgr_closure *closure, grpc_iomgr_cb_func cb,
+                             void *cb_arg);
+
+/** Initializes the iomgr. */
 void grpc_iomgr_init(void);
+
+/** Signals the intention to shutdown the iomgr. */
 void grpc_iomgr_shutdown(void);
 
-/* This function is called from within a callback or from anywhere else
-   and causes the invocation of a callback at some point in the future */
-void grpc_iomgr_add_callback(grpc_iomgr_cb_func cb, void *cb_arg);
+/** Registers a closure to be invoked at some point in the future.
+ *
+ * Can be called from within a callback or from anywhere else */
+void grpc_iomgr_add_callback(grpc_iomgr_closure *closure);
 
 #endif  /* GRPC_INTERNAL_CORE_IOMGR_IOMGR_H */
diff --git a/src/core/iomgr/iomgr_internal.h b/src/core/iomgr/iomgr_internal.h
index 54eadf1edc..6c1e0e1799 100644
--- a/src/core/iomgr/iomgr_internal.h
+++ b/src/core/iomgr/iomgr_internal.h
@@ -35,7 +35,6 @@
 #define GRPC_INTERNAL_CORE_IOMGR_IOMGR_INTERNAL_H
 
 #include "src/core/iomgr/iomgr.h"
-#include "src/core/iomgr/iomgr_internal.h"
 #include <grpc/support/sync.h>
 
 typedef struct grpc_iomgr_object {
@@ -45,8 +44,7 @@ typedef struct grpc_iomgr_object {
 } grpc_iomgr_object;
 
 int grpc_maybe_call_delayed_callbacks(gpr_mu *drop_mu, int success);
-void grpc_iomgr_add_delayed_callback(grpc_iomgr_cb_func cb, void *cb_arg,
-                                     int success);
+void grpc_iomgr_add_delayed_callback(grpc_iomgr_closure *iocb, int success);
 
 void grpc_iomgr_register_object(grpc_iomgr_object *obj, const char *name);
 void grpc_iomgr_unregister_object(grpc_iomgr_object *obj);
diff --git a/src/core/iomgr/pollset_posix.c b/src/core/iomgr/pollset_posix.c
index 96f8acfd7e..6ffba4dbac 100644
--- a/src/core/iomgr/pollset_posix.c
+++ b/src/core/iomgr/pollset_posix.c
@@ -193,6 +193,7 @@ typedef struct grpc_unary_promote_args {
   const grpc_pollset_vtable *original_vtable;
   grpc_pollset *pollset;
   grpc_fd *fd;
+  grpc_iomgr_closure promotion_closure;
 } grpc_unary_promote_args;
 
 static void basic_do_promote(void *args, int success) {
@@ -215,7 +216,7 @@ static void basic_do_promote(void *args, int success) {
   /* First we need to ensure that nobody is polling concurrently */
   if (pollset->counter != 0) {
     grpc_pollset_kick(pollset);
-    grpc_iomgr_add_callback(basic_do_promote, up_args);
+    grpc_iomgr_add_callback(&up_args->promotion_closure);
     gpr_mu_unlock(&pollset->mu);
     return;
   }
@@ -302,7 +303,9 @@ static void basic_pollset_add_fd(grpc_pollset *pollset, grpc_fd *fd) {
   up_args->pollset = pollset;
   up_args->fd = fd;
   up_args->original_vtable = pollset->vtable;
-  grpc_iomgr_add_callback(basic_do_promote, up_args);
+  up_args->promotion_closure.cb = unary_poll_do_promote;
+  up_args->promotion_closure.cb_arg = up_args;
+  grpc_iomgr_add_callback(&up_args->promotion_closure);
 
   grpc_pollset_kick(pollset);
 }
diff --git a/src/core/iomgr/pollset_windows.c b/src/core/iomgr/pollset_windows.c
index 8484bb1ff0..88db774cc4 100644
--- a/src/core/iomgr/pollset_windows.c
+++ b/src/core/iomgr/pollset_windows.c
@@ -64,15 +64,15 @@ int grpc_pollset_work(grpc_pollset *pollset, gpr_timespec deadline) {
   gpr_timespec now;
   now = gpr_now();
   if (gpr_time_cmp(now, deadline) > 0) {
-    return 0;
+    return 0 /* GPR_FALSE */;
   }
-  if (grpc_maybe_call_delayed_callbacks(NULL, 1)) {
-    return 1;
+  if (grpc_maybe_call_delayed_callbacks(NULL, 1 /* GPR_TRUE */)) {
+    return 1 /* GPR_TRUE */;
   }
   if (grpc_alarm_check(NULL, now, &deadline)) {
-    return 1;
+    return 1 /* GPR_TRUE */;
   }
-  return 0;
+  return 0 /* GPR_FALSE */;
 }
 
 void grpc_pollset_kick(grpc_pollset *p) { }
diff --git a/src/core/iomgr/socket_windows.c b/src/core/iomgr/socket_windows.c
index ee5150a696..805fa8a4fc 100644
--- a/src/core/iomgr/socket_windows.c
+++ b/src/core/iomgr/socket_windows.c
@@ -39,7 +39,6 @@
 #include <grpc/support/log.h>
 
 #include "src/core/iomgr/iocp_windows.h"
-#include "src/core/iomgr/iomgr.h"
 #include "src/core/iomgr/iomgr_internal.h"
 #include "src/core/iomgr/pollset.h"
 #include "src/core/iomgr/pollset_windows.h"
@@ -64,13 +63,15 @@ int grpc_winsocket_shutdown(grpc_winsocket *socket) {
   gpr_mu_lock(&socket->state_mu);
   if (socket->read_info.cb) {
     callbacks_set++;
-    grpc_iomgr_add_delayed_callback(socket->read_info.cb,
-                                    socket->read_info.opaque, 0);
+    grpc_iomgr_closure_init(&socket->shutdown_closure, socket->read_info.cb,
+                            socket->read_info.opaque);
+    grpc_iomgr_add_delayed_callback(&socket->shutdown_closure, 0);
   }
   if (socket->write_info.cb) {
     callbacks_set++;
-    grpc_iomgr_add_delayed_callback(socket->write_info.cb,
-                                    socket->write_info.opaque, 0);
+    grpc_iomgr_closure_init(&socket->shutdown_closure, socket->write_info.cb,
+                            socket->write_info.opaque);
+    grpc_iomgr_add_delayed_callback(&socket->shutdown_closure, 0);
   }
   gpr_mu_unlock(&socket->state_mu);
   return callbacks_set;
diff --git a/src/core/iomgr/socket_windows.h b/src/core/iomgr/socket_windows.h
index b27eb14219..d5fee39604 100644
--- a/src/core/iomgr/socket_windows.h
+++ b/src/core/iomgr/socket_windows.h
@@ -39,6 +39,8 @@
 #include <grpc/support/sync.h>
 #include <grpc/support/atm.h>
 
+#include "src/core/iomgr/iomgr.h"
+
 /* This holds the data for an outstanding read or write on a socket.
    The mutex to protect the concurrent access to that data is the one
    inside the winsocket wrapper. */
@@ -93,6 +95,8 @@ typedef struct grpc_winsocket {
      there is a pending operation that the IO Completion Port will have to
      wait for. The socket will be collected at that time. */
   int orphan;
+
+  grpc_iomgr_closure shutdown_closure;
 } grpc_winsocket;
 
 /* Create a wrapped windows handle. This takes ownership of it, meaning that
diff --git a/src/core/iomgr/tcp_posix.c b/src/core/iomgr/tcp_posix.c
index cd6b2ecae6..2f19f9d442 100644
--- a/src/core/iomgr/tcp_posix.c
+++ b/src/core/iomgr/tcp_posix.c
@@ -280,6 +280,8 @@ typedef struct {
 
   grpc_iomgr_closure read_closure;
   grpc_iomgr_closure write_closure;
+
+  grpc_iomgr_closure handle_read_closure;
 } grpc_tcp;
 
 static void grpc_tcp_handle_read(void *arg /* grpc_tcp */, int success);
@@ -443,7 +445,8 @@ static void grpc_tcp_notify_on_read(grpc_endpoint *ep, grpc_endpoint_read_cb cb,
     tcp->finished_edge = 0;
     grpc_fd_notify_on_read(tcp->em_fd, &tcp->read_closure);
   } else {
-    grpc_iomgr_add_callback(grpc_tcp_handle_read, tcp);
+    tcp->handle_read_closure.cb_arg = tcp;
+    grpc_iomgr_add_callback(&tcp->handle_read_closure);
   }
 }
 
@@ -592,6 +595,8 @@ grpc_endpoint *grpc_tcp_create(grpc_fd *em_fd, size_t slice_size) {
   tcp->read_closure.cb_arg = tcp;
   tcp->write_closure.cb = grpc_tcp_handle_write;
   tcp->write_closure.cb_arg = tcp;
+
+  tcp->handle_read_closure.cb = grpc_tcp_handle_read;
   return &tcp->base;
 }
 
diff --git a/src/core/security/credentials.c b/src/core/security/credentials.c
index 3894f1be4f..f3d0cf5452 100644
--- a/src/core/security/credentials.c
+++ b/src/core/security/credentials.c
@@ -54,6 +54,7 @@
 typedef struct {
   grpc_credentials *creds;
   grpc_credentials_metadata_cb cb;
+  grpc_iomgr_closure *on_simulated_token_fetch_done_closure;
   void *user_data;
 } grpc_credentials_metadata_request;
 
@@ -65,6 +66,8 @@ grpc_credentials_metadata_request_create(grpc_credentials *creds,
       gpr_malloc(sizeof(grpc_credentials_metadata_request));
   r->creds = grpc_credentials_ref(creds);
   r->cb = cb;
+  r->on_simulated_token_fetch_done_closure =
+      gpr_malloc(sizeof(grpc_iomgr_closure));
   r->user_data = user_data;
   return r;
 }
@@ -72,6 +75,7 @@ grpc_credentials_metadata_request_create(grpc_credentials *creds,
 static void grpc_credentials_metadata_request_destroy(
     grpc_credentials_metadata_request *r) {
   grpc_credentials_unref(r->creds);
+  gpr_free(r->on_simulated_token_fetch_done_closure);
   gpr_free(r);
 }
 
@@ -843,9 +847,11 @@ static void fake_oauth2_get_request_metadata(grpc_credentials *creds,
   grpc_fake_oauth2_credentials *c = (grpc_fake_oauth2_credentials *)creds;
 
   if (c->is_async) {
-    grpc_iomgr_add_callback(
-        on_simulated_token_fetch_done,
-        grpc_credentials_metadata_request_create(creds, cb, user_data));
+    grpc_credentials_metadata_request *cb_arg =
+        grpc_credentials_metadata_request_create(creds, cb, user_data);
+    grpc_iomgr_closure_init(cb_arg->on_simulated_token_fetch_done_closure,
+                            on_simulated_token_fetch_done, cb_arg);
+    grpc_iomgr_add_callback(cb_arg->on_simulated_token_fetch_done_closure);
   } else {
     cb(user_data, c->access_token_md->entries, 1, GRPC_CREDENTIALS_OK);
   }
diff --git a/src/core/surface/call.c b/src/core/surface/call.c
index 138cd084c5..1e066ea42b 100644
--- a/src/core/surface/call.c
+++ b/src/core/surface/call.c
@@ -31,6 +31,7 @@
  *
  */
 
+#include "src/core/census/grpc_context.h"
 #include "src/core/surface/call.h"
 #include "src/core/channel/channel_stack.h"
 #include "src/core/iomgr/alarm.h"
@@ -228,6 +229,7 @@ struct grpc_call {
 
   gpr_slice_buffer incoming_message;
   gpr_uint32 incoming_message_length;
+  grpc_iomgr_closure destroy_closure;
 };
 
 #define CALL_STACK_FROM_CALL(call) ((grpc_call_stack *)((call) + 1))
@@ -273,6 +275,8 @@ grpc_call *grpc_call_create(grpc_channel *channel, grpc_completion_queue *cq,
   if (call->is_client) {
     call->request_set[GRPC_IOREQ_SEND_TRAILING_METADATA] = REQSET_DONE;
     call->request_set[GRPC_IOREQ_SEND_STATUS] = REQSET_DONE;
+    call->context[GRPC_CONTEXT_TRACING].value = grpc_census_context_create();
+    call->context[GRPC_CONTEXT_TRACING].destroy = grpc_census_context_destroy;
   }
   GPR_ASSERT(add_initial_metadata_count < MAX_SEND_INITIAL_METADATA_COUNT);
   for (i = 0; i < add_initial_metadata_count; i++) {
@@ -374,7 +378,9 @@ void grpc_call_internal_unref(grpc_call *c, int allow_immediate_deletion) {
     if (allow_immediate_deletion) {
       destroy_call(c, 1);
     } else {
-      grpc_iomgr_add_callback(destroy_call, c);
+      c->destroy_closure.cb = destroy_call;
+      c->destroy_closure.cb_arg = c;
+      grpc_iomgr_add_callback(&c->destroy_closure);
     }
   }
 }
@@ -1309,8 +1315,8 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
   return grpc_call_start_ioreq_and_call_back(call, reqs, out, finish_func, tag);
 }
 
-void grpc_call_context_set(grpc_call *call, grpc_context_index elem, void *value,
-                           void (*destroy)(void *value)) {
+void grpc_call_context_set(grpc_call *call, grpc_context_index elem,
+                           void *value, void (*destroy)(void *value)) {
   if (call->context[elem].destroy) {
     call->context[elem].destroy(call->context[elem].value);
   }
diff --git a/src/core/surface/channel.c b/src/core/surface/channel.c
index d8fd442702..c6cfdb014c 100644
--- a/src/core/surface/channel.c
+++ b/src/core/surface/channel.c
@@ -61,6 +61,7 @@ struct grpc_channel {
 
   gpr_mu registered_call_mu;
   registered_call *registered_calls;
+  grpc_iomgr_closure destroy_closure;
 };
 
 #define CHANNEL_STACK_FROM_CHANNEL(c) ((grpc_channel_stack *)((c) + 1))
@@ -204,8 +205,10 @@ void grpc_channel_internal_unref(grpc_channel *c, const char *reason) {
 #else
 void grpc_channel_internal_unref(grpc_channel *c) {
 #endif
-  if (gpr_unref(&c->refs)) {
-    grpc_iomgr_add_callback(destroy_channel, c);
+  if (gpr_unref(&channel->refs)) {
+    channel->destroy_closure.cb = destroy_channel;
+    channel->destroy_closure.cb_arg = channel;
+    grpc_iomgr_add_callback(&channel->destroy_closure);
   }
 }
 
diff --git a/src/core/surface/channel_create.c b/src/core/surface/channel_create.c
index 061669ec6e..a49b754d9a 100644
--- a/src/core/surface/channel_create.c
+++ b/src/core/surface/channel_create.c
@@ -196,9 +196,10 @@ grpc_channel *grpc_channel_create(const char *target,
   const grpc_channel_filter *filters[MAX_FILTERS];
   int n = 0;
   filters[n++] = &grpc_client_surface_filter;
+  /* TODO(census)
   if (grpc_channel_args_is_census_enabled(args)) {
     filters[n++] = &grpc_client_census_filter;
-  }
+    } */
   filters[n++] = &grpc_client_channel_filter;
   GPR_ASSERT(n <= MAX_FILTERS);
   channel = grpc_channel_create_from_filters(filters, n, args, mdctx, 1);
diff --git a/src/core/surface/init.c b/src/core/surface/init.c
index d6eb9b2c24..ac6871c6f2 100644
--- a/src/core/surface/init.c
+++ b/src/core/surface/init.c
@@ -31,11 +31,11 @@
  *
  */
 
+#include <grpc/census.h>
 #include <grpc/grpc.h>
 #include "src/core/channel/channel_stack.h"
 #include "src/core/debug/trace.h"
 #include "src/core/iomgr/iomgr.h"
-#include "src/core/statistics/census_interface.h"
 #include "src/core/profiling/timers.h"
 #include "src/core/surface/call.h"
 #include "src/core/surface/init.h"
@@ -64,7 +64,9 @@ void grpc_init(void) {
     grpc_security_pre_init();
     grpc_iomgr_init();
     grpc_tracer_init("GRPC_TRACE");
-    census_init();
+    if (census_initialize(CENSUS_NONE)) {
+      gpr_log(GPR_ERROR, "Could not initialize census.");
+    }
     grpc_timers_global_init();
   }
   gpr_mu_unlock(&g_init_mu);
diff --git a/src/core/surface/secure_channel_create.c b/src/core/surface/secure_channel_create.c
index b9c6d5f760..3875eb0614 100644
--- a/src/core/surface/secure_channel_create.c
+++ b/src/core/surface/secure_channel_create.c
@@ -235,9 +235,10 @@ grpc_channel *grpc_secure_channel_create(grpc_credentials *creds,
       new_args_from_connector != NULL ? new_args_from_connector : args,
       &connector_arg);
   filters[n++] = &grpc_client_surface_filter;
+  /* TODO(census)
   if (grpc_channel_args_is_census_enabled(args)) {
     filters[n++] = &grpc_client_census_filter;
-  }
+    } */
   filters[n++] = &grpc_client_channel_filter;
   GPR_ASSERT(n <= MAX_FILTERS);
   channel = grpc_channel_create_from_filters(filters, n, args_copy, mdctx, 1);
diff --git a/src/core/surface/server.c b/src/core/surface/server.c
index 99e3ee6d2e..051c325b83 100644
--- a/src/core/surface/server.c
+++ b/src/core/surface/server.c
@@ -123,6 +123,8 @@ struct channel_data {
   channel_registered_method *registered_methods;
   gpr_uint32 registered_method_slots;
   gpr_uint32 registered_method_max_probes;
+  grpc_iomgr_closure finish_shutdown_channel_closure;
+  grpc_iomgr_closure finish_destroy_channel_closure;
 };
 
 typedef struct shutdown_tag {
@@ -184,6 +186,8 @@ struct call_data {
   void (*on_done_recv)(void *user_data, int success);
   void *recv_user_data;
 
+  grpc_iomgr_closure kill_zombie_closure;
+
   call_data **root[CALL_LIST_COUNT];
   call_link links[CALL_LIST_COUNT];
 };
@@ -317,7 +321,9 @@ static void destroy_channel(channel_data *chand) {
   orphan_channel(chand);
   server_ref(chand->server);
   maybe_finish_shutdown(chand->server);
-  grpc_iomgr_add_callback(finish_destroy_channel, chand);
+  chand->finish_destroy_channel_closure.cb = finish_destroy_channel;
+  chand->finish_destroy_channel_closure.cb_arg = chand;
+  grpc_iomgr_add_callback(&chand->finish_destroy_channel_closure);
 }
 
 static void finish_start_new_rpc_and_unlock(grpc_server *server,
@@ -473,7 +479,8 @@ static void server_on_recv(void *ptr, int success) {
       gpr_mu_lock(&chand->server->mu);
       if (calld->state == NOT_STARTED) {
         calld->state = ZOMBIED;
-        grpc_iomgr_add_callback(kill_zombie, elem);
+        grpc_iomgr_closure_init(&calld->kill_zombie_closure, kill_zombie, elem);
+        grpc_iomgr_add_callback(&calld->kill_zombie_closure);
       }
       gpr_mu_unlock(&chand->server->mu);
       break;
@@ -481,11 +488,14 @@ static void server_on_recv(void *ptr, int success) {
       gpr_mu_lock(&chand->server->mu);
       if (calld->state == NOT_STARTED) {
         calld->state = ZOMBIED;
-        grpc_iomgr_add_callback(kill_zombie, elem);
+        grpc_iomgr_closure_init(&calld->kill_zombie_closure, kill_zombie, elem);
+        grpc_iomgr_add_callback(&calld->kill_zombie_closure);
       } else if (calld->state == PENDING) {
         call_list_remove(calld, PENDING_START);
         calld->state = ZOMBIED;
-        grpc_iomgr_add_callback(kill_zombie, elem);
+        grpc_iomgr_closure_init(&calld->kill_zombie_closure, kill_zombie, elem);
+        grpc_iomgr_add_callback(&calld->kill_zombie_closure);
+
       }
       if (call_list_remove(calld, ALL_CALLS)) {
         decrement_call_count(chand);
@@ -580,16 +590,16 @@ static void finish_shutdown_channel(void *p, int success) {
   gpr_free(sca);
 }
 
-static void shutdown_channel(channel_data *chand, int send_goaway,
-                             int send_disconnect) {
+static void shutdown_channel(channel_data *chand) {
   shutdown_channel_args *sca;
-  gpr_log(GPR_DEBUG, "shutdown_channel: %p %d %d", chand, send_goaway, send_disconnect);
   GRPC_CHANNEL_INTERNAL_REF(chand->channel, "shutdown");
   sca = gpr_malloc(sizeof(shutdown_channel_args));
   sca->chand = chand;
   sca->send_goaway = send_goaway;
   sca->send_disconnect = send_disconnect;
-  grpc_iomgr_add_callback(finish_shutdown_channel, sca);
+  chand->finish_shutdown_channel_closure.cb = finish_shutdown_channel;
+  chand->finish_shutdown_channel_closure.cb_arg = sca;
+  grpc_iomgr_add_callback(&chand->finish_shutdown_channel_closure);
 }
 
 static void init_call_elem(grpc_call_element *elem,
@@ -708,7 +718,9 @@ grpc_server *grpc_server_create_from_filters(grpc_channel_filter **filters,
                                              size_t filter_count,
                                              const grpc_channel_args *args) {
   size_t i;
-  int census_enabled = grpc_channel_args_is_census_enabled(args);
+  /* TODO(census): restore this once we finalize census filter etc.
+     int census_enabled = grpc_channel_args_is_census_enabled(args); */
+  int census_enabled = 0;
 
   grpc_server *server = gpr_malloc(sizeof(grpc_server));
 
@@ -733,9 +745,10 @@ grpc_server *grpc_server_create_from_filters(grpc_channel_filter **filters,
   server->channel_filters =
       gpr_malloc(server->channel_filter_count * sizeof(grpc_channel_filter *));
   server->channel_filters[0] = &server_surface_filter;
+  /* TODO(census): restore this once we rework census filter
   if (census_enabled) {
     server->channel_filters[1] = &grpc_server_census_filter;
-  }
+    } */
   for (i = 0; i < filter_count; i++) {
     server->channel_filters[i + 1 + census_enabled] = filters[i];
   }
@@ -1004,6 +1017,7 @@ void grpc_server_destroy(grpc_server *server) {
     server->listeners = l->next;
     gpr_free(l);
   }
+
   gpr_mu_unlock(&server->mu);
 
   server_unref(server);
diff --git a/src/core/transport/chttp2/gen_hpack_tables.c b/src/core/transport/chttp2/gen_hpack_tables.c
index 86b593129b..bdaa3cf094 100644
--- a/src/core/transport/chttp2/gen_hpack_tables.c
+++ b/src/core/transport/chttp2/gen_hpack_tables.c
@@ -219,10 +219,10 @@ static int state_index(int bitofs, symset syms, int *isnew) {
    emit    - the symbol to emit on this nibble (or -1 if no symbol has been
              found)
    syms    - the set of symbols that could be matched */
-static void build_dec_tbl(int state, int nibble, int nibbits, int bitofs,
+static void build_dec_tbl(int state, int nibble, int nibbits, unsigned bitofs,
                           int emit, symset syms) {
   int i;
-  int bit;
+  unsigned bit;
 
   /* If we have four bits in the nibble we're looking at, then we can fill in
      a slot in the lookup tables. */
@@ -338,7 +338,7 @@ static void generate_base64_inverse_table(void) {
   static const char alphabet[] =
       "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
   unsigned char inverse[256];
-  int i;
+  unsigned i;
 
   memset(inverse, 255, sizeof(inverse));
   for (i = 0; i < strlen(alphabet); i++) {
diff --git a/src/cpp/server/thread_pool.cc b/src/cpp/server/thread_pool.cc
index e8d0e89ed2..118cabcb61 100644
--- a/src/cpp/server/thread_pool.cc
+++ b/src/cpp/server/thread_pool.cc
@@ -60,7 +60,7 @@ void ThreadPool::ThreadFunc() {
 
 ThreadPool::ThreadPool(int num_threads) : shutdown_(false) {
   for (int i = 0; i < num_threads; i++) {
-    threads_.push_back(grpc::thread(&ThreadPool::ThreadFunc, this));
+    threads_.push_back(new grpc::thread(&ThreadPool::ThreadFunc, this));
   }
 }
 
@@ -71,7 +71,8 @@ ThreadPool::~ThreadPool() {
     cv_.notify_all();
   }
   for (auto t = threads_.begin(); t != threads_.end(); t++) {
-    t->join();
+    (*t)->join();
+    delete *t;
   }
 }
 
diff --git a/src/cpp/server/thread_pool.h b/src/cpp/server/thread_pool.h
index 0f24d6e9b3..26f25611b5 100644
--- a/src/cpp/server/thread_pool.h
+++ b/src/cpp/server/thread_pool.h
@@ -57,7 +57,7 @@ class ThreadPool GRPC_FINAL : public ThreadPoolInterface {
   grpc::condition_variable cv_;
   bool shutdown_;
   std::queue<std::function<void()>> callbacks_;
-  std::vector<grpc::thread> threads_;
+  std::vector<grpc::thread*> threads_;
 
   void ThreadFunc();
 };
diff --git a/src/python/src/grpc/_adapter/_c.c b/src/python/src/grpc/_adapter/_c.c
deleted file mode 100644
index f096a55b61..0000000000
--- a/src/python/src/grpc/_adapter/_c.c
+++ /dev/null
@@ -1,86 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include <Python.h>
-#include <grpc/grpc.h>
-
-#include "grpc/_adapter/_completion_queue.h"
-#include "grpc/_adapter/_channel.h"
-#include "grpc/_adapter/_call.h"
-#include "grpc/_adapter/_server.h"
-#include "grpc/_adapter/_client_credentials.h"
-#include "grpc/_adapter/_server_credentials.h"
-
-static PyObject *init(PyObject *self) {
-  grpc_init();
-  Py_RETURN_NONE;
-}
-
-static PyObject *shutdown(PyObject *self) {
-  grpc_shutdown();
-  Py_RETURN_NONE;
-}
-
-static PyMethodDef _c_methods[] = {
-    {"init", (PyCFunction)init, METH_NOARGS,
-     "Initialize the module's static state."},
-    {"shut_down", (PyCFunction)shutdown, METH_NOARGS,
-     "Shut down the module's static state."},
-    {NULL},
-};
-
-PyMODINIT_FUNC init_c(void) {
-  PyObject *module;
-
-  module = Py_InitModule3("_c", _c_methods,
-                          "Wrappings of C structures and functions.");
-
-  if (pygrpc_add_completion_queue(module) == -1) {
-    return;
-  }
-  if (pygrpc_add_channel(module) == -1) {
-    return;
-  }
-  if (pygrpc_add_call(module) == -1) {
-    return;
-  }
-  if (pygrpc_add_server(module) == -1) {
-    return;
-  }
-  if (pygrpc_add_client_credentials(module) == -1) {
-    return;
-  }
-  if (pygrpc_add_server_credentials(module) == -1) {
-    return;
-  }
-}
diff --git a/src/python/src/grpc/_adapter/_c/module.c b/src/python/src/grpc/_adapter/_c/module.c
new file mode 100644
index 0000000000..1f3aedd9d8
--- /dev/null
+++ b/src/python/src/grpc/_adapter/_c/module.c
@@ -0,0 +1,61 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <stdlib.h>
+
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include <grpc/grpc.h>
+
+#include "grpc/_adapter/_c/types.h"
+
+static PyMethodDef c_methods[] = {
+    {NULL}
+};
+
+PyMODINIT_FUNC init_c(void) {
+  PyObject *module;
+
+  module = Py_InitModule3("_c", c_methods,
+                          "Wrappings of C structures and functions.");
+
+  if (pygrpc_module_add_types(module) < 0) {
+    return;
+  }
+
+  /* GRPC maintains an internal counter of how many times it has been
+     initialized and handles multiple pairs of grpc_init()/grpc_shutdown()
+     invocations accordingly. */
+  grpc_init();
+  atexit(&grpc_shutdown);
+}
diff --git a/src/python/src/grpc/_adapter/_c/types.c b/src/python/src/grpc/_adapter/_c/types.c
new file mode 100644
index 0000000000..8855c32ca6
--- /dev/null
+++ b/src/python/src/grpc/_adapter/_c/types.c
@@ -0,0 +1,60 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "grpc/_adapter/_c/types.h"
+
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include <grpc/grpc.h>
+
+int pygrpc_module_add_types(PyObject *module) {
+  int i;
+  PyTypeObject *types[] = {
+      &pygrpc_ClientCredentials_type,
+      &pygrpc_ServerCredentials_type,
+      &pygrpc_CompletionQueue_type,
+      &pygrpc_Call_type,
+      &pygrpc_Channel_type,
+      &pygrpc_Server_type
+  };
+  for (i = 0; i < sizeof(types)/sizeof(PyTypeObject *); ++i) {
+    if (PyType_Ready(types[i]) < 0) {
+      return -1;
+    }
+  }
+  for (i = 0; i < sizeof(types)/sizeof(PyTypeObject *); ++i) {
+    Py_INCREF(types[i]);
+    PyModule_AddObject(module, types[i]->tp_name, (PyObject *)types[i]);
+  }
+  return 0;
+}
diff --git a/src/python/src/grpc/_adapter/_c/types.h b/src/python/src/grpc/_adapter/_c/types.h
new file mode 100644
index 0000000000..e189ae2566
--- /dev/null
+++ b/src/python/src/grpc/_adapter/_c/types.h
@@ -0,0 +1,271 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef GRPC__ADAPTER__C_TYPES_H_
+#define GRPC__ADAPTER__C_TYPES_H_
+
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include <grpc/grpc.h>
+#include <grpc/grpc_security.h>
+
+
+/*=========================*/
+/* Client-side credentials */
+/*=========================*/
+
+typedef struct ClientCredentials {
+  PyObject_HEAD
+  grpc_credentials *c_creds;
+} ClientCredentials;
+void pygrpc_ClientCredentials_dealloc(ClientCredentials *self);
+ClientCredentials *pygrpc_ClientCredentials_google_default(
+    PyTypeObject *type, PyObject *ignored);
+ClientCredentials *pygrpc_ClientCredentials_ssl(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs);
+ClientCredentials *pygrpc_ClientCredentials_composite(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs);
+ClientCredentials *pygrpc_ClientCredentials_compute_engine(
+    PyTypeObject *type, PyObject *ignored);
+ClientCredentials *pygrpc_ClientCredentials_service_account(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs);
+ClientCredentials *pygrpc_ClientCredentials_jwt(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs);
+ClientCredentials *pygrpc_ClientCredentials_refresh_token(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs);
+ClientCredentials *pygrpc_ClientCredentials_fake_transport_security(
+    PyTypeObject *type, PyObject *ignored);
+ClientCredentials *pygrpc_ClientCredentials_iam(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs);
+extern PyTypeObject pygrpc_ClientCredentials_type;
+
+
+/*=========================*/
+/* Server-side credentials */
+/*=========================*/
+
+typedef struct ServerCredentials {
+  PyObject_HEAD
+  grpc_server_credentials *c_creds;
+} ServerCredentials;
+void pygrpc_ServerCredentials_dealloc(ServerCredentials *self);
+ServerCredentials *pygrpc_ServerCredentials_ssl(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs);
+ServerCredentials *pygrpc_ServerCredentials_fake_transport_security(
+    PyTypeObject *type, PyObject *ignored);
+extern PyTypeObject pygrpc_ServerCredentials_type;
+
+
+/*==================*/
+/* Completion queue */
+/*==================*/
+
+typedef struct CompletionQueue {
+  PyObject_HEAD
+  grpc_completion_queue *c_cq;
+} CompletionQueue;
+CompletionQueue *pygrpc_CompletionQueue_new(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs);
+void pygrpc_CompletionQueue_dealloc(CompletionQueue *self);
+PyObject *pygrpc_CompletionQueue_next(
+    CompletionQueue *self, PyObject *args, PyObject *kwargs);
+PyObject *pygrpc_CompletionQueue_shutdown(
+    CompletionQueue *self, PyObject *ignored);
+extern PyTypeObject pygrpc_CompletionQueue_type;
+
+
+/*======*/
+/* Call */
+/*======*/
+
+typedef struct Call {
+  PyObject_HEAD
+  grpc_call *c_call;
+  CompletionQueue *cq;
+} Call;
+Call *pygrpc_Call_new_empty(CompletionQueue *cq);
+void pygrpc_Call_dealloc(Call *self);
+PyObject *pygrpc_Call_start_batch(Call *self, PyObject *args, PyObject *kwargs);
+PyObject *pygrpc_Call_cancel(Call *self, PyObject *args, PyObject *kwargs);
+extern PyTypeObject pygrpc_Call_type;
+
+
+/*=========*/
+/* Channel */
+/*=========*/
+
+typedef struct Channel {
+  PyObject_HEAD
+  grpc_channel *c_chan;
+} Channel;
+Channel *pygrpc_Channel_new(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs);
+void pygrpc_Channel_dealloc(Channel *self);
+Call *pygrpc_Channel_create_call(
+    Channel *self, PyObject *args, PyObject *kwargs);
+extern PyTypeObject pygrpc_Channel_type;
+
+
+/*========*/
+/* Server */
+/*========*/
+
+typedef struct Server {
+  PyObject_HEAD
+  grpc_server *c_serv;
+  CompletionQueue *cq;
+} Server;
+Server *pygrpc_Server_new(PyTypeObject *type, PyObject *args, PyObject *kwargs);
+void pygrpc_Server_dealloc(Server *self);
+PyObject *pygrpc_Server_request_call(
+    Server *self, PyObject *args, PyObject *kwargs);
+PyObject *pygrpc_Server_add_http2_port(
+    Server *self, PyObject *args, PyObject *kwargs);
+PyObject *pygrpc_Server_start(Server *self, PyObject *ignored);
+PyObject *pygrpc_Server_shutdown(
+    Server *self, PyObject *args, PyObject *kwargs);
+extern PyTypeObject pygrpc_Server_type;
+
+/*=========*/
+/* Utility */
+/*=========*/
+
+/* Every tag that passes from Python GRPC to GRPC core is of this type. */
+typedef struct pygrpc_tag {
+  PyObject *user_tag;
+  Call *call;
+  grpc_call_details request_call_details;
+  grpc_metadata_array request_metadata;
+  grpc_op *ops;
+  size_t nops;
+  int is_new_call;
+} pygrpc_tag;
+
+/* Construct a tag associated with a batch call. Does not take ownership of the
+   resources in the elements of ops. */
+pygrpc_tag *pygrpc_produce_batch_tag(PyObject *user_tag, Call *call,
+                                     grpc_op *ops, size_t nops);
+
+
+/* Construct a tag associated with a server request. The calling code should
+   use the appropriate fields of the produced tag in the invocation of
+   grpc_server_request_call. */
+pygrpc_tag *pygrpc_produce_request_tag(PyObject *user_tag, Call *empty_call);
+
+/* Construct a tag associated with a server shutdown. */
+pygrpc_tag *pygrpc_produce_server_shutdown_tag(PyObject *user_tag);
+
+/* Frees all resources owned by the tag and the tag itself. */
+void pygrpc_discard_tag(pygrpc_tag *tag);
+
+/* Consumes an event and its associated tag, providing a Python tuple of the
+   form `(type, tag, call, call_details, results)` (where type is an integer
+   corresponding to a grpc_completion_type, tag is an arbitrary PyObject, call
+   is the call object associated with the event [if any], call_details is a
+   tuple of form `(method, host, deadline)` [if such details are available],
+   and resultd is a list of tuples of form `(type, metadata, message, status,
+   cancelled)` [where type corresponds to a grpc_op_type, metadata is a
+   sequence of 2-sequences of strings, message is a byte string, and status is
+   a 2-tuple of an integer corresponding to grpc_status_code and a string of
+   status details]).
+
+   Frees all resources associated with the event tag. */
+PyObject *pygrpc_consume_event(grpc_event event);
+
+/* Transliterate the Python tuple of form `(type, metadata, message,
+   status)` (where type is an integer corresponding to a grpc_op_type, metadata
+   is a sequence of 2-sequences of strings, message is a byte string, and
+   status is 2-tuple of an integer corresponding to grpc_status_code and a
+   string of status details) to a grpc_op suitable for use in a
+   grpc_call_start_batch invocation. The grpc_op is a 'directory' of resources
+   that must be freed after GRPC core is done with them.
+
+   Calls gpr_malloc (or the appropriate type-specific grpc_*_create function)
+   to populate the appropriate union-discriminated members of the op.
+
+   Returns true on success, false on failure. */
+int pygrpc_produce_op(PyObject *op, grpc_op *result);
+
+/* Discards all resources associated with the passed in op that was produced by
+   pygrpc_produce_op. */
+void pygrpc_discard_op(grpc_op op);
+
+/* Transliterate the grpc_ops (which have been sent through a
+   grpc_call_start_batch invocation and whose corresponding event has appeared
+   on a completion queue) to a Python tuple of form `(type, metadata, message,
+   status, cancelled)` (where type is an integer corresponding to a
+   grpc_op_type, metadata is a sequence of 2-sequences of strings, message is a
+   byte string, and status is 2-tuple of an integer corresponding to
+   grpc_status_code and a string of status details).
+
+   Calls gpr_free (or the appropriate type-specific grpc_*_destroy function) on
+   the appropriate union-discriminated populated members of the ops. */
+PyObject *pygrpc_consume_ops(grpc_op *op, size_t nops);
+
+/* Transliterate from a gpr_timespec to a double (in units of seconds, either
+   from the epoch if interpreted absolutely or as a delta otherwise). */
+double pygrpc_cast_gpr_timespec_to_double(gpr_timespec timespec);
+
+/* Transliterate from a double (in units of seconds from the epoch if
+   interpreted absolutely or as a delta otherwise) to a gpr_timespec. */
+gpr_timespec pygrpc_cast_double_to_gpr_timespec(double seconds);
+
+/* Returns true on success, false on failure. */
+int pygrpc_cast_pylist_to_send_metadata(
+    PyObject *pylist, grpc_metadata **metadata, size_t *count);
+/* Returns a metadata array as a Python object on success, else NULL. */
+PyObject *pygrpc_cast_metadata_array_to_pylist(grpc_metadata_array metadata);
+
+/* Transliterate from a list of python channel arguments (2-tuples of string
+   and string|integer|None) to a grpc_channel_args object. The strings placed
+   in the grpc_channel_args object's grpc_arg elements are views of the Python
+   object. The Python object must live long enough for the grpc_channel_args
+   to be used. Arguments set to None are silently ignored. Returns true on
+   success, false on failure. */
+int pygrpc_produce_channel_args(PyObject *py_args, grpc_channel_args *c_args);
+void pygrpc_discard_channel_args(grpc_channel_args args);
+
+/* Read the bytes from grpc_byte_buffer to a gpr_malloc'd array of bytes;
+   output to result and result_size. */
+void pygrpc_byte_buffer_to_bytes(
+    grpc_byte_buffer *buffer, char **result, size_t *result_size);
+
+
+/*========*/
+/* Module */
+/*========*/
+
+/* Returns 0 on success, -1 on failure. */
+int pygrpc_module_add_types(PyObject *module);
+
+#endif  /* GRPC__ADAPTER__C_TYPES_H_ */
diff --git a/src/python/src/grpc/_adapter/_c/types/call.c b/src/python/src/grpc/_adapter/_c/types/call.c
new file mode 100644
index 0000000000..0739070044
--- /dev/null
+++ b/src/python/src/grpc/_adapter/_c/types/call.c
@@ -0,0 +1,163 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "grpc/_adapter/_c/types.h"
+
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include <grpc/grpc.h>
+#include <grpc/support/alloc.h>
+
+
+PyMethodDef pygrpc_Call_methods[] = {
+    {"start_batch", (PyCFunction)pygrpc_Call_start_batch, METH_KEYWORDS, ""},
+    {"cancel", (PyCFunction)pygrpc_Call_cancel, METH_KEYWORDS, ""},
+    {NULL}
+};
+const char pygrpc_Call_doc[] = "See grpc._adapter._types.Call.";
+PyTypeObject pygrpc_Call_type = {
+    PyObject_HEAD_INIT(NULL)
+    0,                                        /* ob_size */
+    "Call",                                   /* tp_name */
+    sizeof(Call),                             /* tp_basicsize */
+    0,                                        /* tp_itemsize */
+    (destructor)pygrpc_Call_dealloc,          /* tp_dealloc */
+    0,                                        /* tp_print */
+    0,                                        /* tp_getattr */
+    0,                                        /* tp_setattr */
+    0,                                        /* tp_compare */
+    0,                                        /* tp_repr */
+    0,                                        /* tp_as_number */
+    0,                                        /* tp_as_sequence */
+    0,                                        /* tp_as_mapping */
+    0,                                        /* tp_hash */
+    0,                                        /* tp_call */
+    0,                                        /* tp_str */
+    0,                                        /* tp_getattro */
+    0,                                        /* tp_setattro */
+    0,                                        /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
+    pygrpc_Call_doc,                          /* tp_doc */
+    0,                                        /* tp_traverse */
+    0,                                        /* tp_clear */
+    0,                                        /* tp_richcompare */
+    0,                                        /* tp_weaklistoffset */
+    0,                                        /* tp_iter */
+    0,                                        /* tp_iternext */
+    pygrpc_Call_methods,                      /* tp_methods */
+    0,                                        /* tp_members */
+    0,                                        /* tp_getset */
+    0,                                        /* tp_base */
+    0,                                        /* tp_dict */
+    0,                                        /* tp_descr_get */
+    0,                                        /* tp_descr_set */
+    0,                                        /* tp_dictoffset */
+    0,                                        /* tp_init */
+    0,                                        /* tp_alloc */
+    0                                         /* tp_new */
+};
+
+Call *pygrpc_Call_new_empty(CompletionQueue *cq) {
+  Call *call = (Call *)pygrpc_Call_type.tp_alloc(&pygrpc_Call_type, 0);
+  call->c_call = NULL;
+  call->cq = cq;
+  Py_XINCREF(call->cq);
+  return call;
+}
+void pygrpc_Call_dealloc(Call *self) {
+  if (self->c_call) {
+    grpc_call_destroy(self->c_call);
+  }
+  Py_XDECREF(self->cq);
+  self->ob_type->tp_free((PyObject *)self);
+}
+PyObject *pygrpc_Call_start_batch(Call *self, PyObject *args, PyObject *kwargs) {
+  PyObject *op_list;
+  PyObject *user_tag;
+  grpc_op *ops;
+  size_t nops;
+  size_t i;
+  size_t j;
+  pygrpc_tag *tag;
+  grpc_call_error errcode;
+  static char *keywords[] = {"ops", "tag", NULL};
+  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "OO:start_batch", keywords,
+                                   &op_list, &user_tag)) {
+    return NULL;
+  }
+  if (!PyList_Check(op_list)) {
+    PyErr_SetString(PyExc_TypeError, "expected a list of OpArgs");
+    return NULL;
+  }
+  nops = PyList_Size(op_list);
+  ops = gpr_malloc(sizeof(grpc_op) * nops);
+  for (i = 0; i < nops; ++i) {
+    PyObject *item = PyList_GET_ITEM(op_list, i);
+    if (!pygrpc_produce_op(item, &ops[i])) {
+      for (j = 0; j < i; ++j) {
+        pygrpc_discard_op(ops[j]);
+      }
+      return NULL;
+    }
+  }
+  tag = pygrpc_produce_batch_tag(user_tag, self, ops, nops);
+  errcode = grpc_call_start_batch(self->c_call, tag->ops, tag->nops, tag);
+  gpr_free(ops);
+  return PyInt_FromLong(errcode);
+}
+PyObject *pygrpc_Call_cancel(Call *self, PyObject *args, PyObject *kwargs) {
+  PyObject *py_code = NULL;
+  grpc_call_error errcode;
+  int code;
+  char *details = NULL;
+  static char *keywords[] = {"code", "details", NULL};
+  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|Os:start_batch", keywords,
+                                   &py_code, &details)) {
+    return NULL;
+  }
+  if (py_code != NULL && details != NULL) {
+    if (!PyInt_Check(py_code)) {
+      PyErr_SetString(PyExc_TypeError, "expected integer code");
+      return NULL;
+    }
+    code = PyInt_AsLong(py_code);
+    errcode = grpc_call_cancel_with_status(self->c_call, code, details);
+  } else if (py_code != NULL || details != NULL) {
+    PyErr_SetString(PyExc_ValueError,
+                    "if `code` is specified, so must `details`");
+    return NULL;
+  } else {
+    errcode = grpc_call_cancel(self->c_call);
+  }
+  return PyInt_FromLong(errcode);
+}
diff --git a/src/python/src/grpc/_adapter/_c/types/channel.c b/src/python/src/grpc/_adapter/_c/types/channel.c
new file mode 100644
index 0000000000..c235597466
--- /dev/null
+++ b/src/python/src/grpc/_adapter/_c/types/channel.c
@@ -0,0 +1,134 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "grpc/_adapter/_c/types.h"
+
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include <grpc/grpc.h>
+
+
+PyMethodDef pygrpc_Channel_methods[] = {
+    {"create_call", (PyCFunction)pygrpc_Channel_create_call, METH_KEYWORDS, ""},
+    {NULL}
+};
+const char pygrpc_Channel_doc[] = "See grpc._adapter._types.Channel.";
+PyTypeObject pygrpc_Channel_type = {
+    PyObject_HEAD_INIT(NULL)
+    0,                                        /* ob_size */
+    "Channel",                                /* tp_name */
+    sizeof(Channel),                          /* tp_basicsize */
+    0,                                        /* tp_itemsize */
+    (destructor)pygrpc_Channel_dealloc,       /* tp_dealloc */
+    0,                                        /* tp_print */
+    0,                                        /* tp_getattr */
+    0,                                        /* tp_setattr */
+    0,                                        /* tp_compare */
+    0,                                        /* tp_repr */
+    0,                                        /* tp_as_number */
+    0,                                        /* tp_as_sequence */
+    0,                                        /* tp_as_mapping */
+    0,                                        /* tp_hash */
+    0,                                        /* tp_call */
+    0,                                        /* tp_str */
+    0,                                        /* tp_getattro */
+    0,                                        /* tp_setattro */
+    0,                                        /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
+    pygrpc_Channel_doc,                       /* tp_doc */
+    0,                                        /* tp_traverse */
+    0,                                        /* tp_clear */
+    0,                                        /* tp_richcompare */
+    0,                                        /* tp_weaklistoffset */
+    0,                                        /* tp_iter */
+    0,                                        /* tp_iternext */
+    pygrpc_Channel_methods,                   /* tp_methods */
+    0,                                        /* tp_members */
+    0,                                        /* tp_getset */
+    0,                                        /* tp_base */
+    0,                                        /* tp_dict */
+    0,                                        /* tp_descr_get */
+    0,                                        /* tp_descr_set */
+    0,                                        /* tp_dictoffset */
+    0,                                        /* tp_init */
+    0,                                        /* tp_alloc */
+    (newfunc)pygrpc_Channel_new               /* tp_new */
+};
+
+Channel *pygrpc_Channel_new(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs) {
+  Channel *self;
+  const char *target;
+  PyObject *py_args;
+  ClientCredentials *creds = NULL;
+  grpc_channel_args c_args;
+  char *keywords[] = {"target", "args", "creds", NULL};
+  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "sO|O!:Channel", keywords,
+        &target, &py_args, &pygrpc_ClientCredentials_type, &creds)) {
+    return NULL;
+  }
+  if (!pygrpc_produce_channel_args(py_args, &c_args)) {
+    return NULL;
+  }
+  self = (Channel *)type->tp_alloc(type, 0);
+  if (creds) {
+    self->c_chan = grpc_secure_channel_create(creds->c_creds, target, &c_args);
+  } else {
+    self->c_chan = grpc_channel_create(target, &c_args);
+  }
+  pygrpc_discard_channel_args(c_args);
+  return self;
+}
+void pygrpc_Channel_dealloc(Channel *self) {
+  grpc_channel_destroy(self->c_chan);
+  self->ob_type->tp_free((PyObject *)self);
+}
+
+Call *pygrpc_Channel_create_call(
+    Channel *self, PyObject *args, PyObject *kwargs) {
+  Call *call;
+  CompletionQueue *cq;
+  const char *method;
+  const char *host;
+  double deadline;
+  char *keywords[] = {"cq", "method", "host", "deadline", NULL};
+  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O!ssd:create_call", keywords,
+        &pygrpc_CompletionQueue_type, &cq, &method, &host, &deadline)) {
+    return NULL;
+  }
+  call = pygrpc_Call_new_empty(cq);
+  call->c_call = grpc_channel_create_call(
+      self->c_chan, cq->c_cq, method, host,
+      pygrpc_cast_double_to_gpr_timespec(deadline));
+  return call;
+}
diff --git a/src/python/src/grpc/_adapter/_c/types/client_credentials.c b/src/python/src/grpc/_adapter/_c/types/client_credentials.c
new file mode 100644
index 0000000000..6a4561c060
--- /dev/null
+++ b/src/python/src/grpc/_adapter/_c/types/client_credentials.c
@@ -0,0 +1,286 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "grpc/_adapter/_c/types.h"
+
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include <grpc/grpc.h>
+#include <grpc/grpc_security.h>
+
+
+PyMethodDef pygrpc_ClientCredentials_methods[] = {
+    {"google_default", (PyCFunction)pygrpc_ClientCredentials_google_default,
+     METH_CLASS|METH_NOARGS, ""},
+    {"ssl", (PyCFunction)pygrpc_ClientCredentials_ssl,
+     METH_CLASS|METH_KEYWORDS, ""},
+    {"composite", (PyCFunction)pygrpc_ClientCredentials_composite,
+     METH_CLASS|METH_KEYWORDS, ""},
+    {"compute_engine", (PyCFunction)pygrpc_ClientCredentials_compute_engine,
+     METH_CLASS|METH_NOARGS, ""},
+    {"service_account", (PyCFunction)pygrpc_ClientCredentials_service_account,
+     METH_CLASS|METH_KEYWORDS, ""},
+    {"jwt", (PyCFunction)pygrpc_ClientCredentials_jwt,
+     METH_CLASS|METH_KEYWORDS, ""},
+    {"refresh_token", (PyCFunction)pygrpc_ClientCredentials_refresh_token,
+     METH_CLASS|METH_KEYWORDS, ""},
+    {"fake_transport_security",
+     (PyCFunction)pygrpc_ClientCredentials_fake_transport_security,
+     METH_CLASS|METH_NOARGS, ""},
+    {"iam", (PyCFunction)pygrpc_ClientCredentials_iam,
+     METH_CLASS|METH_KEYWORDS, ""},
+    {NULL}
+};
+const char pygrpc_ClientCredentials_doc[] = "";
+PyTypeObject pygrpc_ClientCredentials_type = {
+    PyObject_HEAD_INIT(NULL)
+    0,                                        /* ob_size */
+    "ClientCredentials",                      /* tp_name */
+    sizeof(ClientCredentials),                /* tp_basicsize */
+    0,                                        /* tp_itemsize */
+    (destructor)pygrpc_ClientCredentials_dealloc, /* tp_dealloc */
+    0,                                        /* tp_print */
+    0,                                        /* tp_getattr */
+    0,                                        /* tp_setattr */
+    0,                                        /* tp_compare */
+    0,                                        /* tp_repr */
+    0,                                        /* tp_as_number */
+    0,                                        /* tp_as_sequence */
+    0,                                        /* tp_as_mapping */
+    0,                                        /* tp_hash */
+    0,                                        /* tp_call */
+    0,                                        /* tp_str */
+    0,                                        /* tp_getattro */
+    0,                                        /* tp_setattro */
+    0,                                        /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
+    pygrpc_ClientCredentials_doc,             /* tp_doc */
+    0,                                        /* tp_traverse */
+    0,                                        /* tp_clear */
+    0,                                        /* tp_richcompare */
+    0,                                        /* tp_weaklistoffset */
+    0,                                        /* tp_iter */
+    0,                                        /* tp_iternext */
+    pygrpc_ClientCredentials_methods,         /* tp_methods */
+    0,                                        /* tp_members */
+    0,                                        /* tp_getset */
+    0,                                        /* tp_base */
+    0,                                        /* tp_dict */
+    0,                                        /* tp_descr_get */
+    0,                                        /* tp_descr_set */
+    0,                                        /* tp_dictoffset */
+    0,                                        /* tp_init */
+    0,                                        /* tp_alloc */
+    0                                         /* tp_new */
+};
+
+void pygrpc_ClientCredentials_dealloc(ClientCredentials *self) {
+  grpc_credentials_release(self->c_creds);
+  self->ob_type->tp_free((PyObject *)self);
+}
+
+ClientCredentials *pygrpc_ClientCredentials_google_default(
+    PyTypeObject *type, PyObject *ignored) {
+  ClientCredentials *self = (ClientCredentials *)type->tp_alloc(type, 0);
+  self->c_creds = grpc_google_default_credentials_create();
+  if (!self->c_creds) {
+    Py_DECREF(self);
+    PyErr_SetString(PyExc_RuntimeError,
+                    "couldn't create Google default credentials");
+    return NULL;
+  }
+  return self;
+}
+
+ClientCredentials *pygrpc_ClientCredentials_ssl(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs) {
+  ClientCredentials *self;
+  const char *root_certs;
+  const char *private_key = NULL;
+  const char *cert_chain = NULL;
+  grpc_ssl_pem_key_cert_pair key_cert_pair;
+  static char *keywords[] = {"root_certs", "private_key", "cert_chain", NULL};
+  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "z|zz:ssl", keywords,
+        &root_certs, &private_key, &cert_chain)) {
+    return NULL;
+  }
+  self = (ClientCredentials *)type->tp_alloc(type, 0);
+  if (private_key && cert_chain) {
+    key_cert_pair.private_key = private_key;
+    key_cert_pair.cert_chain = cert_chain;
+    self->c_creds = grpc_ssl_credentials_create(root_certs, &key_cert_pair);
+  } else {
+    self->c_creds = grpc_ssl_credentials_create(root_certs, NULL);
+  }
+  if (!self->c_creds) {
+    Py_DECREF(self);
+    PyErr_SetString(PyExc_RuntimeError, "couldn't create ssl credentials");
+    return NULL;
+  }
+  return self;
+}
+
+ClientCredentials *pygrpc_ClientCredentials_composite(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs) {
+  ClientCredentials *self;
+  ClientCredentials *creds1;
+  ClientCredentials *creds2;
+  static char *keywords[] = {"creds1", "creds2", NULL};
+  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O!O!:composite", keywords,
+        &pygrpc_ClientCredentials_type, &creds1,
+        &pygrpc_ClientCredentials_type, &creds2)) {
+    return NULL;
+  }
+  self = (ClientCredentials *)type->tp_alloc(type, 0);
+  self->c_creds = grpc_composite_credentials_create(
+      creds1->c_creds, creds2->c_creds);
+  if (!self->c_creds) {
+    Py_DECREF(self);
+    PyErr_SetString(PyExc_RuntimeError, "couldn't create composite credentials");
+    return NULL;
+  }
+  return self;
+}
+
+ClientCredentials *pygrpc_ClientCredentials_compute_engine(
+    PyTypeObject *type, PyObject *ignored) {
+  ClientCredentials *self = (ClientCredentials *)type->tp_alloc(type, 0);
+  self->c_creds = grpc_compute_engine_credentials_create();
+  if (!self->c_creds) {
+    Py_DECREF(self);
+    PyErr_SetString(PyExc_RuntimeError,
+                    "couldn't create compute engine credentials");
+    return NULL;
+  }
+  return self;
+}
+
+ClientCredentials *pygrpc_ClientCredentials_service_account(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs) {
+  ClientCredentials *self;
+  const char *json_key;
+  const char *scope;
+  double lifetime;
+  static char *keywords[] = {"json_key", "scope", "token_lifetime", NULL};
+  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "ssd:service_account", keywords,
+        &json_key, &scope, &lifetime)) {
+    return NULL;
+  }
+  self = (ClientCredentials *)type->tp_alloc(type, 0);
+  self->c_creds = grpc_service_account_credentials_create(
+      json_key, scope, pygrpc_cast_double_to_gpr_timespec(lifetime));
+  if (!self->c_creds) {
+    Py_DECREF(self);
+    PyErr_SetString(PyExc_RuntimeError,
+                    "couldn't create service account credentials");
+    return NULL;
+  }
+  return self;
+}
+
+ClientCredentials *pygrpc_ClientCredentials_jwt(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs) {
+  ClientCredentials *self;
+  const char *json_key;
+  double lifetime;
+  static char *keywords[] = {"json_key", "token_lifetime", NULL};
+  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "sd:jwt", keywords,
+        &json_key, &lifetime)) {
+    return NULL;
+  }
+  self = (ClientCredentials *)type->tp_alloc(type, 0);
+  self->c_creds = grpc_jwt_credentials_create(
+      json_key, pygrpc_cast_double_to_gpr_timespec(lifetime));
+  if (!self->c_creds) {
+    Py_DECREF(self);
+    PyErr_SetString(PyExc_RuntimeError, "couldn't create JWT credentials");
+    return NULL;
+  }
+  return self;
+}
+
+ClientCredentials *pygrpc_ClientCredentials_refresh_token(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs) {
+  ClientCredentials *self;
+  const char *json_refresh_token;
+  static char *keywords[] = {"json_refresh_token", NULL};
+  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "s:refresh_token", keywords,
+        &json_refresh_token)) {
+    return NULL;
+  }
+  self = (ClientCredentials *)type->tp_alloc(type, 0);
+  self->c_creds = grpc_refresh_token_credentials_create(json_refresh_token);
+  if (!self->c_creds) {
+    Py_DECREF(self);
+    PyErr_SetString(PyExc_RuntimeError,
+                    "couldn't create credentials from refresh token");
+    return NULL;
+  }
+  return self;
+}
+
+ClientCredentials *pygrpc_ClientCredentials_fake_transport_security(
+    PyTypeObject *type, PyObject *ignored) {
+  ClientCredentials *self = (ClientCredentials *)type->tp_alloc(type, 0);
+  self->c_creds = grpc_fake_transport_security_credentials_create();
+  if (!self->c_creds) {
+    Py_DECREF(self);
+    PyErr_SetString(PyExc_RuntimeError,
+                    "couldn't create fake credentials; "
+                    "something is horribly wrong with the universe");
+    return NULL;
+  }
+  return self;
+}
+
+ClientCredentials *pygrpc_ClientCredentials_iam(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs) {
+  ClientCredentials *self;
+  const char *authorization_token;
+  const char *authority_selector;
+  static char *keywords[] = {"authorization_token", "authority_selector", NULL};
+  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "ss:iam", keywords,
+        &authorization_token, &authority_selector)) {
+    return NULL;
+  }
+  self = (ClientCredentials *)type->tp_alloc(type, 0);
+  self->c_creds = grpc_iam_credentials_create(authorization_token,
+                                              authority_selector);
+  if (!self->c_creds) {
+    Py_DECREF(self);
+    PyErr_SetString(PyExc_RuntimeError, "couldn't create IAM credentials");
+    return NULL;
+  }
+  return self;
+}
+
diff --git a/src/python/src/grpc/_adapter/_c/types/completion_queue.c b/src/python/src/grpc/_adapter/_c/types/completion_queue.c
new file mode 100644
index 0000000000..2dd44b6ddd
--- /dev/null
+++ b/src/python/src/grpc/_adapter/_c/types/completion_queue.c
@@ -0,0 +1,124 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "grpc/_adapter/_c/types.h"
+
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include <grpc/grpc.h>
+
+
+PyMethodDef pygrpc_CompletionQueue_methods[] = {
+    {"next", (PyCFunction)pygrpc_CompletionQueue_next, METH_KEYWORDS, ""},
+    {"shutdown", (PyCFunction)pygrpc_CompletionQueue_shutdown, METH_NOARGS, ""},
+    {NULL}
+};
+const char pygrpc_CompletionQueue_doc[] =
+    "See grpc._adapter._types.CompletionQueue.";
+PyTypeObject pygrpc_CompletionQueue_type = {
+    PyObject_HEAD_INIT(NULL)
+    0,                                        /* ob_size */
+    "CompletionQueue",                        /* tp_name */
+    sizeof(CompletionQueue),                  /* tp_basicsize */
+    0,                                        /* tp_itemsize */
+    (destructor)pygrpc_CompletionQueue_dealloc, /* tp_dealloc */
+    0,                                        /* tp_print */
+    0,                                        /* tp_getattr */
+    0,                                        /* tp_setattr */
+    0,                                        /* tp_compare */
+    0,                                        /* tp_repr */
+    0,                                        /* tp_as_number */
+    0,                                        /* tp_as_sequence */
+    0,                                        /* tp_as_mapping */
+    0,                                        /* tp_hash */
+    0,                                        /* tp_call */
+    0,                                        /* tp_str */
+    0,                                        /* tp_getattro */
+    0,                                        /* tp_setattro */
+    0,                                        /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
+    pygrpc_CompletionQueue_doc,               /* tp_doc */
+    0,                                        /* tp_traverse */
+    0,                                        /* tp_clear */
+    0,                                        /* tp_richcompare */
+    0,                                        /* tp_weaklistoffset */
+    0,                                        /* tp_iter */
+    0,                                        /* tp_iternext */
+    pygrpc_CompletionQueue_methods,           /* tp_methods */
+    0,                                        /* tp_members */
+    0,                                        /* tp_getset */
+    0,                                        /* tp_base */
+    0,                                        /* tp_dict */
+    0,                                        /* tp_descr_get */
+    0,                                        /* tp_descr_set */
+    0,                                        /* tp_dictoffset */
+    0,                                        /* tp_init */
+    0,                                        /* tp_alloc */
+    (newfunc)pygrpc_CompletionQueue_new       /* tp_new */
+};
+
+CompletionQueue *pygrpc_CompletionQueue_new(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs) {
+  CompletionQueue *self = (CompletionQueue *)type->tp_alloc(type, 0);
+  self->c_cq = grpc_completion_queue_create();
+  return self;
+}
+
+void pygrpc_CompletionQueue_dealloc(CompletionQueue *self) {
+  grpc_completion_queue_destroy(self->c_cq);
+  self->ob_type->tp_free((PyObject *)self);
+}
+
+PyObject *pygrpc_CompletionQueue_next(
+    CompletionQueue *self, PyObject *args, PyObject *kwargs) {
+  double deadline;
+  grpc_event event;
+  PyObject *transliterated_event;
+  static char *keywords[] = {"deadline", NULL};
+  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "d:next", keywords,
+                                   &deadline)) {
+    return NULL;
+  }
+  Py_BEGIN_ALLOW_THREADS;
+  event = grpc_completion_queue_next(
+      self->c_cq, pygrpc_cast_double_to_gpr_timespec(deadline));
+  Py_END_ALLOW_THREADS;
+  transliterated_event = pygrpc_consume_event(event);
+  return transliterated_event;
+}
+
+PyObject *pygrpc_CompletionQueue_shutdown(
+    CompletionQueue *self, PyObject *ignored) {
+  grpc_completion_queue_shutdown(self->c_cq);
+  Py_RETURN_NONE;
+}
diff --git a/src/python/src/grpc/_adapter/_c/types/server.c b/src/python/src/grpc/_adapter/_c/types/server.c
new file mode 100644
index 0000000000..65d84b58fe
--- /dev/null
+++ b/src/python/src/grpc/_adapter/_c/types/server.c
@@ -0,0 +1,183 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "grpc/_adapter/_c/types.h"
+
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include <grpc/grpc.h>
+
+
+PyMethodDef pygrpc_Server_methods[] = {
+    {"request_call", (PyCFunction)pygrpc_Server_request_call,
+     METH_KEYWORDS, ""},
+    {"add_http2_port", (PyCFunction)pygrpc_Server_add_http2_port,
+     METH_KEYWORDS, ""},
+    {"start", (PyCFunction)pygrpc_Server_start, METH_NOARGS, ""},
+    {"shutdown", (PyCFunction)pygrpc_Server_shutdown, METH_KEYWORDS, ""},
+    {NULL}
+};
+const char pygrpc_Server_doc[] = "See grpc._adapter._types.Server.";
+PyTypeObject pygrpc_Server_type = {
+    PyObject_HEAD_INIT(NULL)
+    0,                                        /* ob_size */
+    "Server",                                 /* tp_name */
+    sizeof(Server),                           /* tp_basicsize */
+    0,                                        /* tp_itemsize */
+    (destructor)pygrpc_Server_dealloc,        /* tp_dealloc */
+    0,                                        /* tp_print */
+    0,                                        /* tp_getattr */
+    0,                                        /* tp_setattr */
+    0,                                        /* tp_compare */
+    0,                                        /* tp_repr */
+    0,                                        /* tp_as_number */
+    0,                                        /* tp_as_sequence */
+    0,                                        /* tp_as_mapping */
+    0,                                        /* tp_hash */
+    0,                                        /* tp_call */
+    0,                                        /* tp_str */
+    0,                                        /* tp_getattro */
+    0,                                        /* tp_setattro */
+    0,                                        /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
+    pygrpc_Server_doc,                        /* tp_doc */
+    0,                                        /* tp_traverse */
+    0,                                        /* tp_clear */
+    0,                                        /* tp_richcompare */
+    0,                                        /* tp_weaklistoffset */
+    0,                                        /* tp_iter */
+    0,                                        /* tp_iternext */
+    pygrpc_Server_methods,                    /* tp_methods */
+    0,                                        /* tp_members */
+    0,                                        /* tp_getset */
+    0,                                        /* tp_base */
+    0,                                        /* tp_dict */
+    0,                                        /* tp_descr_get */
+    0,                                        /* tp_descr_set */
+    0,                                        /* tp_dictoffset */
+    0,                                        /* tp_init */
+    0,                                        /* tp_alloc */
+    (newfunc)pygrpc_Server_new                /* tp_new */
+};
+
+Server *pygrpc_Server_new(PyTypeObject *type, PyObject *args, PyObject *kwargs) {
+  Server *self;
+  CompletionQueue *cq;
+  PyObject *py_args;
+  grpc_channel_args c_args;
+  char *keywords[] = {"cq", "args", NULL};
+  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O!O:Channel", keywords,
+        &pygrpc_CompletionQueue_type, &cq, &py_args)) {
+    return NULL;
+  }
+  if (!pygrpc_produce_channel_args(py_args, &c_args)) {
+    return NULL;
+  }
+  self = (Server *)type->tp_alloc(type, 0);
+  self->c_serv = grpc_server_create(&c_args);
+  pygrpc_discard_channel_args(c_args);
+  self->cq = cq;
+  Py_INCREF(self->cq);
+  return self;
+}
+
+void pygrpc_Server_dealloc(Server *self) {
+  grpc_server_destroy(self->c_serv);
+  Py_XDECREF(self->cq);
+  self->ob_type->tp_free((PyObject *)self);
+}
+
+PyObject *pygrpc_Server_request_call(
+    Server *self, PyObject *args, PyObject *kwargs) {
+  CompletionQueue *cq;
+  PyObject *user_tag;
+  pygrpc_tag *tag;
+  Call *empty_call;
+  grpc_call_error errcode;
+  static char *keywords[] = {"cq", "tag", NULL};
+  if (!PyArg_ParseTupleAndKeywords(
+      args, kwargs, "O!O", keywords,
+      &pygrpc_CompletionQueue_type, &cq, &user_tag)) {
+    return NULL;
+  }
+  empty_call = pygrpc_Call_new_empty(cq);
+  tag = pygrpc_produce_request_tag(user_tag, empty_call);
+  errcode = grpc_server_request_call(
+      self->c_serv, &tag->call->c_call, &tag->request_call_details,
+      &tag->request_metadata, tag->call->cq->c_cq, self->cq->c_cq, tag);
+  Py_DECREF(empty_call);
+  return PyInt_FromLong(errcode);
+}
+
+PyObject *pygrpc_Server_add_http2_port(
+    Server *self, PyObject *args, PyObject *kwargs) {
+  const char *addr;
+  ServerCredentials *creds = NULL;
+  int port;
+  static char *keywords[] = {"addr", "creds", NULL};
+  if (!PyArg_ParseTupleAndKeywords(
+      args, kwargs, "s|O!:add_http2_port", keywords,
+      &addr, &pygrpc_ServerCredentials_type, &creds)) {
+    return NULL;
+  }
+  if (creds) {
+    port = grpc_server_add_secure_http2_port(
+        self->c_serv, addr, creds->c_creds);
+  } else {
+    port = grpc_server_add_http2_port(self->c_serv, addr);
+  }
+  return PyInt_FromLong(port);
+
+}
+
+PyObject *pygrpc_Server_start(Server *self, PyObject *ignored) {
+  grpc_server_start(self->c_serv);
+  Py_RETURN_NONE;
+}
+
+PyObject *pygrpc_Server_shutdown(
+    Server *self, PyObject *args, PyObject *kwargs) {
+  PyObject *user_tag = NULL;
+  pygrpc_tag *tag;
+  static char *keywords[] = {"tag", NULL};
+  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|O", keywords, &user_tag)) {
+    return NULL;
+  }
+  if (user_tag) {
+    tag = pygrpc_produce_server_shutdown_tag(user_tag);
+    grpc_server_shutdown_and_notify(self->c_serv, tag);
+  } else {
+    grpc_server_shutdown(self->c_serv);
+  }
+  Py_RETURN_NONE;
+}
diff --git a/src/python/src/grpc/_adapter/_c/types/server_credentials.c b/src/python/src/grpc/_adapter/_c/types/server_credentials.c
new file mode 100644
index 0000000000..2e02c8fe81
--- /dev/null
+++ b/src/python/src/grpc/_adapter/_c/types/server_credentials.c
@@ -0,0 +1,146 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include "grpc/_adapter/_c/types.h"
+
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include <grpc/grpc.h>
+#include <grpc/grpc_security.h>
+#include <grpc/support/alloc.h>
+
+
+PyMethodDef pygrpc_ServerCredentials_methods[] = {
+    {"ssl", (PyCFunction)pygrpc_ServerCredentials_ssl,
+     METH_CLASS|METH_KEYWORDS, ""},
+    {"fake_transport_security",
+     (PyCFunction)pygrpc_ServerCredentials_fake_transport_security,
+     METH_CLASS|METH_NOARGS, ""},
+    {NULL}
+};
+const char pygrpc_ServerCredentials_doc[] = "";
+PyTypeObject pygrpc_ServerCredentials_type = {
+    PyObject_HEAD_INIT(NULL)
+    0,                                        /* ob_size */
+    "ServerCredentials",                      /* tp_name */
+    sizeof(ServerCredentials),                /* tp_basicsize */
+    0,                                        /* tp_itemsize */
+    (destructor)pygrpc_ServerCredentials_dealloc, /* tp_dealloc */
+    0,                                        /* tp_print */
+    0,                                        /* tp_getattr */
+    0,                                        /* tp_setattr */
+    0,                                        /* tp_compare */
+    0,                                        /* tp_repr */
+    0,                                        /* tp_as_number */
+    0,                                        /* tp_as_sequence */
+    0,                                        /* tp_as_mapping */
+    0,                                        /* tp_hash */
+    0,                                        /* tp_call */
+    0,                                        /* tp_str */
+    0,                                        /* tp_getattro */
+    0,                                        /* tp_setattro */
+    0,                                        /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
+    pygrpc_ServerCredentials_doc,             /* tp_doc */
+    0,                                        /* tp_traverse */
+    0,                                        /* tp_clear */
+    0,                                        /* tp_richcompare */
+    0,                                        /* tp_weaklistoffset */
+    0,                                        /* tp_iter */
+    0,                                        /* tp_iternext */
+    pygrpc_ServerCredentials_methods,         /* tp_methods */
+    0,                                        /* tp_members */
+    0,                                        /* tp_getset */
+    0,                                        /* tp_base */
+    0,                                        /* tp_dict */
+    0,                                        /* tp_descr_get */
+    0,                                        /* tp_descr_set */
+    0,                                        /* tp_dictoffset */
+    0,                                        /* tp_init */
+    0,                                        /* tp_alloc */
+    0                                         /* tp_new */
+};
+
+void pygrpc_ServerCredentials_dealloc(ServerCredentials *self) {
+  grpc_server_credentials_release(self->c_creds);
+  self->ob_type->tp_free((PyObject *)self);
+}
+
+ServerCredentials *pygrpc_ServerCredentials_ssl(
+    PyTypeObject *type, PyObject *args, PyObject *kwargs) {
+  ServerCredentials *self;
+  const char *root_certs;
+  PyObject *py_key_cert_pairs;
+  grpc_ssl_pem_key_cert_pair *key_cert_pairs;
+  size_t num_key_cert_pairs;
+  size_t i;
+  static char *keywords[] = {"root_certs", "key_cert_pairs", NULL};
+  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "zO:ssl", keywords,
+        &root_certs, &py_key_cert_pairs)) {
+    return NULL;
+  }
+  if (!PyList_Check(py_key_cert_pairs)) {
+    PyErr_SetString(PyExc_TypeError, "expected a list of 2-tuples of strings");
+    return NULL;
+  }
+  num_key_cert_pairs = PyList_Size(py_key_cert_pairs);
+  key_cert_pairs =
+      gpr_malloc(sizeof(grpc_ssl_pem_key_cert_pair) * num_key_cert_pairs);
+  for (i = 0; i < num_key_cert_pairs; ++i) {
+    PyObject *item = PyList_GET_ITEM(py_key_cert_pairs, i);
+    const char *key;
+    const char *cert;
+    if (!PyArg_ParseTuple(item, "zz", &key, &cert)) {
+      gpr_free(key_cert_pairs);
+      PyErr_SetString(PyExc_TypeError,
+                      "expected a list of 2-tuples of strings");
+      return NULL;
+    }
+    key_cert_pairs[i].private_key = key;
+    key_cert_pairs[i].cert_chain = cert;
+  }
+
+  self = (ServerCredentials *)type->tp_alloc(type, 0);
+  self->c_creds = grpc_ssl_server_credentials_create(
+      root_certs, key_cert_pairs, num_key_cert_pairs);
+  gpr_free(key_cert_pairs);
+  return self;
+}
+
+ServerCredentials *pygrpc_ServerCredentials_fake_transport_security(
+    PyTypeObject *type, PyObject *ignored) {
+  ServerCredentials *self = (ServerCredentials *)type->tp_alloc(type, 0);
+  self->c_creds = grpc_fake_transport_security_server_credentials_create();
+  return self;
+}
+
diff --git a/src/python/src/grpc/_adapter/_c/utility.c b/src/python/src/grpc/_adapter/_c/utility.c
new file mode 100644
index 0000000000..6d228c73fe
--- /dev/null
+++ b/src/python/src/grpc/_adapter/_c/utility.c
@@ -0,0 +1,460 @@
+/*
+ *
+ * Copyright 2015, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <math.h>
+
+#define PY_SSIZE_T_CLEAN
+#include <Python.h>
+#include <grpc/grpc.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/slice.h>
+#include <grpc/support/time.h>
+
+#include "grpc/_adapter/_c/types.h"
+
+pygrpc_tag *pygrpc_produce_batch_tag(
+    PyObject *user_tag, Call *call, grpc_op *ops, size_t nops) {
+  pygrpc_tag *tag = gpr_malloc(sizeof(pygrpc_tag));
+  tag->user_tag = user_tag;
+  Py_XINCREF(tag->user_tag);
+  tag->call = call;
+  Py_XINCREF(tag->call);
+  tag->ops = gpr_malloc(sizeof(grpc_op)*nops);
+  memcpy(tag->ops, ops, sizeof(grpc_op)*nops);
+  tag->nops = nops;
+  grpc_call_details_init(&tag->request_call_details);
+  grpc_metadata_array_init(&tag->request_metadata);
+  tag->is_new_call = 0;
+  return tag;
+}
+
+pygrpc_tag *pygrpc_produce_request_tag(PyObject *user_tag, Call *empty_call) {
+  pygrpc_tag *tag = gpr_malloc(sizeof(pygrpc_tag));
+  tag->user_tag = user_tag;
+  Py_XINCREF(tag->user_tag);
+  tag->call = empty_call;
+  Py_XINCREF(tag->call);
+  tag->ops = NULL;
+  tag->nops = 0;
+  grpc_call_details_init(&tag->request_call_details);
+  grpc_metadata_array_init(&tag->request_metadata);
+  tag->is_new_call = 1;
+  return tag;
+}
+
+pygrpc_tag *pygrpc_produce_server_shutdown_tag(PyObject *user_tag) {
+  pygrpc_tag *tag = gpr_malloc(sizeof(pygrpc_tag));
+  tag->user_tag = user_tag;
+  Py_XINCREF(tag->user_tag);
+  tag->call = NULL;
+  tag->ops = NULL;
+  tag->nops = 0;
+  grpc_call_details_init(&tag->request_call_details);
+  grpc_metadata_array_init(&tag->request_metadata);
+  tag->is_new_call = 0;
+  return tag;
+}
+
+void pygrpc_discard_tag(pygrpc_tag *tag) {
+  if (!tag) {
+    return;
+  }
+  Py_XDECREF(tag->user_tag);
+  Py_XDECREF(tag->call);
+  gpr_free(tag->ops);
+  grpc_call_details_destroy(&tag->request_call_details);
+  grpc_metadata_array_destroy(&tag->request_metadata);
+  gpr_free(tag);
+}
+
+PyObject *pygrpc_consume_event(grpc_event event) {
+  pygrpc_tag *tag;
+  PyObject *result;
+  if (event.type == GRPC_QUEUE_TIMEOUT) {
+    Py_RETURN_NONE;
+  }
+  tag = event.tag;
+  switch (event.type) {
+  case GRPC_QUEUE_SHUTDOWN:
+    result = Py_BuildValue("iOOOOO", GRPC_QUEUE_SHUTDOWN,
+                           Py_None, Py_None, Py_None, Py_None, Py_True);
+    break;
+  case GRPC_OP_COMPLETE:
+    if (tag->is_new_call) {
+      result = Py_BuildValue(
+          "iOO(ssd)[(iNOOOO)]O", GRPC_OP_COMPLETE, tag->user_tag, tag->call,
+          tag->request_call_details.method, tag->request_call_details.host,
+          pygrpc_cast_gpr_timespec_to_double(tag->request_call_details.deadline),
+          GRPC_OP_RECV_INITIAL_METADATA,
+          pygrpc_cast_metadata_array_to_pylist(tag->request_metadata), Py_None,
+          Py_None, Py_None, Py_None,
+          event.success ? Py_True : Py_False);
+    } else {
+      result = Py_BuildValue("iOOONO", GRPC_OP_COMPLETE, tag->user_tag,
+          tag->call, Py_None, pygrpc_consume_ops(tag->ops, tag->nops),
+          event.success ? Py_True : Py_False);
+    }
+    break;
+  default:
+    PyErr_SetString(PyExc_ValueError,
+                    "unknown completion type; could not translate event");
+    return NULL;
+  }
+  pygrpc_discard_tag(tag);
+  return result;
+}
+
+int pygrpc_produce_op(PyObject *op, grpc_op *result) {
+  static const int OP_TUPLE_SIZE = 5;
+  static const int STATUS_TUPLE_SIZE = 2;
+  static const int TYPE_INDEX = 0;
+  static const int INITIAL_METADATA_INDEX = 1;
+  static const int TRAILING_METADATA_INDEX = 2;
+  static const int MESSAGE_INDEX = 3;
+  static const int STATUS_INDEX = 4;
+  static const int STATUS_CODE_INDEX = 0;
+  static const int STATUS_DETAILS_INDEX = 1;
+  grpc_op c_op;
+  if (!PyTuple_Check(op)) {
+    PyErr_SetString(PyExc_TypeError, "expected tuple op");
+    return 0;
+  }
+  if (PyTuple_Size(op) != OP_TUPLE_SIZE) {
+    char buf[64];
+    snprintf(buf, sizeof(buf), "expected tuple op of length %d", OP_TUPLE_SIZE);
+    PyErr_SetString(PyExc_ValueError, buf);
+    return 0;
+  }
+  int type = PyInt_AsLong(PyTuple_GET_ITEM(op, TYPE_INDEX));
+  if (PyErr_Occurred()) {
+    return 0;
+  }
+  Py_ssize_t message_size;
+  char *message;
+  char *status_details;
+  gpr_slice message_slice;
+  c_op.op = type;
+  switch (type) {
+  case GRPC_OP_SEND_INITIAL_METADATA:
+    if (!pygrpc_cast_pylist_to_send_metadata(
+            PyTuple_GetItem(op, INITIAL_METADATA_INDEX),
+            &c_op.data.send_initial_metadata.metadata,
+            &c_op.data.send_initial_metadata.count)) {
+      return 0;
+    }
+    break;
+  case GRPC_OP_SEND_MESSAGE:
+    PyString_AsStringAndSize(
+        PyTuple_GET_ITEM(op, MESSAGE_INDEX), &message, &message_size);
+    message_slice = gpr_slice_from_copied_buffer(message, message_size);
+    c_op.data.send_message = grpc_byte_buffer_create(&message_slice, 1);
+    gpr_slice_unref(message_slice);
+    break;
+  case GRPC_OP_SEND_CLOSE_FROM_CLIENT:
+    /* Don't need to fill in any other fields. */
+    break;
+  case GRPC_OP_SEND_STATUS_FROM_SERVER:
+    if (!pygrpc_cast_pylist_to_send_metadata(
+            PyTuple_GetItem(op, TRAILING_METADATA_INDEX),
+            &c_op.data.send_status_from_server.trailing_metadata,
+            &c_op.data.send_status_from_server.trailing_metadata_count)) {
+      return 0;
+    }
+    if (!PyTuple_Check(PyTuple_GET_ITEM(op, STATUS_INDEX))) {
+      char buf[64];
+      snprintf(buf, sizeof(buf), "expected tuple status in op of length %d",
+               STATUS_TUPLE_SIZE);
+      PyErr_SetString(PyExc_TypeError, buf);
+      return 0;
+    }
+    c_op.data.send_status_from_server.status = PyInt_AsLong(
+        PyTuple_GET_ITEM(PyTuple_GET_ITEM(op, STATUS_INDEX), STATUS_CODE_INDEX));
+    status_details = PyString_AsString(
+        PyTuple_GET_ITEM(PyTuple_GET_ITEM(op, STATUS_INDEX), STATUS_DETAILS_INDEX));
+    if (PyErr_Occurred()) {
+      return 0;
+    }
+    c_op.data.send_status_from_server.status_details =
+        gpr_malloc(strlen(status_details) + 1);
+    strcpy((char *)c_op.data.send_status_from_server.status_details,
+           status_details);
+    break;
+  case GRPC_OP_RECV_INITIAL_METADATA:
+    c_op.data.recv_initial_metadata = gpr_malloc(sizeof(grpc_metadata_array));
+    grpc_metadata_array_init(c_op.data.recv_initial_metadata);
+    break;
+  case GRPC_OP_RECV_MESSAGE:
+    c_op.data.recv_message = gpr_malloc(sizeof(grpc_byte_buffer *));
+    break;
+  case GRPC_OP_RECV_STATUS_ON_CLIENT:
+    c_op.data.recv_status_on_client.trailing_metadata =
+        gpr_malloc(sizeof(grpc_metadata_array));
+    grpc_metadata_array_init(c_op.data.recv_status_on_client.trailing_metadata);
+    c_op.data.recv_status_on_client.status =
+        gpr_malloc(sizeof(grpc_status_code *));
+    c_op.data.recv_status_on_client.status_details =
+        gpr_malloc(sizeof(char *));
+    *c_op.data.recv_status_on_client.status_details = NULL;
+    c_op.data.recv_status_on_client.status_details_capacity =
+        gpr_malloc(sizeof(size_t));
+    *c_op.data.recv_status_on_client.status_details_capacity = 0;
+    break;
+  case GRPC_OP_RECV_CLOSE_ON_SERVER:
+    c_op.data.recv_close_on_server.cancelled = gpr_malloc(sizeof(int));
+    break;
+  default:
+    return 0;
+  }
+  *result = c_op;
+  return 1;
+}
+
+void pygrpc_discard_op(grpc_op op) {
+  switch(op.op) {
+  case GRPC_OP_SEND_INITIAL_METADATA:
+    gpr_free(op.data.send_initial_metadata.metadata);
+    break;
+  case GRPC_OP_SEND_MESSAGE:
+    grpc_byte_buffer_destroy(op.data.send_message);
+    break;
+  case GRPC_OP_SEND_CLOSE_FROM_CLIENT:
+    /* Don't need to free any fields. */
+    break;
+  case GRPC_OP_SEND_STATUS_FROM_SERVER:
+    gpr_free(op.data.send_status_from_server.trailing_metadata);
+    gpr_free((char *)op.data.send_status_from_server.status_details);
+    break;
+  case GRPC_OP_RECV_INITIAL_METADATA:
+    grpc_metadata_array_destroy(op.data.recv_initial_metadata);
+    gpr_free(op.data.recv_initial_metadata);
+    break;
+  case GRPC_OP_RECV_MESSAGE:
+    grpc_byte_buffer_destroy(*op.data.recv_message);
+    gpr_free(op.data.recv_message);
+    break;
+  case GRPC_OP_RECV_STATUS_ON_CLIENT:
+    grpc_metadata_array_destroy(op.data.recv_status_on_client.trailing_metadata);
+    gpr_free(op.data.recv_status_on_client.trailing_metadata);
+    gpr_free(op.data.recv_status_on_client.status);
+    gpr_free(*op.data.recv_status_on_client.status_details);
+    gpr_free(op.data.recv_status_on_client.status_details);
+    gpr_free(op.data.recv_status_on_client.status_details_capacity);
+    break;
+  case GRPC_OP_RECV_CLOSE_ON_SERVER:
+    gpr_free(op.data.recv_close_on_server.cancelled);
+    break;
+  }
+}
+
+PyObject *pygrpc_consume_ops(grpc_op *op, size_t nops) {
+  static const int TYPE_INDEX = 0;
+  static const int INITIAL_METADATA_INDEX = 1;
+  static const int TRAILING_METADATA_INDEX = 2;
+  static const int MESSAGE_INDEX = 3;
+  static const int STATUS_INDEX = 4;
+  static const int CANCELLED_INDEX = 5;
+  static const int OPRESULT_LENGTH = 6;
+  PyObject *list;
+  size_t i;
+  size_t j;
+  char *bytes;
+  size_t bytes_size;
+  PyObject *results = PyList_New(nops);
+  if (!results) {
+    return NULL;
+  }
+  for (i = 0; i < nops; ++i) {
+    PyObject *result = PyTuple_Pack(OPRESULT_LENGTH, Py_None, Py_None, Py_None,
+                                    Py_None, Py_None, Py_None);
+    PyTuple_SetItem(result, TYPE_INDEX, PyInt_FromLong(op[i].op));
+    switch(op[i].op) {
+    case GRPC_OP_RECV_INITIAL_METADATA:
+      PyTuple_SetItem(result, INITIAL_METADATA_INDEX,
+                      list=PyList_New(op[i].data.recv_initial_metadata->count));
+      for (j = 0; j < op[i].data.recv_initial_metadata->count; ++j) {
+        grpc_metadata md = op[i].data.recv_initial_metadata->metadata[j];
+        PyList_SetItem(list, j, Py_BuildValue("ss#", md.key, md.value,
+                                              (Py_ssize_t)md.value_length));
+      }
+      break;
+    case GRPC_OP_RECV_MESSAGE:
+      if (*op[i].data.recv_message) {
+        pygrpc_byte_buffer_to_bytes(
+            *op[i].data.recv_message, &bytes, &bytes_size);
+        PyTuple_SetItem(result, MESSAGE_INDEX,
+                        PyString_FromStringAndSize(bytes, bytes_size));
+        gpr_free(bytes);
+      } else {
+        PyTuple_SetItem(result, MESSAGE_INDEX, Py_BuildValue(""));
+      }
+      break;
+    case GRPC_OP_RECV_STATUS_ON_CLIENT:
+      PyTuple_SetItem(
+          result, TRAILING_METADATA_INDEX,
+          list = PyList_New(op[i].data.recv_status_on_client.trailing_metadata->count));
+      for (j = 0; j < op[i].data.recv_status_on_client.trailing_metadata->count; ++j) {
+        grpc_metadata md =
+            op[i].data.recv_status_on_client.trailing_metadata->metadata[j];
+        PyList_SetItem(list, j, Py_BuildValue("ss#", md.key, md.value,
+                                              (Py_ssize_t)md.value_length));
+      }
+      PyTuple_SetItem(
+          result, STATUS_INDEX, Py_BuildValue(
+              "is", *op[i].data.recv_status_on_client.status,
+              *op[i].data.recv_status_on_client.status_details));
+      break;
+    case GRPC_OP_RECV_CLOSE_ON_SERVER:
+      PyTuple_SetItem(
+          result, CANCELLED_INDEX,
+          PyBool_FromLong(*op[i].data.recv_close_on_server.cancelled));
+      break;
+    default:
+      break;
+    }
+    pygrpc_discard_op(op[i]);
+    PyList_SetItem(results, i, result);
+  }
+  return results;
+}
+
+double pygrpc_cast_gpr_timespec_to_double(gpr_timespec timespec) {
+  return timespec.tv_sec + 1e-9*timespec.tv_nsec;
+}
+
+gpr_timespec pygrpc_cast_double_to_gpr_timespec(double seconds) {
+  gpr_timespec result;
+  if isinf(seconds) {
+    result = seconds > 0.0 ? gpr_inf_future : gpr_inf_past;
+  } else {
+    result.tv_sec = (time_t)seconds;
+    result.tv_nsec = ((seconds - result.tv_sec) * 1e9);
+  }
+  return result;
+}
+
+int pygrpc_produce_channel_args(PyObject *py_args, grpc_channel_args *c_args) {
+  size_t num_args = PyList_Size(py_args);
+  size_t i;
+  grpc_channel_args args = {num_args, gpr_malloc(sizeof(grpc_arg) * num_args)};
+  for (i = 0; i < args.num_args; ++i) {
+    char *key;
+    PyObject *value;
+    if (!PyArg_ParseTuple(PyList_GetItem(py_args, i), "zO", &key, &value)) {
+      gpr_free(args.args);
+      args.num_args = 0;
+      args.args = NULL;
+      PyErr_SetString(PyExc_TypeError,
+                      "expected a list of 2-tuple of str and str|int|None");
+      return 0;
+    }
+    args.args[i].key = key;
+    if (PyInt_Check(value)) {
+      args.args[i].type = GRPC_ARG_INTEGER;
+      args.args[i].value.integer = PyInt_AsLong(value);
+    } else if (PyString_Check(value)) {
+      args.args[i].type = GRPC_ARG_STRING;
+      args.args[i].value.string = PyString_AsString(value);
+    } else if (value == Py_None) {
+      --args.num_args;
+      --i;
+      continue;
+    } else {
+      gpr_free(args.args);
+      args.num_args = 0;
+      args.args = NULL;
+      PyErr_SetString(PyExc_TypeError,
+                      "expected a list of 2-tuple of str and str|int|None");
+      return 0;
+    }
+  }
+  *c_args = args;
+  return 1;
+}
+
+void pygrpc_discard_channel_args(grpc_channel_args args) {
+  gpr_free(args.args);
+}
+
+int pygrpc_cast_pylist_to_send_metadata(
+    PyObject *pylist, grpc_metadata **metadata, size_t *count) {
+  size_t i;
+  Py_ssize_t value_length;
+  *count = PyList_Size(pylist);
+  *metadata = gpr_malloc(sizeof(grpc_metadata) * *count);
+  for (i = 0; i < *count; ++i) {
+    if (!PyArg_ParseTuple(
+        PyList_GetItem(pylist, i), "ss#",
+        &(*metadata)[i].key, &(*metadata)[i].value, &value_length)) {
+      gpr_free(*metadata);
+      *count = 0;
+      *metadata = NULL;
+      return 0;
+    }
+    (*metadata)[i].value_length = value_length;
+  }
+  return 1;
+}
+
+PyObject *pygrpc_cast_metadata_array_to_pylist(grpc_metadata_array metadata) {
+  PyObject *result = PyList_New(metadata.count);
+  size_t i;
+  for (i = 0; i < metadata.count; ++i) {
+    PyList_SetItem(
+        result, i, Py_BuildValue(
+            "ss#", metadata.metadata[i].key, metadata.metadata[i].value,
+            (Py_ssize_t)metadata.metadata[i].value_length));
+    if (PyErr_Occurred()) {
+      Py_DECREF(result);
+      return NULL;
+    }
+  }
+  return result;
+}
+
+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_create(buffer);
+  gpr_slice slice;
+  char *read_result = NULL;
+  size_t size = 0;
+  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),
+           GPR_SLICE_LENGTH(slice));
+    size = size + GPR_SLICE_LENGTH(slice);
+    gpr_slice_unref(slice);
+  }
+  grpc_byte_buffer_reader_destroy(reader);
+  *result_size = size;
+  *result = read_result;
+}
diff --git a/src/python/src/grpc/_adapter/_c_test.py b/src/python/src/grpc/_adapter/_c_test.py
index b06215f0e5..133b124072 100644
--- a/src/python/src/grpc/_adapter/_c_test.py
+++ b/src/python/src/grpc/_adapter/_c_test.py
@@ -27,192 +27,40 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-"""Tests for _adapter._c."""
-
-import threading
 import time
 import unittest
 
 from grpc._adapter import _c
-from grpc._adapter import _datatypes
-
-_TIMEOUT = 3
-_FUTURE = time.time() + 60 * 60 * 24
-_IDEMPOTENCE_DEMONSTRATION = 7
-
-
-class _CTest(unittest.TestCase):
-
-  def testUpAndDown(self):
-    _c.init()
-    _c.shut_down()
-
-  def testCompletionQueue(self):
-    _c.init()
-
-    completion_queue = _c.CompletionQueue()
-    event = completion_queue.get(0)
-    self.assertIsNone(event)
-    event = completion_queue.get(time.time())
-    self.assertIsNone(event)
-    event = completion_queue.get(time.time() + _TIMEOUT)
-    self.assertIsNone(event)
-    completion_queue.stop()
-    for _ in range(_IDEMPOTENCE_DEMONSTRATION):
-      event = completion_queue.get(time.time() + _TIMEOUT)
-      self.assertIs(event.kind, _datatypes.Event.Kind.STOP)
-
-    del completion_queue
-    del event
+from grpc._adapter import _types
 
-    _c.shut_down()
 
-  def testChannel(self):
-    _c.init()
-
-    channel = _c.Channel(
-        'test host:12345', None, server_host_override='ignored')
-    del channel
-
-    _c.shut_down()
-
-  def testCall(self):
-    method = 'test method'
-    host = 'test host'
-
-    _c.init()
-
-    channel = _c.Channel('%s:%d' % (host, 12345), None)
-    completion_queue = _c.CompletionQueue()
-    call = _c.Call(channel, completion_queue, method, host,
-                   time.time() + _TIMEOUT)
-    del call
-    del completion_queue
-    del channel
+class CTypeSmokeTest(unittest.TestCase):
 
-    _c.shut_down()
+  def testClientCredentialsUpDown(self):
+    credentials = _c.ClientCredentials.fake_transport_security()
+    del credentials
 
-  def testServer(self):
-    _c.init()
+  def testServerCredentialsUpDown(self):
+    credentials = _c.ServerCredentials.fake_transport_security()
+    del credentials
 
+  def testCompletionQueueUpDown(self):
     completion_queue = _c.CompletionQueue()
-    server = _c.Server(completion_queue)
-    server.add_http2_addr('[::]:0')
-    server.start()
-    server.stop()
-    completion_queue.stop()
-    del server
     del completion_queue
 
-    service_tag = object()
+  def testServerUpDown(self):
     completion_queue = _c.CompletionQueue()
-    server = _c.Server(completion_queue)
-    server.add_http2_addr('[::]:0')
-    server.start()
-    server.service(service_tag)
-    server.stop()
-    completion_queue.stop()
-    event = completion_queue.get(time.time() + _TIMEOUT)
-    self.assertIs(event.kind, _datatypes.Event.Kind.SERVICE_ACCEPTED)
-    self.assertIs(event.tag, service_tag)
-    self.assertIsNone(event.service_acceptance)
-    for _ in range(_IDEMPOTENCE_DEMONSTRATION):
-      event = completion_queue.get(time.time() + _TIMEOUT)
-      self.assertIs(event.kind, _datatypes.Event.Kind.STOP)
-    del server
+    serv = _c.Server(completion_queue, [])
+    del serv
     del completion_queue
 
-    completion_queue = _c.CompletionQueue()
-    server = _c.Server(completion_queue)
-    server.add_http2_addr('[::]:0')
-    server.start()
-    thread = threading.Thread(target=completion_queue.get, args=(_FUTURE,))
-    thread.start()
-    time.sleep(1)
-    server.stop()
-    completion_queue.stop()
-    for _ in range(_IDEMPOTENCE_DEMONSTRATION):
-      event = completion_queue.get(time.time() + _TIMEOUT)
-      self.assertIs(event.kind, _datatypes.Event.Kind.STOP)
-    thread.join()
-    del server
-    del completion_queue
-
-    _c.shut_down()
-
-  def test_client_credentials(self):
-    root_certificates = b'Trust starts here. Really.'
-    private_key = b'This is a really bad private key, yo.'
-    certificate_chain = b'Trust me! Do I not look trustworty?'
-
-    _c.init()
-
-    client_credentials = _c.ClientCredentials(
-        None, None, None)
-    self.assertIsNotNone(client_credentials)
-    client_credentials = _c.ClientCredentials(
-        root_certificates, None, None)
-    self.assertIsNotNone(client_credentials)
-    client_credentials = _c.ClientCredentials(
-        None, private_key, certificate_chain)
-    self.assertIsNotNone(client_credentials)
-    client_credentials = _c.ClientCredentials(
-        root_certificates, private_key, certificate_chain)
-    self.assertIsNotNone(client_credentials)
-    del client_credentials
-
-    _c.shut_down()
-
-  def test_server_credentials(self):
-    root_certificates = b'Trust starts here. Really.'
-    first_private_key = b'This is a really bad private key, yo.'
-    first_certificate_chain = b'Trust me! Do I not look trustworty?'
-    second_private_key = b'This is another bad private key, yo.'
-    second_certificate_chain = b'Look into my eyes; you can totes trust me.'
-
-    _c.init()
-
-    server_credentials = _c.ServerCredentials(
-        None, ((first_private_key, first_certificate_chain),))
-    del server_credentials
-    server_credentials = _c.ServerCredentials(
-        root_certificates, ((first_private_key, first_certificate_chain),))
-    del server_credentials
-    server_credentials = _c.ServerCredentials(
-        root_certificates,
-        ((first_private_key, first_certificate_chain),
-         (second_private_key, second_certificate_chain),))
-    del server_credentials
-    with self.assertRaises(TypeError):
-      _c.ServerCredentials(
-          root_certificates, first_private_key, second_certificate_chain)
-
-    _c.shut_down()
-
-  @unittest.skip('TODO(nathaniel): find and use real-enough test credentials')
-  def test_secure_server(self):
-    _c.init()
-
-    server_credentials = _c.ServerCredentials(
-        'root certificate', (('private key', 'certificate chain'),))
-
-    completion_queue = _c.CompletionQueue()
-    server = _c.Server(completion_queue, server_credentials)
-    server.add_http2_addr('[::]:0')
-    server.start()
-    thread = threading.Thread(target=completion_queue.get, args=(_FUTURE,))
-    thread.start()
-    time.sleep(1)
-    server.stop()
-    completion_queue.stop()
-    for _ in range(_IDEMPOTENCE_DEMONSTRATION):
-      event = completion_queue.get(time.time() + _TIMEOUT)
-      self.assertIs(event.kind, _datatypes.Event.Kind.STOP)
-    thread.join()
-    del server
-    del completion_queue
+  def testChannelUpDown(self):
+    channel = _c.Channel('[::]:0', [])
+    del channel
 
-    _c.shut_down()
+  def testSecureChannelUpDown(self):
+    channel = _c.Channel('[::]:0', [], _c.ClientCredentials.fake_transport_security())
+    del channel
 
 
 if __name__ == '__main__':
diff --git a/src/python/src/grpc/_adapter/_call.c b/src/python/src/grpc/_adapter/_call.c
deleted file mode 100644
index d833268fc9..0000000000
--- a/src/python/src/grpc/_adapter/_call.c
+++ /dev/null
@@ -1,438 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include "grpc/_adapter/_call.h"
-
-#include <math.h>
-#include <Python.h>
-#include <grpc/grpc.h>
-#include <grpc/support/alloc.h>
-
-#include "grpc/_adapter/_channel.h"
-#include "grpc/_adapter/_completion_queue.h"
-#include "grpc/_adapter/_error.h"
-#include "grpc/_adapter/_tag.h"
-
-static PyObject *pygrpc_call_new(PyTypeObject *type, PyObject *args, PyObject *kwds) {
-  Call *self = (Call *)type->tp_alloc(type, 0);
-  Channel *channel;
-  CompletionQueue *completion_queue;
-  const char *method;
-  const char *host;
-  double deadline;
-  static char *kwlist[] = {"channel", "completion_queue",
-    "method", "host", "deadline", NULL};
-
-  if (!PyArg_ParseTupleAndKeywords(
-      args, kwds, "O!O!ssd:Call", kwlist,
-      &pygrpc_ChannelType, &channel,
-      &pygrpc_CompletionQueueType, &completion_queue,
-      &method, &host, &deadline)) {
-    return NULL;
-  }
-
-  /* TODO(nathaniel): Hoist the gpr_timespec <-> PyFloat arithmetic into its own
-   * function with its own test coverage.
-   */
-  self->c_call = grpc_channel_create_call(
-      channel->c_channel, completion_queue->c_completion_queue, method, host,
-      gpr_time_from_nanos(deadline * GPR_NS_PER_SEC));
-  self->completion_queue = completion_queue;
-  Py_INCREF(self->completion_queue);
-  self->channel = channel;
-  Py_INCREF(self->channel);
-  grpc_call_details_init(&self->call_details);
-  grpc_metadata_array_init(&self->recv_metadata);
-  grpc_metadata_array_init(&self->recv_trailing_metadata);
-  self->send_metadata = NULL;
-  self->send_metadata_count = 0;
-  self->send_trailing_metadata = NULL;
-  self->send_trailing_metadata_count = 0;
-  self->send_message = NULL;
-  self->recv_message = NULL;
-  self->adding_to_trailing = 0;
-
-  return (PyObject *)self;
-}
-
-static void pygrpc_call_dealloc(Call *self) {
-  if (self->c_call != NULL) {
-    grpc_call_destroy(self->c_call);
-  }
-  Py_XDECREF(self->completion_queue);
-  Py_XDECREF(self->channel);
-  Py_XDECREF(self->server);
-  grpc_call_details_destroy(&self->call_details);
-  grpc_metadata_array_destroy(&self->recv_metadata);
-  grpc_metadata_array_destroy(&self->recv_trailing_metadata);
-  if (self->send_message) {
-    grpc_byte_buffer_destroy(self->send_message);
-  }
-  if (self->recv_message) {
-    grpc_byte_buffer_destroy(self->recv_message);
-  }
-  gpr_free(self->status_details);
-  gpr_free(self->send_metadata);
-  gpr_free(self->send_trailing_metadata);
-  self->ob_type->tp_free((PyObject *)self);
-}
-
-static const PyObject *pygrpc_call_invoke(Call *self, PyObject *args) {
-  PyObject *completion_queue;
-  PyObject *metadata_tag;
-  PyObject *finish_tag;
-  grpc_call_error call_error;
-  const PyObject *result;
-  pygrpc_tag *c_init_metadata_tag;
-  pygrpc_tag *c_metadata_tag;
-  pygrpc_tag *c_finish_tag;
-  grpc_op send_initial_metadata;
-  grpc_op recv_initial_metadata;
-  grpc_op recv_status_on_client;
-
-  if (!(PyArg_ParseTuple(args, "O!OO:invoke", &pygrpc_CompletionQueueType,
-                         &completion_queue, &metadata_tag, &finish_tag))) {
-    return NULL;
-  }
-  send_initial_metadata.op = GRPC_OP_SEND_INITIAL_METADATA;
-  send_initial_metadata.data.send_initial_metadata.metadata = self->send_metadata;
-  send_initial_metadata.data.send_initial_metadata.count = self->send_metadata_count;
-  recv_initial_metadata.op = GRPC_OP_RECV_INITIAL_METADATA;
-  recv_initial_metadata.data.recv_initial_metadata = &self->recv_metadata;
-  recv_status_on_client.op = GRPC_OP_RECV_STATUS_ON_CLIENT;
-  recv_status_on_client.data.recv_status_on_client.trailing_metadata = &self->recv_trailing_metadata;
-  recv_status_on_client.data.recv_status_on_client.status = &self->status;
-  recv_status_on_client.data.recv_status_on_client.status_details = &self->status_details;
-  recv_status_on_client.data.recv_status_on_client.status_details_capacity = &self->status_details_capacity;
-  c_init_metadata_tag = pygrpc_tag_new(PYGRPC_INITIAL_METADATA, NULL, self);
-  c_metadata_tag = pygrpc_tag_new(PYGRPC_CLIENT_METADATA_READ, metadata_tag, self);
-  c_finish_tag = pygrpc_tag_new(PYGRPC_FINISHED_CLIENT, finish_tag, self);
-
-  call_error = grpc_call_start_batch(self->c_call, &send_initial_metadata, 1, c_init_metadata_tag);
-  result = pygrpc_translate_call_error(call_error);
-  if (result == NULL) {
-    pygrpc_tag_destroy(c_init_metadata_tag);
-    pygrpc_tag_destroy(c_metadata_tag);
-    pygrpc_tag_destroy(c_finish_tag);
-    return result;
-  }
-  call_error = grpc_call_start_batch(self->c_call, &recv_initial_metadata, 1, c_metadata_tag);
-  result = pygrpc_translate_call_error(call_error);
-  if (result == NULL) {
-    pygrpc_tag_destroy(c_metadata_tag);
-    pygrpc_tag_destroy(c_finish_tag);
-    return result;
-  }
-  call_error = grpc_call_start_batch(self->c_call, &recv_status_on_client, 1, c_finish_tag);
-  result = pygrpc_translate_call_error(call_error);
-  if (result == NULL) {
-    pygrpc_tag_destroy(c_finish_tag);
-    return result;
-  }
-
-  return result;
-}
-
-static const PyObject *pygrpc_call_write(Call *self, PyObject *args) {
-  const char *bytes;
-  int length;
-  PyObject *tag;
-  gpr_slice slice;
-  grpc_byte_buffer *byte_buffer;
-  grpc_call_error call_error;
-  const PyObject *result;
-  pygrpc_tag *c_tag;
-  grpc_op op;
-
-  if (!(PyArg_ParseTuple(args, "s#O:write", &bytes, &length, &tag))) {
-    return NULL;
-  }
-  c_tag = pygrpc_tag_new(PYGRPC_WRITE_ACCEPTED, tag, self);
-
-  slice = gpr_slice_from_copied_buffer(bytes, length);
-  byte_buffer = grpc_byte_buffer_create(&slice, 1);
-  gpr_slice_unref(slice);
-
-  if (self->send_message) {
-    grpc_byte_buffer_destroy(self->send_message);
-  }
-  self->send_message = byte_buffer;
-
-  op.op = GRPC_OP_SEND_MESSAGE;
-  op.data.send_message = self->send_message;
-
-  call_error = grpc_call_start_batch(self->c_call, &op, 1, c_tag);
-
-  result = pygrpc_translate_call_error(call_error);
-  if (result == NULL) {
-    pygrpc_tag_destroy(c_tag);
-  }
-  return result;
-}
-
-static const PyObject *pygrpc_call_complete(Call *self, PyObject *tag) {
-  grpc_call_error call_error;
-  const PyObject *result;
-  pygrpc_tag *c_tag = pygrpc_tag_new(PYGRPC_FINISH_ACCEPTED, tag, self);
-  grpc_op op;
-
-  op.op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
-
-  call_error = grpc_call_start_batch(self->c_call, &op, 1, c_tag);
-
-  result = pygrpc_translate_call_error(call_error);
-  if (result == NULL) {
-    pygrpc_tag_destroy(c_tag);
-  }
-  return result;
-}
-
-static const PyObject *pygrpc_call_accept(Call *self, PyObject *args) {
-  PyObject *completion_queue;
-  PyObject *tag;
-  grpc_call_error call_error;
-  const PyObject *result;
-  pygrpc_tag *c_tag;
-  grpc_op op;
-
-  if (!(PyArg_ParseTuple(args, "O!O:accept", &pygrpc_CompletionQueueType,
-                         &completion_queue, &tag))) {
-    return NULL;
-  }
-
-  op.op = GRPC_OP_RECV_CLOSE_ON_SERVER;
-  op.data.recv_close_on_server.cancelled = &self->cancelled;
-  c_tag = pygrpc_tag_new(PYGRPC_FINISHED_SERVER, tag, self);
-
-  call_error = grpc_call_start_batch(self->c_call, &op, 1, c_tag);
-  result = pygrpc_translate_call_error(call_error);
-  if (result == NULL) {
-    pygrpc_tag_destroy(c_tag);
-  }
-  return result;
-}
-
-static const PyObject *pygrpc_call_add_metadata(Call *self, PyObject *args) {
-  const char* key = NULL;
-  const char* value = NULL;
-  int value_length = 0;
-  grpc_metadata metadata;
-  if (!PyArg_ParseTuple(args, "ss#", &key, &value, &value_length)) {
-    return NULL;
-  }
-  metadata.key = key;
-  metadata.value = value;
-  metadata.value_length = value_length;
-  if (self->adding_to_trailing) {
-    self->send_trailing_metadata = gpr_realloc(self->send_trailing_metadata, (self->send_trailing_metadata_count + 1) * sizeof(grpc_metadata));
-    self->send_trailing_metadata[self->send_trailing_metadata_count] = metadata;
-    self->send_trailing_metadata_count = self->send_trailing_metadata_count + 1;
-  } else {
-    self->send_metadata = gpr_realloc(self->send_metadata, (self->send_metadata_count + 1) * sizeof(grpc_metadata));
-    self->send_metadata[self->send_metadata_count] = metadata;
-    self->send_metadata_count = self->send_metadata_count + 1;
-  }
-  return pygrpc_translate_call_error(GRPC_CALL_OK);
-}
-
-static const PyObject *pygrpc_call_premetadata(Call *self) {
-  grpc_op op;
-  grpc_call_error call_error;
-  const PyObject *result;
-  pygrpc_tag *c_tag = pygrpc_tag_new(PYGRPC_INITIAL_METADATA, NULL, self);
-  op.op = GRPC_OP_SEND_INITIAL_METADATA;
-  op.data.send_initial_metadata.metadata = self->send_metadata;
-  op.data.send_initial_metadata.count = self->send_metadata_count;
-  self->adding_to_trailing = 1;
-
-  call_error = grpc_call_start_batch(self->c_call, &op, 1, c_tag);
-  result = pygrpc_translate_call_error(call_error);
-  if (result == NULL) {
-    pygrpc_tag_destroy(c_tag);
-  }
-  return result;
-}
-
-static const PyObject *pygrpc_call_read(Call *self, PyObject *tag) {
-  grpc_op op;
-  grpc_call_error call_error;
-  const PyObject *result;
-  pygrpc_tag *c_tag = pygrpc_tag_new(PYGRPC_READ, tag, self);
-
-  op.op = GRPC_OP_RECV_MESSAGE;
-  if (self->recv_message) {
-    grpc_byte_buffer_destroy(self->recv_message);
-    self->recv_message = NULL;
-  }
-  op.data.recv_message = &self->recv_message;
-  call_error = grpc_call_start_batch(self->c_call, &op, 1, c_tag);
-  result = pygrpc_translate_call_error(call_error);
-  if (result == NULL) {
-    pygrpc_tag_destroy(c_tag);
-  }
-  return result;
-}
-
-static const PyObject *pygrpc_call_status(Call *self, PyObject *args) {
-  PyObject *status;
-  PyObject *code;
-  PyObject *details;
-  PyObject *tag;
-  grpc_status_code c_code;
-  char *c_message;
-  grpc_call_error call_error;
-  const PyObject *result;
-  pygrpc_tag *c_tag;
-  grpc_op op;
-
-  if (!(PyArg_ParseTuple(args, "OO:status", &status, &tag))) {
-    return NULL;
-  }
-  c_tag = pygrpc_tag_new(PYGRPC_FINISH_ACCEPTED, tag, self);
-
-  code = PyObject_GetAttrString(status, "code");
-  if (code == NULL) {
-    return NULL;
-  }
-  details = PyObject_GetAttrString(status, "details");
-  if (details == NULL) {
-    Py_DECREF(code);
-    return NULL;
-  }
-  c_code = PyInt_AsLong(code);
-  Py_DECREF(code);
-  if (c_code == -1 && PyErr_Occurred()) {
-    Py_DECREF(details);
-    return NULL;
-  }
-  c_message = PyBytes_AsString(details);
-  Py_DECREF(details);
-  if (c_message == NULL) {
-    return NULL;
-  }
-  if (self->status_details) {
-    gpr_free(self->status_details);
-  }
-  self->status_details = gpr_malloc(strlen(c_message)+1);
-  strcpy(self->status_details, c_message);
-  op.op = GRPC_OP_SEND_STATUS_FROM_SERVER;
-  op.data.send_status_from_server.trailing_metadata_count = self->send_trailing_metadata_count;
-  op.data.send_status_from_server.trailing_metadata = self->send_trailing_metadata;
-  op.data.send_status_from_server.status = c_code;
-  op.data.send_status_from_server.status_details = self->status_details;
-
-  call_error = grpc_call_start_batch(self->c_call, &op, 1, c_tag);
-  result = pygrpc_translate_call_error(call_error);
-  if (result == NULL) {
-    pygrpc_tag_destroy(c_tag);
-  }
-  return result;
-}
-
-static const PyObject *pygrpc_call_cancel(Call *self) {
-  return pygrpc_translate_call_error(grpc_call_cancel(self->c_call));
-}
-
-static PyMethodDef methods[] = {
-    {"invoke", (PyCFunction)pygrpc_call_invoke, METH_VARARGS,
-     "Invoke this call."},
-    {"write", (PyCFunction)pygrpc_call_write, METH_VARARGS,
-     "Write bytes to this call."},
-    {"complete", (PyCFunction)pygrpc_call_complete, METH_O,
-     "Complete writes to this call."},
-    {"accept", (PyCFunction)pygrpc_call_accept, METH_VARARGS, "Accept an RPC."},
-    {"add_metadata", (PyCFunction)pygrpc_call_add_metadata, METH_VARARGS,
-     "Add metadata to the call. May not be called after invoke on the client "
-     "side. On the server side: when called before premetadata it provides "
-     "'leading' metadata, when called after premetadata but before status it "
-     "provides 'trailing metadata'; may not be called after status."},
-    {"premetadata", (PyCFunction)pygrpc_call_premetadata, METH_VARARGS,
-     "Indicate the end of leading metadata in the response."},
-    {"read", (PyCFunction)pygrpc_call_read, METH_O,
-     "Read bytes from this call."},
-    {"status", (PyCFunction)pygrpc_call_status, METH_VARARGS,
-     "Report this call's status."},
-    {"cancel", (PyCFunction)pygrpc_call_cancel, METH_NOARGS,
-     "Cancel this call."},
-    {NULL}};
-
-PyTypeObject pygrpc_CallType = {
-    PyVarObject_HEAD_INIT(NULL, 0)
-    "_grpc.Call",                    /*tp_name*/
-    sizeof(Call),                    /*tp_basicsize*/
-    0,                               /*tp_itemsize*/
-    (destructor)pygrpc_call_dealloc, /*tp_dealloc*/
-    0,                               /*tp_print*/
-    0,                               /*tp_getattr*/
-    0,                               /*tp_setattr*/
-    0,                               /*tp_compare*/
-    0,                               /*tp_repr*/
-    0,                               /*tp_as_number*/
-    0,                               /*tp_as_sequence*/
-    0,                               /*tp_as_mapping*/
-    0,                               /*tp_hash */
-    0,                               /*tp_call*/
-    0,                               /*tp_str*/
-    0,                               /*tp_getattro*/
-    0,                               /*tp_setattro*/
-    0,                               /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT,              /*tp_flags*/
-    "Wrapping of grpc_call.",        /* tp_doc */
-    0,                               /* tp_traverse */
-    0,                               /* tp_clear */
-    0,                               /* tp_richcompare */
-    0,                               /* tp_weaklistoffset */
-    0,                               /* tp_iter */
-    0,                               /* tp_iternext */
-    methods,                         /* tp_methods */
-    0,                               /* tp_members */
-    0,                               /* tp_getset */
-    0,                               /* tp_base */
-    0,                               /* tp_dict */
-    0,                               /* tp_descr_get */
-    0,                               /* tp_descr_set */
-    0,                               /* tp_dictoffset */
-    0,                               /* tp_init */
-    0,                               /* tp_alloc */
-    pygrpc_call_new,                 /* tp_new */
-};
-
-int pygrpc_add_call(PyObject *module) {
-  if (PyType_Ready(&pygrpc_CallType) < 0) {
-    return -1;
-  }
-  if (PyModule_AddObject(module, "Call", (PyObject *)&pygrpc_CallType) == -1) {
-    return -1;
-  }
-  return 0;
-}
diff --git a/src/python/src/grpc/_adapter/_channel.c b/src/python/src/grpc/_adapter/_channel.c
deleted file mode 100644
index 6be8f1c364..0000000000
--- a/src/python/src/grpc/_adapter/_channel.c
+++ /dev/null
@@ -1,135 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include "grpc/_adapter/_channel.h"
-
-#include <Python.h>
-#include <grpc/grpc.h>
-#include <grpc/grpc_security.h>
-
-#include "grpc/_adapter/_client_credentials.h"
-
-static int pygrpc_channel_init(Channel *self, PyObject *args, PyObject *kwds) {
-  const char *hostport;
-  PyObject *client_credentials;
-  char *server_host_override = NULL;
-  static char *kwlist[] = {"hostport", "client_credentials",
-                           "server_host_override", NULL};
-  grpc_arg server_host_override_arg;
-  grpc_channel_args channel_args;
-
-  if (!(PyArg_ParseTupleAndKeywords(args, kwds, "sO|z:Channel", kwlist,
-                                    &hostport, &client_credentials,
-                                    &server_host_override))) {
-    return -1;
-  }
-  if (client_credentials == Py_None) {
-    self->c_channel = grpc_channel_create(hostport, NULL);
-    return 0;
-  } else {
-    if (server_host_override == NULL) {
-      self->c_channel = grpc_secure_channel_create(
-	  ((ClientCredentials *)client_credentials)->c_client_credentials,
-          hostport, NULL);
-    } else {
-      server_host_override_arg.type = GRPC_ARG_STRING;
-      server_host_override_arg.key = GRPC_SSL_TARGET_NAME_OVERRIDE_ARG;
-      server_host_override_arg.value.string = server_host_override;
-      channel_args.num_args = 1;
-      channel_args.args = &server_host_override_arg;
-      self->c_channel = grpc_secure_channel_create(
-          ((ClientCredentials *)client_credentials)->c_client_credentials,
-          hostport, &channel_args);
-    }
-    return 0;
-  }
-}
-
-static void pygrpc_channel_dealloc(Channel *self) {
-  if (self->c_channel != NULL) {
-    grpc_channel_destroy(self->c_channel);
-  }
-  self->ob_type->tp_free((PyObject *)self);
-}
-
-PyTypeObject pygrpc_ChannelType = {
-    PyVarObject_HEAD_INIT(NULL, 0)
-    "_grpc.Channel",                    /*tp_name*/
-    sizeof(Channel),                    /*tp_basicsize*/
-    0,                                  /*tp_itemsize*/
-    (destructor)pygrpc_channel_dealloc, /*tp_dealloc*/
-    0,                                  /*tp_print*/
-    0,                                  /*tp_getattr*/
-    0,                                  /*tp_setattr*/
-    0,                                  /*tp_compare*/
-    0,                                  /*tp_repr*/
-    0,                                  /*tp_as_number*/
-    0,                                  /*tp_as_sequence*/
-    0,                                  /*tp_as_mapping*/
-    0,                                  /*tp_hash */
-    0,                                  /*tp_call*/
-    0,                                  /*tp_str*/
-    0,                                  /*tp_getattro*/
-    0,                                  /*tp_setattro*/
-    0,                                  /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT,                 /*tp_flags*/
-    "Wrapping of grpc_channel.",        /* tp_doc */
-    0,                                  /* tp_traverse */
-    0,                                  /* tp_clear */
-    0,                                  /* tp_richcompare */
-    0,                                  /* tp_weaklistoffset */
-    0,                                  /* tp_iter */
-    0,                                  /* tp_iternext */
-    0,                                  /* tp_methods */
-    0,                                  /* tp_members */
-    0,                                  /* tp_getset */
-    0,                                  /* tp_base */
-    0,                                  /* tp_dict */
-    0,                                  /* tp_descr_get */
-    0,                                  /* tp_descr_set */
-    0,                                  /* tp_dictoffset */
-    (initproc)pygrpc_channel_init,      /* tp_init */
-    0,                                  /* tp_alloc */
-    PyType_GenericNew,                  /* tp_new */
-};
-
-int pygrpc_add_channel(PyObject *module) {
-  if (PyType_Ready(&pygrpc_ChannelType) < 0) {
-    return -1;
-  }
-  if (PyModule_AddObject(module, "Channel", (PyObject *)&pygrpc_ChannelType) ==
-      -1) {
-    return -1;
-  }
-  return 0;
-}
diff --git a/src/python/src/grpc/_adapter/_client_credentials.c b/src/python/src/grpc/_adapter/_client_credentials.c
deleted file mode 100644
index e8ccff8d17..0000000000
--- a/src/python/src/grpc/_adapter/_client_credentials.c
+++ /dev/null
@@ -1,121 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include "grpc/_adapter/_client_credentials.h"
-
-#include <Python.h>
-#include <grpc/grpc_security.h>
-#include <grpc/support/alloc.h>
-
-static int pygrpc_client_credentials_init(ClientCredentials *self,
-                                          PyObject *args, PyObject *kwds) {
-  char *root_certificates;
-  grpc_ssl_pem_key_cert_pair key_certificate_pair;
-  static char *kwlist[] = {"root_certificates", "private_key",
-                           "certificate_chain", NULL};
-
-  if (!PyArg_ParseTupleAndKeywords(args, kwds, "zzz:ClientCredentials", kwlist,
-                                   &root_certificates,
-                                   &key_certificate_pair.private_key,
-                                   &key_certificate_pair.cert_chain)) {
-    return -1;
-  }
-
-  if (key_certificate_pair.private_key != NULL && key_certificate_pair.cert_chain != NULL) {
-    self->c_client_credentials =
-        grpc_ssl_credentials_create(root_certificates, &key_certificate_pair);
-  } else {
-    self->c_client_credentials =
-        grpc_ssl_credentials_create(root_certificates, NULL);
-  }
-  return 0;
-}
-
-static void pygrpc_client_credentials_dealloc(ClientCredentials *self) {
-  if (self->c_client_credentials != NULL) {
-    grpc_credentials_release(self->c_client_credentials);
-  }
-  self->ob_type->tp_free((PyObject *)self);
-}
-
-PyTypeObject pygrpc_ClientCredentialsType = {
-    PyVarObject_HEAD_INIT(NULL, 0)
-    "_grpc.ClientCredencials",                      /*tp_name*/
-    sizeof(ClientCredentials),                      /*tp_basicsize*/
-    0,                                              /*tp_itemsize*/
-    (destructor)pygrpc_client_credentials_dealloc,  /*tp_dealloc*/
-    0,                                              /*tp_print*/
-    0,                                              /*tp_getattr*/
-    0,                                              /*tp_setattr*/
-    0,                                              /*tp_compare*/
-    0,                                              /*tp_repr*/
-    0,                                              /*tp_as_number*/
-    0,                                              /*tp_as_sequence*/
-    0,                                              /*tp_as_mapping*/
-    0,                                              /*tp_hash */
-    0,                                              /*tp_call*/
-    0,                                              /*tp_str*/
-    0,                                              /*tp_getattro*/
-    0,                                              /*tp_setattro*/
-    0,                                              /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT,                             /*tp_flags*/
-    "Wrapping of grpc_credentials.",                /* tp_doc */
-    0,                                              /* tp_traverse */
-    0,                                              /* tp_clear */
-    0,                                              /* tp_richcompare */
-    0,                                              /* tp_weaklistoffset */
-    0,                                              /* tp_iter */
-    0,                                              /* tp_iternext */
-    0,                                              /* tp_methods */
-    0,                                              /* tp_members */
-    0,                                              /* tp_getset */
-    0,                                              /* tp_base */
-    0,                                              /* tp_dict */
-    0,                                              /* tp_descr_get */
-    0,                                              /* tp_descr_set */
-    0,                                              /* tp_dictoffset */
-    (initproc)pygrpc_client_credentials_init,       /* tp_init */
-    0,                                              /* tp_alloc */
-    PyType_GenericNew,                              /* tp_new */
-};
-
-int pygrpc_add_client_credentials(PyObject *module) {
-  if (PyType_Ready(&pygrpc_ClientCredentialsType) < 0) {
-    return -1;
-  }
-  if (PyModule_AddObject(module, "ClientCredentials",
-                         (PyObject *)&pygrpc_ClientCredentialsType) == -1) {
-    return -1;
-  }
-  return 0;
-}
diff --git a/src/python/src/grpc/_adapter/_completion_queue.c b/src/python/src/grpc/_adapter/_completion_queue.c
deleted file mode 100644
index 97828e67ad..0000000000
--- a/src/python/src/grpc/_adapter/_completion_queue.c
+++ /dev/null
@@ -1,653 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include "grpc/_adapter/_completion_queue.h"
-
-#include <Python.h>
-#include <grpc/grpc.h>
-#include <grpc/support/alloc.h>
-
-#include "grpc/_adapter/_call.h"
-#include "grpc/_adapter/_tag.h"
-
-static PyObject *status_class;
-static PyObject *service_acceptance_class;
-static PyObject *event_class;
-
-static PyObject *ok_status_code;
-static PyObject *cancelled_status_code;
-static PyObject *unknown_status_code;
-static PyObject *invalid_argument_status_code;
-static PyObject *expired_status_code;
-static PyObject *not_found_status_code;
-static PyObject *already_exists_status_code;
-static PyObject *permission_denied_status_code;
-static PyObject *unauthenticated_status_code;
-static PyObject *resource_exhausted_status_code;
-static PyObject *failed_precondition_status_code;
-static PyObject *aborted_status_code;
-static PyObject *out_of_range_status_code;
-static PyObject *unimplemented_status_code;
-static PyObject *internal_error_status_code;
-static PyObject *unavailable_status_code;
-static PyObject *data_loss_status_code;
-
-static PyObject *stop_event_kind;
-static PyObject *write_event_kind;
-static PyObject *complete_event_kind;
-static PyObject *service_event_kind;
-static PyObject *read_event_kind;
-static PyObject *metadata_event_kind;
-static PyObject *finish_event_kind;
-
-static PyObject *pygrpc_as_py_time(gpr_timespec *timespec) {
-  return PyFloat_FromDouble(
-                       timespec->tv_sec + ((double)timespec->tv_nsec) / 1.0E9);
-}
-
-static PyObject *pygrpc_status_code(grpc_status_code c_status_code) {
-  switch (c_status_code) {
-    case GRPC_STATUS_OK:
-      return ok_status_code;
-    case GRPC_STATUS_CANCELLED:
-      return cancelled_status_code;
-    case GRPC_STATUS_UNKNOWN:
-      return unknown_status_code;
-    case GRPC_STATUS_INVALID_ARGUMENT:
-      return invalid_argument_status_code;
-    case GRPC_STATUS_DEADLINE_EXCEEDED:
-      return expired_status_code;
-    case GRPC_STATUS_NOT_FOUND:
-      return not_found_status_code;
-    case GRPC_STATUS_ALREADY_EXISTS:
-      return already_exists_status_code;
-    case GRPC_STATUS_PERMISSION_DENIED:
-      return permission_denied_status_code;
-    case GRPC_STATUS_UNAUTHENTICATED:
-      return unauthenticated_status_code;
-    case GRPC_STATUS_RESOURCE_EXHAUSTED:
-      return resource_exhausted_status_code;
-    case GRPC_STATUS_FAILED_PRECONDITION:
-      return failed_precondition_status_code;
-    case GRPC_STATUS_ABORTED:
-      return aborted_status_code;
-    case GRPC_STATUS_OUT_OF_RANGE:
-      return out_of_range_status_code;
-    case GRPC_STATUS_UNIMPLEMENTED:
-      return unimplemented_status_code;
-    case GRPC_STATUS_INTERNAL:
-      return internal_error_status_code;
-    case GRPC_STATUS_UNAVAILABLE:
-      return unavailable_status_code;
-    case GRPC_STATUS_DATA_LOSS:
-      return data_loss_status_code;
-    default:
-      return NULL;
-  }
-}
-
-static PyObject *pygrpc_metadata_collection_get(
-    grpc_metadata *metadata_elements, size_t count) {
-  PyObject *metadata = PyList_New(count);
-  size_t i;
-  for (i = 0; i < count; ++i) {
-    grpc_metadata elem = metadata_elements[i];
-    PyObject *key = PyString_FromString(elem.key);
-    PyObject *value = PyString_FromStringAndSize(elem.value, elem.value_length);
-    PyObject* kvp = PyTuple_Pack(2, key, value);
-    /* n.b. PyList_SetItem *steals* a reference to the set element. */
-    PyList_SetItem(metadata, i, kvp);
-    Py_DECREF(key);
-    Py_DECREF(value);
-  }
-  return metadata;
-}
-
-static PyObject *pygrpc_stop_event_args(grpc_event *c_event) {
-  return PyTuple_Pack(8, stop_event_kind, Py_None, Py_None, Py_None,
-                      Py_None, Py_None, Py_None, Py_None);
-}
-
-static PyObject *pygrpc_write_event_args(grpc_event *c_event) {
-  pygrpc_tag *tag = (pygrpc_tag *)(c_event->tag);
-  PyObject *user_tag = tag->user_tag;
-  PyObject *write_accepted = Py_True;
-  return PyTuple_Pack(8, write_event_kind, user_tag,
-                      write_accepted, Py_None, Py_None, Py_None, Py_None,
-                      Py_None);
-}
-
-static PyObject *pygrpc_complete_event_args(grpc_event *c_event) {
-  pygrpc_tag *tag = (pygrpc_tag *)(c_event->tag);
-  PyObject *user_tag = tag->user_tag;
-  PyObject *complete_accepted = Py_True;
-  return PyTuple_Pack(8, complete_event_kind, user_tag,
-                      Py_None, complete_accepted, Py_None, Py_None, Py_None,
-                      Py_None);
-}
-
-static PyObject *pygrpc_service_event_args(grpc_event *c_event) {
-  pygrpc_tag *tag = (pygrpc_tag *)(c_event->tag);
-  PyObject *user_tag = tag->user_tag;
-  if (tag->call->call_details.method == NULL) {
-    return PyTuple_Pack(
-        8, service_event_kind, user_tag, Py_None, Py_None, Py_None, Py_None,
-        Py_None, Py_None);
-  } else {
-    PyObject *method = NULL;
-    PyObject *host = NULL;
-    PyObject *service_deadline = NULL;
-    PyObject *service_acceptance = NULL;
-    PyObject *metadata = NULL;
-    PyObject *event_args = NULL;
-
-    method = PyBytes_FromString(tag->call->call_details.method);
-    if (method == NULL) {
-      goto error;
-    }
-    host = PyBytes_FromString(tag->call->call_details.host);
-    if (host == NULL) {
-      goto error;
-    }
-    service_deadline =
-        pygrpc_as_py_time(&tag->call->call_details.deadline);
-    if (service_deadline == NULL) {
-      goto error;
-    }
-
-    service_acceptance =
-        PyObject_CallFunctionObjArgs(service_acceptance_class, tag->call,
-                                     method, host, service_deadline, NULL);
-    if (service_acceptance == NULL) {
-      goto error;
-    }
-
-    metadata = pygrpc_metadata_collection_get(
-        tag->call->recv_metadata.metadata,
-        tag->call->recv_metadata.count);
-    event_args = PyTuple_Pack(8, service_event_kind,
-                              user_tag, Py_None, Py_None,
-                              service_acceptance, Py_None, Py_None,
-                              metadata);
-
-    Py_DECREF(service_acceptance);
-    Py_DECREF(metadata);
-error:
-    Py_XDECREF(method);
-    Py_XDECREF(host);
-    Py_XDECREF(service_deadline);
-
-    return event_args;
-  }
-}
-
-static PyObject *pygrpc_read_event_args(grpc_event *c_event) {
-  pygrpc_tag *tag = (pygrpc_tag *)(c_event->tag);
-  PyObject *user_tag = tag->user_tag;
-  if (tag->call->recv_message == NULL) {
-    return PyTuple_Pack(8, read_event_kind, user_tag,
-                        Py_None, Py_None, Py_None, Py_None, Py_None, Py_None);
-  } else {
-    size_t length;
-    size_t offset;
-    grpc_byte_buffer_reader *reader;
-    gpr_slice slice;
-    char *c_bytes;
-    PyObject *bytes;
-    PyObject *event_args;
-
-    length = grpc_byte_buffer_length(tag->call->recv_message);
-    reader = grpc_byte_buffer_reader_create(tag->call->recv_message);
-    c_bytes = gpr_malloc(length);
-    offset = 0;
-    while (grpc_byte_buffer_reader_next(reader, &slice)) {
-      memcpy(c_bytes + offset, GPR_SLICE_START_PTR(slice),
-             GPR_SLICE_LENGTH(slice));
-      offset += GPR_SLICE_LENGTH(slice);
-    }
-    grpc_byte_buffer_reader_destroy(reader);
-    bytes = PyBytes_FromStringAndSize(c_bytes, length);
-    gpr_free(c_bytes);
-    if (bytes == NULL) {
-      return NULL;
-    }
-    event_args = PyTuple_Pack(8, read_event_kind, user_tag,
-                              Py_None, Py_None, Py_None, bytes, Py_None,
-                              Py_None);
-    Py_DECREF(bytes);
-    return event_args;
-  }
-}
-
-static PyObject *pygrpc_metadata_event_args(grpc_event *c_event) {
-  pygrpc_tag *tag = (pygrpc_tag *)(c_event->tag);
-  PyObject *user_tag = tag->user_tag;
-  PyObject *metadata = pygrpc_metadata_collection_get(
-      tag->call->recv_metadata.metadata,
-      tag->call->recv_metadata.count);
-  PyObject* result = PyTuple_Pack(
-      8, metadata_event_kind, user_tag, Py_None, Py_None,
-      Py_None, Py_None, Py_None, metadata);
-  Py_DECREF(metadata);
-  return result;
-}
-
-static PyObject *pygrpc_finished_server_event_args(grpc_event *c_event) {
-  PyObject *code;
-  PyObject *details;
-  PyObject *status;
-  PyObject *event_args;
-  pygrpc_tag *tag = (pygrpc_tag *)(c_event->tag);
-  PyObject *user_tag = tag->user_tag;
-
-  code = pygrpc_status_code(tag->call->cancelled ? GRPC_STATUS_CANCELLED : GRPC_STATUS_OK);
-  if (code == NULL) {
-    PyErr_SetString(PyExc_RuntimeError, "Unrecognized status code!");
-    return NULL;
-  }
-  details = PyBytes_FromString("");
-  if (details == NULL) {
-    return NULL;
-  }
-  status = PyObject_CallFunctionObjArgs(status_class, code, details, NULL);
-  Py_DECREF(details);
-  if (status == NULL) {
-    return NULL;
-  }
-  event_args = PyTuple_Pack(8, finish_event_kind, user_tag,
-                            Py_None, Py_None, Py_None, Py_None, status,
-                            Py_None);
-  Py_DECREF(status);
-  return event_args;
-}
-
-static PyObject *pygrpc_finished_client_event_args(grpc_event *c_event) {
-  PyObject *code;
-  PyObject *details;
-  PyObject *status;
-  PyObject *event_args;
-  PyObject *metadata;
-  pygrpc_tag *tag = (pygrpc_tag *)(c_event->tag);
-  PyObject *user_tag = tag->user_tag;
-
-  code = pygrpc_status_code(tag->call->status);
-  if (code == NULL) {
-    PyErr_SetString(PyExc_RuntimeError, "Unrecognized status code!");
-    return NULL;
-  }
-  if (tag->call->status_details == NULL) {
-    details = PyBytes_FromString("");
-  } else {
-    details = PyBytes_FromString(tag->call->status_details);
-  }
-  if (details == NULL) {
-    return NULL;
-  }
-  status = PyObject_CallFunctionObjArgs(status_class, code, details, NULL);
-  Py_DECREF(details);
-  if (status == NULL) {
-    return NULL;
-  }
-  metadata = pygrpc_metadata_collection_get(
-      tag->call->recv_trailing_metadata.metadata,
-      tag->call->recv_trailing_metadata.count);
-  event_args = PyTuple_Pack(8, finish_event_kind, user_tag,
-                            Py_None, Py_None, Py_None, Py_None, status,
-                            metadata);
-  Py_DECREF(status);
-  Py_DECREF(metadata);
-  return event_args;
-}
-
-static int pygrpc_completion_queue_init(CompletionQueue *self, PyObject *args,
-                                        PyObject *kwds) {
-  static char *kwlist[] = {NULL};
-  if (!PyArg_ParseTupleAndKeywords(args, kwds, ":CompletionQueue", kwlist)) {
-    return -1;
-  }
-  self->c_completion_queue = grpc_completion_queue_create();
-  return 0;
-}
-
-static void pygrpc_completion_queue_dealloc(CompletionQueue *self) {
-  grpc_completion_queue_destroy(self->c_completion_queue);
-  self->ob_type->tp_free((PyObject *)self);
-}
-
-static PyObject *pygrpc_completion_queue_get(CompletionQueue *self,
-                                             PyObject *args) {
-  PyObject *deadline;
-  double double_deadline;
-  gpr_timespec deadline_timespec;
-  grpc_event c_event;
-
-  PyObject *event_args;
-  PyObject *event;
-
-  pygrpc_tag *tag;
-
-  if (!(PyArg_ParseTuple(args, "O:get", &deadline))) {
-    return NULL;
-  }
-
-  if (deadline == Py_None) {
-    deadline_timespec = gpr_inf_future;
-  } else {
-    double_deadline = PyFloat_AsDouble(deadline);
-    if (PyErr_Occurred()) {
-      return NULL;
-    }
-    deadline_timespec = gpr_time_from_nanos((long)(double_deadline * 1.0E9));
-  }
-
-  /* TODO(nathaniel): Suppress clang-format in this block and remove the
-     unnecessary and unPythonic semicolons trailing the _ALLOW_THREADS macros.
-     (Right now clang-format only understands //-demarcated suppressions.) */
-  Py_BEGIN_ALLOW_THREADS;
-  c_event =
-      grpc_completion_queue_next(self->c_completion_queue, deadline_timespec);
-  Py_END_ALLOW_THREADS;
-
-  tag = (pygrpc_tag *)c_event.tag;
-
-  switch (c_event.type) {
-    case GRPC_QUEUE_TIMEOUT:
-      Py_RETURN_NONE;
-      break;
-    case GRPC_QUEUE_SHUTDOWN:
-      event_args = pygrpc_stop_event_args(&c_event);
-      break;
-    case GRPC_OP_COMPLETE: {
-      if (!tag) {
-        PyErr_SetString(PyExc_Exception, "Unrecognized event type!");
-        return NULL;
-      }
-      switch (tag->type) {
-        case PYGRPC_INITIAL_METADATA:
-          if (tag) {
-            pygrpc_tag_destroy(tag);
-          }
-          return pygrpc_completion_queue_get(self, args);
-        case PYGRPC_WRITE_ACCEPTED:
-          event_args = pygrpc_write_event_args(&c_event);
-          break;
-        case PYGRPC_FINISH_ACCEPTED:
-          event_args = pygrpc_complete_event_args(&c_event);
-          break;
-        case PYGRPC_SERVER_RPC_NEW:
-          event_args = pygrpc_service_event_args(&c_event);
-          break;
-        case PYGRPC_READ:
-          event_args = pygrpc_read_event_args(&c_event);
-          break;
-        case PYGRPC_CLIENT_METADATA_READ:
-          event_args = pygrpc_metadata_event_args(&c_event);
-          break;
-        case PYGRPC_FINISHED_CLIENT:
-          event_args = pygrpc_finished_client_event_args(&c_event);
-          break;
-        case PYGRPC_FINISHED_SERVER:
-          event_args = pygrpc_finished_server_event_args(&c_event);
-          break;
-        default:
-          PyErr_SetString(PyExc_Exception, "Unrecognized op event type!");
-          return NULL;
-      }
-      break;
-    }
-    default:
-      PyErr_SetString(PyExc_Exception, "Unrecognized event type!");
-      return NULL;
-  }
-
-  if (event_args == NULL) {
-    return NULL;
-  }
-
-  event = PyObject_CallObject(event_class, event_args);
-
-  Py_DECREF(event_args);
-  if (tag) {
-    pygrpc_tag_destroy(tag);
-  }
-
-  return event;
-}
-
-static PyObject *pygrpc_completion_queue_stop(CompletionQueue *self) {
-  grpc_completion_queue_shutdown(self->c_completion_queue);
-
-  Py_RETURN_NONE;
-}
-
-static PyMethodDef methods[] = {
-    {"get", (PyCFunction)pygrpc_completion_queue_get, METH_VARARGS,
-     "Get the next event."},
-    {"stop", (PyCFunction)pygrpc_completion_queue_stop, METH_NOARGS,
-     "Stop this completion queue."},
-    {NULL}};
-
-PyTypeObject pygrpc_CompletionQueueType = {
-    PyVarObject_HEAD_INIT(NULL, 0)
-    "_gprc.CompletionQueue",                     /*tp_name*/
-    sizeof(CompletionQueue),                     /*tp_basicsize*/
-    0,                                           /*tp_itemsize*/
-    (destructor)pygrpc_completion_queue_dealloc, /*tp_dealloc*/
-    0,                                           /*tp_print*/
-    0,                                           /*tp_getattr*/
-    0,                                           /*tp_setattr*/
-    0,                                           /*tp_compare*/
-    0,                                           /*tp_repr*/
-    0,                                           /*tp_as_number*/
-    0,                                           /*tp_as_sequence*/
-    0,                                           /*tp_as_mapping*/
-    0,                                           /*tp_hash */
-    0,                                           /*tp_call*/
-    0,                                           /*tp_str*/
-    0,                                           /*tp_getattro*/
-    0,                                           /*tp_setattro*/
-    0,                                           /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT,                          /*tp_flags*/
-    "Wrapping of grpc_completion_queue.",        /* tp_doc */
-    0,                                           /* tp_traverse */
-    0,                                           /* tp_clear */
-    0,                                           /* tp_richcompare */
-    0,                                           /* tp_weaklistoffset */
-    0,                                           /* tp_iter */
-    0,                                           /* tp_iternext */
-    methods,                                     /* tp_methods */
-    0,                                           /* tp_members */
-    0,                                           /* tp_getset */
-    0,                                           /* tp_base */
-    0,                                           /* tp_dict */
-    0,                                           /* tp_descr_get */
-    0,                                           /* tp_descr_set */
-    0,                                           /* tp_dictoffset */
-    (initproc)pygrpc_completion_queue_init,      /* tp_init */
-    0,                                           /* tp_alloc */
-    PyType_GenericNew,                           /* tp_new */
-};
-
-static int pygrpc_get_status_codes(PyObject *datatypes_module) {
-  PyObject *code_class = PyObject_GetAttrString(datatypes_module, "Code");
-  if (code_class == NULL) {
-    return -1;
-  }
-  ok_status_code = PyObject_GetAttrString(code_class, "OK");
-  if (ok_status_code == NULL) {
-    return -1;
-  }
-  cancelled_status_code = PyObject_GetAttrString(code_class, "CANCELLED");
-  if (cancelled_status_code == NULL) {
-    return -1;
-  }
-  unknown_status_code = PyObject_GetAttrString(code_class, "UNKNOWN");
-  if (unknown_status_code == NULL) {
-    return -1;
-  }
-  invalid_argument_status_code =
-      PyObject_GetAttrString(code_class, "INVALID_ARGUMENT");
-  if (invalid_argument_status_code == NULL) {
-    return -1;
-  }
-  expired_status_code = PyObject_GetAttrString(code_class, "EXPIRED");
-  if (expired_status_code == NULL) {
-    return -1;
-  }
-  not_found_status_code = PyObject_GetAttrString(code_class, "NOT_FOUND");
-  if (not_found_status_code == NULL) {
-    return -1;
-  }
-  already_exists_status_code =
-      PyObject_GetAttrString(code_class, "ALREADY_EXISTS");
-  if (already_exists_status_code == NULL) {
-    return -1;
-  }
-  permission_denied_status_code =
-      PyObject_GetAttrString(code_class, "PERMISSION_DENIED");
-  if (permission_denied_status_code == NULL) {
-    return -1;
-  }
-  unauthenticated_status_code =
-      PyObject_GetAttrString(code_class, "UNAUTHENTICATED");
-  if (unauthenticated_status_code == NULL) {
-    return -1;
-  }
-  resource_exhausted_status_code =
-      PyObject_GetAttrString(code_class, "RESOURCE_EXHAUSTED");
-  if (resource_exhausted_status_code == NULL) {
-    return -1;
-  }
-  failed_precondition_status_code =
-      PyObject_GetAttrString(code_class, "FAILED_PRECONDITION");
-  if (failed_precondition_status_code == NULL) {
-    return -1;
-  }
-  aborted_status_code = PyObject_GetAttrString(code_class, "ABORTED");
-  if (aborted_status_code == NULL) {
-    return -1;
-  }
-  out_of_range_status_code = PyObject_GetAttrString(code_class, "OUT_OF_RANGE");
-  if (out_of_range_status_code == NULL) {
-    return -1;
-  }
-  unimplemented_status_code =
-      PyObject_GetAttrString(code_class, "UNIMPLEMENTED");
-  if (unimplemented_status_code == NULL) {
-    return -1;
-  }
-  internal_error_status_code =
-      PyObject_GetAttrString(code_class, "INTERNAL_ERROR");
-  if (internal_error_status_code == NULL) {
-    return -1;
-  }
-  unavailable_status_code = PyObject_GetAttrString(code_class, "UNAVAILABLE");
-  if (unavailable_status_code == NULL) {
-    return -1;
-  }
-  data_loss_status_code = PyObject_GetAttrString(code_class, "DATA_LOSS");
-  if (data_loss_status_code == NULL) {
-    return -1;
-  }
-  Py_DECREF(code_class);
-  return 0;
-}
-
-static int pygrpc_get_event_kinds(PyObject *event_class) {
-  PyObject *kind_class = PyObject_GetAttrString(event_class, "Kind");
-  if (kind_class == NULL) {
-    return -1;
-  }
-  stop_event_kind = PyObject_GetAttrString(kind_class, "STOP");
-  if (stop_event_kind == NULL) {
-    return -1;
-  }
-  write_event_kind = PyObject_GetAttrString(kind_class, "WRITE_ACCEPTED");
-  if (write_event_kind == NULL) {
-    return -1;
-  }
-  complete_event_kind = PyObject_GetAttrString(kind_class, "COMPLETE_ACCEPTED");
-  if (complete_event_kind == NULL) {
-    return -1;
-  }
-  service_event_kind = PyObject_GetAttrString(kind_class, "SERVICE_ACCEPTED");
-  if (service_event_kind == NULL) {
-    return -1;
-  }
-  read_event_kind = PyObject_GetAttrString(kind_class, "READ_ACCEPTED");
-  if (read_event_kind == NULL) {
-    return -1;
-  }
-  metadata_event_kind = PyObject_GetAttrString(kind_class, "METADATA_ACCEPTED");
-  if (metadata_event_kind == NULL) {
-    return -1;
-  }
-  finish_event_kind = PyObject_GetAttrString(kind_class, "FINISH");
-  if (finish_event_kind == NULL) {
-    return -1;
-  }
-  Py_DECREF(kind_class);
-  return 0;
-}
-
-int pygrpc_add_completion_queue(PyObject *module) {
-  char *datatypes_module_path = "grpc._adapter._datatypes";
-  PyObject *datatypes_module = PyImport_ImportModule(datatypes_module_path);
-  if (datatypes_module == NULL) {
-    return -1;
-  }
-  status_class = PyObject_GetAttrString(datatypes_module, "Status");
-  service_acceptance_class =
-      PyObject_GetAttrString(datatypes_module, "ServiceAcceptance");
-  event_class = PyObject_GetAttrString(datatypes_module, "Event");
-  if (status_class == NULL || service_acceptance_class == NULL ||
-      event_class == NULL) {
-    return -1;
-  }
-  if (pygrpc_get_status_codes(datatypes_module) == -1) {
-    return -1;
-  }
-  if (pygrpc_get_event_kinds(event_class) == -1) {
-    return -1;
-  }
-  Py_DECREF(datatypes_module);
-
-  if (PyType_Ready(&pygrpc_CompletionQueueType) < 0) {
-    return -1;
-  }
-  if (PyModule_AddObject(module, "CompletionQueue",
-                         (PyObject *)&pygrpc_CompletionQueueType) == -1) {
-    return -1;
-  }
-  return 0;
-}
diff --git a/src/python/src/grpc/_adapter/_datatypes.py b/src/python/src/grpc/_adapter/_datatypes.py
deleted file mode 100644
index 3b22784243..0000000000
--- a/src/python/src/grpc/_adapter/_datatypes.py
+++ /dev/null
@@ -1,86 +0,0 @@
-# Copyright 2015, Google Inc.
-# All rights reserved.
-#
-# Redistribution and use in source and binary forms, with or without
-# modification, are permitted provided that the following conditions are
-# met:
-#
-#     * Redistributions of source code must retain the above copyright
-# notice, this list of conditions and the following disclaimer.
-#     * Redistributions in binary form must reproduce the above
-# copyright notice, this list of conditions and the following disclaimer
-# in the documentation and/or other materials provided with the
-# distribution.
-#     * Neither the name of Google Inc. nor the names of its
-# contributors may be used to endorse or promote products derived from
-# this software without specific prior written permission.
-#
-# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-"""Datatypes passed between Python and C code."""
-
-import collections
-import enum
-
-
-@enum.unique
-class Code(enum.IntEnum):
-  """One Platform error codes (see status.h and codes.proto)."""
-
-  OK = 0
-  CANCELLED = 1
-  UNKNOWN = 2
-  INVALID_ARGUMENT = 3
-  EXPIRED = 4
-  NOT_FOUND = 5
-  ALREADY_EXISTS = 6
-  PERMISSION_DENIED = 7
-  UNAUTHENTICATED = 16
-  RESOURCE_EXHAUSTED = 8
-  FAILED_PRECONDITION = 9
-  ABORTED = 10
-  OUT_OF_RANGE = 11
-  UNIMPLEMENTED = 12
-  INTERNAL_ERROR = 13
-  UNAVAILABLE = 14
-  DATA_LOSS = 15
-
-
-class Status(collections.namedtuple('Status', ['code', 'details'])):
-  """Describes an RPC's overall status."""
-
-
-class ServiceAcceptance(
-    collections.namedtuple(
-        'ServiceAcceptance', ['call', 'method', 'host', 'deadline'])):
-  """Describes an RPC on the service side at the start of service."""
-
-
-class Event(
-    collections.namedtuple(
-        'Event',
-        ['kind', 'tag', 'write_accepted', 'complete_accepted',
-         'service_acceptance', 'bytes', 'status', 'metadata'])):
-  """Describes an event emitted from a completion queue."""
-
-  @enum.unique
-  class Kind(enum.Enum):
-    """Describes the kind of an event."""
-
-    STOP = object()
-    WRITE_ACCEPTED = object()
-    COMPLETE_ACCEPTED = object()
-    SERVICE_ACCEPTED = object()
-    READ_ACCEPTED = object()
-    METADATA_ACCEPTED = object()
-    FINISH = object()
diff --git a/src/python/src/grpc/_adapter/_error.c b/src/python/src/grpc/_adapter/_error.c
deleted file mode 100644
index a8a1dbc1bb..0000000000
--- a/src/python/src/grpc/_adapter/_error.c
+++ /dev/null
@@ -1,79 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include "grpc/_adapter/_error.h"
-
-#include <Python.h>
-#include <grpc/grpc.h>
-
-const PyObject *pygrpc_translate_call_error(grpc_call_error call_error) {
-  switch (call_error) {
-    case GRPC_CALL_OK:
-      Py_RETURN_NONE;
-    case GRPC_CALL_ERROR:
-      PyErr_SetString(PyExc_Exception, "Defect: unknown defect!");
-      return NULL;
-    case GRPC_CALL_ERROR_NOT_ON_SERVER:
-      PyErr_SetString(PyExc_Exception,
-                      "Defect: client-only method called on server!");
-      return NULL;
-    case GRPC_CALL_ERROR_NOT_ON_CLIENT:
-      PyErr_SetString(PyExc_Exception,
-                      "Defect: server-only method called on client!");
-      return NULL;
-    case GRPC_CALL_ERROR_ALREADY_ACCEPTED:
-      PyErr_SetString(PyExc_Exception,
-                      "Defect: attempted to accept already-accepted call!");
-      return NULL;
-    case GRPC_CALL_ERROR_ALREADY_INVOKED:
-      PyErr_SetString(PyExc_Exception,
-                      "Defect: attempted to invoke already-invoked call!");
-      return NULL;
-    case GRPC_CALL_ERROR_NOT_INVOKED:
-      PyErr_SetString(PyExc_Exception, "Defect: Call not yet invoked!");
-      return NULL;
-    case GRPC_CALL_ERROR_ALREADY_FINISHED:
-      PyErr_SetString(PyExc_Exception, "Defect: Call already finished!");
-      return NULL;
-    case GRPC_CALL_ERROR_TOO_MANY_OPERATIONS:
-      PyErr_SetString(PyExc_Exception,
-                      "Defect: Attempted extra read or extra write on call!");
-      return NULL;
-    case GRPC_CALL_ERROR_INVALID_FLAGS:
-      PyErr_SetString(PyExc_Exception, "Defect: invalid flags!");
-      return NULL;
-    default:
-      PyErr_SetString(PyExc_Exception, "Defect: Unknown call error!");
-      return NULL;
-  }
-}
diff --git a/src/python/src/grpc/_adapter/_intermediary_low.py b/src/python/src/grpc/_adapter/_intermediary_low.py
new file mode 100644
index 0000000000..a6e325c4e5
--- /dev/null
+++ b/src/python/src/grpc/_adapter/_intermediary_low.py
@@ -0,0 +1,258 @@
+# 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.
+
+"""Temporary old _low-like layer.
+
+Eases refactoring burden while we overhaul the Python framework.
+
+Plan:
+    The layers used to look like:
+        ...                # outside _adapter
+        fore.py + rear.py  # visible outside _adapter
+        _low
+        _c
+    The layers currently look like:
+        ...                # outside _adapter
+        fore.py + rear.py  # visible outside _adapter
+        _low_intermediary  # adapter for new '_low' to old '_low'
+        _low               # new '_low'
+        _c                 # new '_c'
+    We will later remove _low_intermediary after refactoring of fore.py and
+    rear.py according to the ticket system refactoring and get:
+        ...                # outside _adapter, refactored
+        fore.py + rear.py  # visible outside _adapter, refactored
+        _low               # new '_low'
+        _c                 # new '_c'
+"""
+
+import collections
+import enum
+
+from grpc._adapter import _low
+from grpc._adapter import _types
+
+_IGNORE_ME_TAG = object()
+Code = _types.StatusCode
+
+
+class Status(collections.namedtuple('Status', ['code', 'details'])):
+  """Describes an RPC's overall status."""
+
+
+class ServiceAcceptance(
+    collections.namedtuple(
+        'ServiceAcceptance', ['call', 'method', 'host', 'deadline'])):
+  """Describes an RPC on the service side at the start of service."""
+
+
+class Event(
+    collections.namedtuple(
+        'Event',
+        ['kind', 'tag', 'write_accepted', 'complete_accepted',
+         'service_acceptance', 'bytes', 'status', 'metadata'])):
+  """Describes an event emitted from a completion queue."""
+
+  @enum.unique
+  class Kind(enum.Enum):
+    """Describes the kind of an event."""
+
+    STOP = object()
+    WRITE_ACCEPTED = object()
+    COMPLETE_ACCEPTED = object()
+    SERVICE_ACCEPTED = object()
+    READ_ACCEPTED = object()
+    METADATA_ACCEPTED = object()
+    FINISH = object()
+
+
+class _TagAdapter(collections.namedtuple('_TagAdapter', [
+      'user_tag',
+      'kind'
+  ])):
+  pass
+
+
+class Call(object):
+  """Adapter from old _low.Call interface to new _low.Call."""
+  
+  def __init__(self, channel, completion_queue, method, host, deadline):
+    self._internal = channel._internal.create_call(
+        completion_queue._internal, method, host, deadline)
+    self._metadata = []
+
+  @staticmethod
+  def _from_internal(internal):
+    call = Call.__new__(Call)
+    call._internal = internal
+    call._metadata = []
+    return call
+
+  def invoke(self, completion_queue, metadata_tag, finish_tag):
+    err0 = self._internal.start_batch([
+          _types.OpArgs.send_initial_metadata(self._metadata)
+      ], _IGNORE_ME_TAG)
+    err1 = self._internal.start_batch([
+          _types.OpArgs.recv_initial_metadata()
+      ], _TagAdapter(metadata_tag, Event.Kind.METADATA_ACCEPTED))
+    err2 = self._internal.start_batch([
+          _types.OpArgs.recv_status_on_client()
+      ], _TagAdapter(finish_tag, Event.Kind.FINISH))
+    return err0 if err0 != _types.CallError.OK else err1 if err1 != _types.CallError.OK else err2 if err2 != _types.CallError.OK else _types.CallError.OK
+
+  def write(self, message, tag):
+    return self._internal.start_batch([
+          _types.OpArgs.send_message(message)
+      ], _TagAdapter(tag, Event.Kind.WRITE_ACCEPTED))
+
+  def complete(self, tag):
+    return self._internal.start_batch([
+          _types.OpArgs.send_close_from_client()
+      ], _TagAdapter(tag, Event.Kind.COMPLETE_ACCEPTED))
+
+  def accept(self, completion_queue, tag):
+    return self._internal.start_batch([
+          _types.OpArgs.recv_close_on_server()
+      ], _TagAdapter(tag, Event.Kind.FINISH))
+
+  def add_metadata(self, key, value):
+    self._metadata.append((key, value))
+
+  def premetadata(self):
+    return self._internal.start_batch([
+          _types.OpArgs.send_initial_metadata(self._metadata)
+      ], _IGNORE_ME_TAG)
+    self._metadata = []
+
+  def read(self, tag):
+    return self._internal.start_batch([
+          _types.OpArgs.recv_message()
+      ], _TagAdapter(tag, Event.Kind.READ_ACCEPTED))
+
+  def status(self, status, tag):
+    return self._internal.start_batch([
+          _types.OpArgs.send_status_from_server(self._metadata, status.code, status.details)
+      ], _TagAdapter(tag, Event.Kind.COMPLETE_ACCEPTED))
+
+  def cancel(self):
+    return self._internal.cancel()
+
+
+class Channel(object):
+  """Adapter from old _low.Channel interface to new _low.Channel."""
+
+  def __init__(self, hostport, client_credentials, server_host_override=None):
+    args = []
+    if server_host_override:
+      args.append((_types.GrpcChannelArgumentKeys.SSL_TARGET_NAME_OVERRIDE.value, server_host_override))
+    creds = None
+    if client_credentials:
+      creds = client_credentials._internal
+    self._internal = _low.Channel(hostport, args, creds)
+
+
+class CompletionQueue(object):
+  """Adapter from old _low.CompletionQueue interface to new _low.CompletionQueue."""
+
+  def __init__(self):
+    self._internal = _low.CompletionQueue()
+
+  def get(self, deadline=None):
+    if deadline is None:
+      ev = self._internal.next()
+    else:
+      ev = self._internal.next(deadline)
+    if ev is None:
+      return None
+    elif ev.tag is _IGNORE_ME_TAG:
+      return self.get(deadline)
+    elif ev.type == _types.EventType.QUEUE_SHUTDOWN:
+      kind = Event.Kind.STOP
+      tag = None
+      write_accepted = None
+      complete_accepted = None
+      service_acceptance = None
+      message_bytes = None
+      status = None
+      metadata = None
+    elif ev.type == _types.EventType.OP_COMPLETE:
+      kind = ev.tag.kind
+      tag = ev.tag.user_tag
+      write_accepted = ev.success if kind == Event.Kind.WRITE_ACCEPTED else None
+      complete_accepted = ev.success if kind == Event.Kind.COMPLETE_ACCEPTED else None
+      service_acceptance = ServiceAcceptance(Call._from_internal(ev.call), ev.call_details.method, ev.call_details.host, ev.call_details.deadline) if kind == Event.Kind.SERVICE_ACCEPTED else None
+      message_bytes = ev.results[0].message if kind == Event.Kind.READ_ACCEPTED else None
+      status = Status(ev.results[0].status.code, ev.results[0].status.details) if (kind == Event.Kind.FINISH and ev.results[0].status) else Status(_types.StatusCode.CANCELLED if ev.results[0].cancelled else _types.StatusCode.OK, '') if ev.results[0].cancelled is not None else None
+      metadata = ev.results[0].initial_metadata if (kind in [Event.Kind.SERVICE_ACCEPTED, Event.Kind.METADATA_ACCEPTED]) else (ev.results[0].trailing_metadata if kind == Event.Kind.FINISH else None)
+    else:
+      raise RuntimeError('unknown event')
+    result_ev = Event(kind=kind, tag=tag, write_accepted=write_accepted, complete_accepted=complete_accepted, service_acceptance=service_acceptance, bytes=message_bytes, status=status, metadata=metadata)
+    return result_ev
+
+  def stop(self):
+    self._internal.shutdown()
+
+
+class Server(object):
+  """Adapter from old _low.Server interface to new _low.Server."""
+
+  def __init__(self, completion_queue):
+    self._internal = _low.Server(completion_queue._internal, [])
+    self._internal_cq = completion_queue._internal
+
+  def add_http2_addr(self, addr):
+    return self._internal.add_http2_port(addr)
+
+  def add_secure_http2_addr(self, addr, server_credentials):
+    if server_credentials is None:
+      return self._internal.add_http2_port(addr, None)
+    else:
+      return self._internal.add_http2_port(addr, server_credentials._internal)
+
+  def start(self):
+    return self._internal.start()
+
+  def service(self, tag):
+    return self._internal.request_call(self._internal_cq, _TagAdapter(tag, Event.Kind.SERVICE_ACCEPTED))
+
+  def stop(self):
+    return self._internal.shutdown()
+
+
+class ClientCredentials(object):
+  """Adapter from old _low.ClientCredentials interface to new _low.ClientCredentials."""
+
+  def __init__(self, root_certificates, private_key, certificate_chain):
+    self._internal = _low.ClientCredentials.ssl(root_certificates, private_key, certificate_chain)
+
+
+class ServerCredentials(object):
+  """Adapter from old _low.ServerCredentials interface to new _low.ServerCredentials."""
+  
+  def __init__(self, root_credentials, pair_sequence):
+    self._internal = _low.ServerCredentials.ssl(root_credentials, list(pair_sequence))
diff --git a/src/python/src/grpc/_adapter/_intermediary_low_test.py b/src/python/src/grpc/_adapter/_intermediary_low_test.py
new file mode 100644
index 0000000000..6ff51c43a6
--- /dev/null
+++ b/src/python/src/grpc/_adapter/_intermediary_low_test.py
@@ -0,0 +1,421 @@
+# 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.
+
+"""Tests for the old '_low'."""
+
+import time
+import unittest
+
+from grpc._adapter import _intermediary_low as _low
+
+_STREAM_LENGTH = 300
+_TIMEOUT = 5
+_AFTER_DELAY = 2
+_FUTURE = time.time() + 60 * 60 * 24
+_BYTE_SEQUENCE = b'\abcdefghijklmnopqrstuvwxyz0123456789' * 200
+_BYTE_SEQUENCE_SEQUENCE = tuple(
+    bytes(bytearray((row + column) % 256 for column in range(row)))
+    for row in range(_STREAM_LENGTH))
+
+class LonelyClientTest(unittest.TestCase):
+
+  def testLonelyClient(self):
+    host = 'nosuchhostexists'
+    port = 54321
+    method = 'test method'
+    deadline = time.time() + _TIMEOUT
+    after_deadline = deadline + _AFTER_DELAY
+    metadata_tag = object()
+    finish_tag = object()
+
+    completion_queue = _low.CompletionQueue()
+    channel = _low.Channel('%s:%d' % (host, port), None)
+    client_call = _low.Call(channel, completion_queue, method, host, deadline)
+
+    client_call.invoke(completion_queue, metadata_tag, finish_tag)
+    first_event = completion_queue.get(after_deadline)
+    self.assertIsNotNone(first_event)
+    second_event = completion_queue.get(after_deadline)
+    self.assertIsNotNone(second_event)
+    kinds = [event.kind for event in (first_event, second_event)]
+    self.assertItemsEqual(
+        (_low.Event.Kind.METADATA_ACCEPTED, _low.Event.Kind.FINISH),
+        kinds)
+
+    self.assertIsNone(completion_queue.get(after_deadline))
+
+    completion_queue.stop()
+    stop_event = completion_queue.get(_FUTURE)
+    self.assertEqual(_low.Event.Kind.STOP, stop_event.kind)
+
+    del client_call
+    del channel
+    del completion_queue
+
+
+class EchoTest(unittest.TestCase):
+
+  def setUp(self):
+    self.host = 'localhost'
+
+    self.server_completion_queue = _low.CompletionQueue()
+    self.server = _low.Server(self.server_completion_queue)
+    port = self.server.add_http2_addr('[::]:0')
+    self.server.start()
+
+    self.client_completion_queue = _low.CompletionQueue()
+    self.channel = _low.Channel('%s:%d' % (self.host, port), None)
+
+  def tearDown(self):
+    self.server.stop()
+    # NOTE(nathaniel): Yep, this is weird; it's a consequence of
+    # grpc_server_destroy's being what has the effect of telling the server's
+    # completion queue to pump out all pending events/tags immediately rather
+    # than gracefully completing all outstanding RPCs while accepting no new
+    # ones.
+    # TODO(nathaniel): Deallocation of a Python object shouldn't have this kind
+    # of observable side effect let alone such an important one.
+    del self.server
+    self.server_completion_queue.stop()
+    self.client_completion_queue.stop()
+    while True:
+      event = self.server_completion_queue.get(_FUTURE)
+      if event is not None and event.kind is _low.Event.Kind.STOP:
+        break
+    while True:
+      event = self.client_completion_queue.get(_FUTURE)
+      if event is not None and event.kind is _low.Event.Kind.STOP:
+        break
+    self.server_completion_queue = None
+    self.client_completion_queue = None
+
+  def _perform_echo_test(self, test_data):
+    method = 'test method'
+    details = 'test details'
+    server_leading_metadata_key = 'my_server_leading_key'
+    server_leading_metadata_value = 'my_server_leading_value'
+    server_trailing_metadata_key = 'my_server_trailing_key'
+    server_trailing_metadata_value = 'my_server_trailing_value'
+    client_metadata_key = 'my_client_key'
+    client_metadata_value = 'my_client_value'
+    server_leading_binary_metadata_key = 'my_server_leading_key-bin'
+    server_leading_binary_metadata_value = b'\0'*2047
+    server_trailing_binary_metadata_key = 'my_server_trailing_key-bin'
+    server_trailing_binary_metadata_value = b'\0'*2047
+    client_binary_metadata_key = 'my_client_key-bin'
+    client_binary_metadata_value = b'\0'*2047
+    deadline = _FUTURE
+    metadata_tag = object()
+    finish_tag = object()
+    write_tag = object()
+    complete_tag = object()
+    service_tag = object()
+    read_tag = object()
+    status_tag = object()
+
+    server_data = []
+    client_data = []
+
+    client_call = _low.Call(self.channel, self.client_completion_queue,
+                            method, self.host, deadline)
+    client_call.add_metadata(client_metadata_key, client_metadata_value)
+    client_call.add_metadata(client_binary_metadata_key,
+                             client_binary_metadata_value)
+
+    client_call.invoke(self.client_completion_queue, metadata_tag, finish_tag)
+
+    self.server.service(service_tag)
+    service_accepted = self.server_completion_queue.get(_FUTURE)
+    self.assertIsNotNone(service_accepted)
+    self.assertIs(service_accepted.kind, _low.Event.Kind.SERVICE_ACCEPTED)
+    self.assertIs(service_accepted.tag, service_tag)
+    self.assertEqual(method, service_accepted.service_acceptance.method)
+    self.assertEqual(self.host, service_accepted.service_acceptance.host)
+    self.assertIsNotNone(service_accepted.service_acceptance.call)
+    metadata = dict(service_accepted.metadata)
+    self.assertIn(client_metadata_key, metadata)
+    self.assertEqual(client_metadata_value, metadata[client_metadata_key])
+    self.assertIn(client_binary_metadata_key, metadata)
+    self.assertEqual(client_binary_metadata_value,
+                     metadata[client_binary_metadata_key])
+    server_call = service_accepted.service_acceptance.call
+    server_call.accept(self.server_completion_queue, finish_tag)
+    server_call.add_metadata(server_leading_metadata_key,
+                             server_leading_metadata_value)
+    server_call.add_metadata(server_leading_binary_metadata_key,
+                             server_leading_binary_metadata_value)
+    server_call.premetadata()
+
+    metadata_accepted = self.client_completion_queue.get(_FUTURE)
+    self.assertIsNotNone(metadata_accepted)
+    self.assertEqual(_low.Event.Kind.METADATA_ACCEPTED, metadata_accepted.kind)
+    self.assertEqual(metadata_tag, metadata_accepted.tag)
+    metadata = dict(metadata_accepted.metadata)
+    self.assertIn(server_leading_metadata_key, metadata)
+    self.assertEqual(server_leading_metadata_value,
+                     metadata[server_leading_metadata_key])
+    self.assertIn(server_leading_binary_metadata_key, metadata)
+    self.assertEqual(server_leading_binary_metadata_value,
+                     metadata[server_leading_binary_metadata_key])
+
+    for datum in test_data:
+      client_call.write(datum, write_tag)
+      write_accepted = self.client_completion_queue.get(_FUTURE)
+      self.assertIsNotNone(write_accepted)
+      self.assertIs(write_accepted.kind, _low.Event.Kind.WRITE_ACCEPTED)
+      self.assertIs(write_accepted.tag, write_tag)
+      self.assertIs(write_accepted.write_accepted, True)
+
+      server_call.read(read_tag)
+      read_accepted = self.server_completion_queue.get(_FUTURE)
+      self.assertIsNotNone(read_accepted)
+      self.assertEqual(_low.Event.Kind.READ_ACCEPTED, read_accepted.kind)
+      self.assertEqual(read_tag, read_accepted.tag)
+      self.assertIsNotNone(read_accepted.bytes)
+      server_data.append(read_accepted.bytes)
+
+      server_call.write(read_accepted.bytes, write_tag)
+      write_accepted = self.server_completion_queue.get(_FUTURE)
+      self.assertIsNotNone(write_accepted)
+      self.assertEqual(_low.Event.Kind.WRITE_ACCEPTED, write_accepted.kind)
+      self.assertEqual(write_tag, write_accepted.tag)
+      self.assertTrue(write_accepted.write_accepted)
+
+      client_call.read(read_tag)
+      read_accepted = self.client_completion_queue.get(_FUTURE)
+      self.assertIsNotNone(read_accepted)
+      self.assertEqual(_low.Event.Kind.READ_ACCEPTED, read_accepted.kind)
+      self.assertEqual(read_tag, read_accepted.tag)
+      self.assertIsNotNone(read_accepted.bytes)
+      client_data.append(read_accepted.bytes)
+
+    client_call.complete(complete_tag)
+    complete_accepted = self.client_completion_queue.get(_FUTURE)
+    self.assertIsNotNone(complete_accepted)
+    self.assertIs(complete_accepted.kind, _low.Event.Kind.COMPLETE_ACCEPTED)
+    self.assertIs(complete_accepted.tag, complete_tag)
+    self.assertIs(complete_accepted.complete_accepted, True)
+
+    server_call.read(read_tag)
+    read_accepted = self.server_completion_queue.get(_FUTURE)
+    self.assertIsNotNone(read_accepted)
+    self.assertEqual(_low.Event.Kind.READ_ACCEPTED, read_accepted.kind)
+    self.assertEqual(read_tag, read_accepted.tag)
+    self.assertIsNone(read_accepted.bytes)
+
+    server_call.add_metadata(server_trailing_metadata_key,
+                             server_trailing_metadata_value)
+    server_call.add_metadata(server_trailing_binary_metadata_key,
+                             server_trailing_binary_metadata_value)
+
+    server_call.status(_low.Status(_low.Code.OK, details), status_tag)
+    server_terminal_event_one = self.server_completion_queue.get(_FUTURE)
+    server_terminal_event_two = self.server_completion_queue.get(_FUTURE)
+    if server_terminal_event_one.kind == _low.Event.Kind.COMPLETE_ACCEPTED:
+      status_accepted = server_terminal_event_one
+      rpc_accepted = server_terminal_event_two
+    else:
+      status_accepted = server_terminal_event_two
+      rpc_accepted = server_terminal_event_one
+    self.assertIsNotNone(status_accepted)
+    self.assertIsNotNone(rpc_accepted)
+    self.assertEqual(_low.Event.Kind.COMPLETE_ACCEPTED, status_accepted.kind)
+    self.assertEqual(status_tag, status_accepted.tag)
+    self.assertTrue(status_accepted.complete_accepted)
+    self.assertEqual(_low.Event.Kind.FINISH, rpc_accepted.kind)
+    self.assertEqual(finish_tag, rpc_accepted.tag)
+    self.assertEqual(_low.Status(_low.Code.OK, ''), rpc_accepted.status)
+
+    client_call.read(read_tag)
+    client_terminal_event_one = self.client_completion_queue.get(_FUTURE)
+    client_terminal_event_two = self.client_completion_queue.get(_FUTURE)
+    if client_terminal_event_one.kind == _low.Event.Kind.READ_ACCEPTED:
+      read_accepted = client_terminal_event_one
+      finish_accepted = client_terminal_event_two
+    else:
+      read_accepted = client_terminal_event_two
+      finish_accepted = client_terminal_event_one
+    self.assertIsNotNone(read_accepted)
+    self.assertIsNotNone(finish_accepted)
+    self.assertEqual(_low.Event.Kind.READ_ACCEPTED, read_accepted.kind)
+    self.assertEqual(read_tag, read_accepted.tag)
+    self.assertIsNone(read_accepted.bytes)
+    self.assertEqual(_low.Event.Kind.FINISH, finish_accepted.kind)
+    self.assertEqual(finish_tag, finish_accepted.tag)
+    self.assertEqual(_low.Status(_low.Code.OK, details), finish_accepted.status)
+    metadata = dict(finish_accepted.metadata)
+    self.assertIn(server_trailing_metadata_key, metadata)
+    self.assertEqual(server_trailing_metadata_value,
+                     metadata[server_trailing_metadata_key])
+    self.assertIn(server_trailing_binary_metadata_key, metadata)
+    self.assertEqual(server_trailing_binary_metadata_value,
+                     metadata[server_trailing_binary_metadata_key])
+
+    server_timeout_none_event = self.server_completion_queue.get(0)
+    self.assertIsNone(server_timeout_none_event)
+    client_timeout_none_event = self.client_completion_queue.get(0)
+    self.assertIsNone(client_timeout_none_event)
+
+    self.assertSequenceEqual(test_data, server_data)
+    self.assertSequenceEqual(test_data, client_data)
+
+  def testNoEcho(self):
+    self._perform_echo_test(())
+
+  def testOneByteEcho(self):
+    self._perform_echo_test([b'\x07'])
+
+  def testOneManyByteEcho(self):
+    self._perform_echo_test([_BYTE_SEQUENCE])
+
+  def testManyOneByteEchoes(self):
+    self._perform_echo_test(_BYTE_SEQUENCE)
+
+  def testManyManyByteEchoes(self):
+    self._perform_echo_test(_BYTE_SEQUENCE_SEQUENCE)
+
+
+class CancellationTest(unittest.TestCase):
+
+  def setUp(self):
+    self.host = 'localhost'
+
+    self.server_completion_queue = _low.CompletionQueue()
+    self.server = _low.Server(self.server_completion_queue)
+    port = self.server.add_http2_addr('[::]:0')
+    self.server.start()
+
+    self.client_completion_queue = _low.CompletionQueue()
+    self.channel = _low.Channel('%s:%d' % (self.host, port), None)
+
+  def tearDown(self):
+    self.server.stop()
+    del self.server
+    self.server_completion_queue.stop()
+    self.client_completion_queue.stop()
+    while True:
+      event = self.server_completion_queue.get(0)
+      if event is not None and event.kind is _low.Event.Kind.STOP:
+        break
+    while True:
+      event = self.client_completion_queue.get(0)
+      if event is not None and event.kind is _low.Event.Kind.STOP:
+        break
+
+  def testCancellation(self):
+    method = 'test method'
+    deadline = _FUTURE
+    metadata_tag = object()
+    finish_tag = object()
+    write_tag = object()
+    service_tag = object()
+    read_tag = object()
+    test_data = _BYTE_SEQUENCE_SEQUENCE
+
+    server_data = []
+    client_data = []
+
+    client_call = _low.Call(self.channel, self.client_completion_queue,
+                            method, self.host, deadline)
+
+    client_call.invoke(self.client_completion_queue, metadata_tag, finish_tag)
+
+    self.server.service(service_tag)
+    service_accepted = self.server_completion_queue.get(_FUTURE)
+    server_call = service_accepted.service_acceptance.call
+
+    server_call.accept(self.server_completion_queue, finish_tag)
+    server_call.premetadata()
+
+    metadata_accepted = self.client_completion_queue.get(_FUTURE)
+    self.assertIsNotNone(metadata_accepted)
+
+    for datum in test_data:
+      client_call.write(datum, write_tag)
+      write_accepted = self.client_completion_queue.get(_FUTURE)
+
+      server_call.read(read_tag)
+      read_accepted = self.server_completion_queue.get(_FUTURE)
+      server_data.append(read_accepted.bytes)
+
+      server_call.write(read_accepted.bytes, write_tag)
+      write_accepted = self.server_completion_queue.get(_FUTURE)
+      self.assertIsNotNone(write_accepted)
+
+      client_call.read(read_tag)
+      read_accepted = self.client_completion_queue.get(_FUTURE)
+      client_data.append(read_accepted.bytes)
+
+    client_call.cancel()
+    # cancel() is idempotent.
+    client_call.cancel()
+    client_call.cancel()
+    client_call.cancel()
+
+    server_call.read(read_tag)
+
+    server_terminal_event_one = self.server_completion_queue.get(_FUTURE)
+    server_terminal_event_two = self.server_completion_queue.get(_FUTURE)
+    if server_terminal_event_one.kind == _low.Event.Kind.READ_ACCEPTED:
+      read_accepted = server_terminal_event_one
+      rpc_accepted = server_terminal_event_two
+    else:
+      read_accepted = server_terminal_event_two
+      rpc_accepted = server_terminal_event_one
+    self.assertIsNotNone(read_accepted)
+    self.assertIsNotNone(rpc_accepted)
+    self.assertEqual(_low.Event.Kind.READ_ACCEPTED, read_accepted.kind)
+    self.assertIsNone(read_accepted.bytes)
+    self.assertEqual(_low.Event.Kind.FINISH, rpc_accepted.kind)
+    self.assertEqual(_low.Status(_low.Code.CANCELLED, ''), rpc_accepted.status)
+
+    finish_event = self.client_completion_queue.get(_FUTURE)
+    self.assertEqual(_low.Event.Kind.FINISH, finish_event.kind)
+    self.assertEqual(_low.Status(_low.Code.CANCELLED, 'Cancelled'), 
+                                 finish_event.status)
+
+    server_timeout_none_event = self.server_completion_queue.get(0)
+    self.assertIsNone(server_timeout_none_event)
+    client_timeout_none_event = self.client_completion_queue.get(0)
+    self.assertIsNone(client_timeout_none_event)
+
+    self.assertSequenceEqual(test_data, server_data)
+    self.assertSequenceEqual(test_data, client_data)
+
+
+class ExpirationTest(unittest.TestCase):
+
+  @unittest.skip('TODO(nathaniel): Expiration test!')
+  def testExpiration(self):
+    pass
+
+
+if __name__ == '__main__':
+  unittest.main(verbosity=2)
+
diff --git a/src/python/src/grpc/_adapter/_low.py b/src/python/src/grpc/_adapter/_low.py
index a24baaeb3e..0c1d3b40a5 100644
--- a/src/python/src/grpc/_adapter/_low.py
+++ b/src/python/src/grpc/_adapter/_low.py
@@ -27,31 +27,85 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-"""A Python interface for GRPC C core structures and behaviors."""
-
-import atexit
-import gc
-
 from grpc._adapter import _c
-from grpc._adapter import _datatypes
-
-def _shut_down():
-  # force garbage collection before shutting down grpc, to ensure all grpc
-  # objects are cleaned up
-  gc.collect()
-  _c.shut_down()
-
-_c.init()
-atexit.register(_shut_down)
-
-# pylint: disable=invalid-name
-Code = _datatypes.Code
-Status = _datatypes.Status
-Event = _datatypes.Event
-Call = _c.Call
-Channel = _c.Channel
-CompletionQueue = _c.CompletionQueue
-Server = _c.Server
+from grpc._adapter import _types
+
 ClientCredentials = _c.ClientCredentials
 ServerCredentials = _c.ServerCredentials
-# pylint: enable=invalid-name
+
+
+class CompletionQueue(_types.CompletionQueue):
+
+  def __init__(self):
+    self.completion_queue = _c.CompletionQueue()
+
+  def next(self, deadline=float('+inf')):
+    raw_event = self.completion_queue.next(deadline)
+    if raw_event is None:
+      return None
+    event = _types.Event(*raw_event)
+    if event.call is not None:
+      event = event._replace(call=Call(event.call))
+    if event.call_details is not None:
+      event = event._replace(call_details=_types.CallDetails(*event.call_details))
+    if event.results is not None:
+      new_results = [_types.OpResult(*r) for r in event.results]
+      new_results = [r if r.status is None else r._replace(status=_types.Status(_types.StatusCode(r.status[0]), r.status[1])) for r in new_results]
+      event = event._replace(results=new_results)
+    return event
+
+  def shutdown(self):
+    self.completion_queue.shutdown()
+
+
+class Call(_types.Call):
+
+  def __init__(self, call):
+    self.call = call
+
+  def start_batch(self, ops, tag):
+    return self.call.start_batch(ops, tag)
+
+  def cancel(self, code=None, details=None):
+    if code is None and details is None:
+      return self.call.cancel()
+    else:
+      return self.call.cancel(code, details)
+
+
+class Channel(_types.Channel):
+
+  def __init__(self, target, args, creds=None):
+    if creds is None:
+      self.channel = _c.Channel(target, args)
+    else:
+      self.channel = _c.Channel(target, args, creds)
+
+  def create_call(self, completion_queue, method, host, deadline=None):
+    return Call(self.channel.create_call(completion_queue.completion_queue, method, host, deadline))
+
+
+_NO_TAG = object()
+
+class Server(_types.Server):
+
+  def __init__(self, completion_queue, args):
+    self.server = _c.Server(completion_queue.completion_queue, args)
+
+  def add_http2_port(self, addr, creds=None):
+    if creds is None:
+      return self.server.add_http2_port(addr)
+    else:
+      return self.server.add_http2_port(addr, creds)
+
+  def start(self):
+    return self.server.start()
+
+  def shutdown(self, tag=_NO_TAG):
+    if tag is _NO_TAG:
+      return self.server.shutdown()
+    else:
+      return self.server.shutdown(tag)
+
+  def request_call(self, completion_queue, tag):
+    return self.server.request_call(completion_queue.completion_queue, tag)
diff --git a/src/python/src/grpc/_adapter/_low_test.py b/src/python/src/grpc/_adapter/_low_test.py
index 22006c36b8..e53b176caf 100644
--- a/src/python/src/grpc/_adapter/_low_test.py
+++ b/src/python/src/grpc/_adapter/_low_test.py
@@ -27,375 +27,141 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-"""Tests for _adapter._low."""
-
 import time
 import unittest
 
+from grpc._adapter import _types
 from grpc._adapter import _low
 
-_STREAM_LENGTH = 300
-_TIMEOUT = 5
-_AFTER_DELAY = 2
-_FUTURE = time.time() + 60 * 60 * 24
-_BYTE_SEQUENCE = b'\abcdefghijklmnopqrstuvwxyz0123456789' * 200
-_BYTE_SEQUENCE_SEQUENCE = tuple(
-    bytes(bytearray((row + column) % 256 for column in range(row)))
-    for row in range(_STREAM_LENGTH))
-
-class LonelyClientTest(unittest.TestCase):
-
-  def testLonelyClient(self):
-    host = 'nosuchhostexists'
-    port = 54321
-    method = 'test method'
-    deadline = time.time() + _TIMEOUT
-    after_deadline = deadline + _AFTER_DELAY
-    metadata_tag = object()
-    finish_tag = object()
-
-    completion_queue = _low.CompletionQueue()
-    channel = _low.Channel('%s:%d' % (host, port), None)
-    client_call = _low.Call(channel, completion_queue, method, host, deadline)
-
-    client_call.invoke(completion_queue, metadata_tag, finish_tag)
-    first_event = completion_queue.get(after_deadline)
-    self.assertIsNotNone(first_event)
-    second_event = completion_queue.get(after_deadline)
-    self.assertIsNotNone(second_event)
-    kinds = [event.kind for event in (first_event, second_event)]
-    self.assertItemsEqual(
-        (_low.Event.Kind.METADATA_ACCEPTED, _low.Event.Kind.FINISH),
-        kinds)
-
-    self.assertIsNone(completion_queue.get(after_deadline))
-
-    completion_queue.stop()
-    stop_event = completion_queue.get(_FUTURE)
-    self.assertEqual(_low.Event.Kind.STOP, stop_event.kind)
-
-
-class EchoTest(unittest.TestCase):
-
-  def setUp(self):
-    self.host = 'localhost'
-
-    self.completion_queue = _low.CompletionQueue()
-
-    self.server = _low.Server(self.completion_queue)
-    port = self.server.add_http2_addr('[::]:0')
-    self.server.start()
-
-    self.channel = _low.Channel('%s:%d' % (self.host, port), None)
-
-  def tearDown(self):
-    self.server.stop()
-    # NOTE(nathaniel): Yep, this is weird; it's a consequence of
-    # grpc_server_destroy's being what has the effect of telling the server's
-    # completion queue to pump out all pending events/tags immediately rather
-    # than gracefully completing all outstanding RPCs while accepting no new
-    # ones.
-    # TODO(nathaniel): Deallocation of a Python object shouldn't have this kind
-    # of observable side effect let alone such an important one.
-    del self.server
-    self.completion_queue.stop()
-    while True:
-      event = self.completion_queue.get(_FUTURE)
-      if event is not None and event.kind is _low.Event.Kind.STOP:
-        break
-    self.completion_queue = None
-
-  def _perform_echo_test(self, test_data):
-    method = 'test method'
-    details = 'test details'
-    server_leading_metadata_key = 'my_server_leading_key'
-    server_leading_metadata_value = 'my_server_leading_value'
-    server_trailing_metadata_key = 'my_server_trailing_key'
-    server_trailing_metadata_value = 'my_server_trailing_value'
-    client_metadata_key = 'my_client_key'
-    client_metadata_value = 'my_client_value'
-    server_leading_binary_metadata_key = 'my_server_leading_key-bin'
-    server_leading_binary_metadata_value = b'\0'*2047
-    server_trailing_binary_metadata_key = 'my_server_trailing_key-bin'
-    server_trailing_binary_metadata_value = b'\0'*2047
-    client_binary_metadata_key = 'my_client_key-bin'
-    client_binary_metadata_value = b'\0'*2047
-    deadline = _FUTURE
-    metadata_tag = object()
-    finish_tag = object()
-    write_tag = object()
-    complete_tag = object()
-    service_tag = object()
-    read_tag = object()
-    status_tag = object()
-
-    server_data = []
-    client_data = []
-
-    client_call = _low.Call(self.channel, self.completion_queue,
-                            method, self.host, deadline)
-    client_call.add_metadata(client_metadata_key, client_metadata_value)
-    client_call.add_metadata(client_binary_metadata_key,
-                             client_binary_metadata_value)
-
-    client_call.invoke(self.completion_queue, metadata_tag, finish_tag)
-
-    self.server.service(service_tag)
-    service_accepted = self.completion_queue.get(_FUTURE)
-    self.assertIsNotNone(service_accepted)
-    self.assertIs(service_accepted.kind, _low.Event.Kind.SERVICE_ACCEPTED)
-    self.assertIs(service_accepted.tag, service_tag)
-    self.assertEqual(method, service_accepted.service_acceptance.method)
-    self.assertEqual(self.host, service_accepted.service_acceptance.host)
-    self.assertIsNotNone(service_accepted.service_acceptance.call)
-    metadata = dict(service_accepted.metadata)
-    self.assertIn(client_metadata_key, metadata)
-    self.assertEqual(client_metadata_value, metadata[client_metadata_key])
-    self.assertIn(client_binary_metadata_key, metadata)
-    self.assertEqual(client_binary_metadata_value,
-                     metadata[client_binary_metadata_key])
-    server_call = service_accepted.service_acceptance.call
-    server_call.accept(self.completion_queue, finish_tag)
-    server_call.add_metadata(server_leading_metadata_key,
-                             server_leading_metadata_value)
-    server_call.add_metadata(server_leading_binary_metadata_key,
-                             server_leading_binary_metadata_value)
-    server_call.premetadata()
-
-    metadata_accepted = self.completion_queue.get(_FUTURE)
-    self.assertIsNotNone(metadata_accepted)
-    self.assertEqual(_low.Event.Kind.METADATA_ACCEPTED, metadata_accepted.kind)
-    self.assertEqual(metadata_tag, metadata_accepted.tag)
-    metadata = dict(metadata_accepted.metadata)
-    self.assertIn(server_leading_metadata_key, metadata)
-    self.assertEqual(server_leading_metadata_value,
-                     metadata[server_leading_metadata_key])
-    self.assertIn(server_leading_binary_metadata_key, metadata)
-    self.assertEqual(server_leading_binary_metadata_value,
-                     metadata[server_leading_binary_metadata_key])
-
-    for datum in test_data:
-      client_call.write(datum, write_tag)
-      write_accepted = self.completion_queue.get(_FUTURE)
-      self.assertIsNotNone(write_accepted)
-      self.assertIs(write_accepted.kind, _low.Event.Kind.WRITE_ACCEPTED)
-      self.assertIs(write_accepted.tag, write_tag)
-      self.assertIs(write_accepted.write_accepted, True)
-
-      server_call.read(read_tag)
-      read_accepted = self.completion_queue.get(_FUTURE)
-      self.assertIsNotNone(read_accepted)
-      self.assertEqual(_low.Event.Kind.READ_ACCEPTED, read_accepted.kind)
-      self.assertEqual(read_tag, read_accepted.tag)
-      self.assertIsNotNone(read_accepted.bytes)
-      server_data.append(read_accepted.bytes)
-
-      server_call.write(read_accepted.bytes, write_tag)
-      write_accepted = self.completion_queue.get(_FUTURE)
-      self.assertIsNotNone(write_accepted)
-      self.assertEqual(_low.Event.Kind.WRITE_ACCEPTED, write_accepted.kind)
-      self.assertEqual(write_tag, write_accepted.tag)
-      self.assertTrue(write_accepted.write_accepted)
-
-      client_call.read(read_tag)
-      read_accepted = self.completion_queue.get(_FUTURE)
-      self.assertIsNotNone(read_accepted)
-      self.assertEqual(_low.Event.Kind.READ_ACCEPTED, read_accepted.kind)
-      self.assertEqual(read_tag, read_accepted.tag)
-      self.assertIsNotNone(read_accepted.bytes)
-      client_data.append(read_accepted.bytes)
-
-    client_call.complete(complete_tag)
-    complete_accepted = self.completion_queue.get(_FUTURE)
-    self.assertIsNotNone(complete_accepted)
-    self.assertIs(complete_accepted.kind, _low.Event.Kind.COMPLETE_ACCEPTED)
-    self.assertIs(complete_accepted.tag, complete_tag)
-    self.assertIs(complete_accepted.complete_accepted, True)
-
-    server_call.read(read_tag)
-    read_accepted = self.completion_queue.get(_FUTURE)
-    self.assertIsNotNone(read_accepted)
-    self.assertEqual(_low.Event.Kind.READ_ACCEPTED, read_accepted.kind)
-    self.assertEqual(read_tag, read_accepted.tag)
-    self.assertIsNone(read_accepted.bytes)
 
-    server_call.add_metadata(server_trailing_metadata_key,
-                             server_trailing_metadata_value)
-    server_call.add_metadata(server_trailing_binary_metadata_key,
-                             server_trailing_binary_metadata_value)
-
-    server_call.status(_low.Status(_low.Code.OK, details), status_tag)
-    server_terminal_event_one = self.completion_queue.get(_FUTURE)
-    server_terminal_event_two = self.completion_queue.get(_FUTURE)
-    if server_terminal_event_one.kind == _low.Event.Kind.COMPLETE_ACCEPTED:
-      status_accepted = server_terminal_event_one
-      rpc_accepted = server_terminal_event_two
-    else:
-      status_accepted = server_terminal_event_two
-      rpc_accepted = server_terminal_event_one
-    self.assertIsNotNone(status_accepted)
-    self.assertIsNotNone(rpc_accepted)
-    self.assertEqual(_low.Event.Kind.COMPLETE_ACCEPTED, status_accepted.kind)
-    self.assertEqual(status_tag, status_accepted.tag)
-    self.assertTrue(status_accepted.complete_accepted)
-    self.assertEqual(_low.Event.Kind.FINISH, rpc_accepted.kind)
-    self.assertEqual(finish_tag, rpc_accepted.tag)
-    self.assertEqual(_low.Status(_low.Code.OK, ''), rpc_accepted.status)
-
-    client_call.read(read_tag)
-    client_terminal_event_one = self.completion_queue.get(_FUTURE)
-    client_terminal_event_two = self.completion_queue.get(_FUTURE)
-    if client_terminal_event_one.kind == _low.Event.Kind.READ_ACCEPTED:
-      read_accepted = client_terminal_event_one
-      finish_accepted = client_terminal_event_two
-    else:
-      read_accepted = client_terminal_event_two
-      finish_accepted = client_terminal_event_one
-    self.assertIsNotNone(read_accepted)
-    self.assertIsNotNone(finish_accepted)
-    self.assertEqual(_low.Event.Kind.READ_ACCEPTED, read_accepted.kind)
-    self.assertEqual(read_tag, read_accepted.tag)
-    self.assertIsNone(read_accepted.bytes)
-    self.assertEqual(_low.Event.Kind.FINISH, finish_accepted.kind)
-    self.assertEqual(finish_tag, finish_accepted.tag)
-    self.assertEqual(_low.Status(_low.Code.OK, details), finish_accepted.status)
-    metadata = dict(finish_accepted.metadata)
-    self.assertIn(server_trailing_metadata_key, metadata)
-    self.assertEqual(server_trailing_metadata_value,
-                     metadata[server_trailing_metadata_key])
-    self.assertIn(server_trailing_binary_metadata_key, metadata)
-    self.assertEqual(server_trailing_binary_metadata_value,
-                     metadata[server_trailing_binary_metadata_key])
-
-    server_timeout_none_event = self.completion_queue.get(0)
-    self.assertIsNone(server_timeout_none_event)
-    client_timeout_none_event = self.completion_queue.get(0)
-    self.assertIsNone(client_timeout_none_event)
-
-    self.assertSequenceEqual(test_data, server_data)
-    self.assertSequenceEqual(test_data, client_data)
-
-  def testNoEcho(self):
-    self._perform_echo_test(())
-
-  def testOneByteEcho(self):
-    self._perform_echo_test([b'\x07'])
-
-  def testOneManyByteEcho(self):
-    self._perform_echo_test([_BYTE_SEQUENCE])
-
-  def testManyOneByteEchoes(self):
-    self._perform_echo_test(_BYTE_SEQUENCE)
-
-  def testManyManyByteEchoes(self):
-    self._perform_echo_test(_BYTE_SEQUENCE_SEQUENCE)
-
-class CancellationTest(unittest.TestCase):
+class InsecureServerInsecureClient(unittest.TestCase):
 
   def setUp(self):
-    self.host = 'localhost'
+    self.server_completion_queue = _low.CompletionQueue()
+    self.server = _low.Server(self.server_completion_queue, [])
+    self.port = self.server.add_http2_port('[::]:0')
+    self.client_completion_queue = _low.CompletionQueue()
+    self.client_channel = _low.Channel('localhost:%d'%self.port, [])
 
-    self.completion_queue = _low.CompletionQueue()
-    self.server = _low.Server(self.completion_queue)
-    port = self.server.add_http2_addr('[::]:0')
     self.server.start()
 
-    self.channel = _low.Channel('%s:%d' % (self.host, port), None)
-
   def tearDown(self):
-    self.server.stop()
+    self.server.shutdown()
+    del self.client_channel
     del self.server
-    self.completion_queue.stop()
-    while True:
-      event = self.completion_queue.get(0)
-      if event is not None and event.kind is _low.Event.Kind.STOP:
-        break
-
-  def testCancellation(self):
-    method = 'test method'
-    deadline = _FUTURE
-    metadata_tag = object()
-    client_finish_tag = object()
-    server_finish_tag = object()
-    write_tag = object()
-    service_tag = object()
-    read_tag = object()
-    test_data = _BYTE_SEQUENCE_SEQUENCE
-
-    server_data = []
-    client_data = []
-
-    client_call = _low.Call(self.channel, self.completion_queue,
-                            method, self.host, deadline)
-
-    client_call.invoke(self.completion_queue, metadata_tag, client_finish_tag)
-
-    self.server.service(service_tag)
-    service_accepted = self.completion_queue.get(_FUTURE)
-    server_call = service_accepted.service_acceptance.call
-
-    server_call.accept(self.completion_queue, server_finish_tag)
-    server_call.premetadata()
-
-    metadata_accepted = self.completion_queue.get(_FUTURE)
-    self.assertIsNotNone(metadata_accepted)
-
-    for datum in test_data:
-      client_call.write(datum, write_tag)
-      write_accepted = self.completion_queue.get(_FUTURE)
-
-      server_call.read(read_tag)
-      read_accepted = self.completion_queue.get(_FUTURE)
-      server_data.append(read_accepted.bytes)
-
-      server_call.write(read_accepted.bytes, write_tag)
-      write_accepted = self.completion_queue.get(_FUTURE)
-      self.assertIsNotNone(write_accepted)
-
-      client_call.read(read_tag)
-      read_accepted = self.completion_queue.get(_FUTURE)
-      client_data.append(read_accepted.bytes)
-
-    client_call.cancel()
-    # cancel() is idempotent.
-    client_call.cancel()
-    client_call.cancel()
-    client_call.cancel()
-
-    server_call.read(read_tag)
-
-    events = dict((ev.tag, ev) for ev in [
-        self.completion_queue.get(_FUTURE),
-        self.completion_queue.get(_FUTURE),
-        self.completion_queue.get(_FUTURE)])
-    read_accepted = events[read_tag]
-    rpc_accepted = events[server_finish_tag]
-    finish_event = events[client_finish_tag]
-    self.assertIsNotNone(read_accepted)
-    self.assertIsNotNone(rpc_accepted)
-    self.assertEqual(_low.Event.Kind.READ_ACCEPTED, read_accepted.kind)
-    self.assertIsNone(read_accepted.bytes)
-    self.assertEqual(_low.Event.Kind.FINISH, rpc_accepted.kind)
-    self.assertEqual(_low.Status(_low.Code.CANCELLED, ''), rpc_accepted.status)
-
-    self.assertEqual(_low.Event.Kind.FINISH, finish_event.kind)
-    self.assertEqual(_low.Status(_low.Code.CANCELLED, 'Cancelled'), 
-                                 finish_event.status)
-
-    server_timeout_none_event = self.completion_queue.get(0)
-    self.assertIsNone(server_timeout_none_event)
-    client_timeout_none_event = self.completion_queue.get(0)
-    self.assertIsNone(client_timeout_none_event)
-
-    self.assertSequenceEqual(test_data, server_data)
-    self.assertSequenceEqual(test_data, client_data)
-
-
-class ExpirationTest(unittest.TestCase):
 
-  @unittest.skip('TODO(nathaniel): Expiration test!')
-  def testExpiration(self):
-    pass
+    self.client_completion_queue.shutdown()
+    while self.client_completion_queue.next().type != _types.EventType.QUEUE_SHUTDOWN:
+      pass
+    self.server_completion_queue.shutdown()
+    while self.server_completion_queue.next().type != _types.EventType.QUEUE_SHUTDOWN:
+      pass
+
+    del self.client_completion_queue
+    del self.server_completion_queue
+
+  def testEcho(self):
+    DEADLINE = time.time()+5
+    DEADLINE_TOLERANCE = 0.25
+    CLIENT_METADATA_ASCII_KEY = 'key'
+    CLIENT_METADATA_ASCII_VALUE = 'val'
+    CLIENT_METADATA_BIN_KEY = 'key-bin'
+    CLIENT_METADATA_BIN_VALUE = b'\0'*1000
+    SERVER_INITIAL_METADATA_KEY = 'init_me_me_me'
+    SERVER_INITIAL_METADATA_VALUE = 'whodawha?'
+    SERVER_TRAILING_METADATA_KEY = 'California_is_in_a_drought'
+    SERVER_TRAILING_METADATA_VALUE = 'zomg it is'
+    SERVER_STATUS_CODE = _types.StatusCode.OK
+    SERVER_STATUS_DETAILS = 'our work is never over'
+    REQUEST = 'in death a member of project mayhem has a name'
+    RESPONSE = 'his name is robert paulson'
+    METHOD = 'twinkies'
+    HOST = 'hostess'
+    server_request_tag = object()
+    request_call_result = self.server.request_call(self.server_completion_queue, server_request_tag)
+
+    self.assertEquals(_types.CallError.OK, request_call_result)
+
+    client_call_tag = object()
+    client_call = self.client_channel.create_call(self.client_completion_queue, METHOD, HOST, DEADLINE)
+    client_initial_metadata = [(CLIENT_METADATA_ASCII_KEY, CLIENT_METADATA_ASCII_VALUE), (CLIENT_METADATA_BIN_KEY, CLIENT_METADATA_BIN_VALUE)]
+    client_start_batch_result = client_call.start_batch([
+        _types.OpArgs.send_initial_metadata(client_initial_metadata),
+        _types.OpArgs.send_message(REQUEST),
+        _types.OpArgs.send_close_from_client(),
+        _types.OpArgs.recv_initial_metadata(),
+        _types.OpArgs.recv_message(),
+        _types.OpArgs.recv_status_on_client()
+    ], client_call_tag)
+    self.assertEquals(_types.CallError.OK, client_start_batch_result)
+
+    request_event = self.server_completion_queue.next(DEADLINE)
+    self.assertEquals(_types.EventType.OP_COMPLETE, request_event.type)
+    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))
+    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)
+
+    server_call_tag = object()
+    server_call = request_event.call
+    server_initial_metadata = [(SERVER_INITIAL_METADATA_KEY, SERVER_INITIAL_METADATA_VALUE)]
+    server_trailing_metadata = [(SERVER_TRAILING_METADATA_KEY, SERVER_TRAILING_METADATA_VALUE)]
+    server_start_batch_result = server_call.start_batch([
+        _types.OpArgs.send_initial_metadata(server_initial_metadata),
+        _types.OpArgs.recv_message(),
+        _types.OpArgs.send_message(RESPONSE),
+        _types.OpArgs.recv_close_on_server(),
+        _types.OpArgs.send_status_from_server(server_trailing_metadata, SERVER_STATUS_CODE, SERVER_STATUS_DETAILS)
+    ], server_call_tag)
+    self.assertEquals(_types.CallError.OK, server_start_batch_result)
+
+    client_event = self.client_completion_queue.next(DEADLINE)
+    server_event = self.server_completion_queue.next(DEADLINE)
+
+    self.assertEquals(6, len(client_event.results))
+    found_client_op_types = set()
+    for client_result in client_event.results:
+      self.assertNotIn(client_result.type, found_client_op_types)  # we expect each op type to be unique
+      found_client_op_types.add(client_result.type)
+      if client_result.type == _types.OpType.RECV_INITIAL_METADATA:
+        self.assertEquals(dict(server_initial_metadata), dict(client_result.initial_metadata))
+      elif client_result.type == _types.OpType.RECV_MESSAGE:
+        self.assertEquals(RESPONSE, client_result.message)
+      elif client_result.type == _types.OpType.RECV_STATUS_ON_CLIENT:
+        self.assertEquals(dict(server_trailing_metadata), dict(client_result.trailing_metadata))
+        self.assertEquals(SERVER_STATUS_DETAILS, client_result.status.details)
+        self.assertEquals(SERVER_STATUS_CODE, client_result.status.code)
+    self.assertEquals(set([
+          _types.OpType.SEND_INITIAL_METADATA,
+          _types.OpType.SEND_MESSAGE,
+          _types.OpType.SEND_CLOSE_FROM_CLIENT,
+          _types.OpType.RECV_INITIAL_METADATA,
+          _types.OpType.RECV_MESSAGE,
+          _types.OpType.RECV_STATUS_ON_CLIENT
+      ]), found_client_op_types)
+
+    self.assertEquals(5, len(server_event.results))
+    found_server_op_types = set()
+    for server_result in server_event.results:
+      self.assertNotIn(client_result.type, found_server_op_types)
+      found_server_op_types.add(server_result.type)
+      if server_result.type == _types.OpType.RECV_MESSAGE:
+        self.assertEquals(REQUEST, server_result.message)
+      elif server_result.type == _types.OpType.RECV_CLOSE_ON_SERVER:
+        self.assertFalse(server_result.cancelled)
+    self.assertEquals(set([
+          _types.OpType.SEND_INITIAL_METADATA,
+          _types.OpType.RECV_MESSAGE,
+          _types.OpType.SEND_MESSAGE,
+          _types.OpType.RECV_CLOSE_ON_SERVER,
+          _types.OpType.SEND_STATUS_FROM_SERVER
+      ]), found_server_op_types)
+
+    del client_call
+    del server_call
 
 
 if __name__ == '__main__':
diff --git a/src/python/src/grpc/_adapter/_server.c b/src/python/src/grpc/_adapter/_server.c
deleted file mode 100644
index a6c20bf132..0000000000
--- a/src/python/src/grpc/_adapter/_server.c
+++ /dev/null
@@ -1,202 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include "grpc/_adapter/_server.h"
-
-#include <Python.h>
-#include <grpc/grpc.h>
-
-#include "grpc/_adapter/_call.h"
-#include "grpc/_adapter/_completion_queue.h"
-#include "grpc/_adapter/_error.h"
-#include "grpc/_adapter/_server_credentials.h"
-#include "grpc/_adapter/_tag.h"
-
-static int pygrpc_server_init(Server *self, PyObject *args, PyObject *kwds) {
-  CompletionQueue *completion_queue;
-  static char *kwlist[] = {"completion_queue", NULL};
-
-  if (!PyArg_ParseTupleAndKeywords(args, kwds, "O!:Server", kwlist,
-                                   &pygrpc_CompletionQueueType,
-                                   &completion_queue)) {
-    return -1;
-  }
-  self->c_server = grpc_server_create(NULL);
-  grpc_server_register_completion_queue(self->c_server,
-                                        completion_queue->c_completion_queue);
-  self->completion_queue = completion_queue;
-  Py_INCREF(completion_queue);
-  return 0;
-}
-
-static void pygrpc_server_dealloc(Server *self) {
-  if (self->c_server != NULL) {
-    grpc_server_destroy(self->c_server);
-  }
-  Py_XDECREF(self->completion_queue);
-  self->ob_type->tp_free((PyObject *)self);
-}
-
-static PyObject *pygrpc_server_add_http2_addr(Server *self, PyObject *args) {
-  const char *addr;
-  int port;
-  if (!PyArg_ParseTuple(args, "s:add_http2_addr", &addr)) {
-    return NULL;
-  }
-
-  port = grpc_server_add_http2_port(self->c_server, addr);
-  if (port == 0) {
-    PyErr_SetString(PyExc_RuntimeError, "Couldn't add port to server!");
-    return NULL;
-  }
-
-  return PyInt_FromLong(port);
-}
-
-static PyObject *pygrpc_server_add_secure_http2_addr(Server *self,
-                                                     PyObject *args,
-                                                     PyObject *kwargs) {
-  const char *addr;
-  PyObject *server_credentials;
-  static char *kwlist[] = {"addr", "server_credentials", NULL};
-  int port;
-
-  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "sO!:add_secure_http2_addr",
-                                   kwlist, &addr, &pygrpc_ServerCredentialsType,
-                                   &server_credentials)) {
-    return NULL;
-  }
-  port = grpc_server_add_secure_http2_port(
-      self->c_server, addr,
-      ((ServerCredentials *)server_credentials)->c_server_credentials);
-  if (port == 0) {
-    PyErr_SetString(PyExc_RuntimeError, "Couldn't add port to server!");
-    return NULL;
-  }
-  return PyInt_FromLong(port);
-}
-
-static PyObject *pygrpc_server_start(Server *self) {
-  grpc_server_start(self->c_server);
-
-  Py_RETURN_NONE;
-}
-
-static const PyObject *pygrpc_server_service(Server *self, PyObject *tag) {
-  grpc_call_error call_error;
-  const PyObject *result;
-  pygrpc_tag *c_tag = pygrpc_tag_new_server_rpc_call(tag);
-  c_tag->call->completion_queue = self->completion_queue;
-  c_tag->call->server = self;
-  Py_INCREF(c_tag->call->completion_queue);
-  Py_INCREF(c_tag->call->server);
-  call_error = grpc_server_request_call(
-      self->c_server, &c_tag->call->c_call, &c_tag->call->call_details,
-      &c_tag->call->recv_metadata, self->completion_queue->c_completion_queue,
-      self->completion_queue->c_completion_queue, c_tag);
-
-  result = pygrpc_translate_call_error(call_error);
-  if (result != NULL) {
-    Py_INCREF(tag);
-  }
-  return result;
-}
-
-static PyObject *pygrpc_server_stop(Server *self) {
-  grpc_server_shutdown(self->c_server);
-
-  Py_RETURN_NONE;
-}
-
-static PyMethodDef methods[] = {
-    {"add_http2_addr", (PyCFunction)pygrpc_server_add_http2_addr, METH_VARARGS,
-     "Add an HTTP2 address."},
-    {"add_secure_http2_addr", (PyCFunction)pygrpc_server_add_secure_http2_addr,
-     METH_VARARGS, "Add a secure HTTP2 address."},
-    {"start", (PyCFunction)pygrpc_server_start, METH_NOARGS,
-     "Starts the server."},
-    {"service", (PyCFunction)pygrpc_server_service, METH_O, "Services a call."},
-    {"stop", (PyCFunction)pygrpc_server_stop, METH_NOARGS, "Stops the server."},
-    {NULL}};
-
-static PyTypeObject pygrpc_ServerType = {
-    PyVarObject_HEAD_INIT(NULL, 0)
-    "_gprc.Server",                    /*tp_name*/
-    sizeof(Server),                    /*tp_basicsize*/
-    0,                                 /*tp_itemsize*/
-    (destructor)pygrpc_server_dealloc, /*tp_dealloc*/
-    0,                                 /*tp_print*/
-    0,                                 /*tp_getattr*/
-    0,                                 /*tp_setattr*/
-    0,                                 /*tp_compare*/
-    0,                                 /*tp_repr*/
-    0,                                 /*tp_as_number*/
-    0,                                 /*tp_as_sequence*/
-    0,                                 /*tp_as_mapping*/
-    0,                                 /*tp_hash */
-    0,                                 /*tp_call*/
-    0,                                 /*tp_str*/
-    0,                                 /*tp_getattro*/
-    0,                                 /*tp_setattro*/
-    0,                                 /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT,                /*tp_flags*/
-    "Wrapping of grpc_server.",        /* tp_doc */
-    0,                                 /* tp_traverse */
-    0,                                 /* tp_clear */
-    0,                                 /* tp_richcompare */
-    0,                                 /* tp_weaklistoffset */
-    0,                                 /* tp_iter */
-    0,                                 /* tp_iternext */
-    methods,                           /* tp_methods */
-    0,                                 /* tp_members */
-    0,                                 /* tp_getset */
-    0,                                 /* tp_base */
-    0,                                 /* tp_dict */
-    0,                                 /* tp_descr_get */
-    0,                                 /* tp_descr_set */
-    0,                                 /* tp_dictoffset */
-    (initproc)pygrpc_server_init,      /* tp_init */
-    0,                                 /* tp_alloc */
-    PyType_GenericNew,                 /* tp_new */
-};
-
-int pygrpc_add_server(PyObject *module) {
-  if (PyType_Ready(&pygrpc_ServerType) < 0) {
-    return -1;
-  }
-  if (PyModule_AddObject(module, "Server", (PyObject *)&pygrpc_ServerType) ==
-      -1) {
-    return -1;
-  }
-  return 0;
-}
diff --git a/src/python/src/grpc/_adapter/_server_credentials.c b/src/python/src/grpc/_adapter/_server_credentials.c
deleted file mode 100644
index 06e6b94974..0000000000
--- a/src/python/src/grpc/_adapter/_server_credentials.c
+++ /dev/null
@@ -1,152 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include "grpc/_adapter/_server_credentials.h"
-
-#include <Python.h>
-#include <grpc/grpc_security.h>
-#include <grpc/support/alloc.h>
-
-static int pygrpc_server_credentials_init(ServerCredentials *self,
-                                          PyObject *args, PyObject *kwds) {
-  char *root_certificates;
-  PyObject *pair_sequence;
-  Py_ssize_t pair_count;
-  grpc_ssl_pem_key_cert_pair *pairs;
-  int error;
-  PyObject *iterator;
-  int i;
-  PyObject *pair;
-  static char *kwlist[] = {"root_credentials", "pair_sequence", NULL};
-
-  if (!PyArg_ParseTupleAndKeywords(args, kwds, "zO:ServerCredentials", kwlist,
-                                   &root_certificates, &pair_sequence)) {
-    return -1;
-  }
-
-  pair_count = PySequence_Length(pair_sequence);
-  if (pair_count == -1) {
-    return -1;
-  }
-
-  iterator = PyObject_GetIter(pair_sequence);
-  if (iterator == NULL) {
-    return -1;
-  }
-  pairs = gpr_malloc(pair_count * sizeof(grpc_ssl_pem_key_cert_pair));
-  error = 0;
-  for (i = 0; i < pair_count; i++) {
-    pair = PyIter_Next(iterator);
-    if (pair == NULL) {
-      error = 1;
-      break;
-    }
-    if (!PyArg_ParseTuple(pair, "ss", &pairs[i].private_key,
-                           &pairs[i].cert_chain)) {
-      error = 1;
-      Py_DECREF(pair);
-      break;
-    }
-    Py_DECREF(pair);
-  }
-  Py_DECREF(iterator);
-
-  if (error) {
-    gpr_free(pairs);
-    return -1;
-  } else {
-    self->c_server_credentials = grpc_ssl_server_credentials_create(
-        root_certificates, pairs, pair_count);
-    gpr_free(pairs);
-    return 0;
-  }
-}
-
-static void pygrpc_server_credentials_dealloc(ServerCredentials *self) {
-  if (self->c_server_credentials != NULL) {
-    grpc_server_credentials_release(self->c_server_credentials);
-  }
-  self->ob_type->tp_free((PyObject *)self);
-}
-
-PyTypeObject pygrpc_ServerCredentialsType = {
-    PyVarObject_HEAD_INIT(NULL, 0)
-    "_grpc.ServerCredencials",                     /*tp_name*/
-    sizeof(ServerCredentials),                     /*tp_basicsize*/
-    0,                                             /*tp_itemsize*/
-    (destructor)pygrpc_server_credentials_dealloc, /*tp_dealloc*/
-    0,                                             /*tp_print*/
-    0,                                             /*tp_getattr*/
-    0,                                             /*tp_setattr*/
-    0,                                             /*tp_compare*/
-    0,                                             /*tp_repr*/
-    0,                                             /*tp_as_number*/
-    0,                                             /*tp_as_sequence*/
-    0,                                             /*tp_as_mapping*/
-    0,                                             /*tp_hash */
-    0,                                             /*tp_call*/
-    0,                                             /*tp_str*/
-    0,                                             /*tp_getattro*/
-    0,                                             /*tp_setattro*/
-    0,                                             /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT,                            /*tp_flags*/
-    "Wrapping of grpc_server_credentials.",        /* tp_doc */
-    0,                                             /* tp_traverse */
-    0,                                             /* tp_clear */
-    0,                                             /* tp_richcompare */
-    0,                                             /* tp_weaklistoffset */
-    0,                                             /* tp_iter */
-    0,                                             /* tp_iternext */
-    0,                                             /* tp_methods */
-    0,                                             /* tp_members */
-    0,                                             /* tp_getset */
-    0,                                             /* tp_base */
-    0,                                             /* tp_dict */
-    0,                                             /* tp_descr_get */
-    0,                                             /* tp_descr_set */
-    0,                                             /* tp_dictoffset */
-    (initproc)pygrpc_server_credentials_init,      /* tp_init */
-    0,                                             /* tp_alloc */
-    PyType_GenericNew,                             /* tp_new */
-};
-
-int pygrpc_add_server_credentials(PyObject *module) {
-  if (PyType_Ready(&pygrpc_ServerCredentialsType) < 0) {
-    return -1;
-  }
-  if (PyModule_AddObject(module, "ServerCredentials",
-                         (PyObject *)&pygrpc_ServerCredentialsType) == -1) {
-    return -1;
-  }
-  return 0;
-}
diff --git a/src/python/src/grpc/_adapter/_server_credentials.h b/src/python/src/grpc/_adapter/_server_credentials.h
deleted file mode 100644
index 75af934089..0000000000
--- a/src/python/src/grpc/_adapter/_server_credentials.h
+++ /dev/null
@@ -1,49 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#ifndef _ADAPTER__SERVER_CREDENTIALS_H_
-#define _ADAPTER__SERVER_CREDENTIALS_H_
-
-#include <Python.h>
-#include <grpc/grpc_security.h>
-
-typedef struct {
-  PyObject_HEAD
-  grpc_server_credentials *c_server_credentials;
-} ServerCredentials;
-
-extern PyTypeObject pygrpc_ServerCredentialsType;
-
-int pygrpc_add_server_credentials(PyObject *module);
-
-#endif /* _ADAPTER__SERVER_CREDENTIALS_H_ */
diff --git a/src/python/src/grpc/_adapter/_tag.c b/src/python/src/grpc/_adapter/_tag.c
deleted file mode 100644
index 9c6ee19d79..0000000000
--- a/src/python/src/grpc/_adapter/_tag.c
+++ /dev/null
@@ -1,65 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#include "grpc/_adapter/_tag.h"
-
-#include <Python.h>
-#include <grpc/grpc.h>
-#include <grpc/support/alloc.h>
-
-pygrpc_tag *pygrpc_tag_new(pygrpc_tag_type type, PyObject *user_tag,
-                           Call *call) {
-  pygrpc_tag *self = (pygrpc_tag *)gpr_malloc(sizeof(pygrpc_tag));
-  memset(self, 0, sizeof(pygrpc_tag));
-  if (user_tag == NULL) {
-    self->user_tag = Py_None;
-  } else {
-    self->user_tag = user_tag;
-  }
-  Py_INCREF(self->user_tag);
-  self->type = type;
-  self->call = call;
-  Py_INCREF(call);
-  return self;
-}
-
-pygrpc_tag *pygrpc_tag_new_server_rpc_call(PyObject *user_tag) {
-  return pygrpc_tag_new(PYGRPC_SERVER_RPC_NEW, user_tag,
-                        (Call *)pygrpc_CallType.tp_alloc(&pygrpc_CallType, 0));
-}
-
-void pygrpc_tag_destroy(pygrpc_tag *self) {
-  Py_XDECREF(self->user_tag);
-  Py_XDECREF(self->call);
-  gpr_free(self);
-}
diff --git a/src/python/src/grpc/_adapter/_tag.h b/src/python/src/grpc/_adapter/_tag.h
deleted file mode 100644
index 64812aa7e7..0000000000
--- a/src/python/src/grpc/_adapter/_tag.h
+++ /dev/null
@@ -1,70 +0,0 @@
-/*
- *
- * Copyright 2015, Google Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- *     * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above
- * copyright notice, this list of conditions and the following disclaimer
- * in the documentation and/or other materials provided with the
- * distribution.
- *     * Neither the name of Google Inc. nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- *
- */
-
-#ifndef _ADAPTER__TAG_H_
-#define _ADAPTER__TAG_H_
-
-#include <Python.h>
-#include <grpc/grpc.h>
-
-#include "grpc/_adapter/_call.h"
-#include "grpc/_adapter/_completion_queue.h"
-
-/* grpc_completion_type is becoming meaningless in grpc_event; this is a partial
-   replacement for its descriptive functionality until Python can move its whole
-   C and C adapter stack to more closely resemble the core batching API. */
-typedef enum {
-  PYGRPC_SERVER_RPC_NEW = 0,
-  PYGRPC_INITIAL_METADATA = 1,
-  PYGRPC_READ = 2,
-  PYGRPC_WRITE_ACCEPTED = 3,
-  PYGRPC_FINISH_ACCEPTED = 4,
-  PYGRPC_CLIENT_METADATA_READ = 5,
-  PYGRPC_FINISHED_CLIENT = 6,
-  PYGRPC_FINISHED_SERVER = 7
-} pygrpc_tag_type;
-
-typedef struct {
-  pygrpc_tag_type type;
-  PyObject *user_tag;
-
-  Call *call;
-} pygrpc_tag;
-
-pygrpc_tag *pygrpc_tag_new(pygrpc_tag_type type, PyObject *user_tag,
-                           Call *call);
-pygrpc_tag *pygrpc_tag_new_server_rpc_call(PyObject *user_tag);
-void pygrpc_tag_destroy(pygrpc_tag *self);
-
-#endif /* _ADAPTER__TAG_H_ */
-
diff --git a/src/python/src/grpc/_adapter/_types.py b/src/python/src/grpc/_adapter/_types.py
new file mode 100644
index 0000000000..5ddb1774ea
--- /dev/null
+++ b/src/python/src/grpc/_adapter/_types.py
@@ -0,0 +1,368 @@
+# 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.
+
+import abc
+import collections
+import enum
+
+# TODO(atash): decide whether or not to move these enums to the _c module to
+# force build errors with upstream changes.
+
+class GrpcChannelArgumentKeys(enum.Enum):
+  """Mirrors keys used in grpc_channel_args for GRPC-specific arguments."""
+  SSL_TARGET_NAME_OVERRIDE = 'grpc.ssl_target_name_override'
+
+@enum.unique
+class CallError(enum.IntEnum):
+  """Mirrors grpc_call_error in the C core."""
+  OK                        = 0
+  ERROR                     = 1
+  ERROR_NOT_ON_SERVER       = 2
+  ERROR_NOT_ON_CLIENT       = 3
+  ERROR_ALREADY_ACCEPTED    = 4
+  ERROR_ALREADY_INVOKED     = 5
+  ERROR_NOT_INVOKED         = 6
+  ERROR_ALREADY_FINISHED    = 7
+  ERROR_TOO_MANY_OPERATIONS = 8
+  ERROR_INVALID_FLAGS       = 9
+  ERROR_INVALID_METADATA    = 10
+
+@enum.unique
+class StatusCode(enum.IntEnum):
+  """Mirrors grpc_status_code in the C core."""
+  OK                  = 0
+  CANCELLED           = 1
+  UNKNOWN             = 2
+  INVALID_ARGUMENT    = 3
+  DEADLINE_EXCEEDED   = 4
+  NOT_FOUND           = 5
+  ALREADY_EXISTS      = 6
+  PERMISSION_DENIED   = 7
+  RESOURCE_EXHAUSTED  = 8
+  FAILED_PRECONDITION = 9
+  ABORTED             = 10
+  OUT_OF_RANGE        = 11
+  UNIMPLEMENTED       = 12
+  INTERNAL            = 13
+  UNAVAILABLE         = 14
+  DATA_LOSS           = 15
+  UNAUTHENTICATED     = 16
+
+@enum.unique
+class OpType(enum.IntEnum):
+  """Mirrors grpc_op_type in the C core."""
+  SEND_INITIAL_METADATA   = 0
+  SEND_MESSAGE            = 1
+  SEND_CLOSE_FROM_CLIENT  = 2
+  SEND_STATUS_FROM_SERVER = 3
+  RECV_INITIAL_METADATA   = 4
+  RECV_MESSAGE            = 5
+  RECV_STATUS_ON_CLIENT   = 6
+  RECV_CLOSE_ON_SERVER    = 7
+
+@enum.unique
+class EventType(enum.IntEnum):
+  """Mirrors grpc_completion_type in the C core."""
+  QUEUE_SHUTDOWN  = 0
+  QUEUE_TIMEOUT   = 1  # if seen on the Python side, something went horridly wrong
+  OP_COMPLETE     = 2
+
+class Status(collections.namedtuple(
+    'Status', [
+        'code',
+        'details',
+    ])):
+  """The end status of a GRPC call.
+
+  Attributes:
+    code (StatusCode): ...
+    details (str): ...
+  """
+
+class CallDetails(collections.namedtuple(
+    'CallDetails', [
+        'method',
+        'host',
+        'deadline',
+    ])):
+  """Provides information to the server about the client's call.
+
+  Attributes:
+    method (str): ...
+    host (str): ...
+    deadline (float): ...
+  """
+
+class OpArgs(collections.namedtuple(
+    'OpArgs', [
+        'type',
+        'initial_metadata',
+        'trailing_metadata',
+        'message',
+        'status',
+    ])):
+  """Arguments passed into a GRPC operation.
+
+  Attributes:
+    type (OpType): ...
+    initial_metadata (sequence of 2-sequence of str): Only valid if type ==
+      OpType.SEND_INITIAL_METADATA, else is None.
+    trailing_metadata (sequence of 2-sequence of str): Only valid if type ==
+      OpType.SEND_STATUS_FROM_SERVER, else is None.
+    message (bytes): Only valid if type == OpType.SEND_MESSAGE, else is None.
+    status (Status): Only valid if type == OpType.SEND_STATUS_FROM_SERVER, else
+      is None.
+  """
+
+  @staticmethod
+  def send_initial_metadata(initial_metadata):
+    return OpArgs(OpType.SEND_INITIAL_METADATA, initial_metadata, None, None, None)
+
+  @staticmethod
+  def send_message(message):
+    return OpArgs(OpType.SEND_MESSAGE, None, None, message, None)
+
+  @staticmethod
+  def send_close_from_client():
+    return OpArgs(OpType.SEND_CLOSE_FROM_CLIENT, None, None, None, None)
+
+  @staticmethod
+  def send_status_from_server(trailing_metadata, status_code, status_details):
+    return OpArgs(OpType.SEND_STATUS_FROM_SERVER, None, trailing_metadata, None, Status(status_code, status_details))
+
+  @staticmethod
+  def recv_initial_metadata():
+    return OpArgs(OpType.RECV_INITIAL_METADATA, None, None, None, None);
+
+  @staticmethod
+  def recv_message():
+    return OpArgs(OpType.RECV_MESSAGE, None, None, None, None)
+
+  @staticmethod
+  def recv_status_on_client():
+    return OpArgs(OpType.RECV_STATUS_ON_CLIENT, None, None, None, None)
+
+  @staticmethod
+  def recv_close_on_server():
+    return OpArgs(OpType.RECV_CLOSE_ON_SERVER, None, None, None, None)
+
+
+class OpResult(collections.namedtuple(
+    'OpResult', [
+        'type',
+        'initial_metadata',
+        'trailing_metadata',
+        'message',
+        'status',
+        'cancelled',
+    ])):
+  """Results received from a GRPC operation.
+
+  Attributes:
+    type (OpType): ...
+    initial_metadata (sequence of 2-sequence of str): Only valid if type ==
+      OpType.RECV_INITIAL_METADATA, else is None.
+    trailing_metadata (sequence of 2-sequence of str): Only valid if type ==
+      OpType.RECV_STATUS_ON_CLIENT, else is None.
+    message (bytes): Only valid if type == OpType.RECV_MESSAGE, else is None.
+    status (Status): Only valid if type == OpType.RECV_STATUS_ON_CLIENT, else
+      is None.
+    cancelled (bool): Only valid if type == OpType.RECV_CLOSE_ON_SERVER, else
+      is None.
+  """
+
+
+class Event(collections.namedtuple(
+    'Event', [
+        'type',
+        'tag',
+        'call',
+        'call_details',
+        'results',
+        'success',
+    ])):
+  """An event received from a GRPC completion queue.
+
+  Attributes:
+    type (EventType): ...
+    tag (object): ...
+    call (Call): The Call object associated with this event (if there is one,
+      else None).
+    call_details (CallDetails): The call details associated with the
+      server-side call (if there is such information, else None).
+    results (list of OpResult): ...
+    success (bool): ...
+  """
+
+
+class CompletionQueue:
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def __init__(self):
+    pass
+
+  def __iter__(self):
+    """This class may be iterated over.
+
+    This is the equivalent of calling next() repeatedly with an absolute
+    deadline of None (i.e. no deadline).
+    """
+    return self
+
+  @abc.abstractmethod
+  def next(self, deadline=float('+inf')):
+    """Get the next event on this completion queue.
+
+    Args:
+      deadline (float): absolute deadline in seconds from the Python epoch, or
+        None for no deadline.
+
+    Returns:
+      Event: ...
+    """
+    pass
+
+  @abc.abstractmethod
+  def shutdown(self):
+    """Begin the shutdown process of this completion queue.
+
+    Note that this does not immediately destroy the completion queue.
+    Nevertheless, user code should not pass it around after invoking this.
+    """
+    return None
+
+
+class Call:
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def start_batch(self, ops, tag):
+    """Start a batch of operations.
+
+    Args:
+      ops (sequence of OpArgs): ...
+      tag (object): ...
+
+    Returns:
+      CallError: ...
+    """
+    return CallError.ERROR
+
+  @abc.abstractmethod
+  def cancel(self, code=None, details=None):
+    """Cancel the call.
+
+    Args:
+      code (int): Status code to cancel with (on the server side). If
+        specified, so must `details`.
+      details (str): Status details to cancel with (on the server side). If
+        specified, so must `code`.
+
+    Returns:
+      CallError: ...
+    """
+    return CallError.ERROR
+
+
+class Channel:
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def __init__(self, target, args, credentials=None):
+    """Initialize a Channel.
+
+    Args:
+      target (str): ...
+      args (sequence of 2-sequence of str, (str|integer)): ...
+      credentials (ClientCredentials): If None, create an insecure channel,
+        else create a secure channel using the client credentials.
+    """
+
+  @abc.abstractmethod
+  def create_call(self, completion_queue, method, host, deadline=float('+inf')):
+    """Create a call from this channel.
+
+    Args:
+      completion_queue (CompletionQueue): ...
+      method (str): ...
+      host (str): ...
+      deadline (float): absolute deadline in seconds from the Python epoch, or
+        None for no deadline.
+
+    Returns:
+      Call: call object associated with this Channel and passed parameters.
+    """
+    return None
+
+
+class Server:
+  __metaclass__ = abc.ABCMeta
+
+  @abc.abstractmethod
+  def __init__(self, completion_queue, args):
+    """Initialize a server.
+
+    Args:
+      completion_queue (CompletionQueue): ...
+      args (sequence of 2-sequence of str, (str|integer)): ...
+    """
+
+  @abc.abstractmethod
+  def add_http2_port(self, address, credentials=None):
+    """Adds an HTTP/2 address+port to the server.
+
+    Args:
+      address (str): ...
+      credentials (ServerCredentials): If None, create an insecure port, else
+        create a secure port using the server credentials.
+    """
+
+  @abc.abstractmethod
+  def start(self):
+    """Starts the server."""
+
+  @abc.abstractmethod
+  def shutdown(self, tag=None):
+    """Shuts down the server. Does not immediately destroy the server.
+
+    Args:
+      tag (object): if not None, have the server place an event on its
+        completion queue notifying it when this server has completely shut down.
+    """
+
+  @abc.abstractmethod
+  def request_call(self, completion_queue, tag):
+    """Requests a call from the server on the server's completion queue.
+
+    Args:
+      completion_queue (CompletionQueue): Completion queue for the call. May be
+        the same as the server's completion queue.
+      tag (object) ...
+    """
diff --git a/src/python/src/grpc/_adapter/fore.py b/src/python/src/grpc/_adapter/fore.py
index 69e145e3f6..7d88bda263 100644
--- a/src/python/src/grpc/_adapter/fore.py
+++ b/src/python/src/grpc/_adapter/fore.py
@@ -35,7 +35,7 @@ import threading
 import time
 
 from grpc._adapter import _common
-from grpc._adapter import _low
+from grpc._adapter import _intermediary_low as _low
 from grpc.framework.base import interfaces as base_interfaces
 from grpc.framework.base import null
 from grpc.framework.foundation import activated
@@ -204,7 +204,7 @@ class ForeLink(base_interfaces.ForeLink, activated.Activated):
           call, sequence_number,
           base_interfaces.FrontToBackTicket.Kind.CANCELLATION, None, None,
           None, None, None)
-    elif code is _low.Code.EXPIRED:
+    elif code is _low.Code.DEADLINE_EXCEEDED:
       ticket = base_interfaces.FrontToBackTicket(
           call, sequence_number,
           base_interfaces.FrontToBackTicket.Kind.EXPIRATION, None, None, None,
diff --git a/src/python/src/grpc/_adapter/rear.py b/src/python/src/grpc/_adapter/rear.py
index b3b0b4ed32..fd6f45f7a7 100644
--- a/src/python/src/grpc/_adapter/rear.py
+++ b/src/python/src/grpc/_adapter/rear.py
@@ -35,7 +35,7 @@ import threading
 import time
 
 from grpc._adapter import _common
-from grpc._adapter import _low
+from grpc._adapter import _intermediary_low as _low
 from grpc.framework.base import interfaces as base_interfaces
 from grpc.framework.base import null
 from grpc.framework.foundation import activated
@@ -195,7 +195,7 @@ class RearLink(base_interfaces.RearLink, activated.Activated):
       kind = base_interfaces.BackToFrontTicket.Kind.COMPLETION
     elif event.status.code is _low.Code.CANCELLED:
       kind = base_interfaces.BackToFrontTicket.Kind.CANCELLATION
-    elif event.status.code is _low.Code.EXPIRED:
+    elif event.status.code is _low.Code.DEADLINE_EXCEEDED:
       kind = base_interfaces.BackToFrontTicket.Kind.EXPIRATION
     else:
       kind = base_interfaces.BackToFrontTicket.Kind.TRANSMISSION_FAILURE
diff --git a/src/python/src/setup.py b/src/python/src/setup.py
index d0f4791a1e..dc655a70f9 100644
--- a/src/python/src/setup.py
+++ b/src/python/src/setup.py
@@ -34,15 +34,15 @@ import setuptools
 import sys
 
 _EXTENSION_SOURCES = (
-    'grpc/_adapter/_c.c',
-    'grpc/_adapter/_call.c',
-    'grpc/_adapter/_channel.c',
-    'grpc/_adapter/_completion_queue.c',
-    'grpc/_adapter/_error.c',
-    'grpc/_adapter/_server.c',
-    'grpc/_adapter/_client_credentials.c',
-    'grpc/_adapter/_server_credentials.c',
-    'grpc/_adapter/_tag.c'
+    'grpc/_adapter/_c/module.c',
+    'grpc/_adapter/_c/types.c',
+    'grpc/_adapter/_c/utility.c',
+    'grpc/_adapter/_c/types/client_credentials.c',
+    'grpc/_adapter/_c/types/server_credentials.c',
+    'grpc/_adapter/_c/types/completion_queue.c',
+    'grpc/_adapter/_c/types/call.c',
+    'grpc/_adapter/_c/types/channel.c',
+    'grpc/_adapter/_c/types/server.c',
 )
 
 _EXTENSION_INCLUDE_DIRECTORIES = (