Merge branch 'master' into epollerr

211 files changed, 6240 insertions, 1551 deletions

diff --git a/.pylintrc b/.pylintrc
index 453b45aab5..90e8989ffc 100644
--- a/.pylintrc
+++ b/.pylintrc
@@ -72,6 +72,13 @@ disable=
 	# TODO(https://github.com/grpc/grpc/issues/261): Maybe we could have
 	# this one if we extracted just a few more helper functions...
 	too-many-nested-blocks,
-	# NOTE(nathaniel): I have disputed the premise of this inspection from
-	# the beginning and will continue to do so until it goes away for good.
+	# TODO(https://github.com/grpc/grpc/issues/261): Disable unnecessary
+	# super-init requirement for abstract class implementations for now.
+	super-init-not-called,
+	# NOTE(nathaniel): A single statement that always returns program
+	# control is better than two statements the first of which sometimes
+	# returns program control and the second of which always returns
+	# program control. Probably generally, but definitely in the cases of
+	# if:/else: and for:/else:.
 	useless-else-on-loop,
+	no-else-return,
diff --git a/.pylintrc-tests b/.pylintrc-tests
index b358b2c4a0..ebe9d507cd 100644
--- a/.pylintrc-tests
+++ b/.pylintrc-tests
@@ -103,6 +103,13 @@ disable=
 	# TODO(https://github.com/grpc/grpc/issues/261): Maybe we could have
 	# this one if we extracted just a few more helper functions...
 	too-many-nested-blocks,
-	# NOTE(nathaniel): I have disputed the premise of this inspection from
-	# the beginning and will continue to do so until it goes away for good.
+	# TODO(https://github.com/grpc/grpc/issues/261): Disable unnecessary
+	# super-init requirement for abstract class implementations for now.
+	super-init-not-called,
+	# NOTE(nathaniel): A single statement that always returns program
+	# control is better than two statements the first of which sometimes
+	# returns program control and the second of which always returns
+	# program control. Probably generally, but definitely in the cases of
+	# if:/else: and for:/else:.
 	useless-else-on-loop,
+	no-else-return,
diff --git a/BUILD b/BUILD
index db1bdaa994..ea8cf50587 100644
--- a/BUILD
+++ b/BUILD
@@ -1004,6 +1004,25 @@ grpc_cc_library(
 )
 
 grpc_cc_library(
+    name = "grpc_cfstream",
+    srcs = [
+        "src/core/lib/iomgr/cfstream_handle.cc",
+        "src/core/lib/iomgr/endpoint_cfstream.cc",
+        "src/core/lib/iomgr/error_cfstream.cc",
+        "src/core/lib/iomgr/tcp_client_cfstream.cc",
+    ],
+    hdrs = [
+        "src/core/lib/iomgr/cfstream_handle.h",
+        "src/core/lib/iomgr/endpoint_cfstream.h",
+        "src/core/lib/iomgr/error_cfstream.h",
+    ],
+    deps = [
+        ":gpr_base",
+        ":grpc_base",
+    ],
+)
+
+grpc_cc_library(
     name = "grpc_client_channel",
     srcs = [
         "src/core/ext/filters/client_channel/backup_poller.cc",
diff --git a/CMakeLists.txt b/CMakeLists.txt
index af56886cd9..ca9a1eb679 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -700,6 +700,7 @@ target_include_directories(address_sorting
 )
 
 target_link_libraries(address_sorting
+  ${_gRPC_BASELIB_LIBRARIES}
   ${_gRPC_ALLTARGETS_LIBRARIES}
 )
 
@@ -5297,6 +5298,7 @@ add_library(end2end_tests
   test/core/end2end/tests/max_message_length.cc
   test/core/end2end/tests/negative_deadline.cc
   test/core/end2end/tests/network_status_change.cc
+  test/core/end2end/tests/no_error_on_hotpath.cc
   test/core/end2end/tests/no_logging.cc
   test/core/end2end/tests/no_op.cc
   test/core/end2end/tests/payload.cc
@@ -5415,6 +5417,7 @@ add_library(end2end_nosec_tests
   test/core/end2end/tests/max_message_length.cc
   test/core/end2end/tests/negative_deadline.cc
   test/core/end2end/tests/network_status_change.cc
+  test/core/end2end/tests/no_error_on_hotpath.cc
   test/core/end2end/tests/no_logging.cc
   test/core/end2end/tests/no_op.cc
   test/core/end2end/tests/payload.cc
diff --git a/Makefile b/Makefile
index 0e54fb2683..a55fec4df5 100644
--- a/Makefile
+++ b/Makefile
@@ -501,7 +501,6 @@ endif
 
 ifeq ($(HAS_PKG_CONFIG),true)
 OPENSSL_ALPN_CHECK_CMD = $(PKG_CONFIG) --atleast-version=1.0.2 openssl
-OPENSSL_NPN_CHECK_CMD = $(PKG_CONFIG) --atleast-version=1.0.1 openssl
 ZLIB_CHECK_CMD = $(PKG_CONFIG) --exists zlib
 PROTOBUF_CHECK_CMD = $(PKG_CONFIG) --atleast-version=3.5.0 protobuf
 CARES_CHECK_CMD = $(PKG_CONFIG) --atleast-version=1.11.0 libcares
@@ -514,7 +513,6 @@ OPENSSL_LIBS = ssl crypto
 endif
 
 OPENSSL_ALPN_CHECK_CMD = $(CC) $(CPPFLAGS) $(CFLAGS) -o $(TMPOUT) test/build/openssl-alpn.c $(addprefix -l, $(OPENSSL_LIBS)) $(LDFLAGS)
-OPENSSL_NPN_CHECK_CMD = $(CC) $(CPPFLAGS) $(CFLAGS) -o $(TMPOUT) test/build/openssl-npn.c $(addprefix -l, $(OPENSSL_LIBS)) $(LDFLAGS)
 BORINGSSL_COMPILE_CHECK_CMD = $(CC) $(CPPFLAGS) -Ithird_party/boringssl/include -fvisibility=hidden -DOPENSSL_NO_ASM -D_GNU_SOURCE -DWIN32_LEAN_AND_MEAN -D_HAS_EXCEPTIONS=0 -DNOMINMAX $(CFLAGS) -Wno-sign-conversion -Wno-conversion -Wno-unused-value -Wno-unknown-pragmas -Wno-implicit-function-declaration -Wno-unused-variable -Wno-sign-compare -Wno-implicit-fallthrough $(NO_W_EXTRA_SEMI) -o $(TMPOUT) test/build/boringssl.c $(LDFLAGS)
 ZLIB_CHECK_CMD = $(CC) $(CPPFLAGS) $(CFLAGS) -o $(TMPOUT) test/build/zlib.c -lz $(LDFLAGS)
 PROTOBUF_CHECK_CMD = $(CXX) $(CPPFLAGS) $(CXXFLAGS) -o $(TMPOUT) test/build/protobuf.cc -lprotobuf $(LDFLAGS)
@@ -542,13 +540,7 @@ HAS_SYSTEM_PROTOBUF_VERIFY = $(shell $(PROTOBUF_CHECK_CMD) 2> /dev/null && echo
 ifndef REQUIRE_CUSTOM_LIBRARIES_$(CONFIG)
 HAS_SYSTEM_OPENSSL_ALPN ?= $(shell $(OPENSSL_ALPN_CHECK_CMD) 2> /dev/null && echo true || echo false)
 ifeq ($(HAS_SYSTEM_OPENSSL_ALPN),true)
-HAS_SYSTEM_OPENSSL_NPN = true
 CACHE_MK += HAS_SYSTEM_OPENSSL_ALPN = true,
-else
-HAS_SYSTEM_OPENSSL_NPN ?= $(shell $(OPENSSL_NPN_CHECK_CMD) 2> /dev/null && echo true || echo false)
-endif
-ifeq ($(HAS_SYSTEM_OPENSSL_NPN),true)
-CACHE_MK += HAS_SYSTEM_OPENSSL_NPN = true,
 endif
 HAS_SYSTEM_ZLIB ?= $(shell $(ZLIB_CHECK_CMD) 2> /dev/null && echo true || echo false)
 ifeq ($(HAS_SYSTEM_ZLIB),true)
@@ -565,7 +557,6 @@ endif
 else
 # override system libraries if the config requires a custom compiled library
 HAS_SYSTEM_OPENSSL_ALPN = false
-HAS_SYSTEM_OPENSSL_NPN = false
 HAS_SYSTEM_ZLIB = false
 HAS_SYSTEM_PROTOBUF = false
 HAS_SYSTEM_CARES = false
@@ -712,12 +703,7 @@ ifneq ($(HAS_EMBEDDED_OPENSSL_ALPN),false)
 EMBED_OPENSSL ?= $(HAS_EMBEDDED_OPENSSL_ALPN)
 NO_SECURE ?= false
 else # HAS_EMBEDDED_OPENSSL_ALPN=false
-ifeq ($(HAS_SYSTEM_OPENSSL_NPN),true)
-EMBED_OPENSSL ?= false
-NO_SECURE ?= false
-else
 NO_SECURE ?= true
-endif # HAS_SYSTEM_OPENSSL_NPN=true
 endif # HAS_EMBEDDED_OPENSSL_ALPN
 endif # HAS_SYSTEM_OPENSSL_ALPN
 
@@ -751,10 +737,10 @@ LDFLAGS := $(LDFLAGS_OPENSSL_PKG_CONFIG) $(LDFLAGS)
 else # HAS_PKG_CONFIG=false
 LIBS_SECURE = $(OPENSSL_LIBS)
 endif # HAS_PKG_CONFIG
-ifeq ($(HAS_SYSTEM_OPENSSL_NPN),true)
+ifeq ($(DISABLE_ALPN),true)
 CPPFLAGS += -DTSI_OPENSSL_ALPN_SUPPORT=0
 LIBS_SECURE = $(OPENSSL_LIBS)
-endif # HAS_SYSTEM_OPENSSL_NPN
+endif # DISABLE_ALPN
 PC_LIBS_SECURE = $(addprefix -l, $(LIBS_SECURE))
 endif # EMBED_OPENSSL
 endif # NO_SECURE
@@ -1347,7 +1333,6 @@ uri_fuzzer_test_one_entry: $(BINDIR)/$(CONFIG)/uri_fuzzer_test_one_entry
 
 run_dep_checks:
 	$(OPENSSL_ALPN_CHECK_CMD) || true
-	$(OPENSSL_NPN_CHECK_CMD) || true
 	$(ZLIB_CHECK_CMD) || true
 	$(PERFTOOLS_CHECK_CMD) || true
 	$(PROTOBUF_CHECK_CMD) || true
@@ -10006,6 +9991,7 @@ LIBEND2END_TESTS_SRC = \
     test/core/end2end/tests/max_message_length.cc \
     test/core/end2end/tests/negative_deadline.cc \
     test/core/end2end/tests/network_status_change.cc \
+    test/core/end2end/tests/no_error_on_hotpath.cc \
     test/core/end2end/tests/no_logging.cc \
     test/core/end2end/tests/no_op.cc \
     test/core/end2end/tests/payload.cc \
@@ -10122,6 +10108,7 @@ LIBEND2END_NOSEC_TESTS_SRC = \
     test/core/end2end/tests/max_message_length.cc \
     test/core/end2end/tests/negative_deadline.cc \
     test/core/end2end/tests/network_status_change.cc \
+    test/core/end2end/tests/no_error_on_hotpath.cc \
     test/core/end2end/tests/no_logging.cc \
     test/core/end2end/tests/no_op.cc \
     test/core/end2end/tests/payload.cc \
diff --git a/bazel/cc_grpc_library.bzl b/bazel/cc_grpc_library.bzl
index 5216a7a44b..3288565714 100644
--- a/bazel/cc_grpc_library.bzl
+++ b/bazel/cc_grpc_library.bzl
@@ -43,12 +43,7 @@ def cc_grpc_library(name, srcs, deps, proto_only, well_known_protos, generate_mo
   )
 
   if not proto_only:
-    if use_external:
-      # when this file is used by non-grpc projects
-      plugin = "//external:grpc_cpp_plugin"
-    else:
-      plugin = "//:grpc_cpp_plugin"
-
+    plugin = "@com_github_grpc_grpc//:grpc_cpp_plugin"
     generate_cc(
         name = codegen_grpc_target,
         srcs = [proto_target],
@@ -57,14 +52,8 @@ def cc_grpc_library(name, srcs, deps, proto_only, well_known_protos, generate_mo
         generate_mocks = generate_mocks,
         **kwargs
     )
-
-    if use_external:
-      # when this file is used by non-grpc projects
-      grpc_deps = ["//external:grpc++_codegen_proto",
-                   "//external:protobuf"]
-    else:
-      grpc_deps = ["//:grpc++_codegen_proto", "//external:protobuf"]
-
+    grpc_deps  = ["@com_github_grpc_grpc//:grpc++_codegen_proto",
+                  "//external:protobuf"]
     native.cc_library(
         name = name,
         srcs = [":" + codegen_grpc_target, ":" + codegen_target],
diff --git a/bazel/grpc_deps.bzl b/bazel/grpc_deps.bzl
index 53073941f3..162ec1f5f5 100644
--- a/bazel/grpc_deps.bzl
+++ b/bazel/grpc_deps.bzl
@@ -130,12 +130,12 @@ def grpc_deps():
     if "com_github_bazelbuild_bazeltoolchains" not in native.existing_rules():
         native.http_archive(
             name = "com_github_bazelbuild_bazeltoolchains",
-            strip_prefix = "bazel-toolchains-09c850dbb8e785ded3d23a7003e9a0168fe1fb2f",
+            strip_prefix = "bazel-toolchains-4653c01284d8a4a536f8f9bb47b7d10f94c549e7",
             urls = [
-                "https://mirror.bazel.build/github.com/bazelbuild/bazel-toolchains/archive/09c850dbb8e785ded3d23a7003e9a0168fe1fb2f.tar.gz",
-                "https://github.com/bazelbuild/bazel-toolchains/archive/09c850dbb8e785ded3d23a7003e9a0168fe1fb2f.tar.gz",
+                "https://mirror.bazel.build/github.com/bazelbuild/bazel-toolchains/archive/4653c01284d8a4a536f8f9bb47b7d10f94c549e7.tar.gz",
+                "https://github.com/bazelbuild/bazel-toolchains/archive/4653c01284d8a4a536f8f9bb47b7d10f94c549e7.tar.gz",
             ],
-            sha256 = "08e521cf2d0998e3d27a16c2e2542ebf4d3857b3ddadcfd145d128140754d7bd",
+            sha256 = "1c4a532b396c698e6467a1548554571cb85fa091e472b05e398ebc836c315d77",
         )
 
 # TODO: move some dependencies from "grpc_deps" here?
diff --git a/build.yaml b/build.yaml
index 16c90fbd4c..ff87d5965a 100644
--- a/build.yaml
+++ b/build.yaml
@@ -536,6 +536,19 @@ filegroups:
   uses:
   - grpc_codegen
   - grpc_trace_headers
+- name: grpc_cfstream
+  headers:
+  - src/core/lib/iomgr/cfstream_handle.h
+  - src/core/lib/iomgr/endpoint_cfstream.h
+  - src/core/lib/iomgr/error_cfstream.h
+  src:
+  - src/core/lib/iomgr/cfstream_handle.cc
+  - src/core/lib/iomgr/endpoint_cfstream.cc
+  - src/core/lib/iomgr/error_cfstream.cc
+  - src/core/lib/iomgr/tcp_client_cfstream.cc
+  uses:
+  - grpc_base_headers
+  - gpr_base_headers
 - name: grpc_client_authority_filter
   headers:
   - src/core/ext/filters/http/client_authority_filter.h
diff --git a/examples/ruby/pubsub/.gitignore b/examples/ruby/pubsub/.gitignore
new file mode 100644
index 0000000000..62fcb4fa94
--- /dev/null
+++ b/examples/ruby/pubsub/.gitignore
@@ -0,0 +1,15 @@
+/.bundle/
+/.yardoc
+/Gemfile.lock
+/_yardoc/
+/coverage/
+/doc/
+/pkg/
+/spec/reports/
+/tmp/
+*.bundle
+*.so
+*.o
+*.a
+mkmf.log
+vendor
diff --git a/examples/ruby/pubsub/Gemfile b/examples/ruby/pubsub/Gemfile
new file mode 100644
index 0000000000..4ee8ffe3d6
--- /dev/null
+++ b/examples/ruby/pubsub/Gemfile
@@ -0,0 +1,4 @@
+source 'https://rubygems.org/'
+
+gem 'grpc', '~> 1.0'
+gem 'googleauth', '>= 0.5.1', '< 0.7'
diff --git a/src/ruby/bin/apis/google/protobuf/empty.rb b/examples/ruby/pubsub/google/protobuf/empty.rb
index 4743bded3d..4743bded3d 100644
--- a/src/ruby/bin/apis/google/protobuf/empty.rb
+++ b/examples/ruby/pubsub/google/protobuf/empty.rb
diff --git a/src/ruby/bin/apis/pubsub_demo.rb b/examples/ruby/pubsub/pubsub_demo.rb
index c565771d45..c565771d45 100755
--- a/src/ruby/bin/apis/pubsub_demo.rb
+++ b/examples/ruby/pubsub/pubsub_demo.rb
diff --git a/src/ruby/bin/apis/tech/pubsub/proto/pubsub.rb b/examples/ruby/pubsub/tech/pubsub/proto/pubsub.rb
index 73a0d5d9e4..73a0d5d9e4 100644
--- a/src/ruby/bin/apis/tech/pubsub/proto/pubsub.rb
+++ b/examples/ruby/pubsub/tech/pubsub/proto/pubsub.rb
diff --git a/src/ruby/bin/apis/tech/pubsub/proto/pubsub_services.rb b/examples/ruby/pubsub/tech/pubsub/proto/pubsub_services.rb
index b34db57b44..b34db57b44 100644
--- a/src/ruby/bin/apis/tech/pubsub/proto/pubsub_services.rb
+++ b/examples/ruby/pubsub/tech/pubsub/proto/pubsub_services.rb
diff --git a/gRPC-Core.podspec b/gRPC-Core.podspec
index f3be7129b5..a4d62a76c6 100644
--- a/gRPC-Core.podspec
+++ b/gRPC-Core.podspec
@@ -1080,6 +1080,24 @@ Pod::Spec.new do |s|
                               'src/core/ext/filters/workarounds/workaround_utils.h'
   end
 
+  s.subspec 'CFStream-Implementation' do |ss|
+    ss.header_mappings_dir = '.'
+    ss.dependency "#{s.name}/Implementation", version
+    ss.pod_target_xcconfig = {
+      'GCC_PREPROCESSOR_DEFINITIONS' => 'GRPC_CFSTREAM=1'
+    }
+    ss.source_files = 'src/core/lib/iomgr/cfstream_handle.cc',
+                      'src/core/lib/iomgr/endpoint_cfstream.cc',
+                      'src/core/lib/iomgr/error_cfstream.cc',
+                      'src/core/lib/iomgr/tcp_client_cfstream.cc',
+                      'src/core/lib/iomgr/cfstream_handle.h',
+                      'src/core/lib/iomgr/endpoint_cfstream.h',
+                      'src/core/lib/iomgr/error_cfstream.h'
+    ss.private_header_files = 'src/core/lib/iomgr/cfstream_handle.h',
+                              'src/core/lib/iomgr/endpoint_cfstream.h',
+                              'src/core/lib/iomgr/error_cfstream.h'
+  end
+
   s.subspec 'Cronet-Interface' do |ss|
     ss.header_mappings_dir = 'include/grpc'
     ss.source_files = 'include/grpc/grpc_cronet.h'
@@ -1198,6 +1216,7 @@ Pod::Spec.new do |s|
                       'test/core/end2end/tests/max_message_length.cc',
                       'test/core/end2end/tests/negative_deadline.cc',
                       'test/core/end2end/tests/network_status_change.cc',
+                      'test/core/end2end/tests/no_error_on_hotpath.cc',
                       'test/core/end2end/tests/no_logging.cc',
                       'test/core/end2end/tests/no_op.cc',
                       'test/core/end2end/tests/payload.cc',
diff --git a/gRPC-ProtoRPC.podspec b/gRPC-ProtoRPC.podspec
index 17e650c264..039f3d412b 100644
--- a/gRPC-ProtoRPC.podspec
+++ b/gRPC-ProtoRPC.podspec
@@ -41,12 +41,25 @@ Pod::Spec.new do |s|
   s.header_dir = name
 
   src_dir = 'src/objective-c/ProtoRPC'
-  s.source_files = "#{src_dir}/*.{h,m}"
-  s.header_mappings_dir = "#{src_dir}"
 
-  s.dependency 'gRPC', version
-  s.dependency 'gRPC-RxLibrary', version
-  s.dependency 'Protobuf', '~> 3.0'
+  s.default_subspec = 'Main'
+
+  s.subspec 'Main' do |ss|
+    ss.header_mappings_dir = "#{src_dir}"
+    ss.dependency 'gRPC', version
+    ss.dependency 'gRPC-RxLibrary', version
+    ss.dependency 'Protobuf', '~> 3.0'
+
+    ss.source_files = "#{src_dir}/*.{h,m}"
+  end
+  s.subspec 'CFStream' do |ss|
+    ss.dependency 'gRPC/CFStream', version
+    ss.dependency "#{s.name}/Main", version
+    ss.pod_target_xcconfig = {
+      'GCC_PREPROCESSOR_DEFINITIONS' => 'GRPC_CFSTREAM=1'
+    }
+  end
+
   s.pod_target_xcconfig = {
     # This is needed by all pods that depend on Protobuf:
     'GCC_PREPROCESSOR_DEFINITIONS' => '$(inherited) GPB_USE_PROTOBUF_FRAMEWORK_IMPORTS=1',
diff --git a/gRPC.podspec b/gRPC.podspec
index afc4581091..a1d7720628 100644
--- a/gRPC.podspec
+++ b/gRPC.podspec
@@ -63,6 +63,16 @@ Pod::Spec.new do |s|
     ss.dependency 'gRPC-Core', version
   end
 
+  # This subspec is mutually exclusive with the `Main` subspec
+  s.subspec 'CFStream' do |ss|
+    ss.dependency 'gRPC-Core/CFStream-Implementation', version
+    ss.dependency "#{s.name}/Main", version
+
+    ss.pod_target_xcconfig = {
+      'GCC_PREPROCESSOR_DEFINITIONS' => 'GRPC_CFSTREAM=1'
+    }
+  end
+
   s.subspec 'GID' do |ss|
     ss.ios.deployment_target = '7.0'
 
diff --git a/grpc.gemspec b/grpc.gemspec
index 1e4722d635..5ab3713683 100644
--- a/grpc.gemspec
+++ b/grpc.gemspec
@@ -20,7 +20,9 @@ Gem::Specification.new do |s|
   s.files += Dir.glob('src/ruby/bin/**/*')
   s.files += Dir.glob('src/ruby/ext/**/*')
   s.files += Dir.glob('src/ruby/lib/**/*')
-  s.files += Dir.glob('src/ruby/pb/**/*')
+  s.files += Dir.glob('src/ruby/pb/**/*').reject do |f|
+    f.match(%r{^src/ruby/pb/test})
+  end
   s.files += Dir.glob('include/grpc/**/*')
   s.test_files = Dir.glob('src/ruby/spec/**/*')
   s.bindir = 'src/ruby/bin'
@@ -28,7 +30,6 @@ Gem::Specification.new do |s|
   s.platform      = Gem::Platform::RUBY
 
   s.add_dependency 'google-protobuf', '~> 3.1'
-  s.add_dependency 'googleauth',      '>= 0.5.1', '< 0.7'
   s.add_dependency 'googleapis-common-protos-types', '~> 1.0.0'
 
   s.add_development_dependency 'bundler',            '~> 1.9'
@@ -41,6 +42,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'rspec',              '~> 3.6'
   s.add_development_dependency 'rubocop',            '~> 0.49.1'
   s.add_development_dependency 'signet',             '~> 0.7.0'
+  s.add_development_dependency 'googleauth',         '>= 0.5.1', '< 0.7'
 
   s.extensions = %w(src/ruby/ext/grpc/extconf.rb)
 
diff --git a/grpc.gyp b/grpc.gyp
index 2ceae3fe36..fc4fd3c555 100644
--- a/grpc.gyp
+++ b/grpc.gyp
@@ -2630,6 +2630,7 @@
         'test/core/end2end/tests/max_message_length.cc',
         'test/core/end2end/tests/negative_deadline.cc',
         'test/core/end2end/tests/network_status_change.cc',
+        'test/core/end2end/tests/no_error_on_hotpath.cc',
         'test/core/end2end/tests/no_logging.cc',
         'test/core/end2end/tests/no_op.cc',
         'test/core/end2end/tests/payload.cc',
@@ -2720,6 +2721,7 @@
         'test/core/end2end/tests/max_message_length.cc',
         'test/core/end2end/tests/negative_deadline.cc',
         'test/core/end2end/tests/network_status_change.cc',
+        'test/core/end2end/tests/no_error_on_hotpath.cc',
         'test/core/end2end/tests/no_logging.cc',
         'test/core/end2end/tests/no_op.cc',
         'test/core/end2end/tests/payload.cc',
diff --git a/include/grpc/impl/codegen/grpc_types.h b/include/grpc/impl/codegen/grpc_types.h
index 022be5fec4..9329c61bf2 100644
--- a/include/grpc/impl/codegen/grpc_types.h
+++ b/include/grpc/impl/codegen/grpc_types.h
@@ -332,7 +332,7 @@ typedef struct {
 #define GRPC_ARG_PER_RPC_RETRY_BUFFER_SIZE "grpc.per_rpc_retry_buffer_size"
 /** Channel arg that carries the bridged objective c object for custom metrics
  * logging filter. */
-#define GRPC_ARG_MOBILE_LOG_CONFIG "grpc.mobile_log_config"
+#define GRPC_ARG_MOBILE_LOG_CONTEXT "grpc.mobile_log_context"
 /** If non-zero, client authority filter is disabled for the channel */
 #define GRPC_ARG_DISABLE_CLIENT_AUTHORITY_FILTER \
   "grpc.disable_client_authority_filter"
diff --git a/include/grpc/impl/codegen/port_platform.h b/include/grpc/impl/codegen/port_platform.h
index bf1bf3df6a..01ce5f03e9 100644
--- a/include/grpc/impl/codegen/port_platform.h
+++ b/include/grpc/impl/codegen/port_platform.h
@@ -227,7 +227,10 @@
 #define GPR_POSIX_SYNC 1
 #define GPR_POSIX_TIME 1
 #define GPR_GETPID_IN_UNISTD_H 1
+/* TODO(mxyan): Remove when CFStream becomes default */
+#ifndef GRPC_CFSTREAM
 #define GPR_SUPPORT_CHANNELS_FROM_FD 1
+#endif
 #ifdef _LP64
 #define GPR_ARCH_64 1
 #else /* _LP64 */
diff --git a/include/grpcpp/impl/codegen/call.h b/include/grpcpp/impl/codegen/call.h
index 28cc4a9e20..e324f6b14d 100644
--- a/include/grpcpp/impl/codegen/call.h
+++ b/include/grpcpp/impl/codegen/call.h
@@ -573,10 +573,13 @@ class CallOpClientRecvStatus {
       binary_error_details =
           grpc::string(iter->second.begin(), iter->second.length());
     }
-    *recv_status_ = Status(static_cast<StatusCode>(status_code_),
-                           grpc::string(GRPC_SLICE_START_PTR(error_message_),
-                                        GRPC_SLICE_END_PTR(error_message_)),
-                           binary_error_details);
+    *recv_status_ =
+        Status(static_cast<StatusCode>(status_code_),
+               GRPC_SLICE_IS_EMPTY(error_message_)
+                   ? grpc::string()
+                   : grpc::string(GRPC_SLICE_START_PTR(error_message_),
+                                  GRPC_SLICE_END_PTR(error_message_)),
+               binary_error_details);
     client_context_->set_debug_error_string(
         debug_error_string_ != nullptr ? debug_error_string_ : "");
     g_core_codegen_interface->grpc_slice_unref(error_message_);
diff --git a/setup.py b/setup.py
index 99d1a1c504..43c25aafeb 100644
--- a/setup.py
+++ b/setup.py
@@ -35,7 +35,7 @@ egg_info.manifest_maker.template = 'PYTHON-MANIFEST.in'
 PY3 = sys.version_info.major == 3
 PYTHON_STEM = os.path.join('src', 'python', 'grpcio')
 CORE_INCLUDE = ('include', '.',)
-BORINGSSL_INCLUDE = (os.path.join('third_party', 'boringssl', 'include'),)
+SSL_INCLUDE = (os.path.join('third_party', 'boringssl', 'include'),)
 ZLIB_INCLUDE = (os.path.join('third_party', 'zlib'),)
 CARES_INCLUDE = (
     os.path.join('third_party', 'cares'),
@@ -84,6 +84,24 @@ CLASSIFIERS = [
 # present, then it will still attempt to use Cython.
 BUILD_WITH_CYTHON = os.environ.get('GRPC_PYTHON_BUILD_WITH_CYTHON', False)
 
+# Export this variable to use the system installation of openssl. You need to
+# have the header files installed (in /usr/include/openssl) and during
+# runtime, the shared libary must be installed
+BUILD_WITH_SYSTEM_OPENSSL = os.environ.get('GRPC_PYTHON_BUILD_SYSTEM_OPENSSL',
+                                           False)
+
+# Export this variable to use the system installation of zlib. You need to
+# have the header files installed (in /usr/include/) and during
+# runtime, the shared libary must be installed
+BUILD_WITH_SYSTEM_ZLIB = os.environ.get('GRPC_PYTHON_BUILD_SYSTEM_ZLIB',
+                                        False)
+
+# Export this variable to use the system installation of cares. You need to
+# have the header files installed (in /usr/include/) and during
+# runtime, the shared libary must be installed
+BUILD_WITH_SYSTEM_CARES = os.environ.get('GRPC_PYTHON_BUILD_SYSTEM_CARES',
+                                         False)
+
 # Environment variable to determine whether or not to enable coverage analysis
 # in Cython modules.
 ENABLE_CYTHON_TRACING = os.environ.get(
@@ -148,8 +166,21 @@ CORE_C_FILES = tuple(grpc_core_dependencies.CORE_SOURCE_FILES)
 if "win32" in sys.platform:
   CORE_C_FILES = filter(lambda x: 'third_party/cares' not in x, CORE_C_FILES)
 
+if BUILD_WITH_SYSTEM_OPENSSL:
+  CORE_C_FILES = filter(lambda x: 'third_party/boringssl' not in x, CORE_C_FILES)
+  CORE_C_FILES = filter(lambda x: 'src/boringssl' not in x, CORE_C_FILES)
+  SSL_INCLUDE = (os.path.join('/usr', 'include', 'openssl'),)
+
+if BUILD_WITH_SYSTEM_ZLIB:
+  CORE_C_FILES = filter(lambda x: 'third_party/zlib' not in x, CORE_C_FILES)
+  ZLIB_INCLUDE = (os.path.join('/usr', 'include'),)
+
+if BUILD_WITH_SYSTEM_CARES:
+  CORE_C_FILES = filter(lambda x: 'third_party/cares' not in x, CORE_C_FILES)
+  CARES_INCLUDE = (os.path.join('/usr', 'include'),)
+
 EXTENSION_INCLUDE_DIRECTORIES = (
-    (PYTHON_STEM,) + CORE_INCLUDE + BORINGSSL_INCLUDE + ZLIB_INCLUDE +
+    (PYTHON_STEM,) + CORE_INCLUDE + SSL_INCLUDE + ZLIB_INCLUDE +
     CARES_INCLUDE + ADDRESS_SORTING_INCLUDE)
 
 EXTENSION_LIBRARIES = ()
@@ -159,6 +190,12 @@ if not "win32" in sys.platform:
   EXTENSION_LIBRARIES += ('m',)
 if "win32" in sys.platform:
   EXTENSION_LIBRARIES += ('advapi32', 'ws2_32',)
+if BUILD_WITH_SYSTEM_OPENSSL:
+  EXTENSION_LIBRARIES += ('ssl', 'crypto',)
+if BUILD_WITH_SYSTEM_ZLIB:
+  EXTENSION_LIBRARIES += ('z',)
+if BUILD_WITH_SYSTEM_CARES:
+  EXTENSION_LIBRARIES += ('cares',)
 
 DEFINE_MACROS = (
     ('OPENSSL_NO_ASM', 1), ('_WIN32_WINNT', 0x600),
diff --git a/src/compiler/csharp_generator.cc b/src/compiler/csharp_generator.cc
index 6e2730579a..1c51f6da94 100644
--- a/src/compiler/csharp_generator.cc
+++ b/src/compiler/csharp_generator.cc
@@ -590,19 +590,16 @@ void GenerateBindServiceMethod(Printer* out, const ServiceDescriptor* service) {
   out->Print("{\n");
   out->Indent();
 
-  out->Print("return grpc::ServerServiceDefinition.CreateBuilder()\n");
+  out->Print("return grpc::ServerServiceDefinition.CreateBuilder()");
   out->Indent();
   out->Indent();
   for (int i = 0; i < service->method_count(); i++) {
     const MethodDescriptor* method = service->method(i);
-    out->Print(".AddMethod($methodfield$, serviceImpl.$methodname$)",
+    out->Print("\n.AddMethod($methodfield$, serviceImpl.$methodname$)",
                "methodfield", GetMethodFieldName(method), "methodname",
                method->name());
-    if (i == service->method_count() - 1) {
-      out->Print(".Build();");
-    }
-    out->Print("\n");
   }
+  out->Print(".Build();\n");
   out->Outdent();
   out->Outdent();
 
@@ -676,20 +673,26 @@ grpc::string GetServices(const FileDescriptor* file, bool generate_client,
       out.PrintRaw(leading_comments.c_str());
     }
 
-    out.Print("#pragma warning disable 1591\n");
+    out.Print("#pragma warning disable 0414, 1591\n");
+
     out.Print("#region Designer generated code\n");
     out.Print("\n");
     out.Print("using grpc = global::Grpc.Core;\n");
     out.Print("\n");
 
-    out.Print("namespace $namespace$ {\n", "namespace", GetFileNamespace(file));
-    out.Indent();
+    grpc::string file_namespace = GetFileNamespace(file);
+    if (file_namespace != "") {
+      out.Print("namespace $namespace$ {\n", "namespace", file_namespace);
+      out.Indent();
+    }
     for (int i = 0; i < file->service_count(); i++) {
       GenerateService(&out, file->service(i), generate_client, generate_server,
                       internal_access);
     }
-    out.Outdent();
-    out.Print("}\n");
+    if (file_namespace != "") {
+      out.Outdent();
+      out.Print("}\n");
+    }
     out.Print("#endregion\n");
   }
   return output;
diff --git a/src/core/ext/filters/client_channel/client_channel.cc b/src/core/ext/filters/client_channel/client_channel.cc
index 936d70b959..ea6775a8d8 100644
--- a/src/core/ext/filters/client_channel/client_channel.cc
+++ b/src/core/ext/filters/client_channel/client_channel.cc
@@ -891,6 +891,7 @@ typedef struct client_channel_call_data {
   grpc_closure pick_cancel_closure;
 
   grpc_polling_entity* pollent;
+  bool pollent_added_to_interested_parties;
 
   // Batches are added to this list when received from above.
   // They are removed when we are done handling the batch (i.e., when
@@ -949,7 +950,6 @@ static void retry_commit(grpc_call_element* elem,
 static void start_internal_recv_trailing_metadata(grpc_call_element* elem);
 static void on_complete(void* arg, grpc_error* error);
 static void start_retriable_subchannel_batches(void* arg, grpc_error* ignored);
-static void pick_after_resolver_result_start_locked(grpc_call_element* elem);
 static void start_pick_locked(void* arg, grpc_error* ignored);
 
 //
@@ -2684,59 +2684,133 @@ static void pick_done(void* arg, grpc_error* error) {
   }
 }
 
+static void maybe_add_call_to_channel_interested_parties_locked(
+    grpc_call_element* elem) {
+  channel_data* chand = static_cast<channel_data*>(elem->channel_data);
+  call_data* calld = static_cast<call_data*>(elem->call_data);
+  if (!calld->pollent_added_to_interested_parties) {
+    calld->pollent_added_to_interested_parties = true;
+    grpc_polling_entity_add_to_pollset_set(calld->pollent,
+                                           chand->interested_parties);
+  }
+}
+
+static void maybe_del_call_from_channel_interested_parties_locked(
+    grpc_call_element* elem) {
+  channel_data* chand = static_cast<channel_data*>(elem->channel_data);
+  call_data* calld = static_cast<call_data*>(elem->call_data);
+  if (calld->pollent_added_to_interested_parties) {
+    calld->pollent_added_to_interested_parties = false;
+    grpc_polling_entity_del_from_pollset_set(calld->pollent,
+                                             chand->interested_parties);
+  }
+}
+
 // Invoked when a pick is completed to leave the client_channel combiner
 // and continue processing in the call combiner.
+// If needed, removes the call's polling entity from chand->interested_parties.
 static void pick_done_locked(grpc_call_element* elem, grpc_error* error) {
   call_data* calld = static_cast<call_data*>(elem->call_data);
+  maybe_del_call_from_channel_interested_parties_locked(elem);
   GRPC_CLOSURE_INIT(&calld->pick_closure, pick_done, elem,
                     grpc_schedule_on_exec_ctx);
   GRPC_CLOSURE_SCHED(&calld->pick_closure, error);
 }
 
-// A wrapper around pick_done_locked() that is used in cases where
-// either (a) the pick was deferred pending a resolver result or (b) the
-// pick was done asynchronously.  Removes the call's polling entity from
-// chand->interested_parties before invoking pick_done_locked().
-static void async_pick_done_locked(grpc_call_element* elem, grpc_error* error) {
-  channel_data* chand = static_cast<channel_data*>(elem->channel_data);
-  call_data* calld = static_cast<call_data*>(elem->call_data);
-  grpc_polling_entity_del_from_pollset_set(calld->pollent,
-                                           chand->interested_parties);
-  pick_done_locked(elem, error);
-}
+namespace grpc_core {
 
-// Note: This runs under the client_channel combiner, but will NOT be
-// holding the call combiner.
-static void pick_callback_cancel_locked(void* arg, grpc_error* error) {
-  grpc_call_element* elem = static_cast<grpc_call_element*>(arg);
-  channel_data* chand = static_cast<channel_data*>(elem->channel_data);
-  call_data* calld = static_cast<call_data*>(elem->call_data);
-  // Note: chand->lb_policy may have changed since we started our pick,
-  // in which case we will be cancelling the pick on a policy other than
-  // the one we started it on.  However, this will just be a no-op.
-  if (GPR_LIKELY(error != GRPC_ERROR_NONE && chand->lb_policy != nullptr)) {
+// Performs subchannel pick via LB policy.
+class LbPicker {
+ public:
+  // Starts a pick on chand->lb_policy.
+  static void StartLocked(grpc_call_element* elem) {
+    channel_data* chand = static_cast<channel_data*>(elem->channel_data);
+    call_data* calld = static_cast<call_data*>(elem->call_data);
     if (grpc_client_channel_trace.enabled()) {
-      gpr_log(GPR_INFO, "chand=%p calld=%p: cancelling pick from LB policy %p",
+      gpr_log(GPR_INFO, "chand=%p calld=%p: starting pick on lb_policy=%p",
               chand, calld, chand->lb_policy.get());
     }
-    chand->lb_policy->CancelPickLocked(&calld->pick, GRPC_ERROR_REF(error));
+    // If this is a retry, use the send_initial_metadata payload that
+    // we've cached; otherwise, use the pending batch.  The
+    // send_initial_metadata batch will be the first pending batch in the
+    // list, as set by get_batch_index() above.
+    calld->pick.initial_metadata =
+        calld->seen_send_initial_metadata
+            ? &calld->send_initial_metadata
+            : calld->pending_batches[0]
+                  .batch->payload->send_initial_metadata.send_initial_metadata;
+    calld->pick.initial_metadata_flags =
+        calld->seen_send_initial_metadata
+            ? calld->send_initial_metadata_flags
+            : calld->pending_batches[0]
+                  .batch->payload->send_initial_metadata
+                  .send_initial_metadata_flags;
+    GRPC_CLOSURE_INIT(&calld->pick_closure, &LbPicker::DoneLocked, elem,
+                      grpc_combiner_scheduler(chand->combiner));
+    calld->pick.on_complete = &calld->pick_closure;
+    GRPC_CALL_STACK_REF(calld->owning_call, "pick_callback");
+    const bool pick_done = chand->lb_policy->PickLocked(&calld->pick);
+    if (GPR_LIKELY(pick_done)) {
+      // Pick completed synchronously.
+      if (grpc_client_channel_trace.enabled()) {
+        gpr_log(GPR_INFO, "chand=%p calld=%p: pick completed synchronously",
+                chand, calld);
+      }
+      pick_done_locked(elem, GRPC_ERROR_NONE);
+      GRPC_CALL_STACK_UNREF(calld->owning_call, "pick_callback");
+    } else {
+      // Pick will be returned asynchronously.
+      // Add the polling entity from call_data to the channel_data's
+      // interested_parties, so that the I/O of the LB policy can be done
+      // under it.  It will be removed in pick_done_locked().
+      maybe_add_call_to_channel_interested_parties_locked(elem);
+      // Request notification on call cancellation.
+      GRPC_CALL_STACK_REF(calld->owning_call, "pick_callback_cancel");
+      grpc_call_combiner_set_notify_on_cancel(
+          calld->call_combiner,
+          GRPC_CLOSURE_INIT(&calld->pick_cancel_closure,
+                            &LbPicker::CancelLocked, elem,
+                            grpc_combiner_scheduler(chand->combiner)));
+    }
   }
-  GRPC_CALL_STACK_UNREF(calld->owning_call, "pick_callback_cancel");
-}
 
-// Callback invoked by LoadBalancingPolicy::PickLocked() for async picks.
-// Unrefs the LB policy and invokes async_pick_done_locked().
-static void pick_callback_done_locked(void* arg, grpc_error* error) {
-  grpc_call_element* elem = static_cast<grpc_call_element*>(arg);
-  channel_data* chand = static_cast<channel_data*>(elem->channel_data);
-  call_data* calld = static_cast<call_data*>(elem->call_data);
-  if (grpc_client_channel_trace.enabled()) {
-    gpr_log(GPR_INFO, "chand=%p calld=%p: pick completed asynchronously", chand,
-            calld);
+ private:
+  // Callback invoked by LoadBalancingPolicy::PickLocked() for async picks.
+  // Unrefs the LB policy and invokes pick_done_locked().
+  static void DoneLocked(void* arg, grpc_error* error) {
+    grpc_call_element* elem = static_cast<grpc_call_element*>(arg);
+    channel_data* chand = static_cast<channel_data*>(elem->channel_data);
+    call_data* calld = static_cast<call_data*>(elem->call_data);
+    if (grpc_client_channel_trace.enabled()) {
+      gpr_log(GPR_INFO, "chand=%p calld=%p: pick completed asynchronously",
+              chand, calld);
+    }
+    pick_done_locked(elem, GRPC_ERROR_REF(error));
+    GRPC_CALL_STACK_UNREF(calld->owning_call, "pick_callback");
   }
-  async_pick_done_locked(elem, GRPC_ERROR_REF(error));
-  GRPC_CALL_STACK_UNREF(calld->owning_call, "pick_callback");
-}
+
+  // Note: This runs under the client_channel combiner, but will NOT be
+  // holding the call combiner.
+  static void CancelLocked(void* arg, grpc_error* error) {
+    grpc_call_element* elem = static_cast<grpc_call_element*>(arg);
+    channel_data* chand = static_cast<channel_data*>(elem->channel_data);
+    call_data* calld = static_cast<call_data*>(elem->call_data);
+    // Note: chand->lb_policy may have changed since we started our pick,
+    // in which case we will be cancelling the pick on a policy other than
+    // the one we started it on.  However, this will just be a no-op.
+    if (GPR_UNLIKELY(error != GRPC_ERROR_NONE && chand->lb_policy != nullptr)) {
+      if (grpc_client_channel_trace.enabled()) {
+        gpr_log(GPR_INFO,
+                "chand=%p calld=%p: cancelling pick from LB policy %p", chand,
+                calld, chand->lb_policy.get());
+      }
+      chand->lb_policy->CancelPickLocked(&calld->pick, GRPC_ERROR_REF(error));
+    }
+    GRPC_CALL_STACK_UNREF(calld->owning_call, "pick_callback_cancel");
+  }
+};
+
+}  // namespace grpc_core
 
 // Applies service config to the call.  Must be invoked once we know
 // that the resolver has returned results to the channel.
@@ -2766,6 +2840,24 @@ static void apply_service_config_to_call_locked(grpc_call_element* elem) {
           grpc_deadline_state_reset(elem, calld->deadline);
         }
       }
+      // If the service config set wait_for_ready and the application
+      // did not explicitly set it, use the value from the service config.
+      uint32_t* send_initial_metadata_flags =
+          &calld->pending_batches[0]
+               .batch->payload->send_initial_metadata
+               .send_initial_metadata_flags;
+      if (GPR_UNLIKELY(
+              calld->method_params->wait_for_ready() !=
+                  ClientChannelMethodParams::WAIT_FOR_READY_UNSET &&
+              !(*send_initial_metadata_flags &
+                GRPC_INITIAL_METADATA_WAIT_FOR_READY_EXPLICITLY_SET))) {
+        if (calld->method_params->wait_for_ready() ==
+            ClientChannelMethodParams::WAIT_FOR_READY_TRUE) {
+          *send_initial_metadata_flags |= GRPC_INITIAL_METADATA_WAIT_FOR_READY;
+        } else {
+          *send_initial_metadata_flags &= ~GRPC_INITIAL_METADATA_WAIT_FOR_READY;
+        }
+      }
     }
   }
   // If no retry policy, disable retries.
@@ -2776,215 +2868,164 @@ static void apply_service_config_to_call_locked(grpc_call_element* elem) {
   }
 }
 
-// Starts a pick on chand->lb_policy.
-// Returns true if pick is completed synchronously.
-static bool pick_callback_start_locked(grpc_call_element* elem) {
-  channel_data* chand = static_cast<channel_data*>(elem->channel_data);
+// Invoked once resolver results are available.
+static void process_service_config_and_start_lb_pick_locked(
+    grpc_call_element* elem) {
   call_data* calld = static_cast<call_data*>(elem->call_data);
-  if (grpc_client_channel_trace.enabled()) {
-    gpr_log(GPR_INFO, "chand=%p calld=%p: starting pick on lb_policy=%p", chand,
-            calld, chand->lb_policy.get());
-  }
   // Only get service config data on the first attempt.
   if (GPR_LIKELY(calld->num_attempts_completed == 0)) {
     apply_service_config_to_call_locked(elem);
   }
-  // If the application explicitly set wait_for_ready, use that.
-  // Otherwise, if the service config specified a value for this
-  // method, use that.
-  //
-  // The send_initial_metadata batch will be the first one in the list,
-  // as set by get_batch_index() above.
-  calld->pick.initial_metadata =
-      calld->seen_send_initial_metadata
-          ? &calld->send_initial_metadata
-          : calld->pending_batches[0]
-                .batch->payload->send_initial_metadata.send_initial_metadata;
-  uint32_t send_initial_metadata_flags =
-      calld->seen_send_initial_metadata
-          ? calld->send_initial_metadata_flags
-          : calld->pending_batches[0]
-                .batch->payload->send_initial_metadata
-                .send_initial_metadata_flags;
-  const bool wait_for_ready_set_from_api =
-      send_initial_metadata_flags &
-      GRPC_INITIAL_METADATA_WAIT_FOR_READY_EXPLICITLY_SET;
-  const bool wait_for_ready_set_from_service_config =
-      calld->method_params != nullptr &&
-      calld->method_params->wait_for_ready() !=
-          ClientChannelMethodParams::WAIT_FOR_READY_UNSET;
-  if (GPR_UNLIKELY(!wait_for_ready_set_from_api &&
-                   wait_for_ready_set_from_service_config)) {
-    if (calld->method_params->wait_for_ready() ==
-        ClientChannelMethodParams::WAIT_FOR_READY_TRUE) {
-      send_initial_metadata_flags |= GRPC_INITIAL_METADATA_WAIT_FOR_READY;
-    } else {
-      send_initial_metadata_flags &= ~GRPC_INITIAL_METADATA_WAIT_FOR_READY;
-    }
-  }
-  calld->pick.initial_metadata_flags = send_initial_metadata_flags;
-  GRPC_CLOSURE_INIT(&calld->pick_closure, pick_callback_done_locked, elem,
-                    grpc_combiner_scheduler(chand->combiner));
-  calld->pick.on_complete = &calld->pick_closure;
-  GRPC_CALL_STACK_REF(calld->owning_call, "pick_callback");
-  const bool pick_done = chand->lb_policy->PickLocked(&calld->pick);
-  if (GPR_LIKELY(pick_done)) {
-    // Pick completed synchronously.
-    if (grpc_client_channel_trace.enabled()) {
-      gpr_log(GPR_INFO, "chand=%p calld=%p: pick completed synchronously",
-              chand, calld);
-    }
-    GRPC_CALL_STACK_UNREF(calld->owning_call, "pick_callback");
-  } else {
-    GRPC_CALL_STACK_REF(calld->owning_call, "pick_callback_cancel");
-    grpc_call_combiner_set_notify_on_cancel(
-        calld->call_combiner,
-        GRPC_CLOSURE_INIT(&calld->pick_cancel_closure,
-                          pick_callback_cancel_locked, elem,
-                          grpc_combiner_scheduler(chand->combiner)));
-  }
-  return pick_done;
+  // Start LB pick.
+  grpc_core::LbPicker::StartLocked(elem);
 }
 
-typedef struct {
-  grpc_call_element* elem;
-  bool finished;
-  grpc_closure closure;
-  grpc_closure cancel_closure;
-} pick_after_resolver_result_args;
-
-// Note: This runs under the client_channel combiner, but will NOT be
-// holding the call combiner.
-static void pick_after_resolver_result_cancel_locked(void* arg,
-                                                     grpc_error* error) {
-  pick_after_resolver_result_args* args =
-      static_cast<pick_after_resolver_result_args*>(arg);
-  if (GPR_LIKELY(args->finished)) {
-    gpr_free(args);
-    return;
-  }
-  // If we don't yet have a resolver result, then a closure for
-  // pick_after_resolver_result_done_locked() will have been added to
-  // chand->waiting_for_resolver_result_closures, and it may not be invoked
-  // until after this call has been destroyed.  We mark the operation as
-  // finished, so that when pick_after_resolver_result_done_locked()
-  // is called, it will be a no-op.  We also immediately invoke
-  // async_pick_done_locked() to propagate the error back to the caller.
-  args->finished = true;
-  grpc_call_element* elem = args->elem;
-  channel_data* chand = static_cast<channel_data*>(elem->channel_data);
-  call_data* calld = static_cast<call_data*>(elem->call_data);
-  if (grpc_client_channel_trace.enabled()) {
-    gpr_log(GPR_INFO,
-            "chand=%p calld=%p: cancelling pick waiting for resolver result",
-            chand, calld);
-  }
-  // Note: Although we are not in the call combiner here, we are
-  // basically stealing the call combiner from the pending pick, so
-  // it's safe to call async_pick_done_locked() here -- we are
-  // essentially calling it here instead of calling it in
-  // pick_after_resolver_result_done_locked().
-  async_pick_done_locked(elem, GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
-                                   "Pick cancelled", &error, 1));
-}
-
-static void pick_after_resolver_result_done_locked(void* arg,
-                                                   grpc_error* error) {
-  pick_after_resolver_result_args* args =
-      static_cast<pick_after_resolver_result_args*>(arg);
-  if (GPR_UNLIKELY(args->finished)) {
-    /* cancelled, do nothing */
-    if (grpc_client_channel_trace.enabled()) {
-      gpr_log(GPR_INFO, "call cancelled before resolver result");
-    }
-    gpr_free(args);
-    return;
-  }
-  args->finished = true;
-  grpc_call_element* elem = args->elem;
-  channel_data* chand = static_cast<channel_data*>(elem->channel_data);
-  call_data* calld = static_cast<call_data*>(elem->call_data);
-  if (GPR_UNLIKELY(error != GRPC_ERROR_NONE)) {
+namespace grpc_core {
+
+// Handles waiting for a resolver result.
+// Used only for the first call on an idle channel.
+class ResolverResultWaiter {
+ public:
+  explicit ResolverResultWaiter(grpc_call_element* elem) : elem_(elem) {
+    channel_data* chand = static_cast<channel_data*>(elem->channel_data);
+    call_data* calld = static_cast<call_data*>(elem->call_data);
     if (grpc_client_channel_trace.enabled()) {
-      gpr_log(GPR_INFO, "chand=%p calld=%p: resolver failed to return data",
+      gpr_log(GPR_INFO,
+              "chand=%p calld=%p: deferring pick pending resolver result",
               chand, calld);
     }
-    async_pick_done_locked(elem, GRPC_ERROR_REF(error));
-  } else if (GPR_UNLIKELY(chand->resolver == nullptr)) {
-    // Shutting down.
-    if (grpc_client_channel_trace.enabled()) {
-      gpr_log(GPR_INFO, "chand=%p calld=%p: resolver disconnected", chand,
-              calld);
+    // Add closure to be run when a resolver result is available.
+    GRPC_CLOSURE_INIT(&done_closure_, &ResolverResultWaiter::DoneLocked, this,
+                      grpc_combiner_scheduler(chand->combiner));
+    AddToWaitingList();
+    // Set cancellation closure, so that we abort if the call is cancelled.
+    GRPC_CLOSURE_INIT(&cancel_closure_, &ResolverResultWaiter::CancelLocked,
+                      this, grpc_combiner_scheduler(chand->combiner));
+    grpc_call_combiner_set_notify_on_cancel(calld->call_combiner,
+                                            &cancel_closure_);
+  }
+
+ private:
+  // Adds closure_ to chand->waiting_for_resolver_result_closures.
+  void AddToWaitingList() {
+    channel_data* chand = static_cast<channel_data*>(elem_->channel_data);
+    grpc_closure_list_append(&chand->waiting_for_resolver_result_closures,
+                             &done_closure_, GRPC_ERROR_NONE);
+  }
+
+  // Invoked when a resolver result is available.
+  static void DoneLocked(void* arg, grpc_error* error) {
+    ResolverResultWaiter* self = static_cast<ResolverResultWaiter*>(arg);
+    // If CancelLocked() has already run, delete ourselves without doing
+    // anything.  Note that the call stack may have already been destroyed,
+    // so it's not safe to access anything in elem_.
+    if (GPR_UNLIKELY(self->finished_)) {
+      if (grpc_client_channel_trace.enabled()) {
+        gpr_log(GPR_INFO, "call cancelled before resolver result");
+      }
+      Delete(self);
+      return;
     }
-    async_pick_done_locked(
-        elem, GRPC_ERROR_CREATE_FROM_STATIC_STRING("Disconnected"));
-  } else if (GPR_UNLIKELY(chand->lb_policy == nullptr)) {
-    // Transient resolver failure.
-    // If call has wait_for_ready=true, try again; otherwise, fail.
-    uint32_t send_initial_metadata_flags =
-        calld->seen_send_initial_metadata
-            ? calld->send_initial_metadata_flags
-            : calld->pending_batches[0]
-                  .batch->payload->send_initial_metadata
-                  .send_initial_metadata_flags;
-    if (send_initial_metadata_flags & GRPC_INITIAL_METADATA_WAIT_FOR_READY) {
+    // Otherwise, process the resolver result.
+    grpc_call_element* elem = self->elem_;
+    channel_data* chand = static_cast<channel_data*>(elem->channel_data);
+    call_data* calld = static_cast<call_data*>(elem->call_data);
+    if (GPR_UNLIKELY(error != GRPC_ERROR_NONE)) {
       if (grpc_client_channel_trace.enabled()) {
-        gpr_log(GPR_INFO,
-                "chand=%p calld=%p: resolver returned but no LB policy; "
-                "wait_for_ready=true; trying again",
+        gpr_log(GPR_INFO, "chand=%p calld=%p: resolver failed to return data",
                 chand, calld);
       }
-      pick_after_resolver_result_start_locked(elem);
+      pick_done_locked(elem, GRPC_ERROR_REF(error));
+    } else if (GPR_UNLIKELY(chand->resolver == nullptr)) {
+      // Shutting down.
+      if (grpc_client_channel_trace.enabled()) {
+        gpr_log(GPR_INFO, "chand=%p calld=%p: resolver disconnected", chand,
+                calld);
+      }
+      pick_done_locked(elem,
+                       GRPC_ERROR_CREATE_FROM_STATIC_STRING("Disconnected"));
+    } else if (GPR_UNLIKELY(chand->lb_policy == nullptr)) {
+      // Transient resolver failure.
+      // If call has wait_for_ready=true, try again; otherwise, fail.
+      uint32_t send_initial_metadata_flags =
+          calld->seen_send_initial_metadata
+              ? calld->send_initial_metadata_flags
+              : calld->pending_batches[0]
+                    .batch->payload->send_initial_metadata
+                    .send_initial_metadata_flags;
+      if (send_initial_metadata_flags & GRPC_INITIAL_METADATA_WAIT_FOR_READY) {
+        if (grpc_client_channel_trace.enabled()) {
+          gpr_log(GPR_INFO,
+                  "chand=%p calld=%p: resolver returned but no LB policy; "
+                  "wait_for_ready=true; trying again",
+                  chand, calld);
+        }
+        // Re-add ourselves to the waiting list.
+        self->AddToWaitingList();
+        // Return early so that we don't set finished_ to true below.
+        return;
+      } else {
+        if (grpc_client_channel_trace.enabled()) {
+          gpr_log(GPR_INFO,
+                  "chand=%p calld=%p: resolver returned but no LB policy; "
+                  "wait_for_ready=false; failing",
+                  chand, calld);
+        }
+        pick_done_locked(
+            elem,
+            grpc_error_set_int(
+                GRPC_ERROR_CREATE_FROM_STATIC_STRING("Name resolution failure"),
+                GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAVAILABLE));
+      }
     } else {
       if (grpc_client_channel_trace.enabled()) {
-        gpr_log(GPR_INFO,
-                "chand=%p calld=%p: resolver returned but no LB policy; "
-                "wait_for_ready=false; failing",
+        gpr_log(GPR_INFO, "chand=%p calld=%p: resolver returned, doing LB pick",
                 chand, calld);
       }
-      async_pick_done_locked(
-          elem,
-          grpc_error_set_int(
-              GRPC_ERROR_CREATE_FROM_STATIC_STRING("Name resolution failure"),
-              GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAVAILABLE));
+      process_service_config_and_start_lb_pick_locked(elem);
     }
-  } else {
-    if (grpc_client_channel_trace.enabled()) {
-      gpr_log(GPR_INFO, "chand=%p calld=%p: resolver returned, doing pick",
-              chand, calld);
+    self->finished_ = true;
+  }
+
+  // Invoked when the call is cancelled.
+  // Note: This runs under the client_channel combiner, but will NOT be
+  // holding the call combiner.
+  static void CancelLocked(void* arg, grpc_error* error) {
+    ResolverResultWaiter* self = static_cast<ResolverResultWaiter*>(arg);
+    // If DoneLocked() has already run, delete ourselves without doing anything.
+    if (GPR_LIKELY(self->finished_)) {
+      Delete(self);
+      return;
     }
-    if (GPR_LIKELY(pick_callback_start_locked(elem))) {
-      // Even if the LB policy returns a result synchronously, we have
-      // already added our polling entity to chand->interested_parties
-      // in order to wait for the resolver result, so we need to
-      // remove it here.  Therefore, we call async_pick_done_locked()
-      // instead of pick_done_locked().
-      async_pick_done_locked(elem, GRPC_ERROR_NONE);
+    // If we are being cancelled, immediately invoke pick_done_locked()
+    // to propagate the error back to the caller.
+    if (GPR_UNLIKELY(error != GRPC_ERROR_NONE)) {
+      grpc_call_element* elem = self->elem_;
+      channel_data* chand = static_cast<channel_data*>(elem->channel_data);
+      call_data* calld = static_cast<call_data*>(elem->call_data);
+      if (grpc_client_channel_trace.enabled()) {
+        gpr_log(GPR_INFO,
+                "chand=%p calld=%p: cancelling call waiting for name "
+                "resolution",
+                chand, calld);
+      }
+      // Note: Although we are not in the call combiner here, we are
+      // basically stealing the call combiner from the pending pick, so
+      // it's safe to call pick_done_locked() here -- we are essentially
+      // calling it here instead of calling it in DoneLocked().
+      pick_done_locked(elem, GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+                                 "Pick cancelled", &error, 1));
     }
+    self->finished_ = true;
   }
-}
 
-static void pick_after_resolver_result_start_locked(grpc_call_element* elem) {
-  channel_data* chand = static_cast<channel_data*>(elem->channel_data);
-  call_data* calld = static_cast<call_data*>(elem->call_data);
-  if (grpc_client_channel_trace.enabled()) {
-    gpr_log(GPR_INFO,
-            "chand=%p calld=%p: deferring pick pending resolver result", chand,
-            calld);
-  }
-  pick_after_resolver_result_args* args =
-      static_cast<pick_after_resolver_result_args*>(gpr_zalloc(sizeof(*args)));
-  args->elem = elem;
-  GRPC_CLOSURE_INIT(&args->closure, pick_after_resolver_result_done_locked,
-                    args, grpc_combiner_scheduler(chand->combiner));
-  grpc_closure_list_append(&chand->waiting_for_resolver_result_closures,
-                           &args->closure, GRPC_ERROR_NONE);
-  grpc_call_combiner_set_notify_on_cancel(
-      calld->call_combiner,
-      GRPC_CLOSURE_INIT(&args->cancel_closure,
-                        pick_after_resolver_result_cancel_locked, args,
-                        grpc_combiner_scheduler(chand->combiner)));
-}
+  grpc_call_element* elem_;
+  grpc_closure done_closure_;
+  grpc_closure cancel_closure_;
+  bool finished_ = false;
+};
+
+}  // namespace grpc_core
 
 static void start_pick_locked(void* arg, grpc_error* ignored) {
   grpc_call_element* elem = static_cast<grpc_call_element*>(arg);
@@ -2993,31 +3034,24 @@ static void start_pick_locked(void* arg, grpc_error* ignored) {
   GPR_ASSERT(calld->pick.connected_subchannel == nullptr);
   GPR_ASSERT(calld->subchannel_call == nullptr);
   if (GPR_LIKELY(chand->lb_policy != nullptr)) {
-    // We already have an LB policy, so ask it for a pick.
-    if (GPR_LIKELY(pick_callback_start_locked(elem))) {
-      // Pick completed synchronously.
-      pick_done_locked(elem, GRPC_ERROR_NONE);
-      return;
-    }
+    // We already have resolver results, so process the service config
+    // and start an LB pick.
+    process_service_config_and_start_lb_pick_locked(elem);
+  } else if (GPR_UNLIKELY(chand->resolver == nullptr)) {
+    pick_done_locked(elem,
+                     GRPC_ERROR_CREATE_FROM_STATIC_STRING("Disconnected"));
   } else {
     // We do not yet have an LB policy, so wait for a resolver result.
-    if (GPR_UNLIKELY(chand->resolver == nullptr)) {
-      pick_done_locked(elem,
-                       GRPC_ERROR_CREATE_FROM_STATIC_STRING("Disconnected"));
-      return;
-    }
     if (GPR_UNLIKELY(!chand->started_resolving)) {
       start_resolving_locked(chand);
     }
-    pick_after_resolver_result_start_locked(elem);
+    // Create a new waiter, which will delete itself when done.
+    grpc_core::New<grpc_core::ResolverResultWaiter>(elem);
+    // Add the polling entity from call_data to the channel_data's
+    // interested_parties, so that the I/O of the resolver can be done
+    // under it.  It will be removed in pick_done_locked().
+    maybe_add_call_to_channel_interested_parties_locked(elem);
   }
-  // We need to wait for either a resolver result or for an async result
-  // from the LB policy.  Add the polling entity from call_data to the
-  // channel_data's interested_parties, so that the I/O of the LB policy
-  // and resolver can be done under it.  The polling entity will be
-  // removed in async_pick_done_locked().
-  grpc_polling_entity_add_to_pollset_set(calld->pollent,
-                                         chand->interested_parties);
 }
 
 //
diff --git a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc
index 73d2af6e42..00a84302ed 100644
--- a/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc
+++ b/src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.cc
@@ -18,7 +18,7 @@
 #include <grpc/support/port_platform.h>
 
 #include "src/core/lib/iomgr/port.h"
-#if GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET)
+#if GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_ARES_EV_DRIVER)
 
 #include <ares.h>
 #include <sys/ioctl.h>
@@ -348,4 +348,4 @@ void grpc_ares_ev_driver_start(grpc_ares_ev_driver* ev_driver) {
   gpr_mu_unlock(&ev_driver->mu);
 }
 
-#endif /* GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET) */
+#endif /* GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET_ARES_EV_DRIVER) */
diff --git a/src/core/ext/transport/chttp2/transport/chttp2_transport.cc b/src/core/ext/transport/chttp2/transport/chttp2_transport.cc
index cc4a823798..a8090d18a6 100644
--- a/src/core/ext/transport/chttp2/transport/chttp2_transport.cc
+++ b/src/core/ext/transport/chttp2/transport/chttp2_transport.cc
@@ -1451,10 +1451,8 @@ static void perform_stream_op_locked(void* stream_op,
       }
     }
     if (op_payload->send_initial_metadata.peer_string != nullptr) {
-      char* old_peer_string = (char*)gpr_atm_full_xchg(
-          op_payload->send_initial_metadata.peer_string,
-          (gpr_atm)gpr_strdup(t->peer_string));
-      gpr_free(old_peer_string);
+      gpr_atm_rel_store(op_payload->send_initial_metadata.peer_string,
+                        (gpr_atm)t->peer_string);
     }
   }
 
@@ -1569,10 +1567,8 @@ static void perform_stream_op_locked(void* stream_op,
     s->trailing_metadata_available =
         op_payload->recv_initial_metadata.trailing_metadata_available;
     if (op_payload->recv_initial_metadata.peer_string != nullptr) {
-      char* old_peer_string = (char*)gpr_atm_full_xchg(
-          op_payload->recv_initial_metadata.peer_string,
-          (gpr_atm)gpr_strdup(t->peer_string));
-      gpr_free(old_peer_string);
+      gpr_atm_rel_store(op_payload->recv_initial_metadata.peer_string,
+                        (gpr_atm)t->peer_string);
     }
     grpc_chttp2_maybe_complete_recv_initial_metadata(t, s);
   }
diff --git a/src/core/ext/transport/chttp2/transport/hpack_encoder.cc b/src/core/ext/transport/chttp2/transport/hpack_encoder.cc
index d5ef063883..0eaf63f133 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_encoder.cc
+++ b/src/core/ext/transport/chttp2/transport/hpack_encoder.cc
@@ -41,14 +41,18 @@
 #include "src/core/lib/transport/static_metadata.h"
 #include "src/core/lib/transport/timeout_encoding.h"
 
-#define HASH_FRAGMENT_1(x) ((x)&255)
-#define HASH_FRAGMENT_2(x) ((x >> 8) & 255)
-#define HASH_FRAGMENT_3(x) ((x >> 16) & 255)
-#define HASH_FRAGMENT_4(x) ((x >> 24) & 255)
+#define HASH_FRAGMENT_MASK (GRPC_CHTTP2_HPACKC_NUM_VALUES - 1)
+#define HASH_FRAGMENT_1(x) ((x)&HASH_FRAGMENT_MASK)
+#define HASH_FRAGMENT_2(x) \
+  (((x) >> GRPC_CHTTP2_HPACKC_NUM_VALUES_BITS) & HASH_FRAGMENT_MASK)
+#define HASH_FRAGMENT_3(x) \
+  (((x) >> (GRPC_CHTTP2_HPACKC_NUM_VALUES_BITS * 2)) & HASH_FRAGMENT_MASK)
+#define HASH_FRAGMENT_4(x) \
+  (((x) >> (GRPC_CHTTP2_HPACKC_NUM_VALUES_BITS * 3)) & HASH_FRAGMENT_MASK)
 
 /* if the probability of this item being seen again is < 1/x then don't add
    it to the table */
-#define ONE_ON_ADD_PROBABILITY 128
+#define ONE_ON_ADD_PROBABILITY (GRPC_CHTTP2_HPACKC_NUM_VALUES >> 1)
 /* don't consider adding anything bigger than this to the hpack table */
 #define MAX_DECODER_SPACE_USAGE 512
 
@@ -135,7 +139,7 @@ static void inc_filter(uint8_t idx, uint32_t* sum, uint8_t* elems) {
   } else {
     int i;
     *sum = 0;
-    for (i = 0; i < GRPC_CHTTP2_HPACKC_NUM_FILTERS; i++) {
+    for (i = 0; i < GRPC_CHTTP2_HPACKC_NUM_VALUES; i++) {
       elems[i] /= 2;
       (*sum) += elems[i];
     }
diff --git a/src/core/ext/transport/chttp2/transport/hpack_encoder.h b/src/core/ext/transport/chttp2/transport/hpack_encoder.h
index b370932131..e31a7399d7 100644
--- a/src/core/ext/transport/chttp2/transport/hpack_encoder.h
+++ b/src/core/ext/transport/chttp2/transport/hpack_encoder.h
@@ -28,8 +28,9 @@
 #include "src/core/lib/transport/metadata_batch.h"
 #include "src/core/lib/transport/transport.h"
 
-#define GRPC_CHTTP2_HPACKC_NUM_FILTERS 256
-#define GRPC_CHTTP2_HPACKC_NUM_VALUES 256
+// This should be <= 8. We use 6 to save space.
+#define GRPC_CHTTP2_HPACKC_NUM_VALUES_BITS 6
+#define GRPC_CHTTP2_HPACKC_NUM_VALUES (1 << GRPC_CHTTP2_HPACKC_NUM_VALUES_BITS)
 /* initial table size, per spec */
 #define GRPC_CHTTP2_HPACKC_INITIAL_TABLE_SIZE 4096
 /* maximum table size we'll actually use */
@@ -58,7 +59,7 @@ typedef struct {
      a new literal should be added to the compression table or not.
      They track a single integer that counts how often a particular value has
      been seen. When that count reaches max (255), all values are halved. */
-  uint8_t filter_elems[GRPC_CHTTP2_HPACKC_NUM_FILTERS];
+  uint8_t filter_elems[GRPC_CHTTP2_HPACKC_NUM_VALUES];
 
   /* entry tables for keys & elems: these tables track values that have been
      seen and *may* be in the decompressor table */
diff --git a/src/core/lib/iomgr/cfstream_handle.cc b/src/core/lib/iomgr/cfstream_handle.cc
new file mode 100644
index 0000000000..30f4e65632
--- /dev/null
+++ b/src/core/lib/iomgr/cfstream_handle.cc
@@ -0,0 +1,183 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#include "src/core/lib/iomgr/port.h"
+
+#ifdef GRPC_CFSTREAM
+#import <CoreFoundation/CoreFoundation.h>
+#import "src/core/lib/iomgr/cfstream_handle.h"
+
+#include <grpc/support/atm.h>
+#include <grpc/support/sync.h>
+
+#include "src/core/lib/debug/trace.h"
+#include "src/core/lib/iomgr/closure.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
+
+extern grpc_core::TraceFlag grpc_tcp_trace;
+
+void* CFStreamHandle::Retain(void* info) {
+  CFStreamHandle* handle = static_cast<CFStreamHandle*>(info);
+  CFSTREAM_HANDLE_REF(handle, "retain");
+  return info;
+}
+
+void CFStreamHandle::Release(void* info) {
+  CFStreamHandle* handle = static_cast<CFStreamHandle*>(info);
+  CFSTREAM_HANDLE_UNREF(handle, "release");
+}
+
+CFStreamHandle* CFStreamHandle::CreateStreamHandle(
+    CFReadStreamRef read_stream, CFWriteStreamRef write_stream) {
+  return new CFStreamHandle(read_stream, write_stream);
+}
+
+void CFStreamHandle::ReadCallback(CFReadStreamRef stream,
+                                  CFStreamEventType type,
+                                  void* client_callback_info) {
+  CFStreamHandle* handle = static_cast<CFStreamHandle*>(client_callback_info);
+  CFSTREAM_HANDLE_REF(handle, "read callback");
+  dispatch_async(
+      dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
+        grpc_core::ExecCtx exec_ctx;
+        if (grpc_tcp_trace.enabled()) {
+          gpr_log(GPR_DEBUG, "CFStream ReadCallback (%p, %p, %lu, %p)", handle,
+                  stream, type, client_callback_info);
+        }
+        switch (type) {
+          case kCFStreamEventOpenCompleted:
+            handle->open_event_.SetReady();
+            break;
+          case kCFStreamEventHasBytesAvailable:
+          case kCFStreamEventEndEncountered:
+            handle->read_event_.SetReady();
+            break;
+          case kCFStreamEventErrorOccurred:
+            handle->open_event_.SetReady();
+            handle->read_event_.SetReady();
+            break;
+          default:
+            GPR_UNREACHABLE_CODE(return );
+        }
+        CFSTREAM_HANDLE_UNREF(handle, "read callback");
+      });
+}
+void CFStreamHandle::WriteCallback(CFWriteStreamRef stream,
+                                   CFStreamEventType type,
+                                   void* clientCallBackInfo) {
+  CFStreamHandle* handle = static_cast<CFStreamHandle*>(clientCallBackInfo);
+  CFSTREAM_HANDLE_REF(handle, "write callback");
+  dispatch_async(
+      dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
+        grpc_core::ExecCtx exec_ctx;
+        if (grpc_tcp_trace.enabled()) {
+          gpr_log(GPR_DEBUG, "CFStream WriteCallback (%p, %p, %lu, %p)", handle,
+                  stream, type, clientCallBackInfo);
+        }
+        switch (type) {
+          case kCFStreamEventOpenCompleted:
+            handle->open_event_.SetReady();
+            break;
+          case kCFStreamEventCanAcceptBytes:
+          case kCFStreamEventEndEncountered:
+            handle->write_event_.SetReady();
+            break;
+          case kCFStreamEventErrorOccurred:
+            handle->open_event_.SetReady();
+            handle->write_event_.SetReady();
+            break;
+          default:
+            GPR_UNREACHABLE_CODE(return );
+        }
+        CFSTREAM_HANDLE_UNREF(handle, "write callback");
+      });
+}
+
+CFStreamHandle::CFStreamHandle(CFReadStreamRef read_stream,
+                               CFWriteStreamRef write_stream) {
+  gpr_ref_init(&refcount_, 1);
+  open_event_.InitEvent();
+  read_event_.InitEvent();
+  write_event_.InitEvent();
+  CFStreamClientContext ctx = {0, static_cast<void*>(this), nil, nil, nil};
+  CFReadStreamSetClient(
+      read_stream,
+      kCFStreamEventOpenCompleted | kCFStreamEventHasBytesAvailable |
+          kCFStreamEventErrorOccurred | kCFStreamEventEndEncountered,
+      CFStreamHandle::ReadCallback, &ctx);
+  CFWriteStreamSetClient(
+      write_stream,
+      kCFStreamEventOpenCompleted | kCFStreamEventCanAcceptBytes |
+          kCFStreamEventErrorOccurred | kCFStreamEventEndEncountered,
+      CFStreamHandle::WriteCallback, &ctx);
+  CFReadStreamScheduleWithRunLoop(read_stream, CFRunLoopGetMain(),
+                                  kCFRunLoopCommonModes);
+  CFWriteStreamScheduleWithRunLoop(write_stream, CFRunLoopGetMain(),
+                                   kCFRunLoopCommonModes);
+}
+
+CFStreamHandle::~CFStreamHandle() {
+  open_event_.DestroyEvent();
+  read_event_.DestroyEvent();
+  write_event_.DestroyEvent();
+}
+
+void CFStreamHandle::NotifyOnOpen(grpc_closure* closure) {
+  open_event_.NotifyOn(closure);
+}
+
+void CFStreamHandle::NotifyOnRead(grpc_closure* closure) {
+  read_event_.NotifyOn(closure);
+}
+
+void CFStreamHandle::NotifyOnWrite(grpc_closure* closure) {
+  write_event_.NotifyOn(closure);
+}
+
+void CFStreamHandle::Shutdown(grpc_error* error) {
+  open_event_.SetShutdown(GRPC_ERROR_REF(error));
+  read_event_.SetShutdown(GRPC_ERROR_REF(error));
+  write_event_.SetShutdown(GRPC_ERROR_REF(error));
+  GRPC_ERROR_UNREF(error);
+}
+
+void CFStreamHandle::Ref(const char* file, int line, const char* reason) {
+  if (grpc_tcp_trace.enabled()) {
+    gpr_atm val = gpr_atm_no_barrier_load(&refcount_.count);
+    gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
+            "CFStream Handle ref %p : %s %" PRIdPTR " -> %" PRIdPTR, this,
+            reason, val, val + 1);
+  }
+  gpr_ref(&refcount_);
+}
+
+void CFStreamHandle::Unref(const char* file, int line, const char* reason) {
+  if (grpc_tcp_trace.enabled()) {
+    gpr_atm val = gpr_atm_no_barrier_load(&refcount_.count);
+    gpr_log(GPR_ERROR,
+            "CFStream Handle unref %p : %s %" PRIdPTR " -> %" PRIdPTR, this,
+            reason, val, val - 1);
+  }
+  if (gpr_unref(&refcount_)) {
+    delete this;
+  }
+}
+
+#endif
diff --git a/src/core/lib/iomgr/cfstream_handle.h b/src/core/lib/iomgr/cfstream_handle.h
new file mode 100644
index 0000000000..4258e72431
--- /dev/null
+++ b/src/core/lib/iomgr/cfstream_handle.h
@@ -0,0 +1,80 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+/* The CFStream handle acts as an event synchronization entity for
+ * read/write/open/error/eos events happening on CFStream streams. */
+
+#ifndef GRPC_CORE_LIB_IOMGR_CFSTREAM_HANDLE_H
+#define GRPC_CORE_LIB_IOMGR_CFSTREAM_HANDLE_H
+
+#include <grpc/support/port_platform.h>
+
+#include "src/core/lib/iomgr/port.h"
+
+#ifdef GRPC_CFSTREAM
+#import <CoreFoundation/CoreFoundation.h>
+
+#include "src/core/lib/iomgr/closure.h"
+#include "src/core/lib/iomgr/lockfree_event.h"
+
+class CFStreamHandle final {
+ public:
+  static CFStreamHandle* CreateStreamHandle(CFReadStreamRef read_stream,
+                                            CFWriteStreamRef write_stream);
+  ~CFStreamHandle();
+  CFStreamHandle(const CFReadStreamRef& ref) = delete;
+  CFStreamHandle(CFReadStreamRef&& ref) = delete;
+  CFStreamHandle& operator=(const CFStreamHandle& rhs) = delete;
+
+  void NotifyOnOpen(grpc_closure* closure);
+  void NotifyOnRead(grpc_closure* closure);
+  void NotifyOnWrite(grpc_closure* closure);
+  void Shutdown(grpc_error* error);
+
+  void Ref(const char* file = "", int line = 0, const char* reason = nullptr);
+  void Unref(const char* file = "", int line = 0, const char* reason = nullptr);
+
+ private:
+  CFStreamHandle(CFReadStreamRef read_stream, CFWriteStreamRef write_stream);
+  static void ReadCallback(CFReadStreamRef stream, CFStreamEventType type,
+                           void* client_callback_info);
+  static void WriteCallback(CFWriteStreamRef stream, CFStreamEventType type,
+                            void* client_callback_info);
+  static void* Retain(void* info);
+  static void Release(void* info);
+
+  grpc_core::LockfreeEvent open_event_;
+  grpc_core::LockfreeEvent read_event_;
+  grpc_core::LockfreeEvent write_event_;
+
+  gpr_refcount refcount_;
+};
+
+#ifdef DEBUG
+#define CFSTREAM_HANDLE_REF(handle, reason) \
+  (handle)->Ref(__FILE__, __LINE__, (reason))
+#define CFSTREAM_HANDLE_UNREF(handle, reason) \
+  (handle)->Unref(__FILE__, __LINE__, (reason))
+#else
+#define CFSTREAM_HANDLE_REF(handle, reason) (handle)->Ref()
+#define CFSTREAM_HANDLE_UNREF(handle, reason) (handle)->Unref()
+#endif
+
+#endif
+
+#endif /* GRPC_CORE_LIB_IOMGR_CFSTREAM_HANDLE_H */
diff --git a/src/core/lib/iomgr/endpoint_cfstream.cc b/src/core/lib/iomgr/endpoint_cfstream.cc
new file mode 100644
index 0000000000..c3bc0cc8fd
--- /dev/null
+++ b/src/core/lib/iomgr/endpoint_cfstream.cc
@@ -0,0 +1,372 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#include "src/core/lib/iomgr/port.h"
+
+#ifdef GRPC_CFSTREAM_ENDPOINT
+
+#import <CoreFoundation/CoreFoundation.h>
+#import "src/core/lib/iomgr/endpoint_cfstream.h"
+
+#include <grpc/slice_buffer.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
+
+#include "src/core/lib/gpr/string.h"
+#include "src/core/lib/iomgr/cfstream_handle.h"
+#include "src/core/lib/iomgr/closure.h"
+#include "src/core/lib/iomgr/endpoint.h"
+#include "src/core/lib/iomgr/error_cfstream.h"
+#include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/slice/slice_string_helpers.h"
+
+extern grpc_core::TraceFlag grpc_tcp_trace;
+
+typedef struct {
+  grpc_endpoint base;
+  gpr_refcount refcount;
+
+  CFReadStreamRef read_stream;
+  CFWriteStreamRef write_stream;
+  CFStreamHandle* stream_sync;
+
+  grpc_closure* read_cb;
+  grpc_closure* write_cb;
+  grpc_slice_buffer* read_slices;
+  grpc_slice_buffer* write_slices;
+
+  grpc_closure read_action;
+  grpc_closure write_action;
+
+  char* peer_string;
+  grpc_resource_user* resource_user;
+  grpc_resource_user_slice_allocator slice_allocator;
+} CFStreamEndpoint;
+
+static void CFStreamFree(CFStreamEndpoint* ep) {
+  grpc_resource_user_unref(ep->resource_user);
+  CFRelease(ep->read_stream);
+  CFRelease(ep->write_stream);
+  CFSTREAM_HANDLE_UNREF(ep->stream_sync, "free");
+  gpr_free(ep->peer_string);
+  gpr_free(ep);
+}
+
+#ifndef NDEBUG
+#define EP_REF(ep, reason) CFStreamRef((ep), (reason), __FILE__, __LINE__)
+#define EP_UNREF(ep, reason) CFStreamUnref((ep), (reason), __FILE__, __LINE__)
+static void CFStreamUnref(CFStreamEndpoint* ep, const char* reason,
+                          const char* file, int line) {
+  if (grpc_tcp_trace.enabled()) {
+    gpr_atm val = gpr_atm_no_barrier_load(&ep->refcount.count);
+    gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
+            "CFStream endpoint unref %p : %s %" PRIdPTR " -> %" PRIdPTR, ep,
+            reason, val, val - 1);
+  }
+  if (gpr_unref(&ep->refcount)) {
+    CFStreamFree(ep);
+  }
+}
+static void CFStreamRef(CFStreamEndpoint* ep, const char* reason,
+                        const char* file, int line) {
+  if (grpc_tcp_trace.enabled()) {
+    gpr_atm val = gpr_atm_no_barrier_load(&ep->refcount.count);
+    gpr_log(file, line, GPR_LOG_SEVERITY_DEBUG,
+            "CFStream endpoint ref %p : %s %" PRIdPTR " -> %" PRIdPTR, ep,
+            reason, val, val + 1);
+  }
+  gpr_ref(&ep->refcount);
+}
+#else
+#define EP_REF(ep, reason) CFStreamRef((ep))
+#define EP_UNREF(ep, reason) CFStreamUnref((ep))
+static void CFStreamUnref(CFStreamEndpoint* ep) {
+  if (gpr_unref(&ep->refcount)) {
+    CFStreamFree(ep);
+  }
+}
+static void CFStreamRef(CFStreamEndpoint* ep) { gpr_ref(&ep->refcount); }
+#endif
+
+static grpc_error* CFStreamAnnotateError(grpc_error* src_error,
+                                         CFStreamEndpoint* ep) {
+  return grpc_error_set_str(
+      grpc_error_set_int(src_error, GRPC_ERROR_INT_GRPC_STATUS,
+                         GRPC_STATUS_UNAVAILABLE),
+      GRPC_ERROR_STR_TARGET_ADDRESS,
+      grpc_slice_from_copied_string(ep->peer_string));
+}
+
+static void CallReadCb(CFStreamEndpoint* ep, grpc_error* error) {
+  if (grpc_tcp_trace.enabled()) {
+    gpr_log(GPR_DEBUG, "CFStream endpoint:%p call_read_cb %p %p:%p", ep,
+            ep->read_cb, ep->read_cb->cb, ep->read_cb->cb_arg);
+    size_t i;
+    const char* str = grpc_error_string(error);
+    gpr_log(GPR_DEBUG, "read: error=%s", str);
+
+    for (i = 0; i < ep->read_slices->count; i++) {
+      char* dump = grpc_dump_slice(ep->read_slices->slices[i],
+                                   GPR_DUMP_HEX | GPR_DUMP_ASCII);
+      gpr_log(GPR_DEBUG, "READ %p (peer=%s): %s", ep, ep->peer_string, dump);
+      gpr_free(dump);
+    }
+  }
+  grpc_closure* cb = ep->read_cb;
+  ep->read_cb = nullptr;
+  ep->read_slices = nullptr;
+  GRPC_CLOSURE_SCHED(cb, error);
+}
+
+static void CallWriteCb(CFStreamEndpoint* ep, grpc_error* error) {
+  if (grpc_tcp_trace.enabled()) {
+    gpr_log(GPR_DEBUG, "CFStream endpoint:%p call_write_cb %p %p:%p", ep,
+            ep->write_cb, ep->write_cb->cb, ep->write_cb->cb_arg);
+    const char* str = grpc_error_string(error);
+    gpr_log(GPR_DEBUG, "write: error=%s", str);
+  }
+  grpc_closure* cb = ep->write_cb;
+  ep->write_cb = nullptr;
+  ep->write_slices = nullptr;
+  GRPC_CLOSURE_SCHED(cb, error);
+}
+
+static void ReadAction(void* arg, grpc_error* error) {
+  CFStreamEndpoint* ep = static_cast<CFStreamEndpoint*>(arg);
+  GPR_ASSERT(ep->read_cb != nullptr);
+  if (error) {
+    grpc_slice_buffer_reset_and_unref_internal(ep->read_slices);
+    CallReadCb(ep, GRPC_ERROR_REF(error));
+    EP_UNREF(ep, "read");
+    return;
+  }
+
+  GPR_ASSERT(ep->read_slices->count == 1);
+  grpc_slice slice = ep->read_slices->slices[0];
+  size_t len = GRPC_SLICE_LENGTH(slice);
+  CFIndex read_size =
+      CFReadStreamRead(ep->read_stream, GRPC_SLICE_START_PTR(slice), len);
+  if (read_size == -1) {
+    grpc_slice_buffer_reset_and_unref_internal(ep->read_slices);
+    CFErrorRef stream_error = CFReadStreamCopyError(ep->read_stream);
+    if (stream_error != nullptr) {
+      error = CFStreamAnnotateError(
+          GRPC_ERROR_CREATE_FROM_CFERROR(stream_error, "Read error"), ep);
+      CFRelease(stream_error);
+    } else {
+      error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Read error");
+    }
+    CallReadCb(ep, error);
+    EP_UNREF(ep, "read");
+  } else if (read_size == 0) {
+    grpc_slice_buffer_reset_and_unref_internal(ep->read_slices);
+    CallReadCb(ep,
+               CFStreamAnnotateError(
+                   GRPC_ERROR_CREATE_FROM_STATIC_STRING("Socket closed"), ep));
+    EP_UNREF(ep, "read");
+  } else {
+    if (read_size < len) {
+      grpc_slice_buffer_trim_end(ep->read_slices, len - read_size, nullptr);
+    }
+    CallReadCb(ep, GRPC_ERROR_NONE);
+    EP_UNREF(ep, "read");
+  }
+}
+
+static void WriteAction(void* arg, grpc_error* error) {
+  CFStreamEndpoint* ep = static_cast<CFStreamEndpoint*>(arg);
+  GPR_ASSERT(ep->write_cb != nullptr);
+  if (error) {
+    grpc_slice_buffer_reset_and_unref_internal(ep->write_slices);
+    CallWriteCb(ep, GRPC_ERROR_REF(error));
+    EP_UNREF(ep, "write");
+    return;
+  }
+
+  grpc_slice slice = grpc_slice_buffer_take_first(ep->write_slices);
+  size_t slice_len = GRPC_SLICE_LENGTH(slice);
+  CFIndex write_size = CFWriteStreamWrite(
+      ep->write_stream, GRPC_SLICE_START_PTR(slice), slice_len);
+  if (write_size == -1) {
+    grpc_slice_buffer_reset_and_unref_internal(ep->write_slices);
+    CFErrorRef stream_error = CFWriteStreamCopyError(ep->write_stream);
+    if (stream_error != nullptr) {
+      error = CFStreamAnnotateError(
+          GRPC_ERROR_CREATE_FROM_CFERROR(stream_error, "write failed."), ep);
+      CFRelease(stream_error);
+    } else {
+      error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("write failed.");
+    }
+    CallWriteCb(ep, error);
+    EP_UNREF(ep, "write");
+  } else {
+    if (write_size < GRPC_SLICE_LENGTH(slice)) {
+      grpc_slice_buffer_undo_take_first(
+          ep->write_slices, grpc_slice_sub(slice, write_size, slice_len));
+    }
+    if (ep->write_slices->length > 0) {
+      ep->stream_sync->NotifyOnWrite(&ep->write_action);
+    } else {
+      CallWriteCb(ep, GRPC_ERROR_NONE);
+      EP_UNREF(ep, "write");
+    }
+
+    if (grpc_tcp_trace.enabled()) {
+      grpc_slice trace_slice = grpc_slice_sub(slice, 0, write_size);
+      char* dump = grpc_dump_slice(trace_slice, GPR_DUMP_HEX | GPR_DUMP_ASCII);
+      gpr_log(GPR_DEBUG, "WRITE %p (peer=%s): %s", ep, ep->peer_string, dump);
+      gpr_free(dump);
+      grpc_slice_unref_internal(trace_slice);
+    }
+  }
+  grpc_slice_unref_internal(slice);
+}
+
+static void CFStreamReadAllocationDone(void* arg, grpc_error* error) {
+  CFStreamEndpoint* ep = static_cast<CFStreamEndpoint*>(arg);
+  if (error == GRPC_ERROR_NONE) {
+    ep->stream_sync->NotifyOnRead(&ep->read_action);
+  } else {
+    grpc_slice_buffer_reset_and_unref_internal(ep->read_slices);
+    CallReadCb(ep, error);
+    EP_UNREF(ep, "read");
+  }
+}
+
+static void CFStreamRead(grpc_endpoint* ep, grpc_slice_buffer* slices,
+                         grpc_closure* cb) {
+  CFStreamEndpoint* ep_impl = reinterpret_cast<CFStreamEndpoint*>(ep);
+  if (grpc_tcp_trace.enabled()) {
+    gpr_log(GPR_DEBUG, "CFStream endpoint:%p read (%p, %p) length:%zu", ep_impl,
+            slices, cb, slices->length);
+  }
+  GPR_ASSERT(ep_impl->read_cb == nullptr);
+  ep_impl->read_cb = cb;
+  ep_impl->read_slices = slices;
+  grpc_slice_buffer_reset_and_unref_internal(slices);
+  grpc_resource_user_alloc_slices(&ep_impl->slice_allocator,
+                                  GRPC_TCP_DEFAULT_READ_SLICE_SIZE, 1,
+                                  ep_impl->read_slices);
+  EP_REF(ep_impl, "read");
+}
+
+static void CFStreamWrite(grpc_endpoint* ep, grpc_slice_buffer* slices,
+                          grpc_closure* cb) {
+  CFStreamEndpoint* ep_impl = reinterpret_cast<CFStreamEndpoint*>(ep);
+  if (grpc_tcp_trace.enabled()) {
+    gpr_log(GPR_DEBUG, "CFStream endpoint:%p write (%p, %p) length:%zu",
+            ep_impl, slices, cb, slices->length);
+  }
+  GPR_ASSERT(ep_impl->write_cb == nullptr);
+  ep_impl->write_cb = cb;
+  ep_impl->write_slices = slices;
+  EP_REF(ep_impl, "write");
+  ep_impl->stream_sync->NotifyOnWrite(&ep_impl->write_action);
+}
+
+void CFStreamShutdown(grpc_endpoint* ep, grpc_error* why) {
+  CFStreamEndpoint* ep_impl = reinterpret_cast<CFStreamEndpoint*>(ep);
+  if (grpc_tcp_trace.enabled()) {
+    gpr_log(GPR_DEBUG, "CFStream endpoint:%p shutdown (%p)", ep_impl, why);
+  }
+  CFReadStreamClose(ep_impl->read_stream);
+  CFWriteStreamClose(ep_impl->write_stream);
+  ep_impl->stream_sync->Shutdown(why);
+  grpc_resource_user_shutdown(ep_impl->resource_user);
+  if (grpc_tcp_trace.enabled()) {
+    gpr_log(GPR_DEBUG, "CFStream endpoint:%p shutdown DONE (%p)", ep_impl, why);
+  }
+}
+
+void CFStreamDestroy(grpc_endpoint* ep) {
+  CFStreamEndpoint* ep_impl = reinterpret_cast<CFStreamEndpoint*>(ep);
+  if (grpc_tcp_trace.enabled()) {
+    gpr_log(GPR_DEBUG, "CFStream endpoint:%p destroy", ep_impl);
+  }
+  EP_UNREF(ep_impl, "destroy");
+}
+
+grpc_resource_user* CFStreamGetResourceUser(grpc_endpoint* ep) {
+  CFStreamEndpoint* ep_impl = reinterpret_cast<CFStreamEndpoint*>(ep);
+  return ep_impl->resource_user;
+}
+
+char* CFStreamGetPeer(grpc_endpoint* ep) {
+  CFStreamEndpoint* ep_impl = reinterpret_cast<CFStreamEndpoint*>(ep);
+  return gpr_strdup(ep_impl->peer_string);
+}
+
+int CFStreamGetFD(grpc_endpoint* ep) { return 0; }
+
+void CFStreamAddToPollset(grpc_endpoint* ep, grpc_pollset* pollset) {}
+void CFStreamAddToPollsetSet(grpc_endpoint* ep, grpc_pollset_set* pollset) {}
+void CFStreamDeleteFromPollsetSet(grpc_endpoint* ep,
+                                  grpc_pollset_set* pollset) {}
+
+static const grpc_endpoint_vtable vtable = {CFStreamRead,
+                                            CFStreamWrite,
+                                            CFStreamAddToPollset,
+                                            CFStreamAddToPollsetSet,
+                                            CFStreamDeleteFromPollsetSet,
+                                            CFStreamShutdown,
+                                            CFStreamDestroy,
+                                            CFStreamGetResourceUser,
+                                            CFStreamGetPeer,
+                                            CFStreamGetFD};
+
+grpc_endpoint* grpc_cfstream_endpoint_create(
+    CFReadStreamRef read_stream, CFWriteStreamRef write_stream,
+    const char* peer_string, grpc_resource_quota* resource_quota,
+    CFStreamHandle* stream_sync) {
+  CFStreamEndpoint* ep_impl =
+      static_cast<CFStreamEndpoint*>(gpr_malloc(sizeof(CFStreamEndpoint)));
+  if (grpc_tcp_trace.enabled()) {
+    gpr_log(GPR_DEBUG,
+            "CFStream endpoint:%p create readStream:%p writeStream: %p",
+            ep_impl, read_stream, write_stream);
+  }
+  ep_impl->base.vtable = &vtable;
+  gpr_ref_init(&ep_impl->refcount, 1);
+  ep_impl->read_stream = read_stream;
+  ep_impl->write_stream = write_stream;
+  CFRetain(read_stream);
+  CFRetain(write_stream);
+  ep_impl->stream_sync = stream_sync;
+  CFSTREAM_HANDLE_REF(ep_impl->stream_sync, "endpoint create");
+
+  ep_impl->peer_string = gpr_strdup(peer_string);
+  ep_impl->read_cb = nil;
+  ep_impl->write_cb = nil;
+  ep_impl->read_slices = nil;
+  ep_impl->write_slices = nil;
+  GRPC_CLOSURE_INIT(&ep_impl->read_action, ReadAction,
+                    static_cast<void*>(ep_impl), grpc_schedule_on_exec_ctx);
+  GRPC_CLOSURE_INIT(&ep_impl->write_action, WriteAction,
+                    static_cast<void*>(ep_impl), grpc_schedule_on_exec_ctx);
+  ep_impl->resource_user =
+      grpc_resource_user_create(resource_quota, peer_string);
+  grpc_resource_user_slice_allocator_init(&ep_impl->slice_allocator,
+                                          ep_impl->resource_user,
+                                          CFStreamReadAllocationDone, ep_impl);
+
+  return &ep_impl->base;
+}
+
+#endif /* GRPC_CFSTREAM_ENDPOINT */
diff --git a/src/core/lib/iomgr/endpoint_cfstream.h b/src/core/lib/iomgr/endpoint_cfstream.h
new file mode 100644
index 0000000000..ef957c1f11
--- /dev/null
+++ b/src/core/lib/iomgr/endpoint_cfstream.h
@@ -0,0 +1,49 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_IOMGR_ENDPOINT_CFSTREAM_H
+#define GRPC_CORE_LIB_IOMGR_ENDPOINT_CFSTREAM_H
+/*
+   Low level TCP "bottom half" implementation, for use by transports built on
+   top of a TCP connection.
+
+   Note that this file does not (yet) include APIs for creating the socket in
+   the first place.
+
+   All calls passing slice transfer ownership of a slice refcount unless
+   otherwise specified.
+*/
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GRPC_CFSTREAM
+
+#import <CoreFoundation/CoreFoundation.h>
+
+#include "src/core/lib/debug/trace.h"
+#include "src/core/lib/iomgr/cfstream_handle.h"
+#include "src/core/lib/iomgr/endpoint.h"
+
+grpc_endpoint* grpc_cfstream_endpoint_create(
+    CFReadStreamRef read_stream, CFWriteStreamRef write_stream,
+    const char* peer_string, grpc_resource_quota* resource_quota,
+    CFStreamHandle* stream_sync);
+
+#endif /* GRPC_CFSTREAM */
+
+#endif /* GRPC_CORE_LIB_IOMGR_ENDPOINT_CFSTREAM_H */
diff --git a/src/core/lib/iomgr/error.cc b/src/core/lib/iomgr/error.cc
index 4088cf612e..90ed34da11 100644
--- a/src/core/lib/iomgr/error.cc
+++ b/src/core/lib/iomgr/error.cc
@@ -312,6 +312,12 @@ static void internal_add_error(grpc_error** err, grpc_error* new_err) {
 // It is very common to include and extra int and string in an error
 #define SURPLUS_CAPACITY (2 * SLOTS_PER_INT + SLOTS_PER_TIME)
 
+static bool g_error_creation_allowed = true;
+
+void grpc_disable_error_creation() { g_error_creation_allowed = false; }
+
+void grpc_enable_error_creation() { g_error_creation_allowed = true; }
+
 grpc_error* grpc_error_create(const char* file, int line, grpc_slice desc,
                               grpc_error** referencing,
                               size_t num_referencing) {
@@ -326,6 +332,12 @@ grpc_error* grpc_error_create(const char* file, int line, grpc_slice desc,
     return GRPC_ERROR_OOM;
   }
 #ifndef NDEBUG
+  if (!g_error_creation_allowed) {
+    gpr_log(GPR_ERROR,
+            "Error creation occurred when error creation was disabled [%s:%d]",
+            file, line);
+    abort();
+  }
   if (grpc_trace_error_refcount.enabled()) {
     gpr_log(GPR_DEBUG, "%p create [%s:%d]", err, file, line);
   }
diff --git a/src/core/lib/iomgr/error.h b/src/core/lib/iomgr/error.h
index f8cae4da82..27c4d22fd1 100644
--- a/src/core/lib/iomgr/error.h
+++ b/src/core/lib/iomgr/error.h
@@ -123,6 +123,11 @@ typedef enum {
 #define GRPC_ERROR_OOM ((grpc_error*)2)
 #define GRPC_ERROR_CANCELLED ((grpc_error*)4)
 
+// debug only toggles that allow for a sanity to check that ensures we will
+// never create any errors in the per-RPC hotpath.
+void grpc_disable_error_creation();
+void grpc_enable_error_creation();
+
 const char* grpc_error_string(grpc_error* error);
 
 /// Create an error - but use GRPC_ERROR_CREATE instead
diff --git a/src/core/lib/iomgr/error_cfstream.cc b/src/core/lib/iomgr/error_cfstream.cc
new file mode 100644
index 0000000000..d7af8c377f
--- /dev/null
+++ b/src/core/lib/iomgr/error_cfstream.cc
@@ -0,0 +1,52 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#ifdef GRPC_CFSTREAM
+#include <CoreFoundation/CoreFoundation.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/string_util.h>
+
+#include "src/core/lib/iomgr/error.h"
+
+#define MAX_ERROR_DESCRIPTION 256
+
+grpc_error* grpc_error_create_from_cferror(const char* file, int line,
+                                           void* arg, const char* custom_desc) {
+  CFErrorRef error = static_cast<CFErrorRef>(arg);
+  char buf_domain[MAX_ERROR_DESCRIPTION];
+  char buf_desc[MAX_ERROR_DESCRIPTION];
+  char* error_msg;
+  CFErrorDomain domain = CFErrorGetDomain((error));
+  CFIndex code = CFErrorGetCode((error));
+  CFStringRef desc = CFErrorCopyDescription((error));
+  CFStringGetCString(domain, buf_domain, MAX_ERROR_DESCRIPTION,
+                     kCFStringEncodingUTF8);
+  CFStringGetCString(desc, buf_desc, MAX_ERROR_DESCRIPTION,
+                     kCFStringEncodingUTF8);
+  gpr_asprintf(&error_msg, "%s (error domain:%s, code:%ld, description:%s)",
+               custom_desc, buf_domain, code, buf_desc);
+  CFRelease(desc);
+  grpc_error* return_error = grpc_error_create(
+      file, line, grpc_slice_from_copied_string(error_msg), NULL, 0);
+  gpr_free(error_msg);
+  return return_error;
+}
+#endif /* GRPC_CFSTREAM */
diff --git a/src/core/lib/iomgr/error_cfstream.h b/src/core/lib/iomgr/error_cfstream.h
new file mode 100644
index 0000000000..06ab751329
--- /dev/null
+++ b/src/core/lib/iomgr/error_cfstream.h
@@ -0,0 +1,31 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_IOMGR_ERROR_CFSTREAM_H
+#define GRPC_CORE_LIB_IOMGR_ERROR_CFSTREAM_H
+
+#ifdef GRPC_CFSTREAM
+// Create an error from Apple Core Foundation CFError object
+#define GRPC_ERROR_CREATE_FROM_CFERROR(error, desc)  \
+  grpc_error_create_from_cferror(__FILE__, __LINE__, \
+                                 static_cast<void*>((error)), (desc))
+grpc_error* grpc_error_create_from_cferror(const char* file, int line,
+                                           void* arg, const char* desc);
+#endif /* GRPC_CFSTREAM */
+
+#endif /* GRPC_CORE_LIB_IOMGR_ERROR_CFSTREAM_H */
diff --git a/src/core/lib/iomgr/ev_epoll1_linux.cc b/src/core/lib/iomgr/ev_epoll1_linux.cc
index 554522598c..98ab974057 100644
--- a/src/core/lib/iomgr/ev_epoll1_linux.cc
+++ b/src/core/lib/iomgr/ev_epoll1_linux.cc
@@ -1264,12 +1264,12 @@ const grpc_event_engine_vtable* grpc_init_epoll1_linux(bool explicit_request) {
 }
 
 #else /* defined(GRPC_LINUX_EPOLL) */
-#if defined(GRPC_POSIX_SOCKET)
+#if defined(GRPC_POSIX_SOCKET_EV_EPOLL1)
 #include "src/core/lib/iomgr/ev_epoll1_linux.h"
 /* If GRPC_LINUX_EPOLL is not defined, it means epoll is not available. Return
  * NULL */
 const grpc_event_engine_vtable* grpc_init_epoll1_linux(bool explicit_request) {
   return nullptr;
 }
-#endif /* defined(GRPC_POSIX_SOCKET) */
+#endif /* defined(GRPC_POSIX_SOCKET_EV_EPOLL1) */
 #endif /* !defined(GRPC_LINUX_EPOLL) */
diff --git a/src/core/lib/iomgr/ev_epollex_linux.cc b/src/core/lib/iomgr/ev_epollex_linux.cc
index be400c6ee9..f22eb8ee87 100644
--- a/src/core/lib/iomgr/ev_epollex_linux.cc
+++ b/src/core/lib/iomgr/ev_epollex_linux.cc
@@ -1586,7 +1586,7 @@ const grpc_event_engine_vtable* grpc_init_epollex_linux(
 }
 
 #else /* defined(GRPC_LINUX_EPOLL_CREATE1) */
-#if defined(GRPC_POSIX_SOCKET)
+#if defined(GRPC_POSIX_SOCKET_EV_EPOLLEX)
 #include "src/core/lib/iomgr/ev_epollex_linux.h"
 /* If GRPC_LINUX_EPOLL_CREATE1 is not defined, it means
    epoll_create1 is not available. Return NULL */
@@ -1594,6 +1594,6 @@ const grpc_event_engine_vtable* grpc_init_epollex_linux(
     bool explicitly_requested) {
   return nullptr;
 }
-#endif /* defined(GRPC_POSIX_SOCKET) */
+#endif /* defined(GRPC_POSIX_SOCKET_EV_EPOLLEX) */
 
 #endif /* !defined(GRPC_LINUX_EPOLL_CREATE1) */
diff --git a/src/core/lib/iomgr/ev_epollsig_linux.cc b/src/core/lib/iomgr/ev_epollsig_linux.cc
index 6c0f0c91f3..20512e31ac 100644
--- a/src/core/lib/iomgr/ev_epollsig_linux.cc
+++ b/src/core/lib/iomgr/ev_epollsig_linux.cc
@@ -1750,7 +1750,7 @@ const grpc_event_engine_vtable* grpc_init_epollsig_linux(
 }
 
 #else /* defined(GRPC_LINUX_EPOLL_CREATE1) */
-#if defined(GRPC_POSIX_SOCKET)
+#if defined(GRPC_POSIX_SOCKET_EV_EPOLLSIG)
 #include "src/core/lib/iomgr/ev_epollsig_linux.h"
 /* If GRPC_LINUX_EPOLL_CREATE1 is not defined, it means
    epoll_create1 is not available. Return NULL */
diff --git a/src/core/lib/iomgr/ev_poll_posix.cc b/src/core/lib/iomgr/ev_poll_posix.cc
index 06378bba25..df6b0e1e89 100644
--- a/src/core/lib/iomgr/ev_poll_posix.cc
+++ b/src/core/lib/iomgr/ev_poll_posix.cc
@@ -20,7 +20,7 @@
 
 #include "src/core/lib/iomgr/port.h"
 
-#ifdef GRPC_POSIX_SOCKET
+#ifdef GRPC_POSIX_SOCKET_EV_POLL
 
 #include "src/core/lib/iomgr/ev_poll_posix.h"
 
@@ -1769,4 +1769,4 @@ const grpc_event_engine_vtable* grpc_init_poll_cv_posix(bool explicit_request) {
   return &vtable;
 }
 
-#endif
+#endif /* GRPC_POSIX_SOCKET_EV_POLL */
diff --git a/src/core/lib/iomgr/ev_posix.cc b/src/core/lib/iomgr/ev_posix.cc
index efa91045d4..82b21df7ba 100644
--- a/src/core/lib/iomgr/ev_posix.cc
+++ b/src/core/lib/iomgr/ev_posix.cc
@@ -20,7 +20,7 @@
 
 #include "src/core/lib/iomgr/port.h"
 
-#ifdef GRPC_POSIX_SOCKET
+#ifdef GRPC_POSIX_SOCKET_EV
 
 #include "src/core/lib/iomgr/ev_posix.h"
 
@@ -343,4 +343,4 @@ void grpc_pollset_set_del_fd(grpc_pollset_set* pollset_set, grpc_fd* fd) {
   g_event_engine->pollset_set_del_fd(pollset_set, fd);
 }
 
-#endif  // GRPC_POSIX_SOCKET
+#endif  // GRPC_POSIX_SOCKET_EV
diff --git a/src/core/lib/iomgr/iomgr_posix.cc b/src/core/lib/iomgr/iomgr_posix.cc
index 66c9cb7ff7..ca7334c9a4 100644
--- a/src/core/lib/iomgr/iomgr_posix.cc
+++ b/src/core/lib/iomgr/iomgr_posix.cc
@@ -20,7 +20,7 @@
 
 #include "src/core/lib/iomgr/port.h"
 
-#ifdef GRPC_POSIX_SOCKET
+#ifdef GRPC_POSIX_SOCKET_IOMGR
 
 #include "src/core/lib/debug/trace.h"
 #include "src/core/lib/iomgr/ev_posix.h"
@@ -64,4 +64,4 @@ void grpc_set_default_iomgr_platform() {
   grpc_set_iomgr_platform_vtable(&vtable);
 }
 
-#endif /* GRPC_POSIX_SOCKET */
+#endif /* GRPC_POSIX_SOCKET_IOMGR */
diff --git a/src/core/lib/iomgr/polling_entity.cc b/src/core/lib/iomgr/polling_entity.cc
index 9f164f65b0..dea07cae53 100644
--- a/src/core/lib/iomgr/polling_entity.cc
+++ b/src/core/lib/iomgr/polling_entity.cc
@@ -61,8 +61,11 @@ bool grpc_polling_entity_is_empty(const grpc_polling_entity* pollent) {
 void grpc_polling_entity_add_to_pollset_set(grpc_polling_entity* pollent,
                                             grpc_pollset_set* pss_dst) {
   if (pollent->tag == GRPC_POLLS_POLLSET) {
-    GPR_ASSERT(pollent->pollent.pollset != nullptr);
-    grpc_pollset_set_add_pollset(pss_dst, pollent->pollent.pollset);
+    // CFStream does not use file destriptors. When CFStream is used, the fd
+    // pollset is possible to be null.
+    if (pollent->pollent.pollset != nullptr) {
+      grpc_pollset_set_add_pollset(pss_dst, pollent->pollent.pollset);
+    }
   } else if (pollent->tag == GRPC_POLLS_POLLSET_SET) {
     GPR_ASSERT(pollent->pollent.pollset_set != nullptr);
     grpc_pollset_set_add_pollset_set(pss_dst, pollent->pollent.pollset_set);
@@ -75,8 +78,14 @@ void grpc_polling_entity_add_to_pollset_set(grpc_polling_entity* pollent,
 void grpc_polling_entity_del_from_pollset_set(grpc_polling_entity* pollent,
                                               grpc_pollset_set* pss_dst) {
   if (pollent->tag == GRPC_POLLS_POLLSET) {
+#ifdef GRPC_CFSTREAM
+    if (pollent->pollent.pollset != nullptr) {
+      grpc_pollset_set_del_pollset(pss_dst, pollent->pollent.pollset);
+    }
+#else
     GPR_ASSERT(pollent->pollent.pollset != nullptr);
     grpc_pollset_set_del_pollset(pss_dst, pollent->pollent.pollset);
+#endif
   } else if (pollent->tag == GRPC_POLLS_POLLSET_SET) {
     GPR_ASSERT(pollent->pollent.pollset_set != nullptr);
     grpc_pollset_set_del_pollset_set(pss_dst, pollent->pollent.pollset_set);
diff --git a/src/core/lib/iomgr/port.h b/src/core/lib/iomgr/port.h
index a397012003..80d8e63cdd 100644
--- a/src/core/lib/iomgr/port.h
+++ b/src/core/lib/iomgr/port.h
@@ -97,7 +97,26 @@
 #define GRPC_MSG_IOVLEN_TYPE int
 #define GRPC_POSIX_FORK 1
 #define GRPC_POSIX_NO_SPECIAL_WAKEUP_FD 1
+#ifdef GRPC_CFSTREAM
+#define GRPC_POSIX_SOCKET_IOMGR 1
+#define GRPC_CFSTREAM_ENDPOINT 1
+#define GRPC_CFSTREAM_CLIENT 1
+#define GRPC_POSIX_SOCKET_ARES_EV_DRIVER 1
+#define GRPC_POSIX_SOCKET_EV 1
+#define GRPC_POSIX_SOCKET_EV_EPOLL1 1
+#define GRPC_POSIX_SOCKET_EV_EPOLLEX 1
+#define GRPC_POSIX_SOCKET_EV_EPOLLSIG 1
+#define GRPC_POSIX_SOCKET_EV_POLL 1
+#define GRPC_POSIX_SOCKET_RESOLVE_ADDRESS 1
+#define GRPC_POSIX_SOCKET_SOCKADDR 1
+#define GRPC_POSIX_SOCKET_SOCKET_FACTORY 1
+#define GRPC_POSIX_SOCKET_TCP 1
+#define GRPC_POSIX_SOCKET_TCP_SERVER 1
+#define GRPC_POSIX_SOCKET_TCP_SERVER_UTILS_COMMON 1
+#define GRPC_POSIX_SOCKET_UTILS_COMMON 1
+#else
 #define GRPC_POSIX_SOCKET 1
+#endif
 #define GRPC_POSIX_SOCKETUTILS 1
 #define GRPC_POSIX_SYSCONF 1
 #define GRPC_POSIX_WAKEUP_FD 1
@@ -131,12 +150,30 @@
 #endif
 
 #if defined(GRPC_POSIX_SOCKET) + defined(GRPC_WINSOCK_SOCKET) + \
-        defined(GRPC_CUSTOM_SOCKET) !=                          \
+        defined(GRPC_CUSTOM_SOCKET) + defined(GRPC_CFSTREAM) != \
     1
 #error \
     "Must define exactly one of GRPC_POSIX_SOCKET, GRPC_WINSOCK_SOCKET, GRPC_CUSTOM_SOCKET"
 #endif
 
+#ifdef GRPC_POSIX_SOCKET
+#define GRPC_POSIX_SOCKET_ARES_EV_DRIVER 1
+#define GRPC_POSIX_SOCKET_EV 1
+#define GRPC_POSIX_SOCKET_EV_EPOLLEX 1
+#define GRPC_POSIX_SOCKET_EV_EPOLLSIG 1
+#define GRPC_POSIX_SOCKET_EV_POLL 1
+#define GRPC_POSIX_SOCKET_EV_EPOLL1 1
+#define GRPC_POSIX_SOCKET_IOMGR 1
+#define GRPC_POSIX_SOCKET_RESOLVE_ADDRESS 1
+#define GRPC_POSIX_SOCKET_SOCKADDR 1
+#define GRPC_POSIX_SOCKET_SOCKET_FACTORY 1
+#define GRPC_POSIX_SOCKET_TCP 1
+#define GRPC_POSIX_SOCKET_TCP_CLIENT 1
+#define GRPC_POSIX_SOCKET_TCP_SERVER 1
+#define GRPC_POSIX_SOCKET_TCP_SERVER_UTILS_COMMON 1
+#define GRPC_POSIX_SOCKET_UTILS_COMMON 1
+#endif
+
 #if defined(GRPC_POSIX_HOST_NAME_MAX) && defined(GRPC_POSIX_SYSCONF)
 #error "Cannot define both GRPC_POSIX_HOST_NAME_MAX and GRPC_POSIX_SYSCONF"
 #endif
diff --git a/src/core/lib/iomgr/resolve_address.h b/src/core/lib/iomgr/resolve_address.h
index fe0d834582..6afe94a7a9 100644
--- a/src/core/lib/iomgr/resolve_address.h
+++ b/src/core/lib/iomgr/resolve_address.h
@@ -33,7 +33,7 @@
 #include <ws2tcpip.h>
 #endif
 
-#ifdef GRPC_POSIX_SOCKET
+#if defined(GRPC_POSIX_SOCKET) || defined(GRPC_CFSTREAM)
 #include <sys/socket.h>
 #endif
 
diff --git a/src/core/lib/iomgr/resolve_address_posix.cc b/src/core/lib/iomgr/resolve_address_posix.cc
index a82075542f..7a825643e1 100644
--- a/src/core/lib/iomgr/resolve_address_posix.cc
+++ b/src/core/lib/iomgr/resolve_address_posix.cc
@@ -19,7 +19,7 @@
 #include <grpc/support/port_platform.h>
 
 #include "src/core/lib/iomgr/port.h"
-#ifdef GRPC_POSIX_SOCKET
+#ifdef GRPC_POSIX_SOCKET_RESOLVE_ADDRESS
 
 #include "src/core/lib/iomgr/sockaddr.h"
 
diff --git a/src/core/lib/iomgr/sockaddr_posix.h b/src/core/lib/iomgr/sockaddr_posix.h
index 5b18bbc465..3cedd9082d 100644
--- a/src/core/lib/iomgr/sockaddr_posix.h
+++ b/src/core/lib/iomgr/sockaddr_posix.h
@@ -23,7 +23,7 @@
 
 #include "src/core/lib/iomgr/port.h"
 
-#ifdef GRPC_POSIX_SOCKET
+#ifdef GRPC_POSIX_SOCKET_SOCKADDR
 #include <arpa/inet.h>
 #include <netdb.h>
 #include <netinet/in.h>
diff --git a/src/core/lib/iomgr/socket_factory_posix.cc b/src/core/lib/iomgr/socket_factory_posix.cc
index 1d1e36c0e3..57137769c8 100644
--- a/src/core/lib/iomgr/socket_factory_posix.cc
+++ b/src/core/lib/iomgr/socket_factory_posix.cc
@@ -20,7 +20,7 @@
 
 #include "src/core/lib/iomgr/port.h"
 
-#ifdef GRPC_POSIX_SOCKET
+#ifdef GRPC_POSIX_SOCKET_SOCKET_FACTORY
 
 #include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/gpr/useful.h"
diff --git a/src/core/lib/iomgr/socket_utils_common_posix.cc b/src/core/lib/iomgr/socket_utils_common_posix.cc
index 04a1767731..caee652307 100644
--- a/src/core/lib/iomgr/socket_utils_common_posix.cc
+++ b/src/core/lib/iomgr/socket_utils_common_posix.cc
@@ -20,7 +20,7 @@
 
 #include "src/core/lib/iomgr/port.h"
 
-#ifdef GRPC_POSIX_SOCKET
+#ifdef GRPC_POSIX_SOCKET_UTILS_COMMON
 
 #include "src/core/lib/iomgr/socket_utils.h"
 #include "src/core/lib/iomgr/socket_utils_posix.h"
diff --git a/src/core/lib/iomgr/tcp_client_cfstream.cc b/src/core/lib/iomgr/tcp_client_cfstream.cc
new file mode 100644
index 0000000000..ffed3bbef6
--- /dev/null
+++ b/src/core/lib/iomgr/tcp_client_cfstream.cc
@@ -0,0 +1,216 @@
+
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#include "src/core/lib/iomgr/port.h"
+
+#ifdef GRPC_CFSTREAM_CLIENT
+
+#include <CoreFoundation/CoreFoundation.h>
+
+#include <string.h>
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/sync.h>
+
+#include <netinet/in.h>
+
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/gpr/host_port.h"
+#include "src/core/lib/iomgr/cfstream_handle.h"
+#include "src/core/lib/iomgr/closure.h"
+#include "src/core/lib/iomgr/endpoint_cfstream.h"
+#include "src/core/lib/iomgr/error.h"
+#include "src/core/lib/iomgr/error_cfstream.h"
+#include "src/core/lib/iomgr/sockaddr_utils.h"
+#include "src/core/lib/iomgr/tcp_client.h"
+#include "src/core/lib/iomgr/timer.h"
+
+extern grpc_core::TraceFlag grpc_tcp_trace;
+
+typedef struct CFStreamConnect {
+  gpr_mu mu;
+  gpr_refcount refcount;
+
+  CFReadStreamRef read_stream;
+  CFWriteStreamRef write_stream;
+  CFStreamHandle* stream_sync;
+
+  grpc_timer alarm;
+  grpc_closure on_alarm;
+  grpc_closure on_open;
+
+  bool read_stream_open;
+  bool write_stream_open;
+  bool failed;
+
+  grpc_closure* closure;
+  grpc_endpoint** endpoint;
+  int refs;
+  char* addr_name;
+  grpc_resource_quota* resource_quota;
+} CFStreamConnect;
+
+static void CFStreamConnectCleanup(CFStreamConnect* connect) {
+  grpc_resource_quota_unref_internal(connect->resource_quota);
+  CFSTREAM_HANDLE_UNREF(connect->stream_sync, "async connect clean up");
+  CFRelease(connect->read_stream);
+  CFRelease(connect->write_stream);
+  gpr_mu_destroy(&connect->mu);
+  gpr_free(connect->addr_name);
+  gpr_free(connect);
+}
+
+static void OnAlarm(void* arg, grpc_error* error) {
+  CFStreamConnect* connect = static_cast<CFStreamConnect*>(arg);
+  if (grpc_tcp_trace.enabled()) {
+    gpr_log(GPR_DEBUG, "CLIENT_CONNECT :%p OnAlarm, error:%p", connect, error);
+  }
+  gpr_mu_lock(&connect->mu);
+  grpc_closure* closure = connect->closure;
+  connect->closure = nil;
+  const bool done = (--connect->refs == 0);
+  gpr_mu_unlock(&connect->mu);
+  // Only schedule a callback once, by either OnAlarm or OnOpen. The
+  // first one issues callback while the second one does cleanup.
+  if (done) {
+    CFStreamConnectCleanup(connect);
+  } else {
+    grpc_error* error =
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("connect() timed out");
+    GRPC_CLOSURE_SCHED(closure, error);
+  }
+}
+
+static void OnOpen(void* arg, grpc_error* error) {
+  CFStreamConnect* connect = static_cast<CFStreamConnect*>(arg);
+  if (grpc_tcp_trace.enabled()) {
+    gpr_log(GPR_DEBUG, "CLIENT_CONNECT :%p OnOpen, error:%p", connect, error);
+  }
+  gpr_mu_lock(&connect->mu);
+  grpc_timer_cancel(&connect->alarm);
+  grpc_closure* closure = connect->closure;
+  connect->closure = nil;
+
+  bool done = (--connect->refs == 0);
+  grpc_endpoint** endpoint = connect->endpoint;
+
+  // Only schedule a callback once, by either OnAlarm or OnOpen. The
+  // first one issues callback while the second one does cleanup.
+  if (done) {
+    gpr_mu_unlock(&connect->mu);
+    CFStreamConnectCleanup(connect);
+  } else {
+    if (error == GRPC_ERROR_NONE) {
+      CFErrorRef stream_error = CFReadStreamCopyError(connect->read_stream);
+      if (stream_error == NULL) {
+        stream_error = CFWriteStreamCopyError(connect->write_stream);
+      }
+      if (stream_error) {
+        error = GRPC_ERROR_CREATE_FROM_CFERROR(stream_error, "connect() error");
+        CFRelease(stream_error);
+      }
+      if (error == GRPC_ERROR_NONE) {
+        *endpoint = grpc_cfstream_endpoint_create(
+            connect->read_stream, connect->write_stream, connect->addr_name,
+            connect->resource_quota, connect->stream_sync);
+      }
+    } else {
+      GRPC_ERROR_REF(error);
+    }
+    gpr_mu_unlock(&connect->mu);
+    GRPC_CLOSURE_SCHED(closure, error);
+  }
+}
+
+static void ParseResolvedAddress(const grpc_resolved_address* addr,
+                                 CFStringRef* host, int* port) {
+  char *host_port, *host_string, *port_string;
+  grpc_sockaddr_to_string(&host_port, addr, 1);
+  gpr_split_host_port(host_port, &host_string, &port_string);
+  *host = CFStringCreateWithCString(NULL, host_string, kCFStringEncodingUTF8);
+  gpr_free(host_string);
+  gpr_free(port_string);
+  gpr_free(host_port);
+  *port = grpc_sockaddr_get_port(addr);
+}
+
+static void CFStreamClientConnect(grpc_closure* closure, grpc_endpoint** ep,
+                                  grpc_pollset_set* interested_parties,
+                                  const grpc_channel_args* channel_args,
+                                  const grpc_resolved_address* resolved_addr,
+                                  grpc_millis deadline) {
+  CFStreamConnect* connect;
+
+  connect = (CFStreamConnect*)gpr_zalloc(sizeof(CFStreamConnect));
+  connect->closure = closure;
+  connect->endpoint = ep;
+  connect->addr_name = grpc_sockaddr_to_uri(resolved_addr);
+  // connect->resource_quota = resource_quota;
+  connect->refs = 2;  // One for the connect operation, one for the timer.
+  gpr_ref_init(&connect->refcount, 1);
+  gpr_mu_init(&connect->mu);
+
+  if (grpc_tcp_trace.enabled()) {
+    gpr_log(GPR_DEBUG, "CLIENT_CONNECT: %s: asynchronously connecting",
+            connect->addr_name);
+  }
+
+  grpc_resource_quota* resource_quota = grpc_resource_quota_create(NULL);
+  if (channel_args != NULL) {
+    for (size_t i = 0; i < channel_args->num_args; i++) {
+      if (0 == strcmp(channel_args->args[i].key, GRPC_ARG_RESOURCE_QUOTA)) {
+        grpc_resource_quota_unref_internal(resource_quota);
+        resource_quota = grpc_resource_quota_ref_internal(
+            (grpc_resource_quota*)channel_args->args[i].value.pointer.p);
+      }
+    }
+  }
+  connect->resource_quota = resource_quota;
+
+  CFReadStreamRef read_stream;
+  CFWriteStreamRef write_stream;
+
+  CFStringRef host;
+  int port;
+  ParseResolvedAddress(resolved_addr, &host, &port);
+  CFStreamCreatePairWithSocketToHost(NULL, host, port, &read_stream,
+                                     &write_stream);
+  CFRelease(host);
+  connect->read_stream = read_stream;
+  connect->write_stream = write_stream;
+  connect->stream_sync =
+      CFStreamHandle::CreateStreamHandle(read_stream, write_stream);
+  GRPC_CLOSURE_INIT(&connect->on_open, OnOpen, static_cast<void*>(connect),
+                    grpc_schedule_on_exec_ctx);
+  connect->stream_sync->NotifyOnOpen(&connect->on_open);
+  GRPC_CLOSURE_INIT(&connect->on_alarm, OnAlarm, connect,
+                    grpc_schedule_on_exec_ctx);
+  gpr_mu_lock(&connect->mu);
+  CFReadStreamOpen(read_stream);
+  CFWriteStreamOpen(write_stream);
+  grpc_timer_init(&connect->alarm, deadline, &connect->on_alarm);
+  gpr_mu_unlock(&connect->mu);
+}
+
+grpc_tcp_client_vtable grpc_posix_tcp_client_vtable = {CFStreamClientConnect};
+
+#endif /* GRPC_CFSTREAM_CLIENT */
diff --git a/src/core/lib/iomgr/tcp_client_custom.cc b/src/core/lib/iomgr/tcp_client_custom.cc
index 932c79ea0b..9389861d07 100644
--- a/src/core/lib/iomgr/tcp_client_custom.cc
+++ b/src/core/lib/iomgr/tcp_client_custom.cc
@@ -140,12 +140,12 @@ static void tcp_connect(grpc_closure* closure, grpc_endpoint** ep,
             socket, connect->addr_name);
   }
 
-  grpc_custom_socket_vtable->connect(
-      socket, (const grpc_sockaddr*)resolved_addr->addr, resolved_addr->len,
-      custom_connect_callback);
   GRPC_CLOSURE_INIT(&connect->on_alarm, on_alarm, socket,
                     grpc_schedule_on_exec_ctx);
   grpc_timer_init(&connect->alarm, deadline, &connect->on_alarm);
+  grpc_custom_socket_vtable->connect(
+      socket, (const grpc_sockaddr*)resolved_addr->addr, resolved_addr->len,
+      custom_connect_callback);
 }
 
 grpc_tcp_client_vtable custom_tcp_client_vtable = {tcp_connect};
diff --git a/src/core/lib/iomgr/tcp_client_posix.cc b/src/core/lib/iomgr/tcp_client_posix.cc
index 1b43258a91..71e08f1230 100644
--- a/src/core/lib/iomgr/tcp_client_posix.cc
+++ b/src/core/lib/iomgr/tcp_client_posix.cc
@@ -20,7 +20,7 @@
 
 #include "src/core/lib/iomgr/port.h"
 
-#ifdef GRPC_POSIX_SOCKET
+#ifdef GRPC_POSIX_SOCKET_TCP_CLIENT
 
 #include "src/core/lib/iomgr/tcp_client_posix.h"
 
diff --git a/src/core/lib/iomgr/tcp_posix.cc b/src/core/lib/iomgr/tcp_posix.cc
index b79ffe20f1..43d545846d 100644
--- a/src/core/lib/iomgr/tcp_posix.cc
+++ b/src/core/lib/iomgr/tcp_posix.cc
@@ -20,7 +20,7 @@
 
 #include "src/core/lib/iomgr/port.h"
 
-#ifdef GRPC_POSIX_SOCKET
+#ifdef GRPC_POSIX_SOCKET_TCP
 
 #include "src/core/lib/iomgr/network_status_tracker.h"
 #include "src/core/lib/iomgr/tcp_posix.h"
@@ -70,7 +70,9 @@ struct grpc_tcp {
   grpc_endpoint base;
   grpc_fd* em_fd;
   int fd;
-  bool finished_edge;
+  /* Used by the endpoint read function to distinguish the very first read call
+   * from the rest */
+  bool is_first_read;
   double target_length;
   double bytes_read_this_round;
   gpr_refcount refcount;
@@ -377,7 +379,6 @@ static void tcp_do_read(grpc_tcp* tcp) {
   ssize_t read_bytes;
   size_t i;
 
-  GPR_ASSERT(!tcp->finished_edge);
   GPR_ASSERT(tcp->incoming_buffer->count <= MAX_READ_IOVEC);
 
   for (i = 0; i < tcp->incoming_buffer->count; i++) {
@@ -473,7 +474,6 @@ static void tcp_continue_read(grpc_tcp* tcp) {
 
 static void tcp_handle_read(void* arg /* grpc_tcp */, grpc_error* error) {
   grpc_tcp* tcp = static_cast<grpc_tcp*>(arg);
-  GPR_ASSERT(!tcp->finished_edge);
   if (grpc_tcp_trace.enabled()) {
     gpr_log(GPR_INFO, "TCP:%p got_read: %s", tcp, grpc_error_string(error));
   }
@@ -497,10 +497,17 @@ static void tcp_read(grpc_endpoint* ep, grpc_slice_buffer* incoming_buffer,
   grpc_slice_buffer_reset_and_unref_internal(incoming_buffer);
   grpc_slice_buffer_swap(incoming_buffer, &tcp->last_read_buffer);
   TCP_REF(tcp, "read");
-  if (tcp->finished_edge) {
-    tcp->finished_edge = false;
+  if (tcp->is_first_read) {
+    /* Endpoint read called for the very first time. Register read callback with
+     * the polling engine */
+    tcp->is_first_read = false;
     notify_on_read(tcp);
   } else {
+    /* Not the first time. We may or may not have more bytes available. In any
+     * case call tcp->read_done_closure (i.e tcp_handle_read()) which does the
+     * right thing (i.e calls tcp_do_read() which either reads the available
+     * bytes or calls notify_on_read() to be notified when new bytes become
+     * available */
     GRPC_CLOSURE_SCHED(&tcp->read_done_closure, GRPC_ERROR_NONE);
   }
 }
@@ -778,7 +785,8 @@ grpc_endpoint* grpc_tcp_create(grpc_fd* em_fd,
   tcp->min_read_chunk_size = tcp_min_read_chunk_size;
   tcp->max_read_chunk_size = tcp_max_read_chunk_size;
   tcp->bytes_read_this_round = 0;
-  tcp->finished_edge = true;
+  /* Will be set to false by the very first endpoint read function */
+  tcp->is_first_read = true;
   /* paired with unref in grpc_tcp_destroy */
   gpr_ref_init(&tcp->refcount, 1);
   gpr_atm_no_barrier_store(&tcp->shutdown_count, 0);
@@ -811,4 +819,4 @@ void grpc_tcp_destroy_and_release_fd(grpc_endpoint* ep, int* fd,
   TCP_UNREF(tcp, "destroy");
 }
 
-#endif
+#endif /* GRPC_POSIX_SOCKET_TCP */
diff --git a/src/core/lib/iomgr/tcp_server_posix.cc b/src/core/lib/iomgr/tcp_server_posix.cc
index b39a0754ba..ce18ff99e6 100644
--- a/src/core/lib/iomgr/tcp_server_posix.cc
+++ b/src/core/lib/iomgr/tcp_server_posix.cc
@@ -25,7 +25,7 @@
 
 #include "src/core/lib/iomgr/port.h"
 
-#ifdef GRPC_POSIX_SOCKET
+#ifdef GRPC_POSIX_SOCKET_TCP_SERVER
 
 #include "src/core/lib/iomgr/tcp_server.h"
 
@@ -559,4 +559,4 @@ grpc_tcp_server_vtable grpc_posix_tcp_server_vtable = {
     tcp_server_shutdown_starting_add,
     tcp_server_unref,
     tcp_server_shutdown_listeners};
-#endif
+#endif /* GRPC_POSIX_SOCKET_TCP_SERVER */
diff --git a/src/core/lib/iomgr/tcp_server_utils_posix_common.cc b/src/core/lib/iomgr/tcp_server_utils_posix_common.cc
index f21f4ad015..b9f8145572 100644
--- a/src/core/lib/iomgr/tcp_server_utils_posix_common.cc
+++ b/src/core/lib/iomgr/tcp_server_utils_posix_common.cc
@@ -20,7 +20,7 @@
 
 #include "src/core/lib/iomgr/port.h"
 
-#ifdef GRPC_POSIX_SOCKET
+#ifdef GRPC_POSIX_SOCKET_TCP_SERVER_UTILS_COMMON
 
 #include "src/core/lib/iomgr/tcp_server_utils_posix.h"
 
@@ -217,4 +217,4 @@ error:
   return ret;
 }
 
-#endif /* GRPC_POSIX_SOCKET */
+#endif /* GRPC_POSIX_SOCKET_TCP_SERVER_UTILS_COMMON */
diff --git a/src/core/lib/security/credentials/oauth2/oauth2_credentials.cc b/src/core/lib/security/credentials/oauth2/oauth2_credentials.cc
index 2129029737..43dd68e874 100644
--- a/src/core/lib/security/credentials/oauth2/oauth2_credentials.cc
+++ b/src/core/lib/security/credentials/oauth2/oauth2_credentials.cc
@@ -219,9 +219,11 @@ static void on_oauth2_token_fetcher_http_response(void* user_data,
   gpr_mu_lock(&c->mu);
   c->token_fetch_pending = false;
   c->access_token_md = GRPC_MDELEM_REF(access_token_md);
-  c->token_expiration = status == GRPC_CREDENTIALS_OK
-                            ? grpc_core::ExecCtx::Get()->Now() + token_lifetime
-                            : 0;
+  c->token_expiration =
+      status == GRPC_CREDENTIALS_OK
+          ? gpr_time_add(gpr_now(GPR_CLOCK_MONOTONIC),
+                         gpr_time_from_millis(token_lifetime, GPR_TIMESPAN))
+          : gpr_inf_past(GPR_CLOCK_MONOTONIC);
   grpc_oauth2_pending_get_request_metadata* pending_request =
       c->pending_requests;
   c->pending_requests = nullptr;
@@ -259,8 +261,10 @@ static bool oauth2_token_fetcher_get_request_metadata(
   grpc_mdelem cached_access_token_md = GRPC_MDNULL;
   gpr_mu_lock(&c->mu);
   if (!GRPC_MDISNULL(c->access_token_md) &&
-      (c->token_expiration - grpc_core::ExecCtx::Get()->Now() >
-       refresh_threshold)) {
+      gpr_time_cmp(
+          gpr_time_sub(c->token_expiration, gpr_now(GPR_CLOCK_MONOTONIC)),
+          gpr_time_from_seconds(GRPC_SECURE_TOKEN_REFRESH_THRESHOLD_SECS,
+                                GPR_TIMESPAN)) > 0) {
     cached_access_token_md = GRPC_MDELEM_REF(c->access_token_md);
   }
   if (!GRPC_MDISNULL(cached_access_token_md)) {
@@ -333,7 +337,7 @@ static void init_oauth2_token_fetcher(grpc_oauth2_token_fetcher_credentials* c,
   c->base.type = GRPC_CALL_CREDENTIALS_TYPE_OAUTH2;
   gpr_ref_init(&c->base.refcount, 1);
   gpr_mu_init(&c->mu);
-  c->token_expiration = 0;
+  c->token_expiration = gpr_inf_past(GPR_CLOCK_MONOTONIC);
   c->fetch_func = fetch_func;
   c->pollent =
       grpc_polling_entity_create_from_pollset_set(grpc_pollset_set_create());
diff --git a/src/core/lib/security/credentials/oauth2/oauth2_credentials.h b/src/core/lib/security/credentials/oauth2/oauth2_credentials.h
index c0dd1546e3..12a1d4484f 100644
--- a/src/core/lib/security/credentials/oauth2/oauth2_credentials.h
+++ b/src/core/lib/security/credentials/oauth2/oauth2_credentials.h
@@ -71,7 +71,7 @@ typedef struct {
   grpc_call_credentials base;
   gpr_mu mu;
   grpc_mdelem access_token_md;
-  grpc_millis token_expiration;
+  gpr_timespec token_expiration;
   bool token_fetch_pending;
   grpc_oauth2_pending_get_request_metadata* pending_requests;
   grpc_httpcli_context httpcli_context;
diff --git a/src/core/lib/security/util/json_util.cc b/src/core/lib/security/util/json_util.cc
index 75512a19c9..fe9f5fe3d3 100644
--- a/src/core/lib/security/util/json_util.cc
+++ b/src/core/lib/security/util/json_util.cc
@@ -29,6 +29,10 @@ const char* grpc_json_get_string_property(const grpc_json* json,
                                           const char* prop_name) {
   grpc_json* child;
   for (child = json->child; child != nullptr; child = child->next) {
+    if (child->key == nullptr) {
+      gpr_log(GPR_ERROR, "Invalid (null) JSON key encountered");
+      return nullptr;
+    }
     if (strcmp(child->key, prop_name) == 0) break;
   }
   if (child == nullptr || child->type != GRPC_JSON_STRING) {
diff --git a/src/core/lib/slice/slice_buffer.cc b/src/core/lib/slice/slice_buffer.cc
index fd56997388..1f1c08b159 100644
--- a/src/core/lib/slice/slice_buffer.cc
+++ b/src/core/lib/slice/slice_buffer.cc
@@ -333,14 +333,26 @@ void grpc_slice_buffer_trim_end(grpc_slice_buffer* sb, size_t n,
     size_t slice_len = GRPC_SLICE_LENGTH(slice);
     if (slice_len > n) {
       sb->slices[idx] = grpc_slice_split_head(&slice, slice_len - n);
-      grpc_slice_buffer_add_indexed(garbage, slice);
+      if (garbage) {
+        grpc_slice_buffer_add_indexed(garbage, slice);
+      } else {
+        grpc_slice_unref_internal(slice);
+      }
       return;
     } else if (slice_len == n) {
-      grpc_slice_buffer_add_indexed(garbage, slice);
+      if (garbage) {
+        grpc_slice_buffer_add_indexed(garbage, slice);
+      } else {
+        grpc_slice_unref_internal(slice);
+      }
       sb->count = idx;
       return;
     } else {
-      grpc_slice_buffer_add_indexed(garbage, slice);
+      if (garbage) {
+        grpc_slice_buffer_add_indexed(garbage, slice);
+      } else {
+        grpc_slice_unref_internal(slice);
+      }
       n -= slice_len;
       sb->count = idx;
     }
diff --git a/src/core/lib/surface/call.cc b/src/core/lib/surface/call.cc
index 86e0afa6ee..1cf8ea94e7 100644
--- a/src/core/lib/surface/call.cc
+++ b/src/core/lib/surface/call.cc
@@ -516,7 +516,6 @@ static void release_call(void* call, grpc_error* error) {
   grpc_call* c = static_cast<grpc_call*>(call);
   grpc_channel* channel = c->channel;
   grpc_call_combiner_destroy(&c->call_combiner);
-  gpr_free((char*)c->peer_string);
   grpc_channel_update_call_size_estimate(channel, gpr_arena_destroy(c->arena));
   GRPC_CHANNEL_INTERNAL_UNREF(channel, "call");
 }
diff --git a/src/core/lib/transport/transport.cc b/src/core/lib/transport/transport.cc
index 6b41e4b37e..039d603394 100644
--- a/src/core/lib/transport/transport.cc
+++ b/src/core/lib/transport/transport.cc
@@ -184,7 +184,8 @@ void grpc_transport_set_pops(grpc_transport* transport, grpc_stream* stream,
              nullptr) {
     transport->vtable->set_pollset_set(transport, stream, pollset_set);
   } else {
-    abort();
+    // No-op for empty pollset. Empty pollset is possible when using
+    // non-fd-based event engines such as CFStream.
   }
 }
 
diff --git a/src/core/lib/transport/transport.h b/src/core/lib/transport/transport.h
index 10e9df0f7c..b2e252d939 100644
--- a/src/core/lib/transport/transport.h
+++ b/src/core/lib/transport/transport.h
@@ -168,13 +168,11 @@ struct grpc_transport_stream_op_batch_payload {
     /** Iff send_initial_metadata != NULL, flags associated with
         send_initial_metadata: a bitfield of GRPC_INITIAL_METADATA_xxx */
     uint32_t send_initial_metadata_flags;
-    // If non-NULL, will be set by the transport to the peer string
-    // (a char*, which the caller takes ownership of).
+    // If non-NULL, will be set by the transport to the peer string (a char*).
+    // The transport retains ownership of the string.
     // Note: This pointer may be used by the transport after the
     // send_initial_metadata op is completed.  It must remain valid
     // until the call is destroyed.
-    // Note: When a transport sets this, it must free the previous
-    // value, if any.
     gpr_atm* peer_string;
   } send_initial_metadata;
 
@@ -202,13 +200,11 @@ struct grpc_transport_stream_op_batch_payload {
     // immediately available.  This may be a signal that we received a
     // Trailers-Only response.
     bool* trailing_metadata_available;
-    // If non-NULL, will be set by the transport to the peer string
-    // (a char*, which the caller takes ownership of).
+    // If non-NULL, will be set by the transport to the peer string (a char*).
+    // The transport retains ownership of the string.
     // Note: This pointer may be used by the transport after the
     // recv_initial_metadata op is completed.  It must remain valid
     // until the call is destroyed.
-    // Note: When a transport sets this, it must free the previous
-    // value, if any.
     gpr_atm* peer_string;
   } recv_initial_metadata;
 
diff --git a/src/cpp/server/server_builder.cc b/src/cpp/server/server_builder.cc
index e951801965..7f5b439dfb 100644
--- a/src/cpp/server/server_builder.cc
+++ b/src/cpp/server/server_builder.cc
@@ -39,8 +39,8 @@ static void do_plugin_list_init(void) {
 }
 
 ServerBuilder::ServerBuilder()
-    : max_receive_message_size_(-1),
-      max_send_message_size_(-1),
+    : max_receive_message_size_(INT_MIN),
+      max_send_message_size_(INT_MIN),
       sync_server_settings_(SyncServerSettings()),
       resource_quota_(nullptr),
       generic_service_(nullptr) {
@@ -186,10 +186,12 @@ std::unique_ptr<Server> ServerBuilder::BuildAndStart() {
     (*plugin)->UpdateChannelArguments(&args);
   }
 
-  if (max_receive_message_size_ >= 0) {
+  if (max_receive_message_size_ >= -1) {
     args.SetInt(GRPC_ARG_MAX_RECEIVE_MESSAGE_LENGTH, max_receive_message_size_);
   }
 
+  // The default message size is -1 (max), so no need to explicitly set it for
+  // -1.
   if (max_send_message_size_ >= 0) {
     args.SetInt(GRPC_ARG_MAX_SEND_MESSAGE_LENGTH, max_send_message_size_);
   }
diff --git a/src/csharp/Grpc.Core.NativeDebug.nuspec b/src/csharp/Grpc.Core.NativeDebug.nuspec
new file mode 100644
index 0000000000..d4bb8ad223
--- /dev/null
+++ b/src/csharp/Grpc.Core.NativeDebug.nuspec
@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="utf-8"?>
+<package>
+  <metadata>
+    <id>Grpc.Core.NativeDebug</id>
+    <title>Grpc.Core: Native Debug Symbols</title>
+    <summary>Debug symbols for the native library contained in Grpc.Core</summary>
+    <description>Currently contains grpc_csharp_ext.pdb</description>
+    <version>$version$</version>
+    <authors>Google Inc.</authors>
+    <owners>grpc-packages</owners>
+    <licenseUrl>https://github.com/grpc/grpc/blob/master/LICENSE</licenseUrl>
+    <projectUrl>https://github.com/grpc/grpc</projectUrl>
+    <requireLicenseAcceptance>false</requireLicenseAcceptance>
+    <releaseNotes>Release $version$</releaseNotes>
+    <copyright>Copyright 2015, Google Inc.</copyright>
+    <tags>gRPC RPC Protocol HTTP/2</tags>
+  </metadata>
+  <files>
+    <!-- forward slashes in src path enable building on Linux -->
+    <file src="nativelibs/csharp_ext_windows_x86/grpc_csharp_ext.dll" target="runtimes/win/native/grpc_csharp_ext.x86.dll" />
+    <file src="nativelibs/csharp_ext_windows_x86/grpc_csharp_ext.pdb" target="runtimes/win/native/grpc_csharp_ext.x86.pdb" />
+    <file src="nativelibs/csharp_ext_windows_x64/grpc_csharp_ext.dll" target="runtimes/win/native/grpc_csharp_ext.x64.dll" />
+    <file src="nativelibs/csharp_ext_windows_x64/grpc_csharp_ext.pdb" target="runtimes/win/native/grpc_csharp_ext.x64.pdb" />
+  </files>
+</package>
diff --git a/src/csharp/Grpc.Examples/MathGrpc.cs b/src/csharp/Grpc.Examples/MathGrpc.cs
index 045708b947..a4739da81d 100644
--- a/src/csharp/Grpc.Examples/MathGrpc.cs
+++ b/src/csharp/Grpc.Examples/MathGrpc.cs
@@ -17,7 +17,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 //
-#pragma warning disable 1591
+#pragma warning disable 0414, 1591
 #region Designer generated code
 
 using grpc = global::Grpc.Core;
diff --git a/src/csharp/Grpc.HealthCheck/HealthGrpc.cs b/src/csharp/Grpc.HealthCheck/HealthGrpc.cs
index a26f483981..ebd890e48d 100644
--- a/src/csharp/Grpc.HealthCheck/HealthGrpc.cs
+++ b/src/csharp/Grpc.HealthCheck/HealthGrpc.cs
@@ -20,7 +20,7 @@
 // The canonical version of this proto can be found at
 // https://github.com/grpc/grpc-proto/blob/master/grpc/health/v1/health.proto
 //
-#pragma warning disable 1591
+#pragma warning disable 0414, 1591
 #region Designer generated code
 
 using grpc = global::Grpc.Core;
diff --git a/src/csharp/Grpc.IntegrationTesting/BenchmarkServiceGrpc.cs b/src/csharp/Grpc.IntegrationTesting/BenchmarkServiceGrpc.cs
index 20b933fdfa..e2a4b93cef 100644
--- a/src/csharp/Grpc.IntegrationTesting/BenchmarkServiceGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/BenchmarkServiceGrpc.cs
@@ -19,7 +19,7 @@
 //
 // An integration test service that covers all the method signature permutations
 // of unary/streaming requests/responses.
-#pragma warning disable 1591
+#pragma warning disable 0414, 1591
 #region Designer generated code
 
 using grpc = global::Grpc.Core;
diff --git a/src/csharp/Grpc.IntegrationTesting/EmptyService.cs b/src/csharp/Grpc.IntegrationTesting/EmptyService.cs
new file mode 100644
index 0000000000..e9fe5b79ef
--- /dev/null
+++ b/src/csharp/Grpc.IntegrationTesting/EmptyService.cs
@@ -0,0 +1,38 @@
+// <auto-generated>
+//     Generated by the protocol buffer compiler.  DO NOT EDIT!
+//     source: src/proto/grpc/testing/empty_service.proto
+// </auto-generated>
+#pragma warning disable 1591, 0612, 3021
+#region Designer generated code
+
+using pb = global::Google.Protobuf;
+using pbc = global::Google.Protobuf.Collections;
+using pbr = global::Google.Protobuf.Reflection;
+using scg = global::System.Collections.Generic;
+namespace Grpc.Testing {
+
+  /// <summary>Holder for reflection information generated from src/proto/grpc/testing/empty_service.proto</summary>
+  public static partial class EmptyServiceReflection {
+
+    #region Descriptor
+    /// <summary>File descriptor for src/proto/grpc/testing/empty_service.proto</summary>
+    public static pbr::FileDescriptor Descriptor {
+      get { return descriptor; }
+    }
+    private static pbr::FileDescriptor descriptor;
+
+    static EmptyServiceReflection() {
+      byte[] descriptorData = global::System.Convert.FromBase64String(
+          string.Concat(
+            "CipzcmMvcHJvdG8vZ3JwYy90ZXN0aW5nL2VtcHR5X3NlcnZpY2UucHJvdG8S",
+            "DGdycGMudGVzdGluZzIOCgxFbXB0eVNlcnZpY2ViBnByb3RvMw=="));
+      descriptor = pbr::FileDescriptor.FromGeneratedCode(descriptorData,
+          new pbr::FileDescriptor[] { },
+          new pbr::GeneratedClrTypeInfo(null, null));
+    }
+    #endregion
+
+  }
+}
+
+#endregion Designer generated code
diff --git a/src/csharp/Grpc.IntegrationTesting/EmptyServiceGrpc.cs b/src/csharp/Grpc.IntegrationTesting/EmptyServiceGrpc.cs
new file mode 100644
index 0000000000..2d233fbdc0
--- /dev/null
+++ b/src/csharp/Grpc.IntegrationTesting/EmptyServiceGrpc.cs
@@ -0,0 +1,85 @@
+// <auto-generated>
+//     Generated by the protocol buffer compiler.  DO NOT EDIT!
+//     source: src/proto/grpc/testing/empty_service.proto
+// </auto-generated>
+// Original file comments:
+// Copyright 2018 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#pragma warning disable 0414, 1591
+#region Designer generated code
+
+using grpc = global::Grpc.Core;
+
+namespace Grpc.Testing {
+  /// <summary>
+  /// A service that has zero methods.
+  /// See https://github.com/grpc/grpc/issues/15574
+  /// </summary>
+  public static partial class EmptyService
+  {
+    static readonly string __ServiceName = "grpc.testing.EmptyService";
+
+
+    /// <summary>Service descriptor</summary>
+    public static global::Google.Protobuf.Reflection.ServiceDescriptor Descriptor
+    {
+      get { return global::Grpc.Testing.EmptyServiceReflection.Descriptor.Services[0]; }
+    }
+
+    /// <summary>Base class for server-side implementations of EmptyService</summary>
+    public abstract partial class EmptyServiceBase
+    {
+    }
+
+    /// <summary>Client for EmptyService</summary>
+    public partial class EmptyServiceClient : grpc::ClientBase<EmptyServiceClient>
+    {
+      /// <summary>Creates a new client for EmptyService</summary>
+      /// <param name="channel">The channel to use to make remote calls.</param>
+      public EmptyServiceClient(grpc::Channel channel) : base(channel)
+      {
+      }
+      /// <summary>Creates a new client for EmptyService that uses a custom <c>CallInvoker</c>.</summary>
+      /// <param name="callInvoker">The callInvoker to use to make remote calls.</param>
+      public EmptyServiceClient(grpc::CallInvoker callInvoker) : base(callInvoker)
+      {
+      }
+      /// <summary>Protected parameterless constructor to allow creation of test doubles.</summary>
+      protected EmptyServiceClient() : base()
+      {
+      }
+      /// <summary>Protected constructor to allow creation of configured clients.</summary>
+      /// <param name="configuration">The client configuration.</param>
+      protected EmptyServiceClient(ClientBaseConfiguration configuration) : base(configuration)
+      {
+      }
+
+      /// <summary>Creates a new instance of client from given <c>ClientBaseConfiguration</c>.</summary>
+      protected override EmptyServiceClient NewInstance(ClientBaseConfiguration configuration)
+      {
+        return new EmptyServiceClient(configuration);
+      }
+    }
+
+    /// <summary>Creates service definition that can be registered with a server</summary>
+    /// <param name="serviceImpl">An object implementing the server-side handling logic.</param>
+    public static grpc::ServerServiceDefinition BindService(EmptyServiceBase serviceImpl)
+    {
+      return grpc::ServerServiceDefinition.CreateBuilder().Build();
+    }
+
+  }
+}
+#endregion
diff --git a/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs b/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs
index d18b9e7d5e..e8c566e167 100644
--- a/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/MetricsGrpc.cs
@@ -23,7 +23,7 @@
 // Currently, 'Gauge' (i.e a metric that represents the measured value of
 // something at an instant of time) is the only metric type supported by the
 // service.
-#pragma warning disable 1591
+#pragma warning disable 0414, 1591
 #region Designer generated code
 
 using grpc = global::Grpc.Core;
diff --git a/src/csharp/Grpc.IntegrationTesting/ReportQpsScenarioServiceGrpc.cs b/src/csharp/Grpc.IntegrationTesting/ReportQpsScenarioServiceGrpc.cs
index c9c6f75c8c..60a3890f21 100644
--- a/src/csharp/Grpc.IntegrationTesting/ReportQpsScenarioServiceGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/ReportQpsScenarioServiceGrpc.cs
@@ -19,7 +19,7 @@
 //
 // An integration test service that covers all the method signature permutations
 // of unary/streaming requests/responses.
-#pragma warning disable 1591
+#pragma warning disable 0414, 1591
 #region Designer generated code
 
 using grpc = global::Grpc.Core;
diff --git a/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs b/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs
index 6c4b77f7ac..aec4ce7be7 100644
--- a/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/TestGrpc.cs
@@ -20,7 +20,7 @@
 // An integration test service that covers all the method signature permutations
 // of unary/streaming requests/responses.
 //
-#pragma warning disable 1591
+#pragma warning disable 0414, 1591
 #region Designer generated code
 
 using grpc = global::Grpc.Core;
diff --git a/src/csharp/Grpc.IntegrationTesting/WorkerServiceGrpc.cs b/src/csharp/Grpc.IntegrationTesting/WorkerServiceGrpc.cs
index ede3ace461..85f2cfd871 100644
--- a/src/csharp/Grpc.IntegrationTesting/WorkerServiceGrpc.cs
+++ b/src/csharp/Grpc.IntegrationTesting/WorkerServiceGrpc.cs
@@ -19,7 +19,7 @@
 //
 // An integration test service that covers all the method signature permutations
 // of unary/streaming requests/responses.
-#pragma warning disable 1591
+#pragma warning disable 0414, 1591
 #region Designer generated code
 
 using grpc = global::Grpc.Core;
diff --git a/src/csharp/Grpc.Reflection/ReflectionGrpc.cs b/src/csharp/Grpc.Reflection/ReflectionGrpc.cs
index e2263cfc90..387c9fb52f 100644
--- a/src/csharp/Grpc.Reflection/ReflectionGrpc.cs
+++ b/src/csharp/Grpc.Reflection/ReflectionGrpc.cs
@@ -19,7 +19,7 @@
 //
 // Service exported by server reflection
 //
-#pragma warning disable 1591
+#pragma warning disable 0414, 1591
 #region Designer generated code
 
 using grpc = global::Grpc.Core;
diff --git a/src/csharp/build_packages_dotnetcli.bat b/src/csharp/build_packages_dotnetcli.bat
index 924d7b1697..f1111781e2 100755
--- a/src/csharp/build_packages_dotnetcli.bat
+++ b/src/csharp/build_packages_dotnetcli.bat
@@ -47,6 +47,7 @@ xcopy /Y /I nativelibs\csharp_ext_windows_x64\grpc_csharp_ext.dll ..\..\cmake\bu
 %DOTNET% pack --configuration Release Grpc.Reflection --output ..\..\..\artifacts || goto :error
 
 %NUGET% pack Grpc.nuspec -Version %VERSION% -OutputDirectory ..\..\artifacts || goto :error
+%NUGET% pack Grpc.Core.NativeDebug.nuspec -Version %VERSION% -OutputDirectory ..\..\artifacts
 %NUGET% pack Grpc.Tools.nuspec -Version %VERSION% -OutputDirectory ..\..\artifacts
 
 @rem copy resulting nuget packages to artifacts directory
diff --git a/src/csharp/build_packages_dotnetcli.sh b/src/csharp/build_packages_dotnetcli.sh
index 5c73a8f95f..fb4138a4b2 100755
--- a/src/csharp/build_packages_dotnetcli.sh
+++ b/src/csharp/build_packages_dotnetcli.sh
@@ -46,6 +46,7 @@ dotnet pack --configuration Release Grpc.HealthCheck --output ../../../artifacts
 dotnet pack --configuration Release Grpc.Reflection --output ../../../artifacts
 
 nuget pack Grpc.nuspec -Version "1.13.0-dev" -OutputDirectory ../../artifacts
+nuget pack Grpc.Core.NativeDebug.nuspec -Version "1.13.0-dev" -OutputDirectory ../../artifacts
 nuget pack Grpc.Tools.nuspec -Version "1.13.0-dev" -OutputDirectory ../../artifacts
 
 (cd ../../artifacts && zip csharp_nugets_dotnetcli.zip *.nupkg)
diff --git a/src/csharp/generate_proto_csharp.sh b/src/csharp/generate_proto_csharp.sh
index 1a38f860e8..e79728ff95 100755
--- a/src/csharp/generate_proto_csharp.sh
+++ b/src/csharp/generate_proto_csharp.sh
@@ -42,4 +42,4 @@ $PROTOC --plugin=$PLUGIN --csharp_out=$TESTING_DIR/CoreStats --grpc_out=$TESTING
 # don't match the package names. Setting -I to the correct value src/proto
 # breaks the code generation.
 $PROTOC --plugin=$PLUGIN --csharp_out=$TESTING_DIR --grpc_out=$TESTING_DIR \
-    -I . src/proto/grpc/testing/{control,echo_messages,empty,messages,metrics,payloads,benchmark_service,report_qps_scenario_service,worker_service,stats,test}.proto
+    -I . src/proto/grpc/testing/{control,echo_messages,empty,empty_service,messages,metrics,payloads,benchmark_service,report_qps_scenario_service,worker_service,stats,test}.proto
diff --git a/src/objective-c/BoringSSL.podspec b/src/objective-c/BoringSSL.podspec
index d55a56ec18..363983183e 100644
--- a/src/objective-c/BoringSSL.podspec
+++ b/src/objective-c/BoringSSL.podspec
@@ -31,7 +31,7 @@
 
 Pod::Spec.new do |s|
   s.name     = 'BoringSSL'
-  version = '10.0.4'
+  version = '10.0.5'
   s.version  = version
   s.summary  = 'BoringSSL is a fork of OpenSSL that is designed to meet Google’s needs.'
   # Adapted from the homepage:
@@ -61,8 +61,7 @@ Pod::Spec.new do |s|
     Currently BoringSSL is the SSL library in Chrome/Chromium, Android (but it’s not part of the
     NDK) and a number of other apps/programs.
   DESC
-  s.homepage = 'https://boringssl.googlesource.com/boringssl/'
-  s.documentation_url = 'https://commondatastorage.googleapis.com/chromium-boringssl-docs/headers.html'
+  s.homepage = 'https://github.com/google/boringssl'
   s.license  = { :type => 'Mixed', :file => 'LICENSE' }
   # "The name and email addresses of the library maintainers, not the Podspec maintainer."
   s.authors  = 'Adam Langley', 'David Benjamin', 'Matt Braithwaite'
diff --git a/src/objective-c/GRPCClient/GRPCCall+MobileLog.h b/src/objective-c/GRPCClient/GRPCCall+MobileLog.h
deleted file mode 100644
index 53b347d9ca..0000000000
--- a/src/objective-c/GRPCClient/GRPCCall+MobileLog.h
+++ /dev/null
@@ -1,30 +0,0 @@
-/*
- *
- * Copyright 2017 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-#import "GRPCCall.h"
-
-@interface GRPCCall (MobileLog)
-// Set the object to be passed down along channel stack with channel arg
-// GRPC_ARG_MOBILE_LOG_CONFIG. The setting may be used by custom channel
-// filters for metrics logging.
-+ (void)setLogConfig:(id)logConfig;
-
-// Obtain the object to be passed down along channel stack with channel arg
-// GRPC_ARG_MOBILE_LOG_CONFIG.
-+ (id)logConfig;
-@end
diff --git a/src/objective-c/GRPCClient/GRPCCall+MobileLog.m b/src/objective-c/GRPCClient/GRPCCall+MobileLog.m
deleted file mode 100644
index 4dedb7de8b..0000000000
--- a/src/objective-c/GRPCClient/GRPCCall+MobileLog.m
+++ /dev/null
@@ -1,33 +0,0 @@
-/*
- *
- * Copyright 2017 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-#import "GRPCCall+MobileLog.h"
-
-static id globalLogConfig = nil;
-
-@implementation GRPCCall (MobileLog)
-
-+ (void)setLogConfig:(id)logConfig {
-  globalLogConfig = logConfig;
-}
-
-+ (id)logConfig {
-  return globalLogConfig;
-}
-
-@end
diff --git a/src/objective-c/GRPCClient/private/GRPCCompletionQueue.m b/src/objective-c/GRPCClient/private/GRPCCompletionQueue.m
index 57dbde8d04..bda1c3360b 100644
--- a/src/objective-c/GRPCClient/private/GRPCCompletionQueue.m
+++ b/src/objective-c/GRPCClient/private/GRPCCompletionQueue.m
@@ -20,6 +20,14 @@
 
 #import <grpc/grpc.h>
 
+#ifdef GRPC_CFSTREAM
+const grpc_completion_queue_attributes kCompletionQueueAttr = {GRPC_CQ_CURRENT_VERSION,
+                                                               GRPC_CQ_NEXT, GRPC_CQ_NON_POLLING};
+#else
+const grpc_completion_queue_attributes kCompletionQueueAttr = {
+    GRPC_CQ_CURRENT_VERSION, GRPC_CQ_NEXT, GRPC_CQ_DEFAULT_POLLING};
+#endif
+
 @implementation GRPCCompletionQueue
 
 + (instancetype)completionQueue {
@@ -33,7 +41,8 @@
 
 - (instancetype)init {
   if ((self = [super init])) {
-    _unmanagedQueue = grpc_completion_queue_create_for_next(NULL);
+    _unmanagedQueue = grpc_completion_queue_create(
+        grpc_completion_queue_factory_lookup(&kCompletionQueueAttr), &kCompletionQueueAttr, NULL);
 
     // This is for the following block to capture the pointer by value (instead
     // of retaining self and doing self->_unmanagedQueue). This is essential
diff --git a/src/objective-c/GRPCClient/private/GRPCHost.h b/src/objective-c/GRPCClient/private/GRPCHost.h
index 6697f61be4..d9916d9303 100644
--- a/src/objective-c/GRPCClient/private/GRPCHost.h
+++ b/src/objective-c/GRPCClient/private/GRPCHost.h
@@ -37,6 +37,7 @@ struct grpc_channel_credentials;
 @property(nonatomic) grpc_compression_algorithm compressAlgorithm;
 @property(nonatomic) int keepaliveInterval;
 @property(nonatomic) int keepaliveTimeout;
+@property(nonatomic) id logContext;
 
 /** The following properties should only be modified for testing: */
 
diff --git a/src/objective-c/GRPCClient/private/GRPCHost.m b/src/objective-c/GRPCClient/private/GRPCHost.m
index c3ea9afc37..bd5fd94118 100644
--- a/src/objective-c/GRPCClient/private/GRPCHost.m
+++ b/src/objective-c/GRPCClient/private/GRPCHost.m
@@ -18,7 +18,6 @@
 
 #import "GRPCHost.h"
 
-#import <GRPCClient/GRPCCall+MobileLog.h>
 #import <GRPCClient/GRPCCall.h>
 #include <grpc/grpc.h>
 #include <grpc/grpc_security.h>
@@ -223,9 +222,9 @@ static NSMutableDictionary *kHostCache;
     args[@GRPC_ARG_KEEPALIVE_TIMEOUT_MS] = [NSNumber numberWithInt:_keepaliveTimeout];
   }
 
-  id logConfig = [GRPCCall logConfig];
-  if (logConfig != nil) {
-    args[@GRPC_ARG_MOBILE_LOG_CONFIG] = logConfig;
+  id logContext = self.logContext;
+  if (logContext != nil) {
+    args[@GRPC_ARG_MOBILE_LOG_CONTEXT] = logContext;
   }
 
   if (useCronet) {
diff --git a/src/objective-c/examples/Sample/Sample.xcodeproj/project.pbxproj b/src/objective-c/examples/Sample/Sample.xcodeproj/project.pbxproj
index ab7159cda2..cdd1c6c8f7 100644
--- a/src/objective-c/examples/Sample/Sample.xcodeproj/project.pbxproj
+++ b/src/objective-c/examples/Sample/Sample.xcodeproj/project.pbxproj
@@ -325,6 +325,7 @@
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
 				INFOPLIST_FILE = Sample/Info.plist;
+				LD_GENERATE_MAP_FILE = YES;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = "org.grpc.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
@@ -337,6 +338,7 @@
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
 				INFOPLIST_FILE = Sample/Info.plist;
+				LD_GENERATE_MAP_FILE = YES;
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = "org.grpc.$(PRODUCT_NAME:rfc1034identifier)";
 				PRODUCT_NAME = "$(TARGET_NAME)";
diff --git a/src/objective-c/examples/Sample/Sample.xcodeproj/xcshareddata/xcschemes/Sample.xcscheme b/src/objective-c/examples/Sample/Sample.xcodeproj/xcshareddata/xcschemes/Sample.xcscheme
index d399e22e46..e356ea22a6 100644
--- a/src/objective-c/examples/Sample/Sample.xcodeproj/xcshareddata/xcschemes/Sample.xcscheme
+++ b/src/objective-c/examples/Sample/Sample.xcodeproj/xcshareddata/xcschemes/Sample.xcscheme
@@ -42,7 +42,7 @@
       </AdditionalOptions>
    </TestAction>
    <LaunchAction
-      buildConfiguration = "Debug"
+      buildConfiguration = "Release"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       launchStyle = "0"
diff --git a/src/objective-c/tests/Podfile b/src/objective-c/tests/Podfile
index b6e389715a..3c2a34fb49 100644
--- a/src/objective-c/tests/Podfile
+++ b/src/objective-c/tests/Podfile
@@ -37,6 +37,27 @@ GRPC_LOCAL_SRC = '../../..'
 end
 
 %w(
+  InteropTestsRemoteCFStream
+  InteropTestsLocalSSLCFStream
+  InteropTestsLocalCleartextCFStream
+).each do |target_name|
+  target target_name do
+    pod 'Protobuf', :path => "#{GRPC_LOCAL_SRC}/third_party/protobuf", :inhibit_warnings => true
+
+    pod '!ProtoCompiler',            :path => "#{GRPC_LOCAL_SRC}/src/objective-c"
+    pod '!ProtoCompiler-gRPCPlugin', :path => "#{GRPC_LOCAL_SRC}/src/objective-c"
+
+    pod 'BoringSSL',                 :podspec => "#{GRPC_LOCAL_SRC}/src/objective-c", :inhibit_warnings => true
+
+    pod 'gRPC/CFStream',             :path => GRPC_LOCAL_SRC
+    pod 'gRPC-Core/CFStream-Implementation',       :path => GRPC_LOCAL_SRC
+    pod 'gRPC-RxLibrary', :path => GRPC_LOCAL_SRC
+    pod 'gRPC-ProtoRPC',  :path => GRPC_LOCAL_SRC, :inhibit_warnings => true
+    pod 'RemoteTest', :path => "RemoteTestClient", :inhibit_warnings => true
+  end
+end
+
+%w(
   CoreCronetEnd2EndTests
   CronetUnitTests
 ).each do |target_name|
@@ -65,7 +86,7 @@ end
 # TODO(jcanizales): Send a PR to Cocoapods to get rid of this need.
 pre_install do |installer|
   # This is the gRPC-Core podspec object, as initialized by its podspec file.
-  grpc_core_spec = installer.pod_targets.find{|t| t.name == 'gRPC-Core'}.root_spec
+  grpc_core_spec = installer.pod_targets.find{|t| t.name.start_with?('gRPC-Core')}.root_spec
 
   # Copied from gRPC-Core.podspec, except for the adjusted src_root:
   src_root = "$(PODS_ROOT)/../#{GRPC_LOCAL_SRC}"
@@ -96,7 +117,11 @@ post_install do |installer|
         # GPR_UNREACHABLE_CODE causes "Control may reach end of non-void
         # function" warning
         config.build_settings['GCC_WARN_ABOUT_RETURN_TYPE'] = 'NO'
-        config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] = '$(inherited) COCOAPODS=1 GRPC_CRONET_WITH_PACKET_COALESCING=1'
+        if target.name.include?('CFStream')
+          config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] = '$(inherited) COCOAPODS=1 GRPC_CFSTREAM=1'
+        else
+          config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] = '$(inherited) COCOAPODS=1 GRPC_CRONET_WITH_PACKET_COALESCING=1'
+        end
       end
     end
 
@@ -104,7 +129,7 @@ post_install do |installer|
     # the test target 'InteropTestsRemoteWithCronet'
     # Activate GRPCCall+InternalTests functions for the dedicated build configuration 'Test', which will
     # be used by all test targets using it.
-    if target.name == 'gRPC'
+    if target.name == 'gRPC' || target.name.start_with?('gRPC.')
       target.build_configurations.each do |config|
         if config.name == 'Cronet'
           config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] = '$(inherited) COCOAPODS=1 GRPC_COMPILE_WITH_CRONET=1 GRPC_TEST_OBJC=1'
diff --git a/src/objective-c/tests/Tests.xcodeproj/project.pbxproj b/src/objective-c/tests/Tests.xcodeproj/project.pbxproj
index e0f220eaee..8ff4633582 100644
--- a/src/objective-c/tests/Tests.xcodeproj/project.pbxproj
+++ b/src/objective-c/tests/Tests.xcodeproj/project.pbxproj
@@ -13,11 +13,18 @@
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@@ -213,6 +237,30 @@
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+			files = (
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+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+		5EC5E42E2081856B000EF4AD /* Frameworks */ = {
+			isa = PBXFrameworksBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				C3D6F4270A2FFF634D8849ED /* libPods-InteropTestsLocalCleartextCFStream.a in Frameworks */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+		5EC5E43F208185CE000EF4AD /* Frameworks */ = {
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+			files = (
+				91D4B3C85B6D8562F409CB48 /* libPods-InteropTestsLocalSSLCFStream.a in Frameworks */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
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@@ -291,6 +338,9 @@
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 				C6134277D2EB8B380862A03F /* libPods-CronetUnitTests.a */,
+				F44AC3F44E3491A8C0D890FE /* libPods-InteropTestsRemoteCFStream.a */,
+				0BDA4BA011779D5D25B5618C /* libPods-InteropTestsLocalCleartextCFStream.a */,
+				F3AB031E0E26AC8EF30A2A2A /* libPods-InteropTestsLocalSSLCFStream.a */,
 			);
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 			sourceTree = "<group>";
@@ -310,8 +360,6 @@
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@@ -323,7 +371,6 @@
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-				A0361771A855917162911180 /* Pods-Tests.test.xcconfig */,
+				32748C4078AEB05F8F954361 /* Pods-InteropTestsRemoteCFStream.debug.xcconfig */,
+				C17F57E5BCB989AB1C2F1F25 /* Pods-InteropTestsRemoteCFStream.test.xcconfig */,
+				4A1A42B2E941CCD453489E5B /* Pods-InteropTestsRemoteCFStream.cronet.xcconfig */,
+				303F4A17EB1650FC44603D17 /* Pods-InteropTestsRemoteCFStream.release.xcconfig */,
+				943138072A9605B5B8DC1FC0 /* Pods-InteropTestsLocalCleartextCFStream.debug.xcconfig */,
+				E4FD4606D4AB8D5A314D72F0 /* Pods-InteropTestsLocalCleartextCFStream.test.xcconfig */,
+				8B498B05C6DA0818B2FA91D4 /* Pods-InteropTestsLocalCleartextCFStream.cronet.xcconfig */,
+				7BA53C6D224288D5870FE6F3 /* Pods-InteropTestsLocalCleartextCFStream.release.xcconfig */,
+				3EB55EF291706E3DDE23C3B7 /* Pods-InteropTestsLocalSSLCFStream.debug.xcconfig */,
+				41AA59529240A6BBBD3DB904 /* Pods-InteropTestsLocalSSLCFStream.test.xcconfig */,
+				55B630C1FF8C36D1EFC4E0A4 /* Pods-InteropTestsLocalSSLCFStream.cronet.xcconfig */,
+				5EA908CF4CDA4CE218352A06 /* Pods-InteropTestsLocalSSLCFStream.release.xcconfig */,
 			);
 			name = Pods;
 			sourceTree = "<group>";
@@ -392,6 +450,9 @@
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 				5EE84BF11D4717E40050C6CC /* InteropTestsRemoteWithCronet.xctest */,
 				5EAD6D241E27047400002378 /* CronetUnitTests.xctest */,
+				5EC5E421208177CC000EF4AD /* InteropTestsRemoteCFStream.xctest */,
+				5EC5E4312081856B000EF4AD /* InteropTestsLocalCleartextCFStream.xctest */,
+				5EC5E442208185CE000EF4AD /* InteropTestsLocalSSLCFStream.xctest */,
 			);
 			name = Products;
 			sourceTree = "<group>";
@@ -433,7 +494,6 @@
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 				5E8A5DA21D3840B4000F8BC4 /* Resources */,
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@@ -466,6 +525,63 @@
 			productReference = 5EAD6D241E27047400002378 /* CronetUnitTests.xctest */;
 			productType = "com.apple.product-type.bundle.unit-test";
 		};
+		5EC5E420208177CC000EF4AD /* InteropTestsRemoteCFStream */ = {
+			isa = PBXNativeTarget;
+			buildConfigurationList = 5EC5E42A208177CD000EF4AD /* Build configuration list for PBXNativeTarget "InteropTestsRemoteCFStream" */;
+			buildPhases = (
+				483CDBBAEAEFCB530ADDDDD5 /* [CP] Check Pods Manifest.lock */,
+				5EC5E41D208177CC000EF4AD /* Sources */,
+				5EC5E41E208177CC000EF4AD /* Frameworks */,
+				5EC5E41F208177CC000EF4AD /* Resources */,
+				95FBC48B743503845678584F /* [CP] Copy Pods Resources */,
+			);
+			buildRules = (
+			);
+			dependencies = (
+			);
+			name = InteropTestsRemoteCFStream;
+			productName = InteropTestsRemoteCFStream;
+			productReference = 5EC5E421208177CC000EF4AD /* InteropTestsRemoteCFStream.xctest */;
+			productType = "com.apple.product-type.bundle.unit-test";
+		};
+		5EC5E4302081856B000EF4AD /* InteropTestsLocalCleartextCFStream */ = {
+			isa = PBXNativeTarget;
+			buildConfigurationList = 5EC5E4362081856C000EF4AD /* Build configuration list for PBXNativeTarget "InteropTestsLocalCleartextCFStream" */;
+			buildPhases = (
+				252A376345E38FD452A89C3D /* [CP] Check Pods Manifest.lock */,
+				5EC5E42D2081856B000EF4AD /* Sources */,
+				5EC5E42E2081856B000EF4AD /* Frameworks */,
+				5EC5E42F2081856B000EF4AD /* Resources */,
+				A023FB55205A7EA37D413549 /* [CP] Copy Pods Resources */,
+			);
+			buildRules = (
+			);
+			dependencies = (
+			);
+			name = InteropTestsLocalCleartextCFStream;
+			productName = InteropTestsLocalCleartextCFStream;
+			productReference = 5EC5E4312081856B000EF4AD /* InteropTestsLocalCleartextCFStream.xctest */;
+			productType = "com.apple.product-type.bundle.unit-test";
+		};
+		5EC5E441208185CE000EF4AD /* InteropTestsLocalSSLCFStream */ = {
+			isa = PBXNativeTarget;
+			buildConfigurationList = 5EC5E447208185CE000EF4AD /* Build configuration list for PBXNativeTarget "InteropTestsLocalSSLCFStream" */;
+			buildPhases = (
+				F3D5B2CDA172580341682830 /* [CP] Check Pods Manifest.lock */,
+				5EC5E43E208185CE000EF4AD /* Sources */,
+				5EC5E43F208185CE000EF4AD /* Frameworks */,
+				5EC5E440208185CE000EF4AD /* Resources */,
+				4EB2FFF40BB00AD0C545D7EF /* [CP] Copy Pods Resources */,
+			);
+			buildRules = (
+			);
+			dependencies = (
+			);
+			name = InteropTestsLocalSSLCFStream;
+			productName = InteropTestsLocalSSLCFStream;
+			productReference = 5EC5E442208185CE000EF4AD /* InteropTestsLocalSSLCFStream.xctest */;
+			productType = "com.apple.product-type.bundle.unit-test";
+		};
 		5EE84BF01D4717E40050C6CC /* InteropTestsRemoteWithCronet */ = {
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 			buildConfigurationList = 5EE84BFB1D4717E40050C6CC /* Build configuration list for PBXNativeTarget "InteropTestsRemoteWithCronet" */;
@@ -496,7 +612,6 @@
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-				5F14F59509E10C2852014F9E /* [CP] Embed Pods Frameworks */,
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@@ -512,11 +627,9 @@
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 				635697C51B14FC11007A7283 /* CopyFiles */,
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@@ -535,7 +648,6 @@
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@@ -577,7 +688,6 @@
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@@ -598,7 +708,6 @@
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 			buildRules = (
@@ -626,6 +735,18 @@
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 					};
+					5EC5E420208177CC000EF4AD = {
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+						ProvisioningStyle = Automatic;
+					};
+					5EC5E4302081856B000EF4AD = {
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+						ProvisioningStyle = Automatic;
+					};
+					5EC5E441208185CE000EF4AD = {
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+						ProvisioningStyle = Automatic;
+					};
 					5EE84BF01D4717E40050C6CC = {
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@@ -670,6 +791,9 @@
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 				5EE84BF01D4717E40050C6CC /* InteropTestsRemoteWithCronet */,
 				5EAD6D231E27047400002378 /* CronetUnitTests */,
+				5EC5E420208177CC000EF4AD /* InteropTestsRemoteCFStream */,
+				5EC5E4302081856B000EF4AD /* InteropTestsLocalCleartextCFStream */,
+				5EC5E441208185CE000EF4AD /* InteropTestsLocalSSLCFStream */,
 			);
 		};
 /* End PBXProject section */
@@ -689,6 +813,28 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		5EC5E41F208177CC000EF4AD /* Resources */ = {
+			isa = PBXResourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+		5EC5E42F2081856B000EF4AD /* Resources */ = {
+			isa = PBXResourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+		5EC5E440208185CE000EF4AD /* Resources */ = {
+			isa = PBXResourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				5EC5E44E20818948000EF4AD /* TestCertificates.bundle in Resources */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 		5EE84BEF1D4717E40050C6CC /* Resources */ = {
 			isa = PBXResourcesBuildPhase;
 			buildActionMask = 2147483647;
@@ -736,22 +882,22 @@
 /* End PBXResourcesBuildPhase section */
 
 /* Begin PBXShellScriptBuildPhase section */
-		051806D6A59B19C8A0B76BED /* [CP] Copy Pods Resources */ = {
+		252A376345E38FD452A89C3D /* [CP] Check Pods Manifest.lock */ = {
 			isa = PBXShellScriptBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
 			);
 			inputPaths = (
-				"${SRCROOT}/Pods/Target Support Files/Pods-CronetUnitTests/Pods-CronetUnitTests-resources.sh",
-				"${PODS_CONFIGURATION_BUILD_DIR}/gRPC/gRPCCertificates.bundle",
+				"${PODS_PODFILE_DIR_PATH}/Podfile.lock",
+				"${PODS_ROOT}/Manifest.lock",
 			);
-			name = "[CP] Copy Pods Resources";
+			name = "[CP] Check Pods Manifest.lock";
 			outputPaths = (
-				"${TARGET_BUILD_DIR}/${UNLOCALIZED_RESOURCES_FOLDER_PATH}/gRPCCertificates.bundle",
+				"$(DERIVED_FILE_DIR)/Pods-InteropTestsLocalCleartextCFStream-checkManifestLockResult.txt",
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-CronetUnitTests/Pods-CronetUnitTests-resources.sh\"\n";
+			shellScript = "diff \"${PODS_PODFILE_DIR_PATH}/Podfile.lock\" \"${PODS_ROOT}/Manifest.lock\" > /dev/null\nif [ $? != 0 ] ; then\n    # print error to STDERR\n    echo \"error: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.\" >&2\n    exit 1\nfi\n# This output is used by Xcode 'outputs' to avoid re-running this script phase.\necho \"SUCCESS\" > \"${SCRIPT_OUTPUT_FILE_0}\"\n";
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 			showEnvVarsInLog = 0;
 		};
-		4C406327D3907A5E5FBA8AC9 /* [CP] Check Pods Manifest.lock */ = {
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@@ -783,29 +929,14 @@
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 			name = "[CP] Check Pods Manifest.lock";
 			outputPaths = (
-				"$(DERIVED_FILE_DIR)/Pods-InteropTestsRemote-checkManifestLockResult.txt",
+				"$(DERIVED_FILE_DIR)/Pods-InteropTestsRemoteCFStream-checkManifestLockResult.txt",
 			);
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 			showEnvVarsInLog = 0;
 		};
-		4F5690DC0E6AD6663FE78B8B /* [CP] Embed Pods Frameworks */ = {
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-			buildActionMask = 2147483647;
-			files = (
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-			);
-			name = "[CP] Embed Pods Frameworks";
-			outputPaths = (
-			);
-			runOnlyForDeploymentPostprocessing = 0;
-			shellPath = /bin/sh;
-			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-RxLibraryUnitTests/Pods-RxLibraryUnitTests-frameworks.sh\"\n";
-			showEnvVarsInLog = 0;
-		};
-		5C20DCCB71C3991E6FE78C22 /* [CP] Check Pods Manifest.lock */ = {
+		4C406327D3907A5E5FBA8AC9 /* [CP] Check Pods Manifest.lock */ = {
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 			buildActionMask = 2147483647;
 			files = (
@@ -816,53 +947,56 @@
 			);
 			name = "[CP] Check Pods Manifest.lock";
 			outputPaths = (
-				"$(DERIVED_FILE_DIR)/Pods-InteropTestsLocalSSL-checkManifestLockResult.txt",
+				"$(DERIVED_FILE_DIR)/Pods-InteropTestsRemote-checkManifestLockResult.txt",
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
 			shellScript = "diff \"${PODS_PODFILE_DIR_PATH}/Podfile.lock\" \"${PODS_ROOT}/Manifest.lock\" > /dev/null\nif [ $? != 0 ] ; then\n    # print error to STDERR\n    echo \"error: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.\" >&2\n    exit 1\nfi\n# This output is used by Xcode 'outputs' to avoid re-running this script phase.\necho \"SUCCESS\" > \"${SCRIPT_OUTPUT_FILE_0}\"\n";
 			showEnvVarsInLog = 0;
 		};
-		5F14F59509E10C2852014F9E /* [CP] Embed Pods Frameworks */ = {
+		4EB2FFF40BB00AD0C545D7EF /* [CP] Copy Pods Resources */ = {
 			isa = PBXShellScriptBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
 			);
 			inputPaths = (
+				"${SRCROOT}/Pods/Target Support Files/Pods-InteropTestsLocalSSLCFStream/Pods-InteropTestsLocalSSLCFStream-resources.sh",
+				"${PODS_CONFIGURATION_BUILD_DIR}/gRPC.default-CFStream/gRPCCertificates.bundle",
 			);
-			name = "[CP] Embed Pods Frameworks";
+			name = "[CP] Copy Pods Resources";
 			outputPaths = (
+				"${TARGET_BUILD_DIR}/${UNLOCALIZED_RESOURCES_FOLDER_PATH}/gRPCCertificates.bundle",
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-AllTests/Pods-AllTests-frameworks.sh\"\n";
+			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-InteropTestsLocalSSLCFStream/Pods-InteropTestsLocalSSLCFStream-resources.sh\"\n";
 			showEnvVarsInLog = 0;
 		};
-		693DD0B453431D64EA24FD66 /* [CP] Copy Pods Resources */ = {
+		5C20DCCB71C3991E6FE78C22 /* [CP] Check Pods Manifest.lock */ = {
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 			buildActionMask = 2147483647;
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-				"${PODS_CONFIGURATION_BUILD_DIR}/gRPC/gRPCCertificates.bundle",
+				"${PODS_PODFILE_DIR_PATH}/Podfile.lock",
+				"${PODS_ROOT}/Manifest.lock",
 			);
-			name = "[CP] Copy Pods Resources";
+			name = "[CP] Check Pods Manifest.lock";
 			outputPaths = (
-				"${TARGET_BUILD_DIR}/${UNLOCALIZED_RESOURCES_FOLDER_PATH}/gRPCCertificates.bundle",
+				"$(DERIVED_FILE_DIR)/Pods-InteropTestsLocalSSL-checkManifestLockResult.txt",
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-InteropTestsLocalSSL/Pods-InteropTestsLocalSSL-resources.sh\"\n";
+			shellScript = "diff \"${PODS_PODFILE_DIR_PATH}/Podfile.lock\" \"${PODS_ROOT}/Manifest.lock\" > /dev/null\nif [ $? != 0 ] ; then\n    # print error to STDERR\n    echo \"error: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.\" >&2\n    exit 1\nfi\n# This output is used by Xcode 'outputs' to avoid re-running this script phase.\necho \"SUCCESS\" > \"${SCRIPT_OUTPUT_FILE_0}\"\n";
 			showEnvVarsInLog = 0;
 		};
-		6DFE9E77CAB5760196D79E0F /* [CP] Copy Pods Resources */ = {
+		693DD0B453431D64EA24FD66 /* [CP] Copy Pods Resources */ = {
 			isa = PBXShellScriptBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
 			);
 			inputPaths = (
-				"${SRCROOT}/Pods/Target Support Files/Pods-CoreCronetEnd2EndTests/Pods-CoreCronetEnd2EndTests-resources.sh",
+				"${SRCROOT}/Pods/Target Support Files/Pods-InteropTestsLocalSSL/Pods-InteropTestsLocalSSL-resources.sh",
 				"${PODS_CONFIGURATION_BUILD_DIR}/gRPC/gRPCCertificates.bundle",
 			);
 			name = "[CP] Copy Pods Resources";
@@ -871,7 +1005,7 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-CoreCronetEnd2EndTests/Pods-CoreCronetEnd2EndTests-resources.sh\"\n";
+			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-InteropTestsLocalSSL/Pods-InteropTestsLocalSSL-resources.sh\"\n";
 			showEnvVarsInLog = 0;
 		};
 		7418AC7B3844B29E48D24FC7 /* [CP] Check Pods Manifest.lock */ = {
@@ -892,24 +1026,6 @@
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 			showEnvVarsInLog = 0;
 		};
-		796680C7599CB4ED736DD62A /* [CP] Check Pods Manifest.lock */ = {
-			isa = PBXShellScriptBuildPhase;
-			buildActionMask = 2147483647;
-			files = (
-			);
-			inputPaths = (
-				"${PODS_PODFILE_DIR_PATH}/Podfile.lock",
-				"${PODS_ROOT}/Manifest.lock",
-			);
-			name = "[CP] Check Pods Manifest.lock";
-			outputPaths = (
-				"$(DERIVED_FILE_DIR)/Pods-Tests-checkManifestLockResult.txt",
-			);
-			runOnlyForDeploymentPostprocessing = 0;
-			shellPath = /bin/sh;
-			shellScript = "diff \"${PODS_PODFILE_DIR_PATH}/Podfile.lock\" \"${PODS_ROOT}/Manifest.lock\" > /dev/null\nif [ $? != 0 ] ; then\n    # print error to STDERR\n    echo \"error: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.\" >&2\n    exit 1\nfi\n# This output is used by Xcode 'outputs' to avoid re-running this script phase.\necho \"SUCCESS\" > \"${SCRIPT_OUTPUT_FILE_0}\"\n";
-			showEnvVarsInLog = 0;
-		};
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@@ -946,21 +1062,6 @@
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 			showEnvVarsInLog = 0;
 		};
-		900B6EDD4D16BE7D765C3885 /* [CP] Embed Pods Frameworks */ = {
-			isa = PBXShellScriptBuildPhase;
-			buildActionMask = 2147483647;
-			files = (
-			);
-			inputPaths = (
-			);
-			name = "[CP] Embed Pods Frameworks";
-			outputPaths = (
-			);
-			runOnlyForDeploymentPostprocessing = 0;
-			shellPath = /bin/sh;
-			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-InteropTestsRemote/Pods-InteropTestsRemote-frameworks.sh\"\n";
-			showEnvVarsInLog = 0;
-		};
 		914ADDD7106BA9BB8A7E569F /* [CP] Check Pods Manifest.lock */ = {
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@@ -979,14 +1080,14 @@
 			shellScript = "diff \"${PODS_PODFILE_DIR_PATH}/Podfile.lock\" \"${PODS_ROOT}/Manifest.lock\" > /dev/null\nif [ $? != 0 ] ; then\n    # print error to STDERR\n    echo \"error: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.\" >&2\n    exit 1\nfi\n# This output is used by Xcode 'outputs' to avoid re-running this script phase.\necho \"SUCCESS\" > \"${SCRIPT_OUTPUT_FILE_0}\"\n";
 			showEnvVarsInLog = 0;
 		};
-		A441F71824DCB9D0CA297748 /* [CP] Copy Pods Resources */ = {
+		95FBC48B743503845678584F /* [CP] Copy Pods Resources */ = {
 			isa = PBXShellScriptBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
 			);
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-				"${SRCROOT}/Pods/Target Support Files/Pods-AllTests/Pods-AllTests-resources.sh",
-				"${PODS_CONFIGURATION_BUILD_DIR}/gRPC/gRPCCertificates.bundle",
+				"${SRCROOT}/Pods/Target Support Files/Pods-InteropTestsRemoteCFStream/Pods-InteropTestsRemoteCFStream-resources.sh",
+				"${PODS_CONFIGURATION_BUILD_DIR}/gRPC.default-CFStream/gRPCCertificates.bundle",
 			);
 			name = "[CP] Copy Pods Resources";
 			outputPaths = (
@@ -994,58 +1095,61 @@
 			);
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 			shellPath = /bin/sh;
-			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-AllTests/Pods-AllTests-resources.sh\"\n";
+			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-InteropTestsRemoteCFStream/Pods-InteropTestsRemoteCFStream-resources.sh\"\n";
 			showEnvVarsInLog = 0;
 		};
-		A686B9967BB4CB81B1CBF8F8 /* [CP] Embed Pods Frameworks */ = {
+		A023FB55205A7EA37D413549 /* [CP] Copy Pods Resources */ = {
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 			);
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-				"${SRCROOT}/Pods/Target Support Files/Pods-CronetUnitTests/Pods-CronetUnitTests-frameworks.sh",
-				"${PODS_ROOT}/CronetFramework/Cronet.framework",
+				"${SRCROOT}/Pods/Target Support Files/Pods-InteropTestsLocalCleartextCFStream/Pods-InteropTestsLocalCleartextCFStream-resources.sh",
+				"${PODS_CONFIGURATION_BUILD_DIR}/gRPC.default-CFStream/gRPCCertificates.bundle",
 			);
-			name = "[CP] Embed Pods Frameworks";
+			name = "[CP] Copy Pods Resources";
 			outputPaths = (
-				"${TARGET_BUILD_DIR}/${FRAMEWORKS_FOLDER_PATH}/Cronet.framework",
+				"${TARGET_BUILD_DIR}/${UNLOCALIZED_RESOURCES_FOLDER_PATH}/gRPCCertificates.bundle",
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-CronetUnitTests/Pods-CronetUnitTests-frameworks.sh\"\n";
+			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-InteropTestsLocalCleartextCFStream/Pods-InteropTestsLocalCleartextCFStream-resources.sh\"\n";
 			showEnvVarsInLog = 0;
 		};
-		A8E3AC66DF770B774114A30E /* [CP] Embed Pods Frameworks */ = {
+		A441F71824DCB9D0CA297748 /* [CP] Copy Pods Resources */ = {
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 			);
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+				"${SRCROOT}/Pods/Target Support Files/Pods-AllTests/Pods-AllTests-resources.sh",
+				"${PODS_CONFIGURATION_BUILD_DIR}/gRPC/gRPCCertificates.bundle",
 			);
-			name = "[CP] Embed Pods Frameworks";
+			name = "[CP] Copy Pods Resources";
 			outputPaths = (
+				"${TARGET_BUILD_DIR}/${UNLOCALIZED_RESOURCES_FOLDER_PATH}/gRPCCertificates.bundle",
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-InteropTestsLocalCleartext/Pods-InteropTestsLocalCleartext-frameworks.sh\"\n";
+			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-AllTests/Pods-AllTests-resources.sh\"\n";
 			showEnvVarsInLog = 0;
 		};
-		AEEBFC914CBAEE347382E8C4 /* [CP] Copy Pods Resources */ = {
+		A686B9967BB4CB81B1CBF8F8 /* [CP] Embed Pods Frameworks */ = {
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 			buildActionMask = 2147483647;
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-				"${SRCROOT}/Pods/Target Support Files/Pods-Tests/Pods-Tests-resources.sh",
-				"${PODS_CONFIGURATION_BUILD_DIR}/gRPC/gRPCCertificates.bundle",
+				"${SRCROOT}/Pods/Target Support Files/Pods-CronetUnitTests/Pods-CronetUnitTests-frameworks.sh",
+				"${PODS_ROOT}/CronetFramework/Cronet.framework",
 			);
-			name = "[CP] Copy Pods Resources";
+			name = "[CP] Embed Pods Frameworks";
 			outputPaths = (
-				"${TARGET_BUILD_DIR}/${UNLOCALIZED_RESOURCES_FOLDER_PATH}/gRPCCertificates.bundle",
+				"${TARGET_BUILD_DIR}/${FRAMEWORKS_FOLDER_PATH}/Cronet.framework",
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-Tests/Pods-Tests-resources.sh\"\n";
+			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-CronetUnitTests/Pods-CronetUnitTests-frameworks.sh\"\n";
 			showEnvVarsInLog = 0;
 		};
 		B2986CEEE8CDD4901C97598B /* [CP] Check Pods Manifest.lock */ = {
@@ -1102,21 +1206,6 @@
 			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-InteropTestsRemote/Pods-InteropTestsRemote-resources.sh\"\n";
 			showEnvVarsInLog = 0;
 		};
-		C591129ACE9F6CC5EE03FCDE /* [CP] Embed Pods Frameworks */ = {
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-			buildActionMask = 2147483647;
-			files = (
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-			inputPaths = (
-			);
-			name = "[CP] Embed Pods Frameworks";
-			outputPaths = (
-			);
-			runOnlyForDeploymentPostprocessing = 0;
-			shellPath = /bin/sh;
-			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-InteropTestsLocalSSL/Pods-InteropTestsLocalSSL-frameworks.sh\"\n";
-			showEnvVarsInLog = 0;
-		};
 		C977426A8727267BBAC7D48E /* [CP] Copy Pods Resources */ = {
 			isa = PBXShellScriptBuildPhase;
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@@ -1171,6 +1260,24 @@
 			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-CoreCronetEnd2EndTests/Pods-CoreCronetEnd2EndTests-frameworks.sh\"\n";
 			showEnvVarsInLog = 0;
 		};
+		F3D5B2CDA172580341682830 /* [CP] Check Pods Manifest.lock */ = {
+			isa = PBXShellScriptBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			inputPaths = (
+				"${PODS_PODFILE_DIR_PATH}/Podfile.lock",
+				"${PODS_ROOT}/Manifest.lock",
+			);
+			name = "[CP] Check Pods Manifest.lock";
+			outputPaths = (
+				"$(DERIVED_FILE_DIR)/Pods-InteropTestsLocalSSLCFStream-checkManifestLockResult.txt",
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+			shellPath = /bin/sh;
+			shellScript = "diff \"${PODS_PODFILE_DIR_PATH}/Podfile.lock\" \"${PODS_ROOT}/Manifest.lock\" > /dev/null\nif [ $? != 0 ] ; then\n    # print error to STDERR\n    echo \"error: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.\" >&2\n    exit 1\nfi\n# This output is used by Xcode 'outputs' to avoid re-running this script phase.\necho \"SUCCESS\" > \"${SCRIPT_OUTPUT_FILE_0}\"\n";
+			showEnvVarsInLog = 0;
+		};
 		F58F17E425446B15028B9F74 /* [CP] Check Pods Manifest.lock */ = {
 			isa = PBXShellScriptBuildPhase;
 			buildActionMask = 2147483647;
@@ -1208,6 +1315,34 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
+		5EC5E41D208177CC000EF4AD /* Sources */ = {
+			isa = PBXSourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				5EC5E42B2081782C000EF4AD /* InteropTestsRemote.m in Sources */,
+				5EC5E42C20817832000EF4AD /* InteropTests.m in Sources */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+		5EC5E42D2081856B000EF4AD /* Sources */ = {
+			isa = PBXSourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				5EC5E43B208185A7000EF4AD /* InteropTestsLocalCleartext.m in Sources */,
+				5EC5E43D208185B0000EF4AD /* GRPCClientTests.m in Sources */,
+				5EC5E43C208185AD000EF4AD /* InteropTests.m in Sources */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+		5EC5E43E208185CE000EF4AD /* Sources */ = {
+			isa = PBXSourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				5EC5E44D208185F0000EF4AD /* InteropTestsLocalSSL.m in Sources */,
+				5EC5E44C208185EC000EF4AD /* InteropTests.m in Sources */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
 		5EE84BED1D4717E40050C6CC /* Sources */ = {
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
@@ -1350,6 +1485,7 @@
 					"HOST_PORT_LOCALSSL=$(HOST_PORT_LOCALSSL)",
 					"HOST_PORT_LOCAL=$(HOST_PORT_LOCAL)",
 					"HOST_PORT_REMOTE=$(HOST_PORT_REMOTE)",
+					"GRPC_TEST_OBJC=1",
 				);
 				GCC_SYMBOLS_PRIVATE_EXTERN = NO;
 				GCC_TREAT_WARNINGS_AS_ERRORS = YES;
@@ -1368,7 +1504,6 @@
 		};
 		5E1228991E4D400F00E8504F /* Test */ = {
 			isa = XCBuildConfiguration;
-			baseConfigurationReference = A0361771A855917162911180 /* Pods-Tests.test.xcconfig */;
 			buildSettings = {
 				GCC_TREAT_WARNINGS_AS_ERRORS = YES;
 				PRODUCT_NAME = "$(TARGET_NAME)";
@@ -1668,7 +1803,6 @@
 		};
 		5EC3C7A11D4FC18C000330E2 /* Cronet */ = {
 			isa = XCBuildConfiguration;
-			baseConfigurationReference = F671D4CAD2864FB203B920B4 /* Pods-Tests.cronet.xcconfig */;
 			buildSettings = {
 				GCC_TREAT_WARNINGS_AS_ERRORS = YES;
 				PRODUCT_NAME = "$(TARGET_NAME)";
@@ -1797,6 +1931,360 @@
 			};
 			name = Cronet;
 		};
+		5EC5E426208177CC000EF4AD /* Debug */ = {
+			isa = XCBuildConfiguration;
+			baseConfigurationReference = 32748C4078AEB05F8F954361 /* Pods-InteropTestsRemoteCFStream.debug.xcconfig */;
+			buildSettings = {
+				CLANG_ANALYZER_NONNULL = YES;
+				CLANG_ANALYZER_NUMBER_OBJECT_CONVERSION = YES_AGGRESSIVE;
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++14";
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
+				CLANG_WARN_COMMA = YES;
+				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
+				CLANG_WARN_UNGUARDED_AVAILABILITY = YES_AGGRESSIVE;
+				CODE_SIGN_IDENTITY = "iPhone Developer";
+				CODE_SIGN_STYLE = Automatic;
+				DEBUG_INFORMATION_FORMAT = dwarf;
+				ENABLE_TESTABILITY = YES;
+				GCC_C_LANGUAGE_STANDARD = gnu11;
+				INFOPLIST_FILE = Info.plist;
+				IPHONEOS_DEPLOYMENT_TARGET = 11.2;
+				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
+				PRODUCT_BUNDLE_IDENTIFIER = io.grpc.InteropTestsRemoteCFStream;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				TARGETED_DEVICE_FAMILY = "1,2";
+			};
+			name = Debug;
+		};
+		5EC5E427208177CC000EF4AD /* Test */ = {
+			isa = XCBuildConfiguration;
+			baseConfigurationReference = C17F57E5BCB989AB1C2F1F25 /* Pods-InteropTestsRemoteCFStream.test.xcconfig */;
+			buildSettings = {
+				CLANG_ANALYZER_NONNULL = YES;
+				CLANG_ANALYZER_NUMBER_OBJECT_CONVERSION = YES_AGGRESSIVE;
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++14";
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
+				CLANG_WARN_COMMA = YES;
+				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
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+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
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+				CLANG_WARN_UNGUARDED_AVAILABILITY = YES_AGGRESSIVE;
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+		};
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+				CLANG_ANALYZER_NUMBER_OBJECT_CONVERSION = YES_AGGRESSIVE;
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+			name = Debug;
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+				PRODUCT_BUNDLE_IDENTIFIER = io.grpc.InteropTestsLocalCleartextCFStream;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				TARGETED_DEVICE_FAMILY = "1,2";
+			};
+			name = Test;
+		};
+		5EC5E4392081856C000EF4AD /* Cronet */ = {
+			isa = XCBuildConfiguration;
+			baseConfigurationReference = 8B498B05C6DA0818B2FA91D4 /* Pods-InteropTestsLocalCleartextCFStream.cronet.xcconfig */;
+			buildSettings = {
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+				CLANG_ANALYZER_NUMBER_OBJECT_CONVERSION = YES_AGGRESSIVE;
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+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
+				CLANG_WARN_UNGUARDED_AVAILABILITY = YES_AGGRESSIVE;
+				CODE_SIGN_IDENTITY = "iPhone Developer";
+				CODE_SIGN_STYLE = Automatic;
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+				PRODUCT_BUNDLE_IDENTIFIER = io.grpc.InteropTestsLocalCleartextCFStream;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				TARGETED_DEVICE_FAMILY = "1,2";
+			};
+			name = Cronet;
+		};
+		5EC5E43A2081856C000EF4AD /* Release */ = {
+			isa = XCBuildConfiguration;
+			baseConfigurationReference = 7BA53C6D224288D5870FE6F3 /* Pods-InteropTestsLocalCleartextCFStream.release.xcconfig */;
+			buildSettings = {
+				CLANG_ANALYZER_NONNULL = YES;
+				CLANG_ANALYZER_NUMBER_OBJECT_CONVERSION = YES_AGGRESSIVE;
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++14";
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
+				CLANG_WARN_COMMA = YES;
+				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
+				CLANG_WARN_UNGUARDED_AVAILABILITY = YES_AGGRESSIVE;
+				CODE_SIGN_IDENTITY = "iPhone Developer";
+				CODE_SIGN_STYLE = Automatic;
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+				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
+				PRODUCT_BUNDLE_IDENTIFIER = io.grpc.InteropTestsLocalCleartextCFStream;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				TARGETED_DEVICE_FAMILY = "1,2";
+			};
+			name = Release;
+		};
+		5EC5E448208185CE000EF4AD /* Debug */ = {
+			isa = XCBuildConfiguration;
+			baseConfigurationReference = 3EB55EF291706E3DDE23C3B7 /* Pods-InteropTestsLocalSSLCFStream.debug.xcconfig */;
+			buildSettings = {
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+				CLANG_ANALYZER_NUMBER_OBJECT_CONVERSION = YES_AGGRESSIVE;
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++14";
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
+				CLANG_WARN_COMMA = YES;
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+				CODE_SIGN_IDENTITY = "iPhone Developer";
+				CODE_SIGN_STYLE = Automatic;
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+				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
+				PRODUCT_BUNDLE_IDENTIFIER = io.grpc.InteropTestsLocalSSLCFStream;
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+				TARGETED_DEVICE_FAMILY = "1,2";
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+			name = Debug;
+		};
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+				CLANG_ANALYZER_NUMBER_OBJECT_CONVERSION = YES_AGGRESSIVE;
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+		};
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+				CLANG_ANALYZER_NUMBER_OBJECT_CONVERSION = YES_AGGRESSIVE;
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+				PRODUCT_NAME = "$(TARGET_NAME)";
+				TARGETED_DEVICE_FAMILY = "1,2";
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+			name = Cronet;
+		};
+		5EC5E44B208185CE000EF4AD /* Release */ = {
+			isa = XCBuildConfiguration;
+			baseConfigurationReference = 5EA908CF4CDA4CE218352A06 /* Pods-InteropTestsLocalSSLCFStream.release.xcconfig */;
+			buildSettings = {
+				CLANG_ANALYZER_NONNULL = YES;
+				CLANG_ANALYZER_NUMBER_OBJECT_CONVERSION = YES_AGGRESSIVE;
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++14";
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
+				CLANG_WARN_COMMA = YES;
+				CLANG_WARN_DOCUMENTATION_COMMENTS = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
+				CLANG_WARN_UNGUARDED_AVAILABILITY = YES_AGGRESSIVE;
+				CODE_SIGN_IDENTITY = "iPhone Developer";
+				CODE_SIGN_STYLE = Automatic;
+				GCC_C_LANGUAGE_STANDARD = gnu11;
+				INFOPLIST_FILE = Info.plist;
+				IPHONEOS_DEPLOYMENT_TARGET = 11.2;
+				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks @loader_path/Frameworks";
+				PRODUCT_BUNDLE_IDENTIFIER = io.grpc.InteropTestsLocalSSLCFStream;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				TARGETED_DEVICE_FAMILY = "1,2";
+			};
+			name = Release;
+		};
 		5EE84BF91D4717E40050C6CC /* Debug */ = {
 			isa = XCBuildConfiguration;
 			baseConfigurationReference = 17F60BF2871F6AF85FB3FA12 /* Pods-InteropTestsRemoteWithCronet.debug.xcconfig */;
@@ -1953,7 +2441,6 @@
 		};
 		635697DC1B14FC11007A7283 /* Debug */ = {
 			isa = XCBuildConfiguration;
-			baseConfigurationReference = 060EF32D7EC0DF67ED617507 /* Pods-Tests.debug.xcconfig */;
 			buildSettings = {
 				GCC_TREAT_WARNINGS_AS_ERRORS = YES;
 				PRODUCT_NAME = "$(TARGET_NAME)";
@@ -1963,7 +2450,6 @@
 		};
 		635697DD1B14FC11007A7283 /* Release */ = {
 			isa = XCBuildConfiguration;
-			baseConfigurationReference = E6733B838B28453434B556E2 /* Pods-Tests.release.xcconfig */;
 			buildSettings = {
 				GCC_TREAT_WARNINGS_AS_ERRORS = YES;
 				PRODUCT_NAME = "$(TARGET_NAME)";
@@ -2100,6 +2586,39 @@
 			defaultConfigurationIsVisible = 0;
 			defaultConfigurationName = Release;
 		};
+		5EC5E42A208177CD000EF4AD /* Build configuration list for PBXNativeTarget "InteropTestsRemoteCFStream" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				5EC5E426208177CC000EF4AD /* Debug */,
+				5EC5E427208177CC000EF4AD /* Test */,
+				5EC5E428208177CC000EF4AD /* Cronet */,
+				5EC5E429208177CC000EF4AD /* Release */,
+			);
+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
+		5EC5E4362081856C000EF4AD /* Build configuration list for PBXNativeTarget "InteropTestsLocalCleartextCFStream" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				5EC5E4372081856C000EF4AD /* Debug */,
+				5EC5E4382081856C000EF4AD /* Test */,
+				5EC5E4392081856C000EF4AD /* Cronet */,
+				5EC5E43A2081856C000EF4AD /* Release */,
+			);
+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
+		5EC5E447208185CE000EF4AD /* Build configuration list for PBXNativeTarget "InteropTestsLocalSSLCFStream" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				5EC5E448208185CE000EF4AD /* Debug */,
+				5EC5E449208185CE000EF4AD /* Test */,
+				5EC5E44A208185CE000EF4AD /* Cronet */,
+				5EC5E44B208185CE000EF4AD /* Release */,
+			);
+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
 		5EE84BFB1D4717E40050C6CC /* Build configuration list for PBXNativeTarget "InteropTestsRemoteWithCronet" */ = {
 			isa = XCConfigurationList;
 			buildConfigurations = (
diff --git a/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/AllTests.xcscheme b/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/AllTests.xcscheme
index a2560fee02..b0bb933764 100644
--- a/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/AllTests.xcscheme
+++ b/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/AllTests.xcscheme
@@ -26,6 +26,7 @@
       buildConfiguration = "Test"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
          <TestableReference
@@ -66,6 +67,7 @@
       buildConfiguration = "Test"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
diff --git a/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/InteropTestsLocalCleartext.xcscheme b/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/InteropTestsLocalCleartext.xcscheme
index 6d85b62fab..510115fc75 100644
--- a/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/InteropTestsLocalCleartext.xcscheme
+++ b/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/InteropTestsLocalCleartext.xcscheme
@@ -26,6 +26,7 @@
       buildConfiguration = "Test"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
          <TestableReference
@@ -57,6 +58,7 @@
       buildConfiguration = "Test"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
diff --git a/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/InteropTestsLocalCleartextCFStream.xcscheme b/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/InteropTestsLocalCleartextCFStream.xcscheme
new file mode 100644
index 0000000000..fe766de928
--- /dev/null
+++ b/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/InteropTestsLocalCleartextCFStream.xcscheme
@@ -0,0 +1,63 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "0920"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Test"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "5EC5E4302081856B000EF4AD"
+               BuildableName = "InteropTestsLocalCleartextCFStream.xctest"
+               BlueprintName = "InteropTestsLocalCleartextCFStream"
+               ReferencedContainer = "container:Tests.xcodeproj">
+            </BuildableReference>
+            <SkippedTests>
+               <Test
+                  Identifier = "InteropTests">
+               </Test>
+            </SkippedTests>
+         </TestableReference>
+      </Testables>
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>
diff --git a/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/InteropTestsLocalSSLCFStream.xcscheme b/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/InteropTestsLocalSSLCFStream.xcscheme
new file mode 100644
index 0000000000..bd66327649
--- /dev/null
+++ b/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/InteropTestsLocalSSLCFStream.xcscheme
@@ -0,0 +1,63 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "0920"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Test"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "5EC5E441208185CE000EF4AD"
+               BuildableName = "InteropTestsLocalSSLCFStream.xctest"
+               BlueprintName = "InteropTestsLocalSSLCFStream"
+               ReferencedContainer = "container:Tests.xcodeproj">
+            </BuildableReference>
+            <SkippedTests>
+               <Test
+                  Identifier = "InteropTests">
+               </Test>
+            </SkippedTests>
+         </TestableReference>
+      </Testables>
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>
diff --git a/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/InteropTestsRemote.xcscheme b/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/InteropTestsRemote.xcscheme
index 412bf6a014..48837e57f9 100644
--- a/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/InteropTestsRemote.xcscheme
+++ b/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/InteropTestsRemote.xcscheme
@@ -26,6 +26,7 @@
       buildConfiguration = "Test"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
          <TestableReference
@@ -60,6 +61,7 @@
       buildConfiguration = "Test"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
diff --git a/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/InteropTestsRemoteCFStream.xcscheme b/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/InteropTestsRemoteCFStream.xcscheme
new file mode 100644
index 0000000000..33a5ded038
--- /dev/null
+++ b/src/objective-c/tests/Tests.xcodeproj/xcshareddata/xcschemes/InteropTestsRemoteCFStream.xcscheme
@@ -0,0 +1,61 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "0920"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Test"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "5EC5E420208177CC000EF4AD"
+               BuildableName = "InteropTestsRemoteCFStream.xctest"
+               BlueprintName = "InteropTestsRemoteCFStream"
+               ReferencedContainer = "container:Tests.xcodeproj">
+            </BuildableReference>
+            <SkippedTests>
+               <Test
+                  Identifier = "InteropTests">
+               </Test>
+            </SkippedTests>
+         </TestableReference>
+      </Testables>
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>
diff --git a/src/objective-c/tests/analyze_link_map.py b/src/objective-c/tests/analyze_link_map.py
deleted file mode 100755
index 48e3441087..0000000000
--- a/src/objective-c/tests/analyze_link_map.py
+++ /dev/null
@@ -1,78 +0,0 @@
-#!/usr/bin/python
-# Copyright 2018 gRPC authors.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-# This script analyzes link map file generated by Xcode. It calculates and
-# prints out the sizes of each dependent library and the total sizes of the
-# symbols.
-# The script takes one parameter, which is the path to the link map file.
-
-import sys
-import re
-
-table_tag = {}
-state = "start"
-
-table_stats_symbol = {}
-table_stats_dead = {}
-section_total_size = 0
-symbol_total_size = 0
-
-
-file_import = sys.argv[1]
-lines = list(open(file_import))
-for line in lines:
-  line_stripped = line[:-1]
-  if "# Object files:" == line_stripped:
-    state = "object"
-    continue
-  elif "# Sections:" == line_stripped:
-    state = "section"
-    continue
-  elif "# Symbols:" == line_stripped:
-    state = "symbol"
-    continue
-  elif "# Dead Stripped Symbols:" == line_stripped:
-    state = "dead"
-    continue
-
-  if state == "object":
-    segs = re.search('(\[ *[0-9]*\]) (.*)', line_stripped)
-    table_tag[segs.group(1)] = segs.group(2)
-
-  if state == "section":
-    if len(line_stripped) == 0 or line_stripped[0] == '#':
-      continue
-    segs = re.search('^(.+?)\s+(.+?)\s+.*', line_stripped)
-    section_total_size += int(segs.group(2), 16)
-
-  if state == "symbol":
-    if len(line_stripped) == 0 or line_stripped[0] == '#':
-      continue
-    segs = re.search('^.+?\s+(.+?)\s+(\[.+?\]).*', line_stripped)
-    target = table_tag[segs.group(2)]
-    target_stripped = re.search('^(.*?)(\(.+?\))?$', target).group(1)
-    size = int(segs.group(1), 16)
-    if not target_stripped in table_stats_symbol:
-      table_stats_symbol[target_stripped] = 0
-    table_stats_symbol[target_stripped] += size
-
-print("Sections total size: %d" % section_total_size)
-
-for target in table_stats_symbol:
-  print(target)
-  print(table_stats_symbol[target])
-  symbol_total_size += table_stats_symbol[target]
-
-print("Symbols total size: %d" % symbol_total_size)
diff --git a/src/objective-c/tests/build_one_example.sh b/src/objective-c/tests/build_one_example.sh
index 985d55f3cc..1eace541e6 100755
--- a/src/objective-c/tests/build_one_example.sh
+++ b/src/objective-c/tests/build_one_example.sh
@@ -42,6 +42,9 @@ xcodebuild \
     build \
     -workspace *.xcworkspace \
     -scheme $SCHEME \
-    -destination name="iPhone 6" \
+    -destination generic/platform=iOS \
+    -derivedDataPath Build \
+    CODE_SIGN_IDENTITY="" \
+    CODE_SIGNING_REQUIRED=NO \
     | egrep -v "$XCODEBUILD_FILTER" \
     | egrep -v "^$" -
diff --git a/src/objective-c/tests/run_tests.sh b/src/objective-c/tests/run_tests.sh
index 2fe2326207..9dde07d55c 100755
--- a/src/objective-c/tests/run_tests.sh
+++ b/src/objective-c/tests/run_tests.sh
@@ -53,7 +53,7 @@ while [ $retries -lt 3 ]; do
   out=$(xcodebuild \
         -workspace Tests.xcworkspace \
         -scheme AllTests \
-        -destination name="iPhone 6" \
+        -destination name="iPhone 8" \
         HOST_PORT_LOCALSSL=localhost:5051 \
         HOST_PORT_LOCAL=localhost:5050 \
         HOST_PORT_REMOTE=grpc-test.sandbox.googleapis.com \
@@ -83,7 +83,7 @@ echo "TIME:  $(date)"
 xcodebuild \
     -workspace Tests.xcworkspace \
     -scheme CoreCronetEnd2EndTests \
-    -destination name="iPhone 6" \
+    -destination name="iPhone 8" \
     test \
     | egrep -v "$XCODEBUILD_FILTER" \
     | egrep -v '^$' \
@@ -113,7 +113,7 @@ echo "TIME:  $(date)"
 xcodebuild \
     -workspace Tests.xcworkspace \
     -scheme CronetUnitTests \
-    -destination name="iPhone 6" \
+    -destination name="iPhone 8" \
     test \
     | egrep -v "$XCODEBUILD_FILTER" \
     | egrep -v '^$' \
@@ -123,11 +123,44 @@ echo "TIME:  $(date)"
 xcodebuild \
     -workspace Tests.xcworkspace \
     -scheme InteropTestsRemoteWithCronet \
-    -destination name="iPhone 6" \
+    -destination name="iPhone 8" \
+    HOST_PORT_REMOTE=grpc-test.sandbox.googleapis.com \
+    test \
+    | egrep -v "$XCODEBUILD_FILTER" \
+    | egrep -v '^$' \
+    | egrep -v "(GPBDictionary|GPBArray)" -
+
+echo "TIME:  $(date)"
+xcodebuild \
+    -workspace Tests.xcworkspace \
+    -scheme InteropTestsRemoteCFStream \
+    -destination name="iPhone 8" \
     HOST_PORT_REMOTE=grpc-test.sandbox.googleapis.com \
     test \
     | egrep -v "$XCODEBUILD_FILTER" \
     | egrep -v '^$' \
     | egrep -v "(GPBDictionary|GPBArray)" -
 
+echo "TIME:  $(date)"
+xcodebuild \
+    -workspace Tests.xcworkspace \
+    -scheme InteropTestsLocalCleartextCFStream \
+    -destination name="iPhone 8" \
+    HOST_PORT_LOCAL=localhost:5050 \
+    test \
+    | egrep -v "$XCODEBUILD_FILTER" \
+    | egrep -v '^$' \
+    | egrep -v "(GPBDictionary|GPBArray)" -
+
+echo "TIME:  $(date)"
+xcodebuild \
+    -workspace Tests.xcworkspace \
+    -scheme InteropTestsLocalSSLCFStream \
+    -destination name="iPhone 8" \
+    HOST_PORT_LOCALSSL=localhost:5051 \
+    test \
+    | egrep -v "$XCODEBUILD_FILTER" \
+    | egrep -v '^$' \
+    | egrep -v "(GPBDictionary|GPBArray)" -
+
 exit 0
diff --git a/src/php/README.md b/src/php/README.md
index 11f99e134c..36e242fe01 100644
--- a/src/php/README.md
+++ b/src/php/README.md
@@ -2,11 +2,14 @@
 # Overview
 
 This directory contains source code for PHP implementation of gRPC layered on
-shared C library.
+shared C library. The same installation guides with more examples and
+tutorials can be seen at [grpc.io](https://grpc.io/docs/quickstart/php.html).
+gRPC PHP installation instructions for Google Cloud Platform is in
+[cloud.google.com](https://cloud.google.com/php/grpc).
 
 ## Environment
 
-**Prerequisite:**
+###Prerequisite:
 * `php` 5.5 or above, 7.0 or above
 * `pecl`
 * `composer`
@@ -25,6 +28,10 @@ For PHP7:
 ```sh
 $ sudo apt-get install php7.0 php7.0-dev php-pear phpunit
 ```
+or
+```sh
+$ sudo apt-get install php php-dev php-pear phpunit
+```
 
 **Install PHP and PECL on CentOS/RHEL 7:**
 ```sh
@@ -33,8 +40,9 @@ $ sudo rpm -Uvh https://mirror.webtatic.com/yum/el7/webtatic-release.rpm
 $ sudo yum install php56w php56w-devel php-pear phpunit gcc zlib-devel
 ```
 
-**Install PECL on Mac:**
+**Install PHP and PECL on Mac:**
 ```sh
+$ brew install homebrew/php/php56-grpc
 $ curl -O http://pear.php.net/go-pear.phar
 $ sudo php -d detect_unicode=0 go-pear.phar
 ```
@@ -52,50 +60,33 @@ $ chmod +x phpunit-old.phar
 $ sudo mv phpunit-old.phar /usr/bin/phpunit
 ```
 
-## Quick Install
+## Install the gRPC PHP extension
+
+There are two ways to install gRPC PHP extension.
+* `pecl`
+* `build from source`
 
-**Install the gRPC PHP extension**
+### Using PECL
 
 ```sh
 sudo pecl install grpc
 ```
 
-This will compile and install the gRPC PHP extension into the standard PHP
-extension directory. You should be able to run the [unit tests](#unit-tests),
-with the PHP extension installed.
-
-Note: For users on CentOS/RHEL 6, unfortunately this step won't work. Please
-follow the instructions below to compile the extension from source.
-
-
-**Update php.ini**
-
-Add this line to your `php.ini` file, e.g. `/etc/php5/cli/php.ini`
+or specific version
 
 ```sh
-extension=grpc.so
-```
-
-
-**Add the gRPC PHP library as a Composer dependency**
-
-You need to add this to your project's `composer.json` file.
-
+sudo pecl install grpc-1.12.0
 ```
-  "require": {
-    "grpc/grpc": "v1.1.0"
-  }
-```
-
-To run tests with generated stub code from `.proto` files, you will also need
-the `composer` and `protoc` binaries. You can find out how to get these
-[below](#generated-code-tests).
 
+Note: for users on CentOS/RHEL 6, unfortunately this step won’t work. 
+Please follow the instructions below to compile the PECL extension from source.
 
-## Build from Source
+#### Install on Windows
 
+You can download the pre-compiled gRPC extension from the PECL
+[website](https://pecl.php.net/package/grpc)
 
-### gRPC C core library
+### Build from Source with gRPC C core library
 
 Clone this repository
 
@@ -103,16 +94,16 @@ Clone this repository
 $ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc
 ```
 
-Build and install the gRPC C core library
+#### Build and install the gRPC C core library
 
 ```sh
 $ cd grpc
-$ git pull --recurse-submodules && git submodule update --init --recursive
+$ git submodule update --init
 $ make
 $ sudo make install
 ```
 
-### gRPC PHP extension
+#### Build and install gRPC PHP extension
 
 Compile the gRPC PHP extension
 
@@ -124,44 +115,69 @@ $ make
 $ sudo make install
 ```
 
-## Unit Tests
+This will compile and install the gRPC PHP extension into the 
+standard PHP extension directory. You should be able to run 
+the [unit tests](#unit-tests), with the PHP extension installed.
 
-You will need the source code to run tests
+
+### Update php.ini
+
+After installing the gRPC extension, make sure you add this line 
+to your `php.ini` file, (e.g. `/etc/php5/cli/php.ini`, 
+`/etc/php5/apache2/php.ini`, or `/usr/local/etc/php/5.6/php.ini`), 
+depending on where your PHP installation is.
 
 ```sh
-$ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc
-$ cd grpc
-$ git pull --recurse-submodules && git submodule update --init --recursive
+extension=grpc.so
 ```
 
-Run unit tests
+**Add the gRPC PHP library as a Composer dependency**
 
-```sh
-$ cd grpc/src/php
-$ ./bin/run_tests.sh
+You need to add this to your project's `composer.json` file.
+
+```
+  "require": {
+    "grpc/grpc": "v1.12.0"
+  }
 ```
 
-## Generated Code Tests
+To run tests with generated stub code from `.proto` files, you will also 
+need the `composer` and `protoc` binaries. You can find out how to get these below.
 
-This section specifies the prerequisites for running the generated code tests,
-as well as how to run the tests themselves.
+## Install other prerequisites for both Mac OS X and Linux
 
-### Composer
+* `protoc: protobuf compiler`
+* `protobuf.so: protobuf runtime library`
+* `grpc_php_plugin: Generates PHP gRPC service interface out of Protobuf IDL`
 
-Install the runtime dependencies via `composer install`.
+### Install Protobuf compiler
 
-```sh
-$ cd grpc/src/php
-$ composer install
-```
+If you don't have it already, you need to install the protobuf compiler
+`protoc`, version 3.5.0+ (the newer the better) for the current gRPC version.
+If you installed already, make the protobuf version is compatible to the 
+grpc version you installed. If you build grpc.so from the souce, you can check
+the version of grpc inside package.xml file.
 
-### Protobuf compiler
+The compatibility between the grpc and protobuf version is listed as table below:
 
-Again if you don't have it already, you need to install the protobuf compiler
-`protoc`, version 3.1.0+ (the newer the better).
+grpc | protobuf
+--- | --- 
+v1.0.0 | 3.0.0(GA)
+v1.0.1 | 3.0.2
+v1.1.0 | 3.1.0 
+v1.2.0 | 3.2.0 
+v1.2.0 | 3.2.0 
+v1.3.4 | 3.3.0 
+v1.3.5 | 3.2.0
+v1.4.0 | 3.3.0 
+v1.6.0 | 3.4.0
+v1.8.0 | 3.5.0
+v1.12.0 | 3.5.2
 
 If `protoc` hasn't been installed, you can download the `protoc` binaries from
 [the protocol buffers Github repository](https://github.com/google/protobuf/releases).
+Then unzip this file and update the environment variable `PATH` to include the path to 
+the protoc binary file.
 
 If you really must compile `protoc` from source, you can run the following
 commands, but this is risky because there is no easy way to uninstall /
@@ -173,32 +189,44 @@ $ ./autogen.sh && ./configure && make
 $ sudo make install
 ```
 
-
 ### Protobuf Runtime library
 
-There are two protobuf runtime libraries to choose from. They are idenfical in terms of APIs offered.
+There are two protobuf runtime libraries to choose from. They are identical
+in terms of APIs offered. The C implementation provides better performance, 
+while the native implementation is easier to install. Make sure the installed 
+protobuf version works with grpc version.
 
-1. C implementation (for better performance)
+#### 1. C implementation (for better performance)
 
 ``` sh
 $ sudo pecl install protobuf
 ```
+or specific version
 
-2. PHP implementation (for easier installation)
+``` sh
+$ sudo pecl install protobuf-3.5.1.1
+```
 
+Add this to your `php.ini` file:
+
+```sh
+extension=protobuf.so
+```
+
+#### 2. PHP implementation (for easier installation)
 
 Add this to your `composer.json` file:
 
 ```
   "require": {
-    "google/protobuf": "^v3.3.0"
+    "google/protobuf": "^v3.5.0"
   }
-``` 
-
+```
 
 ### PHP Protoc Plugin
 
 You need the gRPC PHP protoc plugin to generate the client stub classes.
+It can generate server and client code from .proto service definitions.
 
 It should already been compiled when you run `make` from the root directory
 of this repo. The plugin can be found in the `bins/opt` directory. We are
@@ -208,10 +236,47 @@ in the future.
 You can also just build the gRPC PHP protoc plugin by running:
 
 ```sh
+$ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc
 $ cd grpc
+$ git submodule update --init
 $ make grpc_php_plugin
 ```
 
+Plugin may use the new feature of the new protobuf version, thus please also
+make sure that the protobuf version installed is compatible with the grpc version 
+you build this plugin.
+
+## Unit Tests
+
+You will need the source code to run tests
+
+```sh
+$ git clone -b $(curl -L https://grpc.io/release) https://github.com/grpc/grpc
+$ cd grpc
+$ git submodule update --init
+```
+
+Run unit tests
+
+```sh
+$ cd grpc/src/php
+$ ./bin/run_tests.sh
+```
+
+## Generated Code Tests
+
+This section specifies the prerequisites for running the generated code tests,
+as well as how to run the tests themselves.
+
+### Composer
+
+Install the runtime dependencies via `composer install`.
+
+```sh
+$ cd grpc/src/php
+$ composer install
+```
+
 
 ### Client Stub
 
diff --git a/src/php/tests/unit_tests/CallCredentials2Test.php b/src/php/tests/unit_tests/CallCredentials2Test.php
index 1c7e0c0ff6..c63029f121 100644
--- a/src/php/tests/unit_tests/CallCredentials2Test.php
+++ b/src/php/tests/unit_tests/CallCredentials2Test.php
@@ -35,6 +35,7 @@ class CallCredentials2Test extends PHPUnit_Framework_TestCase
         $this->channel = new Grpc\Channel(
             'localhost:'.$this->port,
             [
+            'force_new' => true,
             'grpc.ssl_target_name_override' => $this->host_override,
             'grpc.default_authority' => $this->host_override,
             'credentials' => $credentials,
diff --git a/src/php/tests/unit_tests/CallCredentialsTest.php b/src/php/tests/unit_tests/CallCredentialsTest.php
index 4b5721d76a..818b823da7 100644
--- a/src/php/tests/unit_tests/CallCredentialsTest.php
+++ b/src/php/tests/unit_tests/CallCredentialsTest.php
@@ -41,6 +41,7 @@ class CallCredentialsTest extends PHPUnit_Framework_TestCase
         $this->channel = new Grpc\Channel(
             'localhost:'.$this->port,
             [
+            'force_new' => true,
             'grpc.ssl_target_name_override' => $this->host_override,
             'grpc.default_authority' => $this->host_override,
             'credentials' => $this->credentials,
diff --git a/src/php/tests/unit_tests/CallTest.php b/src/php/tests/unit_tests/CallTest.php
index c5e1890a98..be1d77fe7a 100644
--- a/src/php/tests/unit_tests/CallTest.php
+++ b/src/php/tests/unit_tests/CallTest.php
@@ -24,12 +24,14 @@ class CallTest extends PHPUnit_Framework_TestCase
     public static function setUpBeforeClass()
     {
         self::$server = new Grpc\Server([]);
-        self::$port = self::$server->addHttp2Port('0.0.0.0:0');
+        self::$port = self::$server->addHttp2Port('0.0.0.0:53000');
     }
 
     public function setUp()
     {
-        $this->channel = new Grpc\Channel('localhost:'.self::$port, []);
+        $this->channel = new Grpc\Channel('localhost:'.self::$port, [
+            'force_new' => true,
+        ]);
         $this->call = new Grpc\Call($this->channel,
                                     '/foo',
                                     Grpc\Timeval::infFuture());
diff --git a/src/php/tests/unit_tests/EndToEndTest.php b/src/php/tests/unit_tests/EndToEndTest.php
index b54f1d87c9..d0965655e0 100644
--- a/src/php/tests/unit_tests/EndToEndTest.php
+++ b/src/php/tests/unit_tests/EndToEndTest.php
@@ -22,13 +22,16 @@ class EndToEndTest extends PHPUnit_Framework_TestCase
     {
         $this->server = new Grpc\Server([]);
         $this->port = $this->server->addHttp2Port('0.0.0.0:0');
-        $this->channel = new Grpc\Channel('localhost:'.$this->port, []);
+        $this->channel = new Grpc\Channel('localhost:'.$this->port, [
+            "force_new" => true,
+        ]);
         $this->server->start();
     }
 
     public function tearDown()
     {
         $this->channel->close();
+        unset($this->server);
     }
 
     public function testSimpleRequestBody()
diff --git a/src/php/tests/unit_tests/InterceptorTest.php b/src/php/tests/unit_tests/InterceptorTest.php
index 11c5b4325a..d18c27c2c7 100644
--- a/src/php/tests/unit_tests/InterceptorTest.php
+++ b/src/php/tests/unit_tests/InterceptorTest.php
@@ -206,13 +206,16 @@ class InterceptorTest extends PHPUnit_Framework_TestCase
     {
         $this->server = new Grpc\Server([]);
         $this->port = $this->server->addHttp2Port('0.0.0.0:0');
-        $this->channel = new Grpc\Channel('localhost:'.$this->port, ['credentials' => Grpc\ChannelCredentials::createInsecure()]);
+        $this->channel = new Grpc\Channel('localhost:'.$this->port, [
+            'force_new' => true,
+            'credentials' => Grpc\ChannelCredentials::createInsecure()]);
         $this->server->start();
     }
 
     public function tearDown()
     {
         $this->channel->close();
+        unset($this->server);
     }
 
 
@@ -222,6 +225,7 @@ class InterceptorTest extends PHPUnit_Framework_TestCase
         $channel_matadata_interceptor = new ChangeMetadataInterceptor();
         $intercept_channel = Grpc\Interceptor::intercept($this->channel, $channel_matadata_interceptor);
         $client = new InterceptorClient('localhost:'.$this->port, [
+            'force_new' => true,
             'credentials' => Grpc\ChannelCredentials::createInsecure(),
         ], $intercept_channel);
         $req = new SimpleRequest($req_text);
@@ -250,6 +254,7 @@ class InterceptorTest extends PHPUnit_Framework_TestCase
         $intercept_channel1 = Grpc\Interceptor::intercept($this->channel, $channel_matadata_interceptor);
         $intercept_channel2 = Grpc\Interceptor::intercept($intercept_channel1, $channel_matadata_intercepto2);
         $client = new InterceptorClient('localhost:'.$this->port, [
+            'force_new' => true,
             'credentials' => Grpc\ChannelCredentials::createInsecure(),
         ], $intercept_channel2);
 
@@ -275,6 +280,7 @@ class InterceptorTest extends PHPUnit_Framework_TestCase
         $intercept_channel3 = Grpc\Interceptor::intercept($this->channel,
             [$channel_matadata_intercepto2, $channel_matadata_interceptor]);
         $client = new InterceptorClient('localhost:'.$this->port, [
+            'force_new' => true,
             'credentials' => Grpc\ChannelCredentials::createInsecure(),
         ], $intercept_channel3);
 
@@ -304,6 +310,7 @@ class InterceptorTest extends PHPUnit_Framework_TestCase
         $intercept_channel = Grpc\Interceptor::intercept($this->channel,
             $change_request_interceptor);
         $client = new InterceptorClient('localhost:'.$this->port, [
+            'force_new' => true,
             'credentials' => Grpc\ChannelCredentials::createInsecure(),
         ], $intercept_channel);
 
@@ -354,6 +361,7 @@ class InterceptorTest extends PHPUnit_Framework_TestCase
         $intercept_channel = Grpc\Interceptor::intercept($this->channel,
             $channel_request_interceptor);
         $client = new InterceptorClient('localhost:'.$this->port, [
+            'force_new' => true,
             'credentials' => Grpc\ChannelCredentials::createInsecure(),
         ], $intercept_channel);
 
@@ -374,7 +382,10 @@ class InterceptorTest extends PHPUnit_Framework_TestCase
     {
         $channel = new Grpc\Channel(
             'localhost:0',
-            ['credentials' => Grpc\ChannelCredentials::createInsecure()]
+            [
+                'force_new' => true,
+                'credentials' => Grpc\ChannelCredentials::createInsecure()
+            ]
         );
         $interceptor_channel = Grpc\Interceptor::intercept($channel, new Grpc\Interceptor());
         $state = $interceptor_channel->getConnectivityState();
@@ -386,7 +397,10 @@ class InterceptorTest extends PHPUnit_Framework_TestCase
     {
         $channel = new Grpc\Channel(
             'localhost:0',
-            ['credentials' => Grpc\ChannelCredentials::createInsecure()]
+            [
+                'force_new' => true,
+                'credentials' => Grpc\ChannelCredentials::createInsecure()
+            ]
         );
         $interceptor_channel = Grpc\Interceptor::intercept($channel, new Grpc\Interceptor());
         $now = Grpc\Timeval::now();
@@ -402,7 +416,10 @@ class InterceptorTest extends PHPUnit_Framework_TestCase
     {
         $channel = new Grpc\Channel(
             'localhost:0',
-            ['credentials' => Grpc\ChannelCredentials::createInsecure()]
+            [
+                'force_new' => true,
+                'credentials' => Grpc\ChannelCredentials::createInsecure()
+            ]
         );
         $interceptor_channel = Grpc\Interceptor::intercept($channel, new Grpc\Interceptor());
         $this->assertNotNull($interceptor_channel);
@@ -413,7 +430,10 @@ class InterceptorTest extends PHPUnit_Framework_TestCase
     {
         $channel = new Grpc\Channel(
             'localhost:8888',
-            ['credentials' => Grpc\ChannelCredentials::createInsecure()]
+            [
+                'force_new' => true,
+                'credentials' => Grpc\ChannelCredentials::createInsecure()
+            ]
         );
         $interceptor_channel = Grpc\Interceptor::intercept($channel, new Grpc\Interceptor());
         $target = $interceptor_channel->getTarget();
diff --git a/src/php/tests/unit_tests/SecureEndToEndTest.php b/src/php/tests/unit_tests/SecureEndToEndTest.php
index dff4e878ea..071598c4c1 100644
--- a/src/php/tests/unit_tests/SecureEndToEndTest.php
+++ b/src/php/tests/unit_tests/SecureEndToEndTest.php
@@ -34,6 +34,7 @@ class SecureEndToEndTest extends PHPUnit_Framework_TestCase
         $this->channel = new Grpc\Channel(
             'localhost:'.$this->port,
             [
+            'force_new' => true,
             'grpc.ssl_target_name_override' => $this->host_override,
             'grpc.default_authority' => $this->host_override,
             'credentials' => $credentials,
@@ -44,6 +45,7 @@ class SecureEndToEndTest extends PHPUnit_Framework_TestCase
     public function tearDown()
     {
         $this->channel->close();
+        unset($this->server);
     }
 
     public function testSimpleRequestBody()
diff --git a/src/php/tests/unit_tests/ServerTest.php b/src/php/tests/unit_tests/ServerTest.php
index ac6f2f0312..cab92e5941 100644
--- a/src/php/tests/unit_tests/ServerTest.php
+++ b/src/php/tests/unit_tests/ServerTest.php
@@ -55,7 +55,10 @@ class ServerTest extends PHPUnit_Framework_TestCase
         $port = $this->server->addHttp2Port('0.0.0.0:0');
         $this->server->start();
         $channel = new Grpc\Channel('localhost:'.$port,
-             ['credentials' => Grpc\ChannelCredentials::createInsecure()]);
+             [
+                 'force_new' => true,
+                 'credentials' => Grpc\ChannelCredentials::createInsecure()
+             ]);
 
         $deadline = Grpc\Timeval::infFuture();
         $call = new Grpc\Call($channel, 'dummy_method', $deadline);
diff --git a/src/proto/grpc/testing/empty_service.proto b/src/proto/grpc/testing/empty_service.proto
new file mode 100644
index 0000000000..157629b7a4
--- /dev/null
+++ b/src/proto/grpc/testing/empty_service.proto
@@ -0,0 +1,23 @@
+
+// Copyright 2018 gRPC authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+
+package grpc.testing;
+
+// A service that has zero methods.
+// See https://github.com/grpc/grpc/issues/15574
+service EmptyService {
+}
diff --git a/src/python/grpcio/grpc/__init__.py b/src/python/grpcio/grpc/__init__.py
index b7ed0c8563..d1477fbeb5 100644
--- a/src/python/grpcio/grpc/__init__.py
+++ b/src/python/grpcio/grpc/__init__.py
@@ -1250,19 +1250,20 @@ class Server(six.with_metaclass(abc.ABCMeta)):
         """Stops this Server.
 
         This method immediately stop service of new RPCs in all cases.
+
         If a grace period is specified, this method returns immediately
         and all RPCs active at the end of the grace period are aborted.
-
-        If a grace period is not specified, then all existing RPCs are
-        teriminated immediately and the this method blocks until the last
-        RPC handler terminates.
+        If a grace period is not specified (by passing None for `grace`),
+        all existing RPCs are aborted immediately and this method
+        blocks until the last RPC handler terminates.
 
         This method is idempotent and may be called at any time.
-        Passing a smaller grace value in subsequent call will have
-        the effect of stopping the Server sooner. Passing a larger
-        grace value in subsequent call *will not* have the effect of
-        stopping the server later (i.e. the most restrictive grace
-        value is used).
+        Passing a smaller grace value in a subsequent call will have
+        the effect of stopping the Server sooner (passing None will
+        have the effect of stopping the server immediately). Passing
+        a larger grace value in a subsequent call *will not* have the
+        effect of stopping the server later (i.e. the most restrictive
+        grace value is used).
 
         Args:
           grace: A duration of time in seconds or None.
@@ -1481,7 +1482,7 @@ def ssl_server_credentials(private_key_certificate_chain_pairs,
       A ServerCredentials for use with an SSL-enabled Server. Typically, this
       object is an argument to add_secure_port() method during server setup.
     """
-    if len(private_key_certificate_chain_pairs) == 0:
+    if not private_key_certificate_chain_pairs:
         raise ValueError(
             'At least one private key-certificate chain pair is required!')
     elif require_client_auth and root_certificates is None:
@@ -1511,15 +1512,15 @@ def ssl_server_certificate_configuration(private_key_certificate_chain_pairs,
       A ServerCertificateConfiguration that can be returned in the certificate
         configuration fetching callback.
     """
-    if len(private_key_certificate_chain_pairs) == 0:
-        raise ValueError(
-            'At least one private key-certificate chain pair is required!')
-    else:
+    if private_key_certificate_chain_pairs:
         return ServerCertificateConfiguration(
             _cygrpc.server_certificate_config_ssl(root_certificates, [
                 _cygrpc.SslPemKeyCertPair(key, pem)
                 for key, pem in private_key_certificate_chain_pairs
             ]))
+    else:
+        raise ValueError(
+            'At least one private key-certificate chain pair is required!')
 
 
 def dynamic_ssl_server_credentials(initial_certificate_configuration,
diff --git a/src/python/grpcio/grpc/_channel.py b/src/python/grpcio/grpc/_channel.py
index 2017d47130..e9246991df 100644
--- a/src/python/grpcio/grpc/_channel.py
+++ b/src/python/grpcio/grpc/_channel.py
@@ -24,6 +24,8 @@ from grpc import _grpcio_metadata
 from grpc._cython import cygrpc
 from grpc.framework.foundation import callable_util
 
+_LOGGER = logging.getLogger(__name__)
+
 _USER_AGENT = 'grpc-python/{}'.format(_grpcio_metadata.__version__)
 
 _EMPTY_FLAGS = 0
@@ -181,7 +183,7 @@ def _consume_request_iterator(request_iterator, state, call, request_serializer,
             except Exception:  # pylint: disable=broad-except
                 code = grpc.StatusCode.UNKNOWN
                 details = 'Exception iterating requests!'
-                logging.exception(details)
+                _LOGGER.exception(details)
                 call.cancel(_common.STATUS_CODE_TO_CYGRPC_STATUS_CODE[code],
                             details)
                 _abort(state, code, details)
@@ -190,7 +192,7 @@ def _consume_request_iterator(request_iterator, state, call, request_serializer,
             with state.condition:
                 if state.code is None and not state.cancelled:
                     if serialized_request is None:
-                        code = grpc.StatusCode.INTERNAL  # pylint: disable=redefined-variable-type
+                        code = grpc.StatusCode.INTERNAL
                         details = 'Exception serializing request!'
                         call.cancel(
                             _common.STATUS_CODE_TO_CYGRPC_STATUS_CODE[code],
@@ -811,10 +813,7 @@ def _poll_connectivity(state, channel, initial_try_to_connect):
                     _common.CYGRPC_CONNECTIVITY_STATE_TO_CHANNEL_CONNECTIVITY[
                         connectivity])
                 if not state.delivering:
-                    # NOTE(nathaniel): The field is only ever used as a
-                    # sequence so it's fine that both lists and tuples are
-                    # assigned to it.
-                    callbacks = _deliveries(state)  # pylint: disable=redefined-variable-type
+                    callbacks = _deliveries(state)
                     if callbacks:
                         _spawn_delivery(state, callbacks)
 
diff --git a/src/python/grpcio/grpc/_common.py b/src/python/grpcio/grpc/_common.py
index 862987a0cd..8358cbec5b 100644
--- a/src/python/grpcio/grpc/_common.py
+++ b/src/python/grpcio/grpc/_common.py
@@ -20,6 +20,8 @@ import six
 import grpc
 from grpc._cython import cygrpc
 
+_LOGGER = logging.getLogger(__name__)
+
 CYGRPC_CONNECTIVITY_STATE_TO_CHANNEL_CONNECTIVITY = {
     cygrpc.ConnectivityState.idle:
     grpc.ChannelConnectivity.IDLE,
@@ -73,7 +75,7 @@ def decode(b):
         try:
             return b.decode('utf8')
         except UnicodeDecodeError:
-            logging.exception('Invalid encoding on %s', b)
+            _LOGGER.exception('Invalid encoding on %s', b)
             return b.decode('latin1')
 
 
@@ -84,7 +86,7 @@ def _transform(message, transformer, exception_message):
         try:
             return transformer(message)
         except Exception:  # pylint: disable=broad-except
-            logging.exception(exception_message)
+            _LOGGER.exception(exception_message)
             return None
 
 
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/arguments.pyx.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/arguments.pyx.pxi
index 65de30884c..aecd3d7b11 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/arguments.pyx.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/arguments.pyx.pxi
@@ -15,10 +15,12 @@
 cimport cpython
 
 
+# TODO(https://github.com/grpc/grpc/issues/15662): Reform this.
 cdef void* _copy_pointer(void* pointer):
   return pointer
 
 
+# TODO(https://github.com/grpc/grpc/issues/15662): Reform this.
 cdef void _destroy_pointer(void* pointer):
   pass
 
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/channel.pxd.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/channel.pxd.pxi
index eefc685c0b..f067d76fab 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/channel.pxd.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/channel.pxd.pxi
@@ -69,3 +69,6 @@ cdef class Channel:
 
   cdef grpc_arg_pointer_vtable _vtable
   cdef _ChannelState _state
+
+  # TODO(https://github.com/grpc/grpc/issues/15662): Eliminate this.
+  cdef tuple _arguments
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/channel.pyx.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/channel.pyx.pxi
index 72e74e84ae..8c37a3cf85 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/channel.pyx.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/channel.pyx.pxi
@@ -390,6 +390,7 @@ cdef class Channel:
   def __cinit__(
       self, bytes target, object arguments,
       ChannelCredentials channel_credentials):
+    arguments = () if arguments is None else tuple(arguments)
     grpc_init()
     self._state = _ChannelState()
     self._vtable.copy = &_copy_pointer
@@ -410,6 +411,7 @@ cdef class Channel:
         grpc_completion_queue_create_for_next(NULL))
     self._state.c_connectivity_completion_queue = (
         grpc_completion_queue_create_for_next(NULL))
+    self._arguments = arguments
 
   def target(self):
     cdef char *c_target
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/credentials.pxd.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/credentials.pxd.pxi
index 7e9ea33ca0..8d73215247 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/credentials.pxd.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/credentials.pxd.pxi
@@ -57,6 +57,11 @@ cdef class ChannelCredentials:
   cdef grpc_channel_credentials *c_credentials
 
 
+cdef class SSLSessionCacheLRU:
+
+  cdef grpc_ssl_session_cache *_cache
+
+
 cdef class SSLChannelCredentials(ChannelCredentials):
 
   cdef readonly object _pem_root_certificates
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/credentials.pyx.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/credentials.pyx.pxi
index 500086f6cb..f4ccfbc016 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/credentials.pyx.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/credentials.pyx.pxi
@@ -17,6 +17,21 @@ cimport cpython
 import grpc
 import threading
 
+from libc.stdint cimport uintptr_t
+
+
+def _spawn_callback_in_thread(cb_func, args):
+  threading.Thread(target=cb_func, args=args).start()
+
+async_callback_func = _spawn_callback_in_thread
+
+def set_async_callback_func(callback_func):
+  global async_callback_func
+  async_callback_func = callback_func
+
+def _spawn_callback_async(callback, args):
+  async_callback_func(callback, args)
+
 
 cdef class CallCredentials:
 
@@ -40,7 +55,7 @@ cdef int _get_metadata(
     else:
       cb(user_data, NULL, 0, status, error_details)
   args = context.service_url, context.method_name, callback,
-  threading.Thread(target=<object>state, args=args).start()
+  _spawn_callback_async(<object>state, args)
   return 0  # Asynchronous return
 
 
@@ -96,6 +111,21 @@ cdef class ChannelCredentials:
     raise NotImplementedError()
 
 
+cdef class SSLSessionCacheLRU:
+
+  def __cinit__(self, capacity):
+    grpc_init()
+    self._cache = grpc_ssl_session_cache_create_lru(capacity)
+
+  def __int__(self):
+    return <uintptr_t>self._cache
+
+  def __dealloc__(self):
+    if self._cache != NULL:
+        grpc_ssl_session_cache_destroy(self._cache)
+    grpc_shutdown()
+
+
 cdef class SSLChannelCredentials(ChannelCredentials):
 
   def __cinit__(self, pem_root_certificates, private_key, certificate_chain):
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxi
index 2d6c900c54..cfefeaf938 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxi
@@ -131,6 +131,7 @@ cdef extern from "grpc/grpc.h":
   const char *GRPC_ARG_PRIMARY_USER_AGENT_STRING
   const char *GRPC_ARG_SECONDARY_USER_AGENT_STRING
   const char *GRPC_SSL_TARGET_NAME_OVERRIDE_ARG
+  const char *GRPC_SSL_SESSION_CACHE_ARG
   const char *GRPC_COMPRESSION_CHANNEL_DEFAULT_ALGORITHM
   const char *GRPC_COMPRESSION_CHANNEL_DEFAULT_LEVEL
   const char *GRPC_COMPRESSION_CHANNEL_ENABLED_ALGORITHMS_BITSET
@@ -452,8 +453,16 @@ cdef extern from "grpc/grpc_security.h":
     # We don't care about the internals (and in fact don't know them)
     pass
 
+
+  ctypedef struct grpc_ssl_session_cache:
+    # We don't care about the internals (and in fact don't know them)
+    pass
+
   ctypedef void (*grpc_ssl_roots_override_callback)(char **pem_root_certs)
 
+  grpc_ssl_session_cache *grpc_ssl_session_cache_create_lru(size_t capacity)
+  void grpc_ssl_session_cache_destroy(grpc_ssl_session_cache* cache)
+
   void grpc_set_ssl_roots_override_callback(
       grpc_ssl_roots_override_callback cb) nogil
 
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/grpc_gevent.pyx b/src/python/grpcio/grpc/_cython/_cygrpc/grpc_gevent.pyx
index 31ef671aed..f9a1b2856d 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/grpc_gevent.pyx
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/grpc_gevent.pyx
@@ -418,6 +418,11 @@ def init_grpc_gevent():
 
   g_event = gevent.event.Event()
   g_pool = gevent.pool.Group()
+
+  def cb_func(cb, args):
+    _spawn_greenlet(cb, *args)
+  set_async_callback_func(cb_func)
+
   gevent_resolver_vtable.resolve = socket_resolve
   gevent_resolver_vtable.resolve_async = socket_resolve_async
 
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/grpc_string.pyx.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/grpc_string.pyx.pxi
index 53e06a1596..00a1b23a67 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/grpc_string.pyx.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/grpc_string.pyx.pxi
@@ -14,6 +14,7 @@
 
 import logging
 
+_LOGGER = logging.getLogger(__name__)
 
 # This function will ascii encode unicode string inputs if neccesary.
 # In Python3, unicode strings are the default str type.
@@ -49,5 +50,5 @@ cdef str _decode(bytes bytestring):
         try:
             return bytestring.decode('utf8')
         except UnicodeDecodeError:
-            logging.exception('Invalid encoding on %s', bytestring)
+            _LOGGER.exception('Invalid encoding on %s', bytestring)
             return bytestring.decode('latin1')
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/records.pyx.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/records.pyx.pxi
index ecd991685f..37b98ebbdb 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/records.pyx.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/records.pyx.pxi
@@ -51,6 +51,7 @@ class ChannelArgKey:
   default_authority = GRPC_ARG_DEFAULT_AUTHORITY
   primary_user_agent_string = GRPC_ARG_PRIMARY_USER_AGENT_STRING
   secondary_user_agent_string = GRPC_ARG_SECONDARY_USER_AGENT_STRING
+  ssl_session_cache = GRPC_SSL_SESSION_CACHE_ARG
   ssl_target_name_override = GRPC_SSL_TARGET_NAME_OVERRIDE_ARG
 
 
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/server.pxd.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/server.pxd.pxi
index 4588db30d3..52cfccb677 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/server.pxd.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/server.pxd.pxi
@@ -23,6 +23,7 @@ cdef class Server:
   cdef bint is_shutdown  # notification of complete shutdown received
   # used at dealloc when user forgets to shutdown
   cdef CompletionQueue backup_shutdown_queue
+  # TODO(https://github.com/grpc/grpc/issues/15662): Elide this.
   cdef list references
   cdef list registered_completion_queues
 
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/server.pyx.pxi b/src/python/grpcio/grpc/_cython/_cygrpc/server.pyx.pxi
index 707ec742dd..da3dd21244 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/server.pyx.pxi
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/server.pyx.pxi
@@ -18,6 +18,8 @@ import logging
 import time
 import grpc
 
+_LOGGER = logging.getLogger(__name__)
+
 cdef grpc_ssl_certificate_config_reload_status _server_cert_config_fetcher_wrapper(
         void* user_data, grpc_ssl_server_certificate_config **config) with gil:
   # This is a credentials.ServerCertificateConfig
@@ -34,13 +36,13 @@ cdef grpc_ssl_certificate_config_reload_status _server_cert_config_fetcher_wrapp
     try:
       cert_config_wrapper = user_cb()
     except Exception:
-      logging.exception('Error fetching certificate config')
+      _LOGGER.exception('Error fetching certificate config')
       return GRPC_SSL_CERTIFICATE_CONFIG_RELOAD_FAIL
     if cert_config_wrapper is None:
       return GRPC_SSL_CERTIFICATE_CONFIG_RELOAD_UNCHANGED
     elif not isinstance(
         cert_config_wrapper, grpc.ServerCertificateConfiguration):
-      logging.error(
+      _LOGGER.error(
           'Error fetching certificate configuration: certificate '
           'configuration must be of type grpc.ServerCertificateConfiguration, '
           'not %s' % type(cert_config_wrapper).__name__)
diff --git a/src/python/grpcio/grpc/_interceptor.py b/src/python/grpcio/grpc/_interceptor.py
index f465e35a9c..6b7a912a94 100644
--- a/src/python/grpcio/grpc/_interceptor.py
+++ b/src/python/grpcio/grpc/_interceptor.py
@@ -100,6 +100,12 @@ class _LocalFailure(grpc.RpcError, grpc.Future, grpc.Call):
     def cancelled(self):
         return False
 
+    def is_active(self):
+        return False
+
+    def time_remaining(self):
+        return None
+
     def running(self):
         return False
 
@@ -115,6 +121,9 @@ class _LocalFailure(grpc.RpcError, grpc.Future, grpc.Call):
     def traceback(self, ignored_timeout=None):
         return self._traceback
 
+    def add_callback(self, callback):
+        return False
+
     def add_done_callback(self, fn):
         fn(self)
 
@@ -288,11 +297,11 @@ class _Channel(grpc.Channel):
         self._channel = channel
         self._interceptor = interceptor
 
-    def subscribe(self, *args, **kwargs):
-        self._channel.subscribe(*args, **kwargs)
+    def subscribe(self, callback, try_to_connect=False):
+        self._channel.subscribe(callback, try_to_connect=try_to_connect)
 
-    def unsubscribe(self, *args, **kwargs):
-        self._channel.unsubscribe(*args, **kwargs)
+    def unsubscribe(self, callback):
+        self._channel.unsubscribe(callback)
 
     def unary_unary(self,
                     method,
diff --git a/src/python/grpcio/grpc/_plugin_wrapping.py b/src/python/grpcio/grpc/_plugin_wrapping.py
index 6785e5876a..916ee080b6 100644
--- a/src/python/grpcio/grpc/_plugin_wrapping.py
+++ b/src/python/grpcio/grpc/_plugin_wrapping.py
@@ -20,6 +20,8 @@ import grpc
 from grpc import _common
 from grpc._cython import cygrpc
 
+_LOGGER = logging.getLogger(__name__)
+
 
 class _AuthMetadataContext(
         collections.namedtuple('AuthMetadataContext', (
@@ -76,7 +78,7 @@ class _Plugin(object):
                                   _AuthMetadataPluginCallback(
                                       callback_state, callback))
         except Exception as exception:  # pylint: disable=broad-except
-            logging.exception(
+            _LOGGER.exception(
                 'AuthMetadataPluginCallback "%s" raised exception!',
                 self._metadata_plugin)
             with callback_state.lock:
diff --git a/src/python/grpcio/grpc/_server.py b/src/python/grpcio/grpc/_server.py
index d849cadbee..2761022f21 100644
--- a/src/python/grpcio/grpc/_server.py
+++ b/src/python/grpcio/grpc/_server.py
@@ -27,6 +27,8 @@ from grpc import _interceptor
 from grpc._cython import cygrpc
 from grpc.framework.foundation import callable_util
 
+_LOGGER = logging.getLogger(__name__)
+
 _SHUTDOWN_TAG = 'shutdown'
 _REQUEST_CALL_TAG = 'request_call'
 
@@ -279,7 +281,7 @@ class _Context(grpc.ServicerContext):
     def abort(self, code, details):
         # treat OK like other invalid arguments: fail the RPC
         if code == grpc.StatusCode.OK:
-            logging.error(
+            _LOGGER.error(
                 'abort() called with StatusCode.OK; returning UNKNOWN')
             code = grpc.StatusCode.UNKNOWN
             details = ''
@@ -328,6 +330,8 @@ class _RequestIterator(object):
             self._state.request = None
             return request
 
+        raise AssertionError()  # should never run
+
     def _next(self):
         with self._state.condition:
             self._raise_or_start_receive_message()
@@ -390,7 +394,7 @@ def _call_behavior(rpc_event, state, behavior, argument, request_deserializer):
                        b'RPC Aborted')
             elif exception not in state.rpc_errors:
                 details = 'Exception calling application: {}'.format(exception)
-                logging.exception(details)
+                _LOGGER.exception(details)
                 _abort(state, rpc_event.call, cygrpc.StatusCode.unknown,
                        _common.encode(details))
         return None, False
@@ -408,7 +412,7 @@ def _take_response_from_response_iterator(rpc_event, state, response_iterator):
                        b'RPC Aborted')
             elif exception not in state.rpc_errors:
                 details = 'Exception iterating responses: {}'.format(exception)
-                logging.exception(details)
+                _LOGGER.exception(details)
                 _abort(state, rpc_event.call, cygrpc.StatusCode.unknown,
                        _common.encode(details))
         return None, False
@@ -617,7 +621,7 @@ def _handle_call(rpc_event, generic_handlers, interceptor_pipeline, thread_pool,
                                                   interceptor_pipeline)
         except Exception as exception:  # pylint: disable=broad-except
             details = 'Exception servicing handler: {}'.format(exception)
-            logging.exception(details)
+            _LOGGER.exception(details)
             return _reject_rpc(rpc_event, cygrpc.StatusCode.unknown,
                                b'Error in service handler!'), None
         if method_handler is None:
diff --git a/src/python/grpcio/grpc/_utilities.py b/src/python/grpcio/grpc/_utilities.py
index 25bd1ceae2..d90b34bcbd 100644
--- a/src/python/grpcio/grpc/_utilities.py
+++ b/src/python/grpcio/grpc/_utilities.py
@@ -116,6 +116,8 @@ class _ChannelReadyFuture(grpc.Future):
             callable_util.call_logging_exceptions(
                 done_callback, _DONE_CALLBACK_EXCEPTION_LOG_MESSAGE, self)
 
+        return True
+
     def cancelled(self):
         with self._condition:
             return self._cancelled
diff --git a/src/python/grpcio/grpc/beta/_server_adaptations.py b/src/python/grpcio/grpc/beta/_server_adaptations.py
index ccafec8951..80ac65b649 100644
--- a/src/python/grpcio/grpc/beta/_server_adaptations.py
+++ b/src/python/grpcio/grpc/beta/_server_adaptations.py
@@ -305,6 +305,7 @@ def _simple_method_handler(implementation, request_deserializer,
                                         response_serializer, None, None, None,
                                         _adapt_stream_stream_event(
                                             implementation.stream_stream_event))
+    raise ValueError()
 
 
 def _flatten_method_pair_map(method_pair_map):
diff --git a/src/python/grpcio/grpc/beta/utilities.py b/src/python/grpcio/grpc/beta/utilities.py
index b5d8aac71a..fe3ce606c9 100644
--- a/src/python/grpcio/grpc/beta/utilities.py
+++ b/src/python/grpcio/grpc/beta/utilities.py
@@ -85,6 +85,8 @@ class _ChannelReadyFuture(future.Future):
             callable_util.call_logging_exceptions(
                 done_callback, _DONE_CALLBACK_EXCEPTION_LOG_MESSAGE, self)
 
+        return True
+
     def cancelled(self):
         with self._condition:
             return self._cancelled
diff --git a/src/python/grpcio/grpc/experimental/session_cache.py b/src/python/grpcio/grpc/experimental/session_cache.py
new file mode 100644
index 0000000000..5c55f7c327
--- /dev/null
+++ b/src/python/grpcio/grpc/experimental/session_cache.py
@@ -0,0 +1,45 @@
+# Copyright 2018 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""gRPC's APIs for TLS Session Resumption support"""
+
+from grpc._cython import cygrpc as _cygrpc
+
+
+def ssl_session_cache_lru(capacity):
+    """Creates an SSLSessionCache with LRU replacement policy
+
+    Args:
+      capacity: Size of the cache
+
+    Returns:
+      An SSLSessionCache with LRU replacement policy that can be passed as a value for
+      the grpc.ssl_session_cache option to a grpc.Channel. SSL session caches are used
+      to store session tickets, which clients can present to resume previous TLS sessions
+      with a server.
+    """
+    return SSLSessionCache(_cygrpc.SSLSessionCacheLRU(capacity))
+
+
+class SSLSessionCache(object):
+    """An encapsulation of a session cache used for TLS session resumption.
+
+    Instances of this class can be passed to a Channel as values for the
+    grpc.ssl_session_cache option
+    """
+
+    def __init__(self, cache):
+        self._cache = cache
+
+    def __int__(self):
+        return int(self._cache)
diff --git a/src/python/grpcio/grpc/framework/foundation/callable_util.py b/src/python/grpcio/grpc/framework/foundation/callable_util.py
index b9b9c49f17..24daf3406f 100644
--- a/src/python/grpcio/grpc/framework/foundation/callable_util.py
+++ b/src/python/grpcio/grpc/framework/foundation/callable_util.py
@@ -21,6 +21,8 @@ import logging
 
 import six
 
+_LOGGER = logging.getLogger(__name__)
+
 
 class Outcome(six.with_metaclass(abc.ABCMeta)):
     """A sum type describing the outcome of some call.
@@ -53,7 +55,7 @@ def _call_logging_exceptions(behavior, message, *args, **kwargs):
         return _EasyOutcome(Outcome.Kind.RETURNED, behavior(*args, **kwargs),
                             None)
     except Exception as e:  # pylint: disable=broad-except
-        logging.exception(message)
+        _LOGGER.exception(message)
         return _EasyOutcome(Outcome.Kind.RAISED, None, e)
 
 
diff --git a/src/python/grpcio/grpc/framework/foundation/logging_pool.py b/src/python/grpcio/grpc/framework/foundation/logging_pool.py
index f75df10042..216e3990db 100644
--- a/src/python/grpcio/grpc/framework/foundation/logging_pool.py
+++ b/src/python/grpcio/grpc/framework/foundation/logging_pool.py
@@ -17,6 +17,8 @@ import logging
 
 from concurrent import futures
 
+_LOGGER = logging.getLogger(__name__)
+
 
 def _wrap(behavior):
     """Wraps an arbitrary callable behavior in exception-logging."""
@@ -25,7 +27,7 @@ def _wrap(behavior):
         try:
             return behavior(*args, **kwargs)
         except Exception:
-            logging.exception(
+            _LOGGER.exception(
                 'Unexpected exception from %s executed in logging pool!',
                 behavior)
             raise
diff --git a/src/python/grpcio/grpc/framework/foundation/stream_util.py b/src/python/grpcio/grpc/framework/foundation/stream_util.py
index 04631d9899..1faaf29bd7 100644
--- a/src/python/grpcio/grpc/framework/foundation/stream_util.py
+++ b/src/python/grpcio/grpc/framework/foundation/stream_util.py
@@ -19,6 +19,7 @@ import threading
 from grpc.framework.foundation import stream
 
 _NO_VALUE = object()
+_LOGGER = logging.getLogger(__name__)
 
 
 class TransformingConsumer(stream.Consumer):
@@ -46,10 +47,10 @@ class IterableConsumer(stream.Consumer):
         self._values = []
         self._active = True
 
-    def consume(self, stock_reply):
+    def consume(self, value):
         with self._condition:
             if self._active:
-                self._values.append(stock_reply)
+                self._values.append(value)
                 self._condition.notify()
 
     def terminate(self):
@@ -57,10 +58,10 @@ class IterableConsumer(stream.Consumer):
             self._active = False
             self._condition.notify()
 
-    def consume_and_terminate(self, stock_reply):
+    def consume_and_terminate(self, value):
         with self._condition:
             if self._active:
-                self._values.append(stock_reply)
+                self._values.append(value)
                 self._active = False
                 self._condition.notify()
 
@@ -103,7 +104,7 @@ class ThreadSwitchingConsumer(stream.Consumer):
                 else:
                     sink.consume(value)
             except Exception as e:  # pylint:disable=broad-except
-                logging.exception(e)
+                _LOGGER.exception(e)
 
             with self._lock:
                 if terminate:
diff --git a/src/python/grpcio_testing/grpc_testing/__init__.py b/src/python/grpcio_testing/grpc_testing/__init__.py
index e87d0ffc96..65fdd1b8ca 100644
--- a/src/python/grpcio_testing/grpc_testing/__init__.py
+++ b/src/python/grpcio_testing/grpc_testing/__init__.py
@@ -14,9 +14,9 @@
 """Objects for use in testing gRPC Python-using application code."""
 
 import abc
+import six
 
 from google.protobuf import descriptor
-import six
 
 import grpc
 
diff --git a/src/python/grpcio_testing/grpc_testing/_channel/_invocation.py b/src/python/grpcio_testing/grpc_testing/_channel/_invocation.py
index ebce652eeb..191b1c1726 100644
--- a/src/python/grpcio_testing/grpc_testing/_channel/_invocation.py
+++ b/src/python/grpcio_testing/grpc_testing/_channel/_invocation.py
@@ -18,6 +18,7 @@ import threading
 import grpc
 
 _NOT_YET_OBSERVED = object()
+_LOGGER = logging.getLogger(__name__)
 
 
 def _cancel(handler):
@@ -248,7 +249,7 @@ def consume_requests(request_iterator, handler):
                 break
             except Exception:  # pylint: disable=broad-except
                 details = 'Exception iterating requests!'
-                logging.exception(details)
+                _LOGGER.exception(details)
                 handler.cancel(grpc.StatusCode.UNKNOWN, details)
 
     consumption = threading.Thread(target=_consume)
diff --git a/src/python/grpcio_testing/grpc_testing/_server/_handler.py b/src/python/grpcio_testing/grpc_testing/_server/_handler.py
index d4f50f6863..0e3404b0d0 100644
--- a/src/python/grpcio_testing/grpc_testing/_server/_handler.py
+++ b/src/python/grpcio_testing/grpc_testing/_server/_handler.py
@@ -105,10 +105,10 @@ class _Handler(Handler):
                 self._expiration_future.cancel()
             self._condition.notify_all()
 
-    def add_termination_callback(self, termination_callback):
+    def add_termination_callback(self, callback):
         with self._condition:
             if self._code is None:
-                self._termination_callbacks.append(termination_callback)
+                self._termination_callbacks.append(callback)
                 return True
             else:
                 return False
diff --git a/src/python/grpcio_testing/grpc_testing/_server/_rpc.py b/src/python/grpcio_testing/grpc_testing/_server/_rpc.py
index 2060e8daff..b856da100f 100644
--- a/src/python/grpcio_testing/grpc_testing/_server/_rpc.py
+++ b/src/python/grpcio_testing/grpc_testing/_server/_rpc.py
@@ -18,6 +18,8 @@ import threading
 import grpc
 from grpc_testing import _common
 
+_LOGGER = logging.getLogger(__name__)
+
 
 class Rpc(object):
 
@@ -47,7 +49,7 @@ class Rpc(object):
                 try:
                     callback()
                 except Exception:  # pylint: disable=broad-except
-                    logging.exception('Exception calling server-side callback!')
+                    _LOGGER.exception('Exception calling server-side callback!')
 
         callback_calling_thread = threading.Thread(target=call_back)
         callback_calling_thread.start()
@@ -86,7 +88,7 @@ class Rpc(object):
     def application_exception_abort(self, exception):
         with self._condition:
             if exception not in self._rpc_errors:
-                logging.exception('Exception calling application!')
+                _LOGGER.exception('Exception calling application!')
                 self._abort(
                     grpc.StatusCode.UNKNOWN,
                     'Exception calling application: {}'.format(exception))
diff --git a/src/python/grpcio_testing/grpc_testing/_time.py b/src/python/grpcio_testing/grpc_testing/_time.py
index afbdad3524..75e6db3458 100644
--- a/src/python/grpcio_testing/grpc_testing/_time.py
+++ b/src/python/grpcio_testing/grpc_testing/_time.py
@@ -21,13 +21,15 @@ import time as _time
 import grpc
 import grpc_testing
 
+_LOGGER = logging.getLogger(__name__)
+
 
 def _call(behaviors):
     for behavior in behaviors:
         try:
             behavior()
         except Exception:  # pylint: disable=broad-except
-            logging.exception('Exception calling behavior "%r"!', behavior)
+            _LOGGER.exception('Exception calling behavior "%r"!', behavior)
 
 
 def _call_in_thread(behaviors):
diff --git a/src/python/grpcio_tests/tests/_loader.py b/src/python/grpcio_tests/tests/_loader.py
index be0af64646..80c107aa8e 100644
--- a/src/python/grpcio_tests/tests/_loader.py
+++ b/src/python/grpcio_tests/tests/_loader.py
@@ -48,12 +48,13 @@ class Loader(object):
         # measure unnecessarily suffers)
         coverage_context = coverage.Coverage(data_suffix=True)
         coverage_context.start()
-        modules = [importlib.import_module(name) for name in names]
-        for module in modules:
-            self.visit_module(module)
-        for module in modules:
+        imported_modules = tuple(
+            importlib.import_module(name) for name in names)
+        for imported_module in imported_modules:
+            self.visit_module(imported_module)
+        for imported_module in imported_modules:
             try:
-                package_paths = module.__path__
+                package_paths = imported_module.__path__
             except AttributeError:
                 continue
             self.walk_packages(package_paths)
diff --git a/src/python/grpcio_tests/tests/_result.py b/src/python/grpcio_tests/tests/_result.py
index b105f18e78..e5378b7ea3 100644
--- a/src/python/grpcio_tests/tests/_result.py
+++ b/src/python/grpcio_tests/tests/_result.py
@@ -144,10 +144,6 @@ class AugmentedResult(unittest.TestResult):
         super(AugmentedResult, self).startTestRun()
         self.cases = dict()
 
-    def stopTestRun(self):
-        """See unittest.TestResult.stopTestRun."""
-        super(AugmentedResult, self).stopTestRun()
-
     def startTest(self, test):
         """See unittest.TestResult.startTest."""
         super(AugmentedResult, self).startTest(test)
@@ -155,19 +151,19 @@ class AugmentedResult(unittest.TestResult):
         self.cases[case_id] = CaseResult(
             id=case_id, name=test.id(), kind=CaseResult.Kind.RUNNING)
 
-    def addError(self, test, error):
+    def addError(self, test, err):
         """See unittest.TestResult.addError."""
-        super(AugmentedResult, self).addError(test, error)
+        super(AugmentedResult, self).addError(test, err)
         case_id = self.id_map(test)
         self.cases[case_id] = self.cases[case_id].updated(
-            kind=CaseResult.Kind.ERROR, traceback=error)
+            kind=CaseResult.Kind.ERROR, traceback=err)
 
-    def addFailure(self, test, error):
+    def addFailure(self, test, err):
         """See unittest.TestResult.addFailure."""
-        super(AugmentedResult, self).addFailure(test, error)
+        super(AugmentedResult, self).addFailure(test, err)
         case_id = self.id_map(test)
         self.cases[case_id] = self.cases[case_id].updated(
-            kind=CaseResult.Kind.FAILURE, traceback=error)
+            kind=CaseResult.Kind.FAILURE, traceback=err)
 
     def addSuccess(self, test):
         """See unittest.TestResult.addSuccess."""
@@ -183,12 +179,12 @@ class AugmentedResult(unittest.TestResult):
         self.cases[case_id] = self.cases[case_id].updated(
             kind=CaseResult.Kind.SKIP, skip_reason=reason)
 
-    def addExpectedFailure(self, test, error):
+    def addExpectedFailure(self, test, err):
         """See unittest.TestResult.addExpectedFailure."""
-        super(AugmentedResult, self).addExpectedFailure(test, error)
+        super(AugmentedResult, self).addExpectedFailure(test, err)
         case_id = self.id_map(test)
         self.cases[case_id] = self.cases[case_id].updated(
-            kind=CaseResult.Kind.EXPECTED_FAILURE, traceback=error)
+            kind=CaseResult.Kind.EXPECTED_FAILURE, traceback=err)
 
     def addUnexpectedSuccess(self, test):
         """See unittest.TestResult.addUnexpectedSuccess."""
@@ -249,13 +245,6 @@ class CoverageResult(AugmentedResult):
         self.coverage_context.save()
         self.coverage_context = None
 
-    def stopTestRun(self):
-        """See unittest.TestResult.stopTestRun."""
-        super(CoverageResult, self).stopTestRun()
-        # TODO(atash): Dig deeper into why the following line fails to properly
-        # combine coverage data from the Cython plugin.
-        #coverage.Coverage().combine()
-
 
 class _Colors(object):
     """Namespaced constants for terminal color magic numbers."""
@@ -295,16 +284,16 @@ class TerminalResult(CoverageResult):
         self.out.write(summary(self))
         self.out.flush()
 
-    def addError(self, test, error):
+    def addError(self, test, err):
         """See unittest.TestResult.addError."""
-        super(TerminalResult, self).addError(test, error)
+        super(TerminalResult, self).addError(test, err)
         self.out.write(
             _Colors.FAIL + 'ERROR         {}\n'.format(test.id()) + _Colors.END)
         self.out.flush()
 
-    def addFailure(self, test, error):
+    def addFailure(self, test, err):
         """See unittest.TestResult.addFailure."""
-        super(TerminalResult, self).addFailure(test, error)
+        super(TerminalResult, self).addFailure(test, err)
         self.out.write(
             _Colors.FAIL + 'FAILURE       {}\n'.format(test.id()) + _Colors.END)
         self.out.flush()
@@ -323,9 +312,9 @@ class TerminalResult(CoverageResult):
             _Colors.INFO + 'SKIP          {}\n'.format(test.id()) + _Colors.END)
         self.out.flush()
 
-    def addExpectedFailure(self, test, error):
+    def addExpectedFailure(self, test, err):
         """See unittest.TestResult.addExpectedFailure."""
-        super(TerminalResult, self).addExpectedFailure(test, error)
+        super(TerminalResult, self).addExpectedFailure(test, err)
         self.out.write(
             _Colors.INFO + 'FAILURE_OK    {}\n'.format(test.id()) + _Colors.END)
         self.out.flush()
diff --git a/src/python/grpcio_tests/tests/interop/methods.py b/src/python/grpcio_tests/tests/interop/methods.py
index b728ffd704..cda15a68a3 100644
--- a/src/python/grpcio_tests/tests/interop/methods.py
+++ b/src/python/grpcio_tests/tests/interop/methods.py
@@ -144,8 +144,8 @@ def _large_unary_common_behavior(stub, fill_username, fill_oauth_scope,
 def _empty_unary(stub):
     response = stub.EmptyCall(empty_pb2.Empty())
     if not isinstance(response, empty_pb2.Empty):
-        raise TypeError('response is of type "%s", not empty_pb2.Empty!',
-                        type(response))
+        raise TypeError(
+            'response is of type "%s", not empty_pb2.Empty!' % type(response))
 
 
 def _large_unary(stub):
diff --git a/src/python/grpcio_tests/tests/interop/server.py b/src/python/grpcio_tests/tests/interop/server.py
index 0810de2394..fd28d498a1 100644
--- a/src/python/grpcio_tests/tests/interop/server.py
+++ b/src/python/grpcio_tests/tests/interop/server.py
@@ -26,6 +26,7 @@ from tests.interop import resources
 from tests.unit import test_common
 
 _ONE_DAY_IN_SECONDS = 60 * 60 * 24
+_LOGGER = logging.getLogger(__name__)
 
 
 def serve():
@@ -52,14 +53,14 @@ def serve():
         server.add_insecure_port('[::]:{}'.format(args.port))
 
     server.start()
-    logging.info('Server serving.')
+    _LOGGER.info('Server serving.')
     try:
         while True:
             time.sleep(_ONE_DAY_IN_SECONDS)
     except BaseException as e:
-        logging.info('Caught exception "%s"; stopping server...', e)
+        _LOGGER.info('Caught exception "%s"; stopping server...', e)
         server.stop(None)
-        logging.info('Server stopped; exiting.')
+        _LOGGER.info('Server stopped; exiting.')
 
 
 if __name__ == '__main__':
diff --git a/src/python/grpcio_tests/tests/tests.json b/src/python/grpcio_tests/tests/tests.json
index 0d94426413..65460a9540 100644
--- a/src/python/grpcio_tests/tests/tests.json
+++ b/src/python/grpcio_tests/tests/tests.json
@@ -53,6 +53,7 @@
   "unit._server_ssl_cert_config_test.ServerSSLCertReloadTestCertConfigReuse",
   "unit._server_ssl_cert_config_test.ServerSSLCertReloadTestWithClientAuth",
   "unit._server_ssl_cert_config_test.ServerSSLCertReloadTestWithoutClientAuth",
+  "unit._session_cache_test.SSLSessionCacheTest",
   "unit.beta._beta_features_test.BetaFeaturesTest",
   "unit.beta._beta_features_test.ContextManagementAndLifecycleTest",
   "unit.beta._connectivity_channel_test.ConnectivityStatesTest",
diff --git a/src/python/grpcio_tests/tests/unit/_auth_context_test.py b/src/python/grpcio_tests/tests/unit/_auth_context_test.py
index 8c1a30e032..d174051070 100644
--- a/src/python/grpcio_tests/tests/unit/_auth_context_test.py
+++ b/src/python/grpcio_tests/tests/unit/_auth_context_test.py
@@ -18,6 +18,7 @@ import unittest
 
 import grpc
 from grpc import _channel
+from grpc.experimental import session_cache
 import six
 
 from tests.unit import test_common
@@ -140,6 +141,50 @@ class AuthContextTest(unittest.TestCase):
         self.assertSequenceEqual([b'*.test.google.com'],
                                  auth_ctx['x509_common_name'])
 
+    def _do_one_shot_client_rpc(self, channel_creds, channel_options, port,
+                                expect_ssl_session_reused):
+        channel = grpc.secure_channel(
+            'localhost:{}'.format(port), channel_creds, options=channel_options)
+        response = channel.unary_unary(_UNARY_UNARY)(_REQUEST)
+        auth_data = pickle.loads(response)
+        self.assertEqual(expect_ssl_session_reused,
+                         auth_data[_AUTH_CTX]['ssl_session_reused'])
+        channel.close()
+
+    def testSessionResumption(self):
+        # Set up a secure server
+        handler = grpc.method_handlers_generic_handler('test', {
+            'UnaryUnary':
+            grpc.unary_unary_rpc_method_handler(handle_unary_unary)
+        })
+        server = test_common.test_server()
+        server.add_generic_rpc_handlers((handler,))
+        server_cred = grpc.ssl_server_credentials(_SERVER_CERTS)
+        port = server.add_secure_port('[::]:0', server_cred)
+        server.start()
+
+        # Create a cache for TLS session tickets
+        cache = session_cache.ssl_session_cache_lru(1)
+        channel_creds = grpc.ssl_channel_credentials(
+            root_certificates=_TEST_ROOT_CERTIFICATES)
+        channel_options = _PROPERTY_OPTIONS + (
+            ('grpc.ssl_session_cache', cache),)
+
+        # Initial connection has no session to resume
+        self._do_one_shot_client_rpc(
+            channel_creds,
+            channel_options,
+            port,
+            expect_ssl_session_reused=[b'false'])
+
+        # Subsequent connections resume sessions
+        self._do_one_shot_client_rpc(
+            channel_creds,
+            channel_options,
+            port,
+            expect_ssl_session_reused=[b'true'])
+        server.stop(None)
+
 
 if __name__ == '__main__':
     unittest.main(verbosity=2)
diff --git a/src/python/grpcio_tests/tests/unit/_junkdrawer/__init__.py b/src/python/grpcio_tests/tests/unit/_junkdrawer/__init__.py
deleted file mode 100644
index 5fb4f3c3cf..0000000000
--- a/src/python/grpcio_tests/tests/unit/_junkdrawer/__init__.py
+++ /dev/null
@@ -1,13 +0,0 @@
-# Copyright 2015 gRPC authors.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
diff --git a/src/python/grpcio_tests/tests/unit/_junkdrawer/stock_pb2.py b/src/python/grpcio_tests/tests/unit/_junkdrawer/stock_pb2.py
deleted file mode 100644
index 2bf1e1cc0d..0000000000
--- a/src/python/grpcio_tests/tests/unit/_junkdrawer/stock_pb2.py
+++ /dev/null
@@ -1,164 +0,0 @@
-# Copyright 2015 gRPC authors.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-# TODO(nathaniel): Remove this from source control after having made
-# generation from the stock.proto source part of GRPC's build-and-test
-# process.
-
-# Generated by the protocol buffer compiler.  DO NOT EDIT!
-# source: stock.proto
-
-import sys
-_b = sys.version_info[0] < 3 and (lambda x: x) or (lambda x: x.encode('latin1'))
-from google.protobuf import descriptor as _descriptor
-from google.protobuf import message as _message
-from google.protobuf import reflection as _reflection
-from google.protobuf import symbol_database as _symbol_database
-from google.protobuf import descriptor_pb2
-# @@protoc_insertion_point(imports)
-
-_sym_db = _symbol_database.Default()
-
-DESCRIPTOR = _descriptor.FileDescriptor(
-    name='stock.proto',
-    package='stock',
-    serialized_pb=_b(
-        '\n\x0bstock.proto\x12\x05stock\">\n\x0cStockRequest\x12\x0e\n\x06symbol\x18\x01 \x01(\t\x12\x1e\n\x13num_trades_to_watch\x18\x02 \x01(\x05:\x01\x30\"+\n\nStockReply\x12\r\n\x05price\x18\x01 \x01(\x02\x12\x0e\n\x06symbol\x18\x02 \x01(\t2\x96\x02\n\x05Stock\x12=\n\x11GetLastTradePrice\x12\x13.stock.StockRequest\x1a\x11.stock.StockReply\"\x00\x12I\n\x19GetLastTradePriceMultiple\x12\x13.stock.StockRequest\x1a\x11.stock.StockReply\"\x00(\x01\x30\x01\x12?\n\x11WatchFutureTrades\x12\x13.stock.StockRequest\x1a\x11.stock.StockReply\"\x00\x30\x01\x12\x42\n\x14GetHighestTradePrice\x12\x13.stock.StockRequest\x1a\x11.stock.StockReply\"\x00(\x01'
-    ))
-_sym_db.RegisterFileDescriptor(DESCRIPTOR)
-
-_STOCKREQUEST = _descriptor.Descriptor(
-    name='StockRequest',
-    full_name='stock.StockRequest',
-    filename=None,
-    file=DESCRIPTOR,
-    containing_type=None,
-    fields=[
-        _descriptor.FieldDescriptor(
-            name='symbol',
-            full_name='stock.StockRequest.symbol',
-            index=0,
-            number=1,
-            type=9,
-            cpp_type=9,
-            label=1,
-            has_default_value=False,
-            default_value=_b("").decode('utf-8'),
-            message_type=None,
-            enum_type=None,
-            containing_type=None,
-            is_extension=False,
-            extension_scope=None,
-            options=None),
-        _descriptor.FieldDescriptor(
-            name='num_trades_to_watch',
-            full_name='stock.StockRequest.num_trades_to_watch',
-            index=1,
-            number=2,
-            type=5,
-            cpp_type=1,
-            label=1,
-            has_default_value=True,
-            default_value=0,
-            message_type=None,
-            enum_type=None,
-            containing_type=None,
-            is_extension=False,
-            extension_scope=None,
-            options=None),
-    ],
-    extensions=[],
-    nested_types=[],
-    enum_types=[],
-    options=None,
-    is_extendable=False,
-    extension_ranges=[],
-    oneofs=[],
-    serialized_start=22,
-    serialized_end=84,)
-
-_STOCKREPLY = _descriptor.Descriptor(
-    name='StockReply',
-    full_name='stock.StockReply',
-    filename=None,
-    file=DESCRIPTOR,
-    containing_type=None,
-    fields=[
-        _descriptor.FieldDescriptor(
-            name='price',
-            full_name='stock.StockReply.price',
-            index=0,
-            number=1,
-            type=2,
-            cpp_type=6,
-            label=1,
-            has_default_value=False,
-            default_value=0,
-            message_type=None,
-            enum_type=None,
-            containing_type=None,
-            is_extension=False,
-            extension_scope=None,
-            options=None),
-        _descriptor.FieldDescriptor(
-            name='symbol',
-            full_name='stock.StockReply.symbol',
-            index=1,
-            number=2,
-            type=9,
-            cpp_type=9,
-            label=1,
-            has_default_value=False,
-            default_value=_b("").decode('utf-8'),
-            message_type=None,
-            enum_type=None,
-            containing_type=None,
-            is_extension=False,
-            extension_scope=None,
-            options=None),
-    ],
-    extensions=[],
-    nested_types=[],
-    enum_types=[],
-    options=None,
-    is_extendable=False,
-    extension_ranges=[],
-    oneofs=[],
-    serialized_start=86,
-    serialized_end=129,)
-
-DESCRIPTOR.message_types_by_name['StockRequest'] = _STOCKREQUEST
-DESCRIPTOR.message_types_by_name['StockReply'] = _STOCKREPLY
-
-StockRequest = _reflection.GeneratedProtocolMessageType(
-    'StockRequest',
-    (_message.Message,),
-    dict(
-        DESCRIPTOR=_STOCKREQUEST,
-        __module__='stock_pb2'
-        # @@protoc_insertion_point(class_scope:stock.StockRequest)
-    ))
-_sym_db.RegisterMessage(StockRequest)
-
-StockReply = _reflection.GeneratedProtocolMessageType(
-    'StockReply',
-    (_message.Message,),
-    dict(
-        DESCRIPTOR=_STOCKREPLY,
-        __module__='stock_pb2'
-        # @@protoc_insertion_point(class_scope:stock.StockReply)
-    ))
-_sym_db.RegisterMessage(StockReply)
-
-# @@protoc_insertion_point(module_scope)
diff --git a/src/python/grpcio_tests/tests/unit/_session_cache_test.py b/src/python/grpcio_tests/tests/unit/_session_cache_test.py
new file mode 100644
index 0000000000..b4e4670fa7
--- /dev/null
+++ b/src/python/grpcio_tests/tests/unit/_session_cache_test.py
@@ -0,0 +1,145 @@
+# Copyright 2018 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Tests experimental TLS Session Resumption API"""
+
+import pickle
+import unittest
+
+import grpc
+from grpc import _channel
+from grpc.experimental import session_cache
+
+from tests.unit import test_common
+from tests.unit import resources
+
+_REQUEST = b'\x00\x00\x00'
+_RESPONSE = b'\x00\x00\x00'
+
+_UNARY_UNARY = '/test/UnaryUnary'
+
+_SERVER_HOST_OVERRIDE = 'foo.test.google.fr'
+_ID = 'id'
+_ID_KEY = 'id_key'
+_AUTH_CTX = 'auth_ctx'
+
+_PRIVATE_KEY = resources.private_key()
+_CERTIFICATE_CHAIN = resources.certificate_chain()
+_TEST_ROOT_CERTIFICATES = resources.test_root_certificates()
+_SERVER_CERTS = ((_PRIVATE_KEY, _CERTIFICATE_CHAIN),)
+_PROPERTY_OPTIONS = ((
+    'grpc.ssl_target_name_override',
+    _SERVER_HOST_OVERRIDE,
+),)
+
+
+def handle_unary_unary(request, servicer_context):
+    return pickle.dumps({
+        _ID: servicer_context.peer_identities(),
+        _ID_KEY: servicer_context.peer_identity_key(),
+        _AUTH_CTX: servicer_context.auth_context()
+    })
+
+
+def start_secure_server():
+    handler = grpc.method_handlers_generic_handler('test', {
+        'UnaryUnary':
+        grpc.unary_unary_rpc_method_handler(handle_unary_unary)
+    })
+    server = test_common.test_server()
+    server.add_generic_rpc_handlers((handler,))
+    server_cred = grpc.ssl_server_credentials(_SERVER_CERTS)
+    port = server.add_secure_port('[::]:0', server_cred)
+    server.start()
+
+    return server, port
+
+
+class SSLSessionCacheTest(unittest.TestCase):
+
+    def _do_one_shot_client_rpc(self, channel_creds, channel_options, port,
+                                expect_ssl_session_reused):
+        channel = grpc.secure_channel(
+            'localhost:{}'.format(port), channel_creds, options=channel_options)
+        response = channel.unary_unary(_UNARY_UNARY)(_REQUEST)
+        auth_data = pickle.loads(response)
+        self.assertEqual(expect_ssl_session_reused,
+                         auth_data[_AUTH_CTX]['ssl_session_reused'])
+        channel.close()
+
+    def testSSLSessionCacheLRU(self):
+        server_1, port_1 = start_secure_server()
+
+        cache = session_cache.ssl_session_cache_lru(1)
+        channel_creds = grpc.ssl_channel_credentials(
+            root_certificates=_TEST_ROOT_CERTIFICATES)
+        channel_options = _PROPERTY_OPTIONS + (
+            ('grpc.ssl_session_cache', cache),)
+
+        # Initial connection has no session to resume
+        self._do_one_shot_client_rpc(
+            channel_creds,
+            channel_options,
+            port_1,
+            expect_ssl_session_reused=[b'false'])
+
+        # Connection to server_1 resumes from initial session
+        self._do_one_shot_client_rpc(
+            channel_creds,
+            channel_options,
+            port_1,
+            expect_ssl_session_reused=[b'true'])
+
+        # Connection to a different server with the same name overwrites the cache entry
+        server_2, port_2 = start_secure_server()
+        self._do_one_shot_client_rpc(
+            channel_creds,
+            channel_options,
+            port_2,
+            expect_ssl_session_reused=[b'false'])
+        self._do_one_shot_client_rpc(
+            channel_creds,
+            channel_options,
+            port_2,
+            expect_ssl_session_reused=[b'true'])
+        server_2.stop(None)
+
+        # Connection to server_1 now falls back to full TLS handshake
+        self._do_one_shot_client_rpc(
+            channel_creds,
+            channel_options,
+            port_1,
+            expect_ssl_session_reused=[b'false'])
+
+        # Re-creating server_1 causes old sessions to become invalid
+        server_1.stop(None)
+        server_1, port_1 = start_secure_server()
+
+        # Old sessions should no longer be valid
+        self._do_one_shot_client_rpc(
+            channel_creds,
+            channel_options,
+            port_1,
+            expect_ssl_session_reused=[b'false'])
+
+        # Resumption should work for subsequent connections
+        self._do_one_shot_client_rpc(
+            channel_creds,
+            channel_options,
+            port_1,
+            expect_ssl_session_reused=[b'true'])
+        server_1.stop(None)
+
+
+if __name__ == '__main__':
+    unittest.main(verbosity=2)
diff --git a/templates/CMakeLists.txt.template b/templates/CMakeLists.txt.template
index 06adb33739..435217bacd 100644
--- a/templates/CMakeLists.txt.template
+++ b/templates/CMakeLists.txt.template
@@ -35,7 +35,7 @@
 
   def get_deps(target_dict):
     deps = []
-    if target_dict.get('baselib', False):
+    if target_dict.get('baselib', False) or target_dict['name'] == 'address_sorting':
       deps.append("${_gRPC_BASELIB_LIBRARIES}")
     if target_dict.get('build', None) in ['protoc']:
       deps.append("${_gRPC_PROTOBUF_PROTOC_LIBRARIES}")
diff --git a/templates/Makefile.template b/templates/Makefile.template
index 901dbfc9c8..43fa904768 100644
--- a/templates/Makefile.template
+++ b/templates/Makefile.template
@@ -414,7 +414,6 @@
 
   ifeq ($(HAS_PKG_CONFIG),true)
   OPENSSL_ALPN_CHECK_CMD = $(PKG_CONFIG) --atleast-version=1.0.2 openssl
-  OPENSSL_NPN_CHECK_CMD = $(PKG_CONFIG) --atleast-version=1.0.1 openssl
   ZLIB_CHECK_CMD = $(PKG_CONFIG) --exists zlib
   PROTOBUF_CHECK_CMD = $(PKG_CONFIG) --atleast-version=3.5.0 protobuf
   CARES_CHECK_CMD = $(PKG_CONFIG) --atleast-version=1.11.0 libcares
@@ -427,7 +426,6 @@
   endif
 
   OPENSSL_ALPN_CHECK_CMD = $(CC) $(CPPFLAGS) $(CFLAGS) -o $(TMPOUT) test/build/openssl-alpn.c $(addprefix -l, $(OPENSSL_LIBS)) $(LDFLAGS)
-  OPENSSL_NPN_CHECK_CMD = $(CC) $(CPPFLAGS) $(CFLAGS) -o $(TMPOUT) test/build/openssl-npn.c $(addprefix -l, $(OPENSSL_LIBS)) $(LDFLAGS)
   BORINGSSL_COMPILE_CHECK_CMD = $(CC) $(CPPFLAGS) ${defaults.boringssl.CPPFLAGS} $(CFLAGS) ${defaults.boringssl.CFLAGS} -o $(TMPOUT) test/build/boringssl.c $(LDFLAGS)
   ZLIB_CHECK_CMD = $(CC) $(CPPFLAGS) $(CFLAGS) -o $(TMPOUT) test/build/zlib.c -lz $(LDFLAGS)
   PROTOBUF_CHECK_CMD = $(CXX) $(CPPFLAGS) $(CXXFLAGS) -o $(TMPOUT) test/build/protobuf.cc -lprotobuf $(LDFLAGS)
@@ -455,13 +453,7 @@
   ifndef REQUIRE_CUSTOM_LIBRARIES_$(CONFIG)
   HAS_SYSTEM_OPENSSL_ALPN ?= $(shell $(OPENSSL_ALPN_CHECK_CMD) 2> /dev/null && echo true || echo false)
   ifeq ($(HAS_SYSTEM_OPENSSL_ALPN),true)
-  HAS_SYSTEM_OPENSSL_NPN = true
   CACHE_MK += HAS_SYSTEM_OPENSSL_ALPN = true,
-  else
-  HAS_SYSTEM_OPENSSL_NPN ?= $(shell $(OPENSSL_NPN_CHECK_CMD) 2> /dev/null && echo true || echo false)
-  endif
-  ifeq ($(HAS_SYSTEM_OPENSSL_NPN),true)
-  CACHE_MK += HAS_SYSTEM_OPENSSL_NPN = true,
   endif
   HAS_SYSTEM_ZLIB ?= $(shell $(ZLIB_CHECK_CMD) 2> /dev/null && echo true || echo false)
   ifeq ($(HAS_SYSTEM_ZLIB),true)
@@ -478,7 +470,6 @@
   else
   # override system libraries if the config requires a custom compiled library
   HAS_SYSTEM_OPENSSL_ALPN = false
-  HAS_SYSTEM_OPENSSL_NPN = false
   HAS_SYSTEM_ZLIB = false
   HAS_SYSTEM_PROTOBUF = false
   HAS_SYSTEM_CARES = false
@@ -625,12 +616,7 @@
   EMBED_OPENSSL ?= $(HAS_EMBEDDED_OPENSSL_ALPN)
   NO_SECURE ?= false
   else # HAS_EMBEDDED_OPENSSL_ALPN=false
-  ifeq ($(HAS_SYSTEM_OPENSSL_NPN),true)
-  EMBED_OPENSSL ?= false
-  NO_SECURE ?= false
-  else
   NO_SECURE ?= true
-  endif # HAS_SYSTEM_OPENSSL_NPN=true
   endif # HAS_EMBEDDED_OPENSSL_ALPN
   endif # HAS_SYSTEM_OPENSSL_ALPN
 
@@ -664,10 +650,10 @@
   else # HAS_PKG_CONFIG=false
   LIBS_SECURE = $(OPENSSL_LIBS)
   endif # HAS_PKG_CONFIG
-  ifeq ($(HAS_SYSTEM_OPENSSL_NPN),true)
+  ifeq ($(DISABLE_ALPN),true)
   CPPFLAGS += -DTSI_OPENSSL_ALPN_SUPPORT=0
   LIBS_SECURE = $(OPENSSL_LIBS)
-  endif # HAS_SYSTEM_OPENSSL_NPN
+  endif # DISABLE_ALPN
   PC_LIBS_SECURE = $(addprefix -l, $(LIBS_SECURE))
   endif # EMBED_OPENSSL
   endif # NO_SECURE
@@ -888,7 +874,6 @@
 
   run_dep_checks:
   	$(OPENSSL_ALPN_CHECK_CMD) || true
-  	$(OPENSSL_NPN_CHECK_CMD) || true
   	$(ZLIB_CHECK_CMD) || true
   	$(PERFTOOLS_CHECK_CMD) || true
   	$(PROTOBUF_CHECK_CMD) || true
diff --git a/templates/gRPC-Core.podspec.template b/templates/gRPC-Core.podspec.template
index af97d81834..a767a612a6 100644
--- a/templates/gRPC-Core.podspec.template
+++ b/templates/gRPC-Core.podspec.template
@@ -68,6 +68,14 @@
     excl = grpc_private_files(libs)
     return [file for file in out if not file in excl]
 
+  def cfstream_private_headers(libs):
+    out = grpc_lib_files(libs, ("grpc_cfstream",), ("own_headers",))
+    return out
+
+  def cfstream_private_files(libs):
+    out = grpc_lib_files(libs, ("grpc_cfstream",), ("own_src", "own_headers"))
+    return out
+
   def ruby_multiline_list(files, indent):
     return (',\n' + indent*' ').join('\'%s\'' % f for f in files)
   %>
@@ -175,6 +183,16 @@
       ss.private_header_files = ${ruby_multiline_list(grpc_private_headers(libs), 30)}
     end
 
+    s.subspec 'CFStream-Implementation' do |ss|
+      ss.header_mappings_dir = '.'
+      ss.dependency "#{s.name}/Implementation", version
+      ss.pod_target_xcconfig = {
+        'GCC_PREPROCESSOR_DEFINITIONS' => 'GRPC_CFSTREAM=1'
+      }
+      ss.source_files = ${ruby_multiline_list(cfstream_private_files(filegroups), 22)}
+      ss.private_header_files = ${ruby_multiline_list(cfstream_private_headers(filegroups), 30)}
+    end
+
     s.subspec 'Cronet-Interface' do |ss|
       ss.header_mappings_dir = 'include/grpc'
       ss.source_files = ${ruby_multiline_list(grpc_cronet_public_headers(libs), 22)}
diff --git a/templates/gRPC-ProtoRPC.podspec.template b/templates/gRPC-ProtoRPC.podspec.template
index d2dcc429ef..96966784f1 100644
--- a/templates/gRPC-ProtoRPC.podspec.template
+++ b/templates/gRPC-ProtoRPC.podspec.template
@@ -43,12 +43,25 @@
     s.header_dir = name
 
     src_dir = 'src/objective-c/ProtoRPC'
-    s.source_files = "#{src_dir}/*.{h,m}"
-    s.header_mappings_dir = "#{src_dir}"
 
-    s.dependency 'gRPC', version
-    s.dependency 'gRPC-RxLibrary', version
-    s.dependency 'Protobuf', '~> 3.0'
+    s.default_subspec = 'Main'
+
+    s.subspec 'Main' do |ss|
+      ss.header_mappings_dir = "#{src_dir}"
+      ss.dependency 'gRPC', version
+      ss.dependency 'gRPC-RxLibrary', version
+      ss.dependency 'Protobuf', '~> 3.0'
+
+      ss.source_files = "#{src_dir}/*.{h,m}"
+    end
+    s.subspec 'CFStream' do |ss|
+      ss.dependency 'gRPC/CFStream', version
+      ss.dependency "#{s.name}/Main", version
+      ss.pod_target_xcconfig = {
+        'GCC_PREPROCESSOR_DEFINITIONS' => 'GRPC_CFSTREAM=1'
+      }
+    end
+
     s.pod_target_xcconfig = {
       # This is needed by all pods that depend on Protobuf:
       'GCC_PREPROCESSOR_DEFINITIONS' => '$(inherited) GPB_USE_PROTOBUF_FRAMEWORK_IMPORTS=1',
diff --git a/templates/gRPC.podspec.template b/templates/gRPC.podspec.template
index 6616e74bd7..a3190c2d8e 100644
--- a/templates/gRPC.podspec.template
+++ b/templates/gRPC.podspec.template
@@ -65,6 +65,16 @@
       ss.dependency 'gRPC-Core', version
     end
 
+    # This subspec is mutually exclusive with the `Main` subspec
+    s.subspec 'CFStream' do |ss|
+      ss.dependency 'gRPC-Core/CFStream-Implementation', version
+      ss.dependency "#{s.name}/Main", version
+
+      ss.pod_target_xcconfig = {
+        'GCC_PREPROCESSOR_DEFINITIONS' => 'GRPC_CFSTREAM=1'
+      }
+    end
+
     s.subspec 'GID' do |ss|
       ss.ios.deployment_target = '7.0'
 
diff --git a/templates/grpc.gemspec.template b/templates/grpc.gemspec.template
index fb54de1c8e..842035b664 100644
--- a/templates/grpc.gemspec.template
+++ b/templates/grpc.gemspec.template
@@ -22,7 +22,9 @@
     s.files += Dir.glob('src/ruby/bin/**/*')
     s.files += Dir.glob('src/ruby/ext/**/*')
     s.files += Dir.glob('src/ruby/lib/**/*')
-    s.files += Dir.glob('src/ruby/pb/**/*')
+    s.files += Dir.glob('src/ruby/pb/**/*').reject do |f|
+      f.match(%r{^src/ruby/pb/test})
+    end
     s.files += Dir.glob('include/grpc/**/*')
     s.test_files = Dir.glob('src/ruby/spec/**/*')
     s.bindir = 'src/ruby/bin'
@@ -30,7 +32,6 @@
     s.platform      = Gem::Platform::RUBY
 
     s.add_dependency 'google-protobuf', '~> 3.1'
-    s.add_dependency 'googleauth',      '>= 0.5.1', '< 0.7'
     s.add_dependency 'googleapis-common-protos-types', '~> 1.0.0'
 
     s.add_development_dependency 'bundler',            '~> 1.9'
@@ -43,6 +44,7 @@
     s.add_development_dependency 'rspec',              '~> 3.6'
     s.add_development_dependency 'rubocop',            '~> 0.49.1'
     s.add_development_dependency 'signet',             '~> 0.7.0'
+    s.add_development_dependency 'googleauth',         '>= 0.5.1', '< 0.7'
 
     s.extensions = %w(src/ruby/ext/grpc/extconf.rb)
 
diff --git a/templates/src/csharp/build_packages_dotnetcli.bat.template b/templates/src/csharp/build_packages_dotnetcli.bat.template
index 1bf78c4d23..45010fec74 100755
--- a/templates/src/csharp/build_packages_dotnetcli.bat.template
+++ b/templates/src/csharp/build_packages_dotnetcli.bat.template
@@ -49,6 +49,7 @@
   %%DOTNET% pack --configuration Release Grpc.Reflection --output ..\..\..\artifacts || goto :error
   
   %%NUGET% pack Grpc.nuspec -Version %VERSION% -OutputDirectory ..\..\artifacts || goto :error
+  %%NUGET% pack Grpc.Core.NativeDebug.nuspec -Version %VERSION% -OutputDirectory ..\..\artifacts
   %%NUGET% pack Grpc.Tools.nuspec -Version %VERSION% -OutputDirectory ..\..\artifacts
   
   @rem copy resulting nuget packages to artifacts directory
diff --git a/templates/src/csharp/build_packages_dotnetcli.sh.template b/templates/src/csharp/build_packages_dotnetcli.sh.template
index ddfea74744..1172582ebd 100755
--- a/templates/src/csharp/build_packages_dotnetcli.sh.template
+++ b/templates/src/csharp/build_packages_dotnetcli.sh.template
@@ -48,6 +48,7 @@
   dotnet pack --configuration Release Grpc.Reflection --output ../../../artifacts
   
   nuget pack Grpc.nuspec -Version "${settings.csharp_version}" -OutputDirectory ../../artifacts
+  nuget pack Grpc.Core.NativeDebug.nuspec -Version "${settings.csharp_version}" -OutputDirectory ../../artifacts
   nuget pack Grpc.Tools.nuspec -Version "${settings.csharp_version}" -OutputDirectory ../../artifacts
   
   (cd ../../artifacts && zip csharp_nugets_dotnetcli.zip *.nupkg)
diff --git a/templates/tools/dockerfile/apt_get_pyenv.include b/templates/tools/dockerfile/apt_get_pyenv.include
index ef0964e597..e12b3e2c7f 100644
--- a/templates/tools/dockerfile/apt_get_pyenv.include
+++ b/templates/tools/dockerfile/apt_get_pyenv.include
@@ -10,7 +10,7 @@ RUN apt-get update && apt-get install -y ${'\\'}
   mercurial ${'\\'}
   zlib1g-dev && apt-get clean
 
-# Install Pyenv and dev Python versions 3.5 and 3.6
+# Install Pyenv and dev Python versions 3.{5,6,7}
 RUN curl -L https://raw.githubusercontent.com/yyuu/pyenv-installer/master/bin/pyenv-installer | bash
 ENV PATH /root/.pyenv/bin:$PATH
 RUN eval "$(pyenv init -)"
@@ -18,5 +18,6 @@ RUN eval "$(pyenv virtualenv-init -)"
 RUN pyenv update
 RUN pyenv install 3.5-dev
 RUN pyenv install 3.6-dev
+RUN pyenv install 3.7-dev
 RUN pyenv install pypy-5.3.1
-RUN pyenv local 3.5-dev 3.6-dev pypy-5.3.1
+RUN pyenv local 3.5-dev 3.6-dev 3.7-dev pypy-5.3.1
diff --git a/templates/tools/dockerfile/test/python_pyenv_x64/Dockerfile.template b/templates/tools/dockerfile/test/python_pyenv_x64/Dockerfile.template
index ba65c06a3b..1e013b742c 100644
--- a/templates/tools/dockerfile/test/python_pyenv_x64/Dockerfile.template
+++ b/templates/tools/dockerfile/test/python_pyenv_x64/Dockerfile.template
@@ -14,15 +14,15 @@
   # See the License for the specific language governing permissions and
   # limitations under the License.
   
-  FROM debian:jessie
+  FROM debian:stretch
   
   <%include file="../../apt_get_basic.include"/>
   <%include file="../../gcp_api_libraries.include"/>
   <%include file="../../python_deps.include"/>
   <%include file="../../apt_get_pyenv.include"/>
-  # Install pip and virtualenv for Python 3.4
-  RUN curl https://bootstrap.pypa.io/get-pip.py | python3.4
-  RUN python3.4 -m pip install virtualenv
+  # Install pip and virtualenv for Python 3.5
+  RUN curl https://bootstrap.pypa.io/get-pip.py | python3.5
+  RUN python3.5 -m pip install virtualenv
 
   <%include file="../../run_tests_addons.include"/>
   # Define the default command.
diff --git a/test/build/openssl-npn.c b/test/build/openssl-npn.c
deleted file mode 100644
index 9c71382720..0000000000
--- a/test/build/openssl-npn.c
+++ /dev/null
@@ -1,30 +0,0 @@
-/*
- *
- * Copyright 2015 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-/* This is just a compilation test, to see if we have a version of OpenSSL with
-   NPN support installed. It's not meant to be run, and all of the values and
-   function calls there are non-sensical. The code is only meant to test the
-   presence of symbols, and we're expecting a compilation failure otherwise. */
-
-#include <stdlib.h>
-#include <openssl/ssl.h>
-
-int main() {
-  SSL_get0_next_proto_negotiated(NULL, NULL, NULL);
-  return OPENSSL_NPN_UNSUPPORTED;
-}
diff --git a/test/core/end2end/end2end_nosec_tests.cc b/test/core/end2end/end2end_nosec_tests.cc
index 59eb643a93..a70128254a 100644
--- a/test/core/end2end/end2end_nosec_tests.cc
+++ b/test/core/end2end/end2end_nosec_tests.cc
@@ -100,6 +100,8 @@ extern void negative_deadline(grpc_end2end_test_config config);
 extern void negative_deadline_pre_init(void);
 extern void network_status_change(grpc_end2end_test_config config);
 extern void network_status_change_pre_init(void);
+extern void no_error_on_hotpath(grpc_end2end_test_config config);
+extern void no_error_on_hotpath_pre_init(void);
 extern void no_logging(grpc_end2end_test_config config);
 extern void no_logging_pre_init(void);
 extern void no_op(grpc_end2end_test_config config);
@@ -222,6 +224,7 @@ void grpc_end2end_tests_pre_init(void) {
   max_message_length_pre_init();
   negative_deadline_pre_init();
   network_status_change_pre_init();
+  no_error_on_hotpath_pre_init();
   no_logging_pre_init();
   no_op_pre_init();
   payload_pre_init();
@@ -307,6 +310,7 @@ void grpc_end2end_tests(int argc, char **argv,
     max_message_length(config);
     negative_deadline(config);
     network_status_change(config);
+    no_error_on_hotpath(config);
     no_logging(config);
     no_op(config);
     payload(config);
@@ -492,6 +496,10 @@ void grpc_end2end_tests(int argc, char **argv,
       network_status_change(config);
       continue;
     }
+    if (0 == strcmp("no_error_on_hotpath", argv[i])) {
+      no_error_on_hotpath(config);
+      continue;
+    }
     if (0 == strcmp("no_logging", argv[i])) {
       no_logging(config);
       continue;
diff --git a/test/core/end2end/end2end_tests.cc b/test/core/end2end/end2end_tests.cc
index 9f164b4ead..bf75dd4579 100644
--- a/test/core/end2end/end2end_tests.cc
+++ b/test/core/end2end/end2end_tests.cc
@@ -102,6 +102,8 @@ extern void negative_deadline(grpc_end2end_test_config config);
 extern void negative_deadline_pre_init(void);
 extern void network_status_change(grpc_end2end_test_config config);
 extern void network_status_change_pre_init(void);
+extern void no_error_on_hotpath(grpc_end2end_test_config config);
+extern void no_error_on_hotpath_pre_init(void);
 extern void no_logging(grpc_end2end_test_config config);
 extern void no_logging_pre_init(void);
 extern void no_op(grpc_end2end_test_config config);
@@ -225,6 +227,7 @@ void grpc_end2end_tests_pre_init(void) {
   max_message_length_pre_init();
   negative_deadline_pre_init();
   network_status_change_pre_init();
+  no_error_on_hotpath_pre_init();
   no_logging_pre_init();
   no_op_pre_init();
   payload_pre_init();
@@ -311,6 +314,7 @@ void grpc_end2end_tests(int argc, char **argv,
     max_message_length(config);
     negative_deadline(config);
     network_status_change(config);
+    no_error_on_hotpath(config);
     no_logging(config);
     no_op(config);
     payload(config);
@@ -500,6 +504,10 @@ void grpc_end2end_tests(int argc, char **argv,
       network_status_change(config);
       continue;
     }
+    if (0 == strcmp("no_error_on_hotpath", argv[i])) {
+      no_error_on_hotpath(config);
+      continue;
+    }
     if (0 == strcmp("no_logging", argv[i])) {
       no_logging(config);
       continue;
diff --git a/test/core/end2end/gen_build_yaml.py b/test/core/end2end/gen_build_yaml.py
index c355fc24b5..1851214191 100755
--- a/test/core/end2end/gen_build_yaml.py
+++ b/test/core/end2end/gen_build_yaml.py
@@ -138,6 +138,7 @@ END2END_TESTS = {
     'max_message_length': default_test_options._replace(cpu_cost=LOWCPU),
     'negative_deadline': default_test_options,
     'network_status_change': default_test_options._replace(cpu_cost=LOWCPU),
+    'no_error_on_hotpath': default_test_options._replace(proxyable=False),
     'no_logging': default_test_options._replace(traceable=False),
     'no_op': default_test_options,
     'payload': default_test_options,
diff --git a/test/core/end2end/generate_tests.bzl b/test/core/end2end/generate_tests.bzl
index 11fc576165..706f4fa86d 100755
--- a/test/core/end2end/generate_tests.bzl
+++ b/test/core/end2end/generate_tests.bzl
@@ -134,6 +134,7 @@ END2END_TESTS = {
     'max_message_length': test_options(),
     'negative_deadline': test_options(),
     'network_status_change': test_options(),
+    'no_error_on_hotpath': test_options(proxyable=False),
     'no_logging': test_options(traceable=False),
     'no_op': test_options(),
     'payload': test_options(),
diff --git a/test/core/end2end/tests/no_error_on_hotpath.cc b/test/core/end2end/tests/no_error_on_hotpath.cc
new file mode 100644
index 0000000000..7afadf7d3a
--- /dev/null
+++ b/test/core/end2end/tests/no_error_on_hotpath.cc
@@ -0,0 +1,246 @@
+/*
+ *
+ * Copyright 2016 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include "test/core/end2end/end2end_tests.h"
+
+#include <stdio.h>
+#include <string.h>
+
+#include <grpc/byte_buffer.h>
+#include <grpc/grpc.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+#include <grpc/support/time.h>
+#include "src/core/lib/gpr/string.h"
+#include "src/core/lib/iomgr/error.h"
+#include "test/core/end2end/cq_verifier.h"
+
+static void* tag(intptr_t t) { return (void*)t; }
+
+static grpc_end2end_test_fixture begin_test(grpc_end2end_test_config config,
+                                            const char* test_name,
+                                            grpc_channel_args* client_args,
+                                            grpc_channel_args* server_args) {
+  grpc_end2end_test_fixture f;
+  gpr_log(GPR_INFO, "Running test: %s/%s", test_name, config.name);
+  f = config.create_fixture(client_args, server_args);
+  config.init_server(&f, server_args);
+  config.init_client(&f, client_args);
+  return f;
+}
+
+static gpr_timespec n_seconds_from_now(int n) {
+  return grpc_timeout_seconds_to_deadline(n);
+}
+
+static gpr_timespec five_seconds_from_now(void) {
+  return n_seconds_from_now(5);
+}
+
+static void drain_cq(grpc_completion_queue* cq) {
+  grpc_event ev;
+  do {
+    ev = grpc_completion_queue_next(cq, five_seconds_from_now(), nullptr);
+  } while (ev.type != GRPC_QUEUE_SHUTDOWN);
+}
+
+static void shutdown_server(grpc_end2end_test_fixture* f) {
+  if (!f->server) return;
+  grpc_server_shutdown_and_notify(f->server, f->shutdown_cq, tag(1000));
+  GPR_ASSERT(grpc_completion_queue_pluck(f->shutdown_cq, tag(1000),
+                                         grpc_timeout_seconds_to_deadline(5),
+                                         nullptr)
+                 .type == GRPC_OP_COMPLETE);
+  grpc_server_destroy(f->server);
+  f->server = nullptr;
+}
+
+static void shutdown_client(grpc_end2end_test_fixture* f) {
+  if (!f->client) return;
+  grpc_channel_destroy(f->client);
+  f->client = nullptr;
+}
+
+static void end_test(grpc_end2end_test_fixture* f) {
+  shutdown_server(f);
+  shutdown_client(f);
+
+  grpc_completion_queue_shutdown(f->cq);
+  drain_cq(f->cq);
+  grpc_completion_queue_destroy(f->cq);
+  grpc_completion_queue_destroy(f->shutdown_cq);
+}
+
+static void simple_request_body(grpc_end2end_test_config config,
+                                grpc_end2end_test_fixture f) {
+  grpc_call* c;
+  grpc_call* s;
+  cq_verifier* cqv = cq_verifier_create(f.cq);
+  grpc_op ops[6];
+  grpc_op* op;
+  grpc_metadata_array initial_metadata_recv;
+  grpc_metadata_array trailing_metadata_recv;
+  grpc_metadata_array request_metadata_recv;
+  grpc_call_details call_details;
+  grpc_status_code status;
+  grpc_call_error error;
+  grpc_slice details;
+  int was_cancelled = 2;
+  char* peer;
+
+  gpr_timespec deadline = five_seconds_from_now();
+  c = grpc_channel_create_call(f.client, nullptr, GRPC_PROPAGATE_DEFAULTS, f.cq,
+                               grpc_slice_from_static_string("/foo"), nullptr,
+                               deadline, nullptr);
+  GPR_ASSERT(c);
+
+  peer = grpc_call_get_peer(c);
+  GPR_ASSERT(peer != nullptr);
+  gpr_free(peer);
+
+  grpc_metadata_array_init(&initial_metadata_recv);
+  grpc_metadata_array_init(&trailing_metadata_recv);
+  grpc_metadata_array_init(&request_metadata_recv);
+  grpc_call_details_init(&call_details);
+
+  memset(ops, 0, sizeof(ops));
+  op = ops;
+  op->op = GRPC_OP_SEND_INITIAL_METADATA;
+  op->data.send_initial_metadata.count = 0;
+  op->flags = 0;
+  op->reserved = nullptr;
+  op++;
+  op->op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
+  op->flags = 0;
+  op->reserved = nullptr;
+  op++;
+  op->op = GRPC_OP_RECV_INITIAL_METADATA;
+  op->data.recv_initial_metadata.recv_initial_metadata = &initial_metadata_recv;
+  op->flags = 0;
+  op->reserved = nullptr;
+  op++;
+  op->op = GRPC_OP_RECV_STATUS_ON_CLIENT;
+  op->data.recv_status_on_client.trailing_metadata = &trailing_metadata_recv;
+  op->data.recv_status_on_client.status = &status;
+  op->data.recv_status_on_client.status_details = &details;
+  op->flags = 0;
+  op->reserved = nullptr;
+  op++;
+  error = grpc_call_start_batch(c, ops, static_cast<size_t>(op - ops), tag(1),
+                                nullptr);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  error =
+      grpc_server_request_call(f.server, &s, &call_details,
+                               &request_metadata_recv, f.cq, f.cq, tag(101));
+  GPR_ASSERT(GRPC_CALL_OK == error);
+  CQ_EXPECT_COMPLETION(cqv, tag(101), 1);
+  cq_verify(cqv);
+
+  peer = grpc_call_get_peer(s);
+  GPR_ASSERT(peer != nullptr);
+  gpr_free(peer);
+  peer = grpc_call_get_peer(c);
+  GPR_ASSERT(peer != nullptr);
+  gpr_free(peer);
+
+  memset(ops, 0, sizeof(ops));
+  op = ops;
+  op->op = GRPC_OP_SEND_INITIAL_METADATA;
+  op->data.send_initial_metadata.count = 0;
+  op->flags = 0;
+  op->reserved = nullptr;
+  op++;
+  op->op = GRPC_OP_SEND_STATUS_FROM_SERVER;
+  op->data.send_status_from_server.trailing_metadata_count = 0;
+  op->data.send_status_from_server.status = GRPC_STATUS_OK;
+  op->data.send_status_from_server.status_details = nullptr;
+  op->flags = 0;
+  op->reserved = nullptr;
+  op++;
+  op->op = GRPC_OP_RECV_CLOSE_ON_SERVER;
+  op->data.recv_close_on_server.cancelled = &was_cancelled;
+  op->flags = 0;
+  op->reserved = nullptr;
+  op++;
+  error = grpc_call_start_batch(s, ops, static_cast<size_t>(op - ops), tag(102),
+                                nullptr);
+  GPR_ASSERT(GRPC_CALL_OK == error);
+
+  CQ_EXPECT_COMPLETION(cqv, tag(102), 1);
+  CQ_EXPECT_COMPLETION(cqv, tag(1), 1);
+  cq_verify(cqv);
+
+  GPR_ASSERT(status == GRPC_STATUS_OK);
+  GPR_ASSERT(GRPC_SLICE_LENGTH(details) == 0);
+  GPR_ASSERT(0 == grpc_slice_str_cmp(call_details.method, "/foo"));
+  GPR_ASSERT(0 == call_details.flags);
+  GPR_ASSERT(was_cancelled == 0);
+
+  grpc_slice_unref(details);
+  grpc_metadata_array_destroy(&initial_metadata_recv);
+  grpc_metadata_array_destroy(&trailing_metadata_recv);
+  grpc_metadata_array_destroy(&request_metadata_recv);
+  grpc_call_details_destroy(&call_details);
+
+  grpc_call_unref(c);
+  grpc_call_unref(s);
+
+  cq_verifier_destroy(cqv);
+}
+
+static void test_no_error_on_hotpath_one_request(
+    grpc_end2end_test_config config) {
+  grpc_end2end_test_fixture f;
+
+  f = begin_test(config, "test_invoke_simple_request_with_no_error_logging",
+                 nullptr, nullptr);
+  // First RPC is not considered the hotpath, since there are lots of things to
+  // set up.
+  simple_request_body(config, f);
+  grpc_disable_error_creation();
+  simple_request_body(config, f);
+  grpc_enable_error_creation();
+  end_test(&f);
+  config.tear_down_data(&f);
+}
+
+static void test_no_error_on_hotpath_10_requests(
+    grpc_end2end_test_config config) {
+  int i;
+  grpc_end2end_test_fixture f = begin_test(
+      config, "test_no_error_on_hotpath_in_one_request", nullptr, nullptr);
+  // First RPC is not considered the hotpath, since there are lots of things to
+  // set up.
+  simple_request_body(config, f);
+  grpc_disable_error_creation();
+  for (i = 0; i < 10; i++) {
+    simple_request_body(config, f);
+  }
+  grpc_enable_error_creation();
+  end_test(&f);
+  config.tear_down_data(&f);
+}
+
+void no_error_on_hotpath(grpc_end2end_test_config config) {
+  test_no_error_on_hotpath_one_request(config);
+  test_no_error_on_hotpath_10_requests(config);
+}
+
+void no_error_on_hotpath_pre_init(void) {}
diff --git a/test/core/end2end/tests/retry_server_pushback_delay.cc b/test/core/end2end/tests/retry_server_pushback_delay.cc
index f6a979613d..221b416828 100644
--- a/test/core/end2end/tests/retry_server_pushback_delay.cc
+++ b/test/core/end2end/tests/retry_server_pushback_delay.cc
@@ -249,7 +249,7 @@ static void test_retry_server_pushback_delay(grpc_end2end_test_config config) {
           retry_delay.tv_sec, retry_delay.tv_nsec);
   GPR_ASSERT(retry_delay.tv_sec >= 1);
   if (retry_delay.tv_sec == 1) {
-    GPR_ASSERT(retry_delay.tv_nsec >= 900000000);
+    GPR_ASSERT(retry_delay.tv_nsec >= 800000000);
   }
 
   peer = grpc_call_get_peer(s);
diff --git a/test/core/gpr/arena_test.cc b/test/core/gpr/arena_test.cc
index 111414ea3e..3e7c906591 100644
--- a/test/core/gpr/arena_test.cc
+++ b/test/core/gpr/arena_test.cc
@@ -71,7 +71,7 @@ static void test(const char* name, size_t init_size, const size_t* allocs,
   static const size_t allocs_##name[] = {__VA_ARGS__}; \
   test(#name, init_size, allocs_##name, GPR_ARRAY_SIZE(allocs_##name))
 
-#define CONCURRENT_TEST_THREADS 100
+#define CONCURRENT_TEST_THREADS 10
 
 size_t concurrent_test_iterations() {
   if (sizeof(void*) < 8) return 1000;
diff --git a/test/core/iomgr/ios/CFStreamTests/CFStreamClientTests.mm b/test/core/iomgr/ios/CFStreamTests/CFStreamClientTests.mm
new file mode 100644
index 0000000000..414b6c78c0
--- /dev/null
+++ b/test/core/iomgr/ios/CFStreamTests/CFStreamClientTests.mm
@@ -0,0 +1,201 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#import <XCTest/XCTest.h>
+
+#include "src/core/lib/iomgr/port.h"
+
+#ifdef GRPC_CFSTREAM
+
+#include <netinet/in.h>
+
+#include <grpc/impl/codegen/sync.h>
+#include <grpc/support/sync.h>
+
+#include "src/core/lib/iomgr/endpoint.h"
+#include "src/core/lib/iomgr/resolve_address.h"
+#include "src/core/lib/iomgr/tcp_client.h"
+#include "test/core/util/test_config.h"
+
+// static int g_connections_complete = 0;
+static gpr_mu g_mu;
+static int g_connections_complete = 0;
+static grpc_endpoint* g_connecting = nullptr;
+
+static void finish_connection() {
+  gpr_mu_lock(&g_mu);
+  g_connections_complete++;
+  gpr_mu_unlock(&g_mu);
+}
+
+static void must_succeed(void* arg, grpc_error* error) {
+  GPR_ASSERT(g_connecting != nullptr);
+  GPR_ASSERT(error == GRPC_ERROR_NONE);
+  grpc_endpoint_shutdown(g_connecting, GRPC_ERROR_CREATE_FROM_STATIC_STRING("must_succeed called"));
+  grpc_endpoint_destroy(g_connecting);
+  g_connecting = nullptr;
+  finish_connection();
+}
+
+static void must_fail(void* arg, grpc_error* error) {
+  GPR_ASSERT(g_connecting == nullptr);
+  GPR_ASSERT(error != GRPC_ERROR_NONE);
+  const char* error_str = grpc_error_string(error);
+  NSLog(@"%s", error_str);
+  finish_connection();
+}
+
+@interface CFStreamClientTests : XCTestCase
+
+@end
+
+@implementation CFStreamClientTests
+
++ (void)setUp {
+  grpc_init();
+  gpr_mu_init(&g_mu);
+}
+
++ (void)tearDown {
+  grpc_shutdown();
+}
+
+- (void)testSucceeds {
+  grpc_resolved_address resolved_addr;
+  struct sockaddr_in* addr = reinterpret_cast<struct sockaddr_in*>(resolved_addr.addr);
+  int svr_fd;
+  int r;
+  int connections_complete_before;
+  grpc_closure done;
+  grpc_core::ExecCtx exec_ctx;
+
+  gpr_log(GPR_DEBUG, "test_succeeds");
+
+  memset(&resolved_addr, 0, sizeof(resolved_addr));
+  resolved_addr.len = sizeof(struct sockaddr_in);
+  addr->sin_family = AF_INET;
+
+  /* create a dummy server */
+  svr_fd = socket(AF_INET, SOCK_STREAM, 0);
+  GPR_ASSERT(svr_fd >= 0);
+  GPR_ASSERT(0 == bind(svr_fd, (struct sockaddr*)addr, (socklen_t)resolved_addr.len));
+  GPR_ASSERT(0 == listen(svr_fd, 1));
+
+  gpr_mu_lock(&g_mu);
+  connections_complete_before = g_connections_complete;
+  gpr_mu_unlock(&g_mu);
+
+  /* connect to it */
+  GPR_ASSERT(getsockname(svr_fd, (struct sockaddr*)addr, (socklen_t*)&resolved_addr.len) == 0);
+  GRPC_CLOSURE_INIT(&done, must_succeed, nullptr, grpc_schedule_on_exec_ctx);
+  grpc_tcp_client_connect(&done, &g_connecting, nullptr, nullptr, &resolved_addr,
+                          GRPC_MILLIS_INF_FUTURE);
+
+  /* await the connection */
+  do {
+    resolved_addr.len = sizeof(addr);
+    r = accept(svr_fd, reinterpret_cast<struct sockaddr*>(addr),
+               reinterpret_cast<socklen_t*>(&resolved_addr.len));
+  } while (r == -1 && errno == EINTR);
+  GPR_ASSERT(r >= 0);
+  close(r);
+
+  grpc_core::ExecCtx::Get()->Flush();
+
+  /* wait for the connection callback to finish */
+  gpr_mu_lock(&g_mu);
+  NSDate* deadline = [NSDate dateWithTimeIntervalSinceNow:5];
+  while (connections_complete_before == g_connections_complete) {
+    gpr_mu_unlock(&g_mu);
+    [[NSRunLoop mainRunLoop] runMode:NSDefaultRunLoopMode beforeDate:deadline];
+    gpr_mu_lock(&g_mu);
+  }
+  XCTAssertGreaterThan(g_connections_complete, connections_complete_before);
+
+  gpr_mu_unlock(&g_mu);
+}
+
+- (void)testFails {
+  grpc_core::ExecCtx exec_ctx;
+
+  grpc_resolved_address resolved_addr;
+  struct sockaddr_in* addr = reinterpret_cast<struct sockaddr_in*>(resolved_addr.addr);
+  int connections_complete_before;
+  grpc_closure done;
+  int svr_fd;
+
+  gpr_log(GPR_DEBUG, "test_fails");
+
+  memset(&resolved_addr, 0, sizeof(resolved_addr));
+  resolved_addr.len = static_cast<socklen_t>(sizeof(struct sockaddr_in));
+  addr->sin_family = AF_INET;
+
+  svr_fd = socket(AF_INET, SOCK_STREAM, 0);
+  GPR_ASSERT(svr_fd >= 0);
+  GPR_ASSERT(0 == bind(svr_fd, (struct sockaddr*)addr, (socklen_t)resolved_addr.len));
+  GPR_ASSERT(0 == listen(svr_fd, 1));
+  GPR_ASSERT(getsockname(svr_fd, (struct sockaddr*)addr, (socklen_t*)&resolved_addr.len) == 0);
+  close(svr_fd);
+
+  gpr_mu_lock(&g_mu);
+  connections_complete_before = g_connections_complete;
+  gpr_mu_unlock(&g_mu);
+
+  /* connect to a broken address */
+  GRPC_CLOSURE_INIT(&done, must_fail, nullptr, grpc_schedule_on_exec_ctx);
+  grpc_tcp_client_connect(&done, &g_connecting, nullptr, nullptr, &resolved_addr,
+                          GRPC_MILLIS_INF_FUTURE);
+
+  grpc_core::ExecCtx::Get()->Flush();
+
+  /* wait for the connection callback to finish */
+  gpr_mu_lock(&g_mu);
+  NSDate* deadline = [NSDate dateWithTimeIntervalSinceNow:5];
+  while (g_connections_complete == connections_complete_before) {
+    gpr_mu_unlock(&g_mu);
+    [[NSRunLoop mainRunLoop] runMode:NSDefaultRunLoopMode beforeDate:deadline];
+    gpr_mu_lock(&g_mu);
+  }
+
+  XCTAssertGreaterThan(g_connections_complete, connections_complete_before);
+
+  gpr_mu_unlock(&g_mu);
+}
+
+@end
+
+#else  // GRPC_CFSTREAM
+
+// Dummy test suite
+@interface CFStreamClientTests : XCTestCase
+
+@end
+
+@implementation CFStreamClientTests
+
+- (void)setUp {
+  [super setUp];
+}
+
+- (void)tearDown {
+  [super tearDown];
+}
+
+@end
+
+#endif  // GRPC_CFSTREAM
diff --git a/test/core/iomgr/ios/CFStreamTests/CFStreamEndpointTests.mm b/test/core/iomgr/ios/CFStreamTests/CFStreamEndpointTests.mm
new file mode 100644
index 0000000000..fbc34c74d6
--- /dev/null
+++ b/test/core/iomgr/ios/CFStreamTests/CFStreamEndpointTests.mm
@@ -0,0 +1,344 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#import <XCTest/XCTest.h>
+
+#include "src/core/lib/iomgr/port.h"
+
+#ifdef GRPC_CFSTREAM
+
+#include <netinet/in.h>
+
+#include <grpc/impl/codegen/sync.h>
+#include <grpc/support/sync.h>
+
+#include "src/core/lib/iomgr/endpoint.h"
+#include "src/core/lib/iomgr/resolve_address.h"
+#include "src/core/lib/iomgr/tcp_client.h"
+#include "test/core/util/test_config.h"
+
+static const int kConnectTimeout = 5;
+static const int kWriteTimeout = 5;
+static const int kReadTimeout = 5;
+
+static const int kBufferSize = 10000;
+
+static const int kRunLoopTimeout = 1;
+
+static void set_atm(void *arg, grpc_error *error) {
+  gpr_atm *p = static_cast<gpr_atm *>(arg);
+  gpr_atm_full_cas(p, -1, reinterpret_cast<gpr_atm>(error));
+}
+
+static void init_event_closure(grpc_closure *closure, gpr_atm *atm) {
+  *atm = -1;
+  GRPC_CLOSURE_INIT(closure, set_atm, static_cast<void *>(atm), grpc_schedule_on_exec_ctx);
+}
+
+static bool compare_slice_buffer_with_buffer(grpc_slice_buffer *slices, const char *buffer,
+                                             size_t buffer_len) {
+  if (slices->length != buffer_len) {
+    return false;
+  }
+
+  for (int i = 0; i < slices->count; i++) {
+    grpc_slice slice = slices->slices[i];
+    if (0 != memcmp(buffer, GRPC_SLICE_START_PTR(slice), GRPC_SLICE_LENGTH(slice))) {
+      return false;
+    }
+    buffer += GRPC_SLICE_LENGTH(slice);
+  }
+
+  return true;
+}
+
+@interface CFStreamEndpointTests : XCTestCase
+
+@end
+
+@implementation CFStreamEndpointTests {
+  grpc_endpoint *ep_;
+  int svr_fd_;
+}
+
+- (BOOL)waitForEvent:(gpr_atm *)event timeout:(int)timeout {
+  grpc_core::ExecCtx::Get()->Flush();
+
+  NSDate *deadline = [NSDate dateWithTimeIntervalSinceNow:kConnectTimeout];
+  while (gpr_atm_acq_load(event) == -1 && [deadline timeIntervalSinceNow] > 0) {
+    NSDate *deadline = [NSDate dateWithTimeIntervalSinceNow:kRunLoopTimeout];
+    [[NSRunLoop mainRunLoop] runMode:NSDefaultRunLoopMode beforeDate:deadline];
+  }
+
+  return (gpr_atm_acq_load(event) != -1);
+}
+
++ (void)setUp {
+  grpc_init();
+}
+
++ (void)tearDown {
+  grpc_shutdown();
+}
+
+- (void)setUp {
+  self.continueAfterFailure = NO;
+
+  // Set up CFStream connection before testing the endpoint
+
+  grpc_core::ExecCtx exec_ctx;
+
+  grpc_resolved_address resolved_addr;
+  struct sockaddr_in *addr = reinterpret_cast<struct sockaddr_in *>(resolved_addr.addr);
+  int svr_fd;
+  int r;
+  gpr_atm connected = -1;
+  grpc_closure done;
+
+  gpr_log(GPR_DEBUG, "test_succeeds");
+
+  memset(&resolved_addr, 0, sizeof(resolved_addr));
+  resolved_addr.len = sizeof(struct sockaddr_in);
+  addr->sin_family = AF_INET;
+
+  /* create a dummy server */
+  svr_fd = socket(AF_INET, SOCK_STREAM, 0);
+  XCTAssertGreaterThanOrEqual(svr_fd, 0);
+  XCTAssertEqual(bind(svr_fd, (struct sockaddr *)addr, (socklen_t)resolved_addr.len), 0);
+  XCTAssertEqual(listen(svr_fd, 1), 0);
+
+  /* connect to it */
+  XCTAssertEqual(getsockname(svr_fd, (struct sockaddr *)addr, (socklen_t *)&resolved_addr.len), 0);
+  init_event_closure(&done, &connected);
+  grpc_tcp_client_connect(&done, &ep_, nullptr, nullptr, &resolved_addr, GRPC_MILLIS_INF_FUTURE);
+
+  /* await the connection */
+  do {
+    resolved_addr.len = sizeof(addr);
+    r = accept(svr_fd, reinterpret_cast<struct sockaddr *>(addr),
+               reinterpret_cast<socklen_t *>(&resolved_addr.len));
+  } while (r == -1 && errno == EINTR);
+  XCTAssertGreaterThanOrEqual(r, 0);
+  svr_fd_ = r;
+
+  /* wait for the connection callback to finish */
+  XCTAssertEqual([self waitForEvent:&connected timeout:kConnectTimeout], YES);
+  XCTAssertEqual(reinterpret_cast<grpc_error *>(connected), GRPC_ERROR_NONE);
+}
+
+- (void)tearDown {
+  grpc_core::ExecCtx exec_ctx;
+  close(svr_fd_);
+  grpc_endpoint_destroy(ep_);
+}
+
+- (void)testReadWrite {
+  grpc_core::ExecCtx exec_ctx;
+
+  gpr_atm read;
+  grpc_closure read_done;
+  grpc_slice_buffer read_slices;
+  grpc_slice_buffer read_one_slice;
+  gpr_atm write;
+  grpc_closure write_done;
+  grpc_slice_buffer write_slices;
+
+  grpc_slice slice;
+  char write_buffer[kBufferSize];
+  char read_buffer[kBufferSize];
+  size_t recv_size = 0;
+
+  grpc_slice_buffer_init(&write_slices);
+  slice = grpc_slice_from_static_buffer(write_buffer, kBufferSize);
+  grpc_slice_buffer_add(&write_slices, slice);
+  init_event_closure(&write_done, &write);
+  grpc_endpoint_write(ep_, &write_slices, &write_done);
+
+  XCTAssertEqual([self waitForEvent:&write timeout:kWriteTimeout], YES);
+  XCTAssertEqual(reinterpret_cast<grpc_error *>(write), GRPC_ERROR_NONE);
+
+  while (recv_size < kBufferSize) {
+    ssize_t size = recv(svr_fd_, read_buffer, kBufferSize, 0);
+    XCTAssertGreaterThanOrEqual(size, 0);
+    recv_size += size;
+  }
+
+  XCTAssertEqual(recv_size, kBufferSize);
+  XCTAssertEqual(memcmp(read_buffer, write_buffer, kBufferSize), 0);
+  ssize_t send_size = send(svr_fd_, read_buffer, kBufferSize, 0);
+  XCTAssertGreaterThanOrEqual(send_size, 0);
+
+  grpc_slice_buffer_init(&read_slices);
+  grpc_slice_buffer_init(&read_one_slice);
+  while (read_slices.length < kBufferSize) {
+    init_event_closure(&read_done, &read);
+    grpc_endpoint_read(ep_, &read_one_slice, &read_done);
+    XCTAssertEqual([self waitForEvent:&read timeout:kReadTimeout], YES);
+    XCTAssertEqual(reinterpret_cast<grpc_error *>(read), GRPC_ERROR_NONE);
+    grpc_slice_buffer_move_into(&read_one_slice, &read_slices);
+    XCTAssertLessThanOrEqual(read_slices.length, kBufferSize);
+  }
+  XCTAssertTrue(compare_slice_buffer_with_buffer(&read_slices, read_buffer, kBufferSize));
+
+  grpc_endpoint_shutdown(ep_, GRPC_ERROR_NONE);
+  grpc_slice_buffer_reset_and_unref(&read_slices);
+  grpc_slice_buffer_reset_and_unref(&write_slices);
+  grpc_slice_buffer_reset_and_unref(&read_one_slice);
+}
+
+- (void)testShutdownBeforeRead {
+  grpc_core::ExecCtx exec_ctx;
+
+  gpr_atm read;
+  grpc_closure read_done;
+  grpc_slice_buffer read_slices;
+  gpr_atm write;
+  grpc_closure write_done;
+  grpc_slice_buffer write_slices;
+
+  grpc_slice slice;
+  char write_buffer[kBufferSize];
+  char read_buffer[kBufferSize];
+  size_t recv_size = 0;
+
+  grpc_slice_buffer_init(&read_slices);
+  init_event_closure(&read_done, &read);
+  grpc_endpoint_read(ep_, &read_slices, &read_done);
+
+  grpc_slice_buffer_init(&write_slices);
+  slice = grpc_slice_from_static_buffer(write_buffer, kBufferSize);
+  grpc_slice_buffer_add(&write_slices, slice);
+  init_event_closure(&write_done, &write);
+  grpc_endpoint_write(ep_, &write_slices, &write_done);
+
+  XCTAssertEqual([self waitForEvent:&write timeout:kWriteTimeout], YES);
+  XCTAssertEqual(reinterpret_cast<grpc_error *>(write), GRPC_ERROR_NONE);
+
+  while (recv_size < kBufferSize) {
+    ssize_t size = recv(svr_fd_, read_buffer, kBufferSize, 0);
+    XCTAssertGreaterThanOrEqual(size, 0);
+    recv_size += size;
+  }
+
+  XCTAssertEqual(recv_size, kBufferSize);
+  XCTAssertEqual(memcmp(read_buffer, write_buffer, kBufferSize), 0);
+
+  XCTAssertEqual([self waitForEvent:&read timeout:kReadTimeout], NO);
+
+  grpc_endpoint_shutdown(ep_, GRPC_ERROR_NONE);
+
+  grpc_core::ExecCtx::Get()->Flush();
+  XCTAssertEqual([self waitForEvent:&read timeout:kReadTimeout], YES);
+  XCTAssertNotEqual(reinterpret_cast<grpc_error *>(read), GRPC_ERROR_NONE);
+
+  grpc_slice_buffer_reset_and_unref(&read_slices);
+  grpc_slice_buffer_reset_and_unref(&write_slices);
+}
+
+- (void)testRemoteClosed {
+  grpc_core::ExecCtx exec_ctx;
+
+  gpr_atm read;
+  grpc_closure read_done;
+  grpc_slice_buffer read_slices;
+  gpr_atm write;
+  grpc_closure write_done;
+  grpc_slice_buffer write_slices;
+
+  grpc_slice slice;
+  char write_buffer[kBufferSize];
+  char read_buffer[kBufferSize];
+  size_t recv_size = 0;
+
+  init_event_closure(&read_done, &read);
+  grpc_slice_buffer_init(&read_slices);
+  grpc_endpoint_read(ep_, &read_slices, &read_done);
+
+  grpc_slice_buffer_init(&write_slices);
+  slice = grpc_slice_from_static_buffer(write_buffer, kBufferSize);
+  grpc_slice_buffer_add(&write_slices, slice);
+  init_event_closure(&write_done, &write);
+  grpc_endpoint_write(ep_, &write_slices, &write_done);
+
+  XCTAssertEqual([self waitForEvent:&write timeout:kWriteTimeout], YES);
+  XCTAssertEqual(reinterpret_cast<grpc_error *>(write), GRPC_ERROR_NONE);
+
+  while (recv_size < kBufferSize) {
+    ssize_t size = recv(svr_fd_, read_buffer, kBufferSize, 0);
+    XCTAssertGreaterThanOrEqual(size, 0);
+    recv_size += size;
+  }
+
+  XCTAssertEqual(recv_size, kBufferSize);
+  XCTAssertEqual(memcmp(read_buffer, write_buffer, kBufferSize), 0);
+
+  close(svr_fd_);
+
+  XCTAssertEqual([self waitForEvent:&read timeout:kReadTimeout], YES);
+  XCTAssertNotEqual(reinterpret_cast<grpc_error *>(read), GRPC_ERROR_NONE);
+
+  grpc_endpoint_shutdown(ep_, GRPC_ERROR_NONE);
+  grpc_slice_buffer_reset_and_unref(&read_slices);
+  grpc_slice_buffer_reset_and_unref(&write_slices);
+}
+
+- (void)testRemoteReset {
+  grpc_core::ExecCtx exec_ctx;
+
+  gpr_atm read;
+  grpc_closure read_done;
+  grpc_slice_buffer read_slices;
+
+  init_event_closure(&read_done, &read);
+  grpc_slice_buffer_init(&read_slices);
+  grpc_endpoint_read(ep_, &read_slices, &read_done);
+
+  struct linger so_linger;
+  so_linger.l_onoff = 1;
+  so_linger.l_linger = 0;
+  setsockopt(svr_fd_, SOL_SOCKET, SO_LINGER, &so_linger, sizeof(so_linger));
+
+  close(svr_fd_);
+
+  XCTAssertEqual([self waitForEvent:&read timeout:kReadTimeout], YES);
+  XCTAssertNotEqual(reinterpret_cast<grpc_error *>(read), GRPC_ERROR_NONE);
+
+  grpc_endpoint_shutdown(ep_, GRPC_ERROR_NONE);
+  grpc_slice_buffer_reset_and_unref(&read_slices);
+}
+
+@end
+
+#else  // GRPC_CFSTREAM
+
+// Dummy test suite
+@interface CFStreamEndpointTests : XCTestCase
+@end
+
+@implementation CFStreamEndpointTests
+- (void)setUp {
+  [super setUp];
+}
+
+- (void)tearDown {
+  [super tearDown];
+}
+
+@end
+
+#endif  // GRPC_CFSTREAM
diff --git a/test/core/iomgr/ios/CFStreamTests/CFStreamTests.xcodeproj/project.pbxproj b/test/core/iomgr/ios/CFStreamTests/CFStreamTests.xcodeproj/project.pbxproj
new file mode 100644
index 0000000000..2218f129ae
--- /dev/null
+++ b/test/core/iomgr/ios/CFStreamTests/CFStreamTests.xcodeproj/project.pbxproj
@@ -0,0 +1,338 @@
+// !$*UTF8*$!
+{
+	archiveVersion = 1;
+	classes = {
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new file mode 100644
index 0000000000..25d6f780a1
--- /dev/null
+++ b/test/core/iomgr/ios/CFStreamTests/CFStreamTests.xcodeproj/xcshareddata/xcschemes/CFStreamTests.xcscheme
@@ -0,0 +1,56 @@
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diff --git a/test/core/iomgr/ios/CFStreamTests/CFStreamTests.xcodeproj/xcshareddata/xcschemes/CFStreamTests_Asan.xcscheme b/test/core/iomgr/ios/CFStreamTests/CFStreamTests.xcodeproj/xcshareddata/xcschemes/CFStreamTests_Asan.xcscheme
new file mode 100644
index 0000000000..6c5c43aa72
--- /dev/null
+++ b/test/core/iomgr/ios/CFStreamTests/CFStreamTests.xcodeproj/xcshareddata/xcschemes/CFStreamTests_Asan.xcscheme
@@ -0,0 +1,61 @@
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diff --git a/test/core/iomgr/ios/CFStreamTests/CFStreamTests.xcodeproj/xcshareddata/xcschemes/CFStreamTests_Msan.xcscheme b/test/core/iomgr/ios/CFStreamTests/CFStreamTests.xcodeproj/xcshareddata/xcschemes/CFStreamTests_Msan.xcscheme
new file mode 100644
index 0000000000..3e39ff84d0
--- /dev/null
+++ b/test/core/iomgr/ios/CFStreamTests/CFStreamTests.xcodeproj/xcshareddata/xcschemes/CFStreamTests_Msan.xcscheme
@@ -0,0 +1,78 @@
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+         <AdditionalOption
+            key = "NSZombieEnabled"
+            value = "YES"
+            isEnabled = "YES">
+         </AdditionalOption>
+         <AdditionalOption
+            key = "MallocGuardEdges"
+            value = ""
+            isEnabled = "YES">
+         </AdditionalOption>
+         <AdditionalOption
+            key = "MallocScribble"
+            value = ""
+            isEnabled = "YES">
+         </AdditionalOption>
+      </AdditionalOptions>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>
diff --git a/test/core/iomgr/ios/CFStreamTests/CFStreamTests.xcodeproj/xcshareddata/xcschemes/CFStreamTests_Tsan.xcscheme b/test/core/iomgr/ios/CFStreamTests/CFStreamTests.xcodeproj/xcshareddata/xcschemes/CFStreamTests_Tsan.xcscheme
new file mode 100644
index 0000000000..f0bde837c5
--- /dev/null
+++ b/test/core/iomgr/ios/CFStreamTests/CFStreamTests.xcodeproj/xcshareddata/xcschemes/CFStreamTests_Tsan.xcscheme
@@ -0,0 +1,60 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "0920"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      enableThreadSanitizer = "YES"
+      language = ""
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "5E143B782069D67300715A6E"
+               BuildableName = "CFStreamTests.xctest"
+               BlueprintName = "CFStreamTests"
+               ReferencedContainer = "container:CFStreamTests.xcodeproj">
+            </BuildableReference>
+         </TestableReference>
+      </Testables>
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      stopOnEveryThreadSanitizerIssue = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>
diff --git a/test/core/iomgr/ios/CFStreamTests/Info.plist b/test/core/iomgr/ios/CFStreamTests/Info.plist
new file mode 100644
index 0000000000..6c40a6cd0c
--- /dev/null
+++ b/test/core/iomgr/ios/CFStreamTests/Info.plist
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>$(DEVELOPMENT_LANGUAGE)</string>
+	<key>CFBundleExecutable</key>
+	<string>$(EXECUTABLE_NAME)</string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>$(PRODUCT_NAME)</string>
+	<key>CFBundlePackageType</key>
+	<string>BNDL</string>
+	<key>CFBundleShortVersionString</key>
+	<string>1.0</string>
+	<key>CFBundleVersion</key>
+	<string>1</string>
+</dict>
+</plist>
diff --git a/test/core/iomgr/ios/CFStreamTests/Podfile b/test/core/iomgr/ios/CFStreamTests/Podfile
new file mode 100644
index 0000000000..630168a363
--- /dev/null
+++ b/test/core/iomgr/ios/CFStreamTests/Podfile
@@ -0,0 +1,50 @@
+source 'https://github.com/CocoaPods/Specs.git'
+platform :ios, '8.0'
+
+install! 'cocoapods', :deterministic_uuids => false
+
+# Location of gRPC's repo root relative to this file.
+GRPC_LOCAL_SRC = '../../../../..'
+
+# Install the dependencies in the main target plus all test targets.
+target 'CFStreamTests' do
+  pod 'gRPC-Core/CFStream-Implementation', :path => GRPC_LOCAL_SRC
+end
+
+pre_install do |installer|
+  # This is the gRPC-Core podspec object, as initialized by its podspec file.
+  grpc_core_spec = installer.pod_targets.find{|t| t.name == 'gRPC-Core'}.root_spec
+
+  # Copied from gRPC-Core.podspec, except for the adjusted src_root:
+  src_root = "$(PODS_ROOT)/../#{GRPC_LOCAL_SRC}"
+  grpc_core_spec.pod_target_xcconfig = {
+    'GRPC_SRC_ROOT' => src_root,
+    'HEADER_SEARCH_PATHS' => '"$(inherited)" "$(GRPC_SRC_ROOT)/include"',
+    'USER_HEADER_SEARCH_PATHS' => '"$(GRPC_SRC_ROOT)"',
+    # If we don't set these two settings, `include/grpc/support/time.h` and
+    # `src/core/lib/gpr/string.h` shadow the system `<time.h>` and `<string.h>`, breaking the
+    # build.
+    'USE_HEADERMAP' => 'NO',
+    'ALWAYS_SEARCH_USER_PATHS' => 'NO',
+  }
+end
+
+post_install do |installer|
+  installer.pods_project.targets.each do |target|
+    target.build_configurations.each do |config|
+      config.build_settings['GCC_TREAT_WARNINGS_AS_ERRORS'] = 'YES'
+    end
+
+    # CocoaPods creates duplicated library targets of gRPC-Core when the test targets include
+    # non-default subspecs of gRPC-Core. All of these library targets start with prefix 'gRPC-Core'
+    # and require the same error suppresion.
+    if target.name.start_with?('gRPC-Core')
+      target.build_configurations.each do |config|
+        # TODO(zyc): Remove this setting after the issue is resolved
+        # GPR_UNREACHABLE_CODE causes "Control may reach end of non-void
+        # function" warning
+        config.build_settings['GCC_WARN_ABOUT_RETURN_TYPE'] = 'NO'
+      end
+    end
+  end
+end
diff --git a/test/core/iomgr/ios/CFStreamTests/build_tests.sh b/test/core/iomgr/ios/CFStreamTests/build_tests.sh
new file mode 100755
index 0000000000..d23f26f5db
--- /dev/null
+++ b/test/core/iomgr/ios/CFStreamTests/build_tests.sh
@@ -0,0 +1,39 @@
+#!/bin/bash
+# Copyright 2018 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Don't run this script standalone. Instead, run from the repository root:
+# ./tools/run_tests/run_tests.py -l objc
+
+set -e
+
+# CocoaPods requires the terminal to be using UTF-8 encoding.
+export LANG=en_US.UTF-8
+
+cd "$(dirname "$0")"
+
+hash pod 2>/dev/null || { echo >&2 "Cocoapods needs to be installed."; exit 1; }
+hash xcodebuild 2>/dev/null || {
+    echo >&2 "XCode command-line tools need to be installed."
+    exit 1
+}
+
+# clean the directory
+rm -rf Pods
+rm -rf CFStreamTests.xcworkspace
+rm -f Podfile.lock
+
+echo "TIME:  $(date)"
+pod install
+
diff --git a/test/core/iomgr/ios/CFStreamTests/run_tests.sh b/test/core/iomgr/ios/CFStreamTests/run_tests.sh
new file mode 100755
index 0000000000..1045ec10a8
--- /dev/null
+++ b/test/core/iomgr/ios/CFStreamTests/run_tests.sh
@@ -0,0 +1,67 @@
+#!/bin/bash
+# Copyright 2018 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Don't run this script standalone. Instead, run from the repository root:
+# ./tools/run_tests/run_tests.py -l objc
+
+set -ev
+
+cd "$(dirname "$0")"
+
+echo "TIME:  $(date)"
+
+XCODEBUILD_FILTER='(^CompileC |^Ld |^ *[^ ]*clang |^ *cd |^ *export |^Libtool |^ *[^ ]*libtool |^CpHeader |^ *builtin-copy )'
+
+xcodebuild \
+    -workspace CFStreamTests.xcworkspace \
+    -scheme CFStreamTests \
+    -destination name="iPhone 8" \
+    test \
+    | egrep -v "$XCODEBUILD_FILTER" \
+    | egrep -v '^$' \
+    | egrep -v "(GPBDictionary|GPBArray)" -
+
+echo "TIME:  $(date)"
+
+xcodebuild \
+    -workspace CFStreamTests.xcworkspace \
+    -scheme CFStreamTests_Asan \
+    -destination name="iPhone 8" \
+    test \
+    | egrep -v "$XCODEBUILD_FILTER" \
+    | egrep -v '^$' \
+    | egrep -v "(GPBDictionary|GPBArray)" -
+
+echo "TIME:  $(date)"
+
+xcodebuild \
+    -workspace CFStreamTests.xcworkspace \
+    -scheme CFStreamTests_Tsan \
+    -destination name="iPhone 8" \
+    test \
+    | egrep -v "$XCODEBUILD_FILTER" \
+    | egrep -v '^$' \
+    | egrep -v "(GPBDictionary|GPBArray)" -
+
+echo "TIME:  $(date)"
+
+xcodebuild \
+    -workspace CFStreamTests.xcworkspace \
+    -scheme CFStreamTests_Msan \
+    -destination name="iPhone 8" \
+    test \
+    | egrep -v "$XCODEBUILD_FILTER" \
+    | egrep -v '^$' \
+    | egrep -v "(GPBDictionary|GPBArray)" -
diff --git a/test/core/transport/chttp2/hpack_encoder_test.cc b/test/core/transport/chttp2/hpack_encoder_test.cc
index d3ba50a91c..2a57198ab6 100644
--- a/test/core/transport/chttp2/hpack_encoder_test.cc
+++ b/test/core/transport/chttp2/hpack_encoder_test.cc
@@ -160,6 +160,8 @@ static void encode_int_to_str(int i, char* p) {
 }
 
 static void test_decode_table_overflow() {
+  // Decrease the default table size to make decode table overflow easier.
+  grpc_chttp2_hpack_compressor_set_max_table_size(&g_compressor, 1024);
   int i;
   char key[3], value[3];
   char* expect;
@@ -170,27 +172,20 @@ static void test_decode_table_overflow() {
       false,
   };
 
-  for (i = 0; i < 114; i++) {
+  for (i = 0; i < 29; i++) {
     encode_int_to_str(i, key);
     encode_int_to_str(i + 1, value);
-
-    if (i + 61 >= 127) {
+    if (i == 0) {
+      // 3fe107 corresponds to the table size update.
       gpr_asprintf(&expect,
-                   "000009 0104 deadbeef ff%02x 40 02%02x%02x 02%02x%02x",
-                   i + 61 - 127, key[0], key[1], value[0], value[1]);
-    } else if (i > 0) {
+                   "00000a 0104 deadbeef 3fe107 40 02%02x%02x 02%02x%02x",
+                   key[0], key[1], value[0], value[1]);
+      verify(params, expect, 1, key, value);
+    } else {
       gpr_asprintf(&expect,
                    "000008 0104 deadbeef %02x 40 02%02x%02x 02%02x%02x",
                    0x80 + 61 + i, key[0], key[1], value[0], value[1]);
-    } else {
-      gpr_asprintf(&expect, "000007 0104 deadbeef 40 02%02x%02x 02%02x%02x",
-                   key[0], key[1], value[0], value[1]);
-    }
-
-    if (i > 0) {
       verify(params, expect, 2, "aa", "ba", key, value);
-    } else {
-      verify(params, expect, 1, key, value);
     }
     gpr_free(expect);
   }
diff --git a/test/cpp/end2end/end2end_test.cc b/test/cpp/end2end/end2end_test.cc
index 60238e930d..3c1d48cc1e 100644
--- a/test/cpp/end2end/end2end_test.cc
+++ b/test/cpp/end2end/end2end_test.cc
@@ -1209,8 +1209,13 @@ TEST_P(End2endTest, ExpectErrorTest) {
   std::vector<ErrorStatus> expected_status;
   expected_status.emplace_back();
   expected_status.back().set_code(13);  // INTERNAL
+  // No Error message or details
+
+  expected_status.emplace_back();
+  expected_status.back().set_code(13);  // INTERNAL
   expected_status.back().set_error_message("text error message");
   expected_status.back().set_binary_error_details("text error details");
+
   expected_status.emplace_back();
   expected_status.back().set_code(13);  // INTERNAL
   expected_status.back().set_error_message("text error message");
diff --git a/test/cpp/end2end/grpclb_end2end_test.cc b/test/cpp/end2end/grpclb_end2end_test.cc
index 7aab035e76..28f9ae6f40 100644
--- a/test/cpp/end2end/grpclb_end2end_test.cc
+++ b/test/cpp/end2end/grpclb_end2end_test.cc
@@ -1380,7 +1380,7 @@ TEST_F(SingleBalancerTest, DropAll) {
 
 class SingleBalancerWithClientLoadReportingTest : public GrpclbEnd2endTest {
  public:
-  SingleBalancerWithClientLoadReportingTest() : GrpclbEnd2endTest(4, 1, 2) {}
+  SingleBalancerWithClientLoadReportingTest() : GrpclbEnd2endTest(4, 1, 3) {}
 };
 
 TEST_F(SingleBalancerWithClientLoadReportingTest, Vanilla) {
diff --git a/test/cpp/end2end/round_robin_end2end_test.cc b/test/cpp/end2end/round_robin_end2end_test.cc
deleted file mode 100644
index 846347e110..0000000000
--- a/test/cpp/end2end/round_robin_end2end_test.cc
+++ /dev/null
@@ -1,226 +0,0 @@
-/*
- *
- * Copyright 2016 gRPC authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- */
-
-#include <memory>
-#include <mutex>
-#include <thread>
-
-#include <grpc/grpc.h>
-#include <grpc/support/log.h>
-#include <grpc/support/time.h>
-#include <grpcpp/channel.h>
-#include <grpcpp/client_context.h>
-#include <grpcpp/create_channel.h>
-#include <grpcpp/server.h>
-#include <grpcpp/server_builder.h>
-
-#include "src/proto/grpc/testing/echo.grpc.pb.h"
-#include "test/core/util/port.h"
-#include "test/core/util/test_config.h"
-#include "test/cpp/end2end/test_service_impl.h"
-
-#include <gtest/gtest.h>
-
-using grpc::testing::EchoRequest;
-using grpc::testing::EchoResponse;
-using std::chrono::system_clock;
-
-namespace grpc {
-namespace testing {
-namespace {
-
-// Subclass of TestServiceImpl that increments a request counter for
-// every call to the Echo RPC.
-class MyTestServiceImpl : public TestServiceImpl {
- public:
-  MyTestServiceImpl() : request_count_(0) {}
-
-  Status Echo(ServerContext* context, const EchoRequest* request,
-              EchoResponse* response) override {
-    {
-      std::unique_lock<std::mutex> lock(mu_);
-      ++request_count_;
-    }
-    return TestServiceImpl::Echo(context, request, response);
-  }
-
-  int request_count() {
-    std::unique_lock<std::mutex> lock(mu_);
-    return request_count_;
-  }
-
- private:
-  std::mutex mu_;
-  int request_count_;
-};
-
-class RoundRobinEnd2endTest : public ::testing::Test {
- protected:
-  RoundRobinEnd2endTest() : server_host_("localhost") {}
-
-  void StartServers(size_t num_servers,
-                    std::vector<int> ports = std::vector<int>()) {
-    for (size_t i = 0; i < num_servers; ++i) {
-      int port = 0;
-      if (ports.size() == num_servers) port = ports[i];
-      servers_.emplace_back(new ServerData(server_host_, port));
-    }
-  }
-
-  void TearDown() override {
-    for (size_t i = 0; i < servers_.size(); ++i) {
-      servers_[i]->Shutdown();
-    }
-  }
-
-  void ResetStub(bool round_robin) {
-    ChannelArguments args;
-    if (round_robin) args.SetLoadBalancingPolicyName("round_robin");
-    std::ostringstream uri;
-    uri << "ipv4:///";
-    for (size_t i = 0; i < servers_.size() - 1; ++i) {
-      uri << "127.0.0.1:" << servers_[i]->port_ << ",";
-    }
-    uri << "127.0.0.1:" << servers_[servers_.size() - 1]->port_;
-    channel_ =
-        CreateCustomChannel(uri.str(), InsecureChannelCredentials(), args);
-    stub_ = grpc::testing::EchoTestService::NewStub(channel_);
-  }
-
-  void SendRpc(int num_rpcs, bool expect_ok = true) {
-    EchoRequest request;
-    EchoResponse response;
-    request.set_message("Live long and prosper.");
-    for (int i = 0; i < num_rpcs; i++) {
-      ClientContext context;
-      Status status = stub_->Echo(&context, request, &response);
-      if (expect_ok) {
-        EXPECT_TRUE(status.ok());
-        EXPECT_EQ(response.message(), request.message());
-      } else {
-        EXPECT_FALSE(status.ok());
-      }
-    }
-  }
-
-  struct ServerData {
-    int port_;
-    std::unique_ptr<Server> server_;
-    MyTestServiceImpl service_;
-
-    explicit ServerData(const grpc::string& server_host, int port = 0) {
-      port_ = port > 0 ? port : grpc_pick_unused_port_or_die();
-      gpr_log(GPR_INFO, "starting server on port %d", port_);
-      std::ostringstream server_address;
-      server_address << server_host << ":" << port_;
-      ServerBuilder builder;
-      builder.AddListeningPort(server_address.str(),
-                               InsecureServerCredentials());
-      builder.RegisterService(&service_);
-      server_ = builder.BuildAndStart();
-      gpr_log(GPR_INFO, "server startup complete");
-    }
-
-    void Shutdown() { server_->Shutdown(); }
-  };
-
-  const grpc::string server_host_;
-  std::shared_ptr<Channel> channel_;
-  std::unique_ptr<grpc::testing::EchoTestService::Stub> stub_;
-  std::vector<std::unique_ptr<ServerData>> servers_;
-};
-
-TEST_F(RoundRobinEnd2endTest, PickFirst) {
-  // Start servers and send one RPC per server.
-  const int kNumServers = 3;
-  StartServers(kNumServers);
-  ResetStub(false /* round_robin */);
-  SendRpc(kNumServers);
-  // All requests should have gone to a single server.
-  bool found = false;
-  for (size_t i = 0; i < servers_.size(); ++i) {
-    const int request_count = servers_[i]->service_.request_count();
-    if (request_count == kNumServers) {
-      found = true;
-    } else {
-      EXPECT_EQ(0, request_count);
-    }
-  }
-  EXPECT_TRUE(found);
-  // Check LB policy name for the channel.
-  EXPECT_EQ("pick_first", channel_->GetLoadBalancingPolicyName());
-}
-
-TEST_F(RoundRobinEnd2endTest, RoundRobin) {
-  // Start servers and send one RPC per server.
-  const int kNumServers = 3;
-  StartServers(kNumServers);
-  ResetStub(true /* round_robin */);
-  // Send one RPC per backend and make sure they are used in order.
-  // Note: This relies on the fact that the subchannels are reported in
-  // state READY in the order in which the addresses are specified,
-  // which is only true because the backends are all local.
-  for (size_t i = 0; i < servers_.size(); ++i) {
-    SendRpc(1);
-    EXPECT_EQ(1, servers_[i]->service_.request_count()) << "for backend #" << i;
-  }
-  // Check LB policy name for the channel.
-  EXPECT_EQ("round_robin", channel_->GetLoadBalancingPolicyName());
-}
-
-TEST_F(RoundRobinEnd2endTest, RoundRobinReconnect) {
-  // Start servers and send one RPC per server.
-  const int kNumServers = 1;
-  std::vector<int> ports;
-  ports.push_back(grpc_pick_unused_port_or_die());
-  StartServers(kNumServers, ports);
-  ResetStub(true /* round_robin */);
-  // Send one RPC per backend and make sure they are used in order.
-  // Note: This relies on the fact that the subchannels are reported in
-  // state READY in the order in which the addresses are specified,
-  // which is only true because the backends are all local.
-  for (size_t i = 0; i < servers_.size(); ++i) {
-    SendRpc(1);
-    EXPECT_EQ(1, servers_[i]->service_.request_count()) << "for backend #" << i;
-  }
-  // Check LB policy name for the channel.
-  EXPECT_EQ("round_robin", channel_->GetLoadBalancingPolicyName());
-
-  // Kill all servers
-  for (size_t i = 0; i < servers_.size(); ++i) {
-    servers_[i]->Shutdown();
-  }
-  // Client request should fail.
-  SendRpc(1, false);
-
-  // Bring servers back up on the same port (we aren't recreating the channel).
-  StartServers(kNumServers, ports);
-
-  // Client request should succeed.
-  SendRpc(1);
-}
-
-}  // namespace
-}  // namespace testing
-}  // namespace grpc
-
-int main(int argc, char** argv) {
-  grpc_test_init(argc, argv);
-  ::testing::InitGoogleTest(&argc, argv);
-  return RUN_ALL_TESTS();
-}
diff --git a/test/cpp/util/grpc_tool.cc b/test/cpp/util/grpc_tool.cc
index 195b6bd304..840ca07d2b 100644
--- a/test/cpp/util/grpc_tool.cc
+++ b/test/cpp/util/grpc_tool.cc
@@ -471,17 +471,26 @@ bool GrpcTool::CallMethod(int argc, const char** argv,
   std::shared_ptr<grpc::Channel> channel =
       grpc::CreateChannel(server_address, cred.GetCredentials());
 
-  parser.reset(new grpc::testing::ProtoFileParser(
-      FLAGS_remotedb ? channel : nullptr, FLAGS_proto_path, FLAGS_protofiles));
+  if (!FLAGS_binary_input || !FLAGS_binary_output) {
+    parser.reset(
+        new grpc::testing::ProtoFileParser(FLAGS_remotedb ? channel : nullptr,
+                                           FLAGS_proto_path, FLAGS_protofiles));
+    if (parser->HasError()) {
+      fprintf(
+          stderr,
+          "Failed to find remote reflection service and local proto files.\n");
+      return false;
+    }
+  }
 
   if (FLAGS_binary_input) {
     formatted_method_name = method_name;
   } else {
     formatted_method_name = parser->GetFormattedMethodName(method_name);
-  }
-
-  if (parser->HasError()) {
-    return false;
+    if (parser->HasError()) {
+      fprintf(stderr, "Failed to find method %s in proto files.\n",
+              method_name.c_str());
+    }
   }
 
   if (argc == 3) {
@@ -711,6 +720,7 @@ bool GrpcTool::CallMethod(int argc, const char** argv,
       serialized_request_proto = parser->GetSerializedProtoFromMethod(
           method_name, request_text, true /* is_request */);
       if (parser->HasError()) {
+        fprintf(stderr, "Failed to parse request.\n");
         return false;
       }
     }
@@ -735,6 +745,7 @@ bool GrpcTool::CallMethod(int argc, const char** argv,
         serialized_response_proto = parser->GetTextFormatFromMethod(
             method_name, serialized_response_proto, false /* is_request */);
         if (parser->HasError()) {
+          fprintf(stderr, "Failed to parse response.\n");
           return false;
         }
       }
@@ -814,6 +825,9 @@ bool GrpcTool::ParseMessage(int argc, const char** argv,
         new grpc::testing::ProtoFileParser(FLAGS_remotedb ? channel : nullptr,
                                            FLAGS_proto_path, FLAGS_protofiles));
     if (parser->HasError()) {
+      fprintf(
+          stderr,
+          "Failed to find remote reflection service and local proto files.\n");
       return false;
     }
   }
@@ -824,6 +838,7 @@ bool GrpcTool::ParseMessage(int argc, const char** argv,
     serialized_request_proto =
         parser->GetSerializedProtoFromMessageType(type_name, message_text);
     if (parser->HasError()) {
+      fprintf(stderr, "Failed to serialize the message.\n");
       return false;
     }
   }
@@ -834,6 +849,7 @@ bool GrpcTool::ParseMessage(int argc, const char** argv,
     grpc::string output_text = parser->GetTextFormatFromMessageType(
         type_name, serialized_request_proto);
     if (parser->HasError()) {
+      fprintf(stderr, "Failed to deserialize the message.\n");
       return false;
     }
     output_ss << output_text << std::endl;
diff --git a/test/distrib/csharp/DistribTest/packages.config b/test/distrib/csharp/DistribTest/packages.config
index 84be8f76b5..3cb2c46bcf 100644
--- a/test/distrib/csharp/DistribTest/packages.config
+++ b/test/distrib/csharp/DistribTest/packages.config
@@ -6,6 +6,7 @@
   <package id="Grpc" version="__GRPC_NUGET_VERSION__" targetFramework="net45" />
   <package id="Grpc.Auth" version="__GRPC_NUGET_VERSION__" targetFramework="net45" />
   <package id="Grpc.Core" version="__GRPC_NUGET_VERSION__" targetFramework="net45" />
+  <package id="Grpc.Tools" version="__GRPC_NUGET_VERSION__" targetFramework="net45" />
   <package id="System.Interactive.Async" version="3.0.0" targetFramework="net45" />
   <package id="Newtonsoft.Json" version="7.0.1" targetFramework="net45" />
 </packages>
\ No newline at end of file
diff --git a/test/distrib/csharp/run_distrib_test.sh b/test/distrib/csharp/run_distrib_test.sh
index eee24d0e57..f9371410e7 100755
--- a/test/distrib/csharp/run_distrib_test.sh
+++ b/test/distrib/csharp/run_distrib_test.sh
@@ -26,3 +26,6 @@ nuget restore
 xbuild DistribTest.sln
 
 mono DistribTest/bin/Debug/DistribTest.exe
+
+# test that codegen work
+test_codegen/test_codegen.sh
diff --git a/test/distrib/csharp/test_codegen/test_codegen.sh b/test/distrib/csharp/test_codegen/test_codegen.sh
new file mode 100755
index 0000000000..fa101889f6
--- /dev/null
+++ b/test/distrib/csharp/test_codegen/test_codegen.sh
@@ -0,0 +1,38 @@
+#!/bin/bash
+# Copyright 2018 The gRPC Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -ex
+
+cd "$(dirname "$0")"
+
+ls -lR "../packages/Grpc.Tools.__GRPC_NUGET_VERSION__/tools"
+
+PLATFORM_ARCH=linux_x64
+if [ "$(uname)" == "Darwin" ]
+then
+  PLATFORM_ARCH=macosx_x64
+elif [ "$(getconf LONG_BIT)" == "32" ]
+then
+  PLATFORM_ARCH=linux_x86
+fi
+
+PROTOC=../packages/Grpc.Tools.__GRPC_NUGET_VERSION__/tools/${PLATFORM_ARCH}/protoc
+PLUGIN=../packages/Grpc.Tools.__GRPC_NUGET_VERSION__/tools/${PLATFORM_ARCH}/grpc_csharp_plugin
+
+"${PROTOC}" --plugin="protoc-gen-grpc=${PLUGIN}" --csharp_out=. --grpc_out=. -I . testcodegen.proto
+
+ls ./*.cs
+
+echo 'Code generation works.'
diff --git a/test/distrib/csharp/test_codegen/testcodegen.proto b/test/distrib/csharp/test_codegen/testcodegen.proto
new file mode 100644
index 0000000000..5c228b81db
--- /dev/null
+++ b/test/distrib/csharp/test_codegen/testcodegen.proto
@@ -0,0 +1,29 @@
+// Copyright 2018 The gRPC Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+
+package testcodegen;
+
+service Greeter {
+  rpc SayHello (HelloRequest) returns (HelloReply) {}
+}
+
+message HelloRequest {
+  string name = 1;
+}
+
+message HelloReply {
+  string message = 1;
+}
diff --git a/test/distrib/csharp/update_version.sh b/test/distrib/csharp/update_version.sh
index 9759cc5648..0e47ed3abd 100755
--- a/test/distrib/csharp/update_version.sh
+++ b/test/distrib/csharp/update_version.sh
@@ -28,4 +28,4 @@ then
 fi
 
 # Replaces version placeholder with value provided as first argument.
-sed -ibak "s/__GRPC_NUGET_VERSION__/${CSHARP_VERSION}/g" DistribTest/packages.config DistribTest/DistribTest.csproj DistribTest/DistribTestDotNet.csproj
+sed -ibak "s/__GRPC_NUGET_VERSION__/${CSHARP_VERSION}/g" DistribTest/packages.config DistribTest/DistribTest.csproj DistribTest/DistribTestDotNet.csproj test_codegen/test_codegen.sh
diff --git a/tools/distrib/pylint_code.sh b/tools/distrib/pylint_code.sh
index 013b6660eb..82a818cce5 100755
--- a/tools/distrib/pylint_code.sh
+++ b/tools/distrib/pylint_code.sh
@@ -1,5 +1,5 @@
 #!/bin/bash
-# Copyright 2017 gRPC authors.
+# Copyright 2017 The gRPC Authors
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -35,14 +35,15 @@ python -m virtualenv $VIRTUALENV
 PYTHON=$VIRTUALENV/bin/python
 
 $PYTHON -m pip install --upgrade pip==10.0.1
-$PYTHON -m pip install pylint==1.6.5
+$PYTHON -m pip install pylint==1.9.2
 
+EXIT=0
 for dir in "${DIRS[@]}"; do
-  $PYTHON -m pylint --rcfile=.pylintrc -rn "$dir" || exit $?
+  $PYTHON -m pylint --rcfile=.pylintrc -rn "$dir" || EXIT=1
 done
 
 for dir in "${TEST_DIRS[@]}"; do
-  $PYTHON -m pylint --rcfile=.pylintrc-tests -rn "$dir" || exit $?
+  $PYTHON -m pylint --rcfile=.pylintrc-tests -rn "$dir" || EXIT=1
 done
 
-exit 0
+exit $EXIT
diff --git a/tools/dockerfile/distribtest/csharp_centos7_x64/Dockerfile b/tools/dockerfile/distribtest/csharp_centos7_x64/Dockerfile
index 088635b0ea..3e1faafdc0 100644
--- a/tools/dockerfile/distribtest/csharp_centos7_x64/Dockerfile
+++ b/tools/dockerfile/distribtest/csharp_centos7_x64/Dockerfile
@@ -14,21 +14,11 @@
 
 FROM centos:7
 
-RUN rpm --import "http://keyserver.ubuntu.com/pks/lookup?op=get&search=0x3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF"
-RUN yum-config-manager --add-repo http://download.mono-project.com/repo/centos/
+RUN rpm --import "https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF"
+RUN curl https://download.mono-project.com/repo/centos7-stable.repo | tee /etc/yum.repos.d/mono-centos7-stable.repo
 
-RUN yum install -y mono
+RUN yum install -y mono-devel
 
-RUN yum install -y unzip
-
-# --nogpgcheck because nuget-2.12 package is not signed.
-RUN yum install -y nuget --nogpgcheck
+RUN yum install -y nuget
 
-# Help mono correctly locate libMonoPosixHelper.so
-# as a workaround for issue https://bugzilla.xamarin.com/show_bug.cgi?id=42820
-# The error message you'll get without this workaround:
-# ```
-# WARNING: /usr/lib/libMonoPosixHelper.so
-# WARNING: Unable to read package from path 'Grpc.1.1.0-dev.nupkg'.
-# ```
-RUN cp /usr/lib64/libMonoPosixHelper.so /usr/lib/
+RUN yum install -y unzip
diff --git a/tools/dockerfile/distribtest/csharp_jessie_x64/Dockerfile b/tools/dockerfile/distribtest/csharp_jessie_x64/Dockerfile
index 02ec4c278a..03fb7a5343 100644
--- a/tools/dockerfile/distribtest/csharp_jessie_x64/Dockerfile
+++ b/tools/dockerfile/distribtest/csharp_jessie_x64/Dockerfile
@@ -14,14 +14,13 @@
 
 FROM debian:jessie
 
+RUN apt-get update && apt-get install -y apt-transport-https && apt-get clean
+
 RUN apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
-RUN echo "deb http://download.mono-project.com/repo/debian jessie main" | tee /etc/apt/sources.list.d/mono-official.list
-RUN echo "deb http://download.mono-project.com/repo/debian wheezy-apache24-compat main" | tee -a /etc/apt/sources.list.d/mono-xamarin.list
-RUN echo "deb http://download.mono-project.com/repo/debian wheezy-libjpeg62-compat main" | tee -a /etc/apt/sources.list.d/mono-xamarin.list
+RUN echo "deb https://download.mono-project.com/repo/debian stable-jessie main" | tee /etc/apt/sources.list.d/mono-official-stable.list
 
 RUN apt-get update && apt-get install -y \
     mono-devel \
-    ca-certificates-mono \
     nuget \
     && apt-get clean
 
diff --git a/tools/dockerfile/distribtest/csharp_jessie_x86/Dockerfile b/tools/dockerfile/distribtest/csharp_jessie_x86/Dockerfile
index 758f314572..f2fa61a691 100644
--- a/tools/dockerfile/distribtest/csharp_jessie_x86/Dockerfile
+++ b/tools/dockerfile/distribtest/csharp_jessie_x86/Dockerfile
@@ -14,14 +14,13 @@
 
 FROM 32bit/debian:jessie
 
+RUN apt-get update && apt-get install -y apt-transport-https && apt-get clean
+
 RUN apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
-RUN echo "deb http://download.mono-project.com/repo/debian jessie main" | tee /etc/apt/sources.list.d/mono-official.list
-RUN echo "deb http://download.mono-project.com/repo/debian wheezy-apache24-compat main" | tee -a /etc/apt/sources.list.d/mono-xamarin.list
-RUN echo "deb http://download.mono-project.com/repo/debian wheezy-libjpeg62-compat main" | tee -a /etc/apt/sources.list.d/mono-xamarin.list
+RUN echo "deb https://download.mono-project.com/repo/debian stable-jessie main" | tee /etc/apt/sources.list.d/mono-official-stable.list
 
 RUN apt-get update && apt-get install -y \
     mono-devel \
-    ca-certificates-mono \
     nuget \
     && apt-get clean
 
diff --git a/tools/dockerfile/distribtest/csharp_ubuntu1404_x64/Dockerfile b/tools/dockerfile/distribtest/csharp_ubuntu1404_x64/Dockerfile
index 10279c5925..3edc31e170 100644
--- a/tools/dockerfile/distribtest/csharp_ubuntu1404_x64/Dockerfile
+++ b/tools/dockerfile/distribtest/csharp_ubuntu1404_x64/Dockerfile
@@ -14,15 +14,17 @@
 
 FROM ubuntu:14.04
 
-RUN apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
-RUN echo "deb http://download.mono-project.com/repo/debian wheezy main" | tee /etc/apt/sources.list.d/mono-xamarin.list
+RUN apt-get update && apt-get install -y apt-transport-https && apt-get clean
+
+RUN apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
+RUN echo "deb https://download.mono-project.com/repo/ubuntu stable-trusty main" | tee /etc/apt/sources.list.d/mono-official-stable.list
 
 RUN apt-get update && apt-get install -y \
     mono-devel \
-    ca-certificates-mono \
-    nuget
+    nuget \
+    && apt-get clean
 
-RUN apt-get update && apt-get install -y unzip
+RUN apt-get update && apt-get install -y unzip && apt-get clean
 
 # Install dotnet CLI
 RUN apt-get install -y apt-transport-https
diff --git a/tools/dockerfile/distribtest/csharp_ubuntu1604_x64/Dockerfile b/tools/dockerfile/distribtest/csharp_ubuntu1604_x64/Dockerfile
index 0f40f18e38..1a58f9784b 100644
--- a/tools/dockerfile/distribtest/csharp_ubuntu1604_x64/Dockerfile
+++ b/tools/dockerfile/distribtest/csharp_ubuntu1604_x64/Dockerfile
@@ -14,19 +14,14 @@
 
 FROM ubuntu:16.04
 
+RUN apt-get update && apt-get install -y apt-transport-https && apt-get clean
+
+RUN apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
+RUN echo "deb https://download.mono-project.com/repo/ubuntu stable-xenial main" | tee /etc/apt/sources.list.d/mono-official-stable.list
+
 RUN apt-get update && apt-get install -y \
     mono-devel \
-    ca-certificates-mono \
     nuget \
     && apt-get clean
 
-# make sure we have nuget 2.12+ (in case there's an older cached docker image)
-RUN apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
-RUN echo "deb http://download.mono-project.com/repo/debian wheezy main" | tee /etc/apt/sources.list.d/mono-xamarin.list
-RUN apt-get update && apt-get install -y nuget && apt-get clean
-
-# Prevent "Error: SendFailure (Error writing headers)" when fetching nuget packages
-# See https://github.com/tianon/docker-brew-ubuntu-core/issues/86
-RUN apt-get update && apt-get install -y tzdata && apt-get clean
-
 RUN apt-get update && apt-get install -y unzip && apt-get clean
diff --git a/tools/dockerfile/distribtest/csharp_wheezy_x64/Dockerfile b/tools/dockerfile/distribtest/csharp_wheezy_x64/Dockerfile
deleted file mode 100644
index fb9c82c92b..0000000000
--- a/tools/dockerfile/distribtest/csharp_wheezy_x64/Dockerfile
+++ /dev/null
@@ -1,20 +0,0 @@
-# Copyright 2015 gRPC authors.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-FROM mono:4.4.2.11
-
-# make sure we have nuget 2.12+ (in case there's an older cached docker image)
-RUN apt-get update && apt-get install -y nuget
-
-RUN apt-get update && apt-get install -y unzip
diff --git a/tools/dockerfile/interoptest/grpc_interop_python/build_interop.sh b/tools/dockerfile/interoptest/grpc_interop_python/build_interop.sh
index a8898f85fa..7917e1cd60 100755
--- a/tools/dockerfile/interoptest/grpc_interop_python/build_interop.sh
+++ b/tools/dockerfile/interoptest/grpc_interop_python/build_interop.sh
@@ -28,4 +28,5 @@ cp -r /var/local/jenkins/service_account $HOME || true
 
 cd /var/local/git/grpc
 
-tools/run_tests/run_tests.py -l python -c opt --build_only
+# interop tests only run using python2.7 currently (and python build is slow)
+tools/run_tests/run_tests.py -l python --compiler python2.7 -c opt --build_only
diff --git a/tools/dockerfile/test/python_pyenv_x64/Dockerfile b/tools/dockerfile/test/python_pyenv_x64/Dockerfile
index 43854aa689..c23e67c904 100644
--- a/tools/dockerfile/test/python_pyenv_x64/Dockerfile
+++ b/tools/dockerfile/test/python_pyenv_x64/Dockerfile
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-FROM debian:jessie
+FROM debian:stretch
 
 # Install Git and basic packages.
 RUN apt-get update && apt-get install -y \
@@ -80,7 +80,7 @@ RUN apt-get update && apt-get install -y \
   mercurial \
   zlib1g-dev && apt-get clean
 
-# Install Pyenv and dev Python versions 3.5 and 3.6
+# Install Pyenv and dev Python versions 3.{5,6,7}
 RUN curl -L https://raw.githubusercontent.com/yyuu/pyenv-installer/master/bin/pyenv-installer | bash
 ENV PATH /root/.pyenv/bin:$PATH
 RUN eval "$(pyenv init -)"
@@ -88,12 +88,13 @@ RUN eval "$(pyenv virtualenv-init -)"
 RUN pyenv update
 RUN pyenv install 3.5-dev
 RUN pyenv install 3.6-dev
+RUN pyenv install 3.7-dev
 RUN pyenv install pypy-5.3.1
-RUN pyenv local 3.5-dev 3.6-dev pypy-5.3.1
+RUN pyenv local 3.5-dev 3.6-dev 3.7-dev pypy-5.3.1
 
-# Install pip and virtualenv for Python 3.4
-RUN curl https://bootstrap.pypa.io/get-pip.py | python3.4
-RUN python3.4 -m pip install virtualenv
+# Install pip and virtualenv for Python 3.5
+RUN curl https://bootstrap.pypa.io/get-pip.py | python3.5
+RUN python3.5 -m pip install virtualenv
 
 
 RUN mkdir /var/local/jenkins
diff --git a/tools/internal_ci/helper_scripts/prepare_build_macos_rc b/tools/internal_ci/helper_scripts/prepare_build_macos_rc
index d2b77691d4..2f12471a85 100644
--- a/tools/internal_ci/helper_scripts/prepare_build_macos_rc
+++ b/tools/internal_ci/helper_scripts/prepare_build_macos_rc
@@ -34,7 +34,8 @@ sudo systemsetup -setusingnetworktime on
 date
 
 # Add GCP credentials for BQ access
-pip install google-api-python-client --user python
+# pin google-api-python-client to avoid https://github.com/grpc/grpc/issues/15600
+pip install google-api-python-client==1.6.7 --user python
 export GOOGLE_APPLICATION_CREDENTIALS=${KOKORO_GFILE_DIR}/GrpcTesting-d0eeee2db331.json
 
 # If this is a PR using RUN_TESTS_FLAGS var, then add flags to filter tests
diff --git a/tools/internal_ci/linux/grpc_bazel_on_foundry_base.sh b/tools/internal_ci/linux/grpc_bazel_on_foundry_base.sh
index 7881e3a7fb..d2dded051d 100755
--- a/tools/internal_ci/linux/grpc_bazel_on_foundry_base.sh
+++ b/tools/internal_ci/linux/grpc_bazel_on_foundry_base.sh
@@ -22,8 +22,8 @@ mkdir -p ${KOKORO_KEYSTORE_DIR}
 cp ${KOKORO_GFILE_DIR}/GrpcTesting-d0eeee2db331.json ${KOKORO_KEYSTORE_DIR}/4321_grpc-testing-service
 
 temp_dir=$(mktemp -d)
-ln -f "${KOKORO_GFILE_DIR}/bazel-release-0.12.0" ${temp_dir}/bazel
-chmod 755 "${KOKORO_GFILE_DIR}/bazel-release-0.12.0"
+ln -f "${KOKORO_GFILE_DIR}/bazel-rc-0.14.0rc5" ${temp_dir}/bazel
+chmod 755 "${KOKORO_GFILE_DIR}/bazel-rc-0.14.0rc5"
 export PATH="${temp_dir}:${PATH}"
 # This should show ${temp_dir}/bazel
 which bazel
@@ -49,9 +49,12 @@ source tools/internal_ci/helper_scripts/prepare_build_linux_rc
   --strategy=Closure=remote  \
   --genrule_strategy=remote  \
   --experimental_strict_action_env=true \
-  --experimental_remote_platform_override='properties:{name:"container-image" value:"docker://gcr.io/cloud-marketplace/google/rbe-debian8@sha256:1ede2a929b44d629ec5abe86eee6d7ffea1d5a4d247489a8867d46cfde3e38bd" }' \
-  --crosstool_top=@com_github_bazelbuild_bazeltoolchains//configs/debian8_clang/0.3.0/bazel_0.10.0:toolchain \
+  --experimental_remote_platform_override='properties:{name:"container-image" value:"docker://gcr.io/cloud-marketplace/google/rbe-ubuntu16-04@sha256:59bf0e191a6b5cc1ab62c2224c810681d1326bad5a27b1d36c9f40113e79da7f" }' \
+  --crosstool_top=@com_github_bazelbuild_bazeltoolchains//configs/ubuntu16_04_clang/1.0/bazel_0.13.0/default:toolchain \
   --define GRPC_PORT_ISOLATED_RUNTIME=1 \
+  --action_env=BAZEL_DO_NOT_DETECT_CPP_TOOLCHAIN=1 \
+  --extra_toolchains=@com_github_bazelbuild_bazeltoolchains//configs/ubuntu16_04_clang/1.0/bazel_0.13.0/cpp:cc-toolchain-clang-x86_64-default \
+  --extra_execution_platforms=@com_github_bazelbuild_bazeltoolchains//configs/ubuntu16_04_clang/1.0:rbe_ubuntu1604 \
   $1 \
   -- //test/... || FAILED="true"
 
diff --git a/tools/internal_ci/linux/grpc_msan_on_foundry.sh b/tools/internal_ci/linux/grpc_msan_on_foundry.sh
index 5e644793ad..e8ef249aa5 100644
--- a/tools/internal_ci/linux/grpc_msan_on_foundry.sh
+++ b/tools/internal_ci/linux/grpc_msan_on_foundry.sh
@@ -23,8 +23,8 @@ mkdir -p ${KOKORO_KEYSTORE_DIR}
 cp ${KOKORO_GFILE_DIR}/GrpcTesting-d0eeee2db331.json ${KOKORO_KEYSTORE_DIR}/4321_grpc-testing-service
 
 temp_dir=$(mktemp -d)
-ln -f "${KOKORO_GFILE_DIR}/bazel-release-0.12.0" ${temp_dir}/bazel
-chmod 755 "${KOKORO_GFILE_DIR}/bazel-release-0.12.0"
+ln -f "${KOKORO_GFILE_DIR}/bazel-rc-0.14.0rc5" ${temp_dir}/bazel
+chmod 755 "${KOKORO_GFILE_DIR}/bazel-rc-0.14.0rc5"
 export PATH="${temp_dir}:${PATH}"
 # This should show ${temp_dir}/bazel
 which bazel
@@ -50,7 +50,7 @@ source tools/internal_ci/helper_scripts/prepare_build_linux_rc
   --strategy=Closure=remote  \
   --genrule_strategy=remote  \
   --experimental_strict_action_env=true \
-  --experimental_remote_platform_override='properties:{name:"container-image" value:"docker://gcr.io/asci-toolchain/nosla-debian8-clang-msan@sha256:8f381d55c0456fb65821c90ada902c2584977e03a1eaca8fba8ce77e644c775b" }' \
+  --experimental_remote_platform_override='properties:{name:"container-image" value:"docker://gcr.io/cloud-marketplace/google/rbe-ubuntu16-04@sha256:59bf0e191a6b5cc1ab62c2224c810681d1326bad5a27b1d36c9f40113e79da7f" }' \
   --define GRPC_PORT_ISOLATED_RUNTIME=1 \
   --copt=-gmlt \
   --strip=never \
@@ -59,8 +59,11 @@ source tools/internal_ci/helper_scripts/prepare_build_linux_rc
   --linkopt=-fsanitize=memory \
   --copt=-fsanitize-memory-track-origins \
   --action_env=LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH \
-  --host_crosstool_top=@com_github_bazelbuild_bazeltoolchains//configs/debian8_clang/0.3.0/bazel_0.10.0:toolchain \
-  --crosstool_top=@com_github_bazelbuild_bazeltoolchains//configs/experimental/debian8_clang/0.3.0/bazel_0.10.0/msan:msan_experimental_toolchain \
+  --host_crosstool_top=@com_github_bazelbuild_bazeltoolchains//configs/ubuntu16_04_clang/1.0/bazel_0.13.0/default:toolchain \
+  --crosstool_top=@com_github_bazelbuild_bazeltoolchains//configs/ubuntu16_04_clang/1.0/bazel_0.13.0/msan:toolchain \
+  --action_env=BAZEL_DO_NOT_DETECT_CPP_TOOLCHAIN=1 \
+  --extra_toolchains=@com_github_bazelbuild_bazeltoolchains//configs/ubuntu16_04_clang/1.0/bazel_0.13.0/cpp:cc-toolchain-clang-x86_64-default \
+  --extra_execution_platforms=@com_github_bazelbuild_bazeltoolchains//configs/ubuntu16_04_clang/1.0:rbe_ubuntu1604 \
   -- //test/... || FAILED="true"
 
 # Sleep to let ResultStore finish writing results before querying
diff --git a/tools/internal_ci/linux/grpc_ubsan_on_foundry.sh b/tools/internal_ci/linux/grpc_ubsan_on_foundry.sh
index 5c0e2df09d..f5c12c27a3 100644
--- a/tools/internal_ci/linux/grpc_ubsan_on_foundry.sh
+++ b/tools/internal_ci/linux/grpc_ubsan_on_foundry.sh
@@ -23,8 +23,8 @@ mkdir -p ${KOKORO_KEYSTORE_DIR}
 cp ${KOKORO_GFILE_DIR}/GrpcTesting-d0eeee2db331.json ${KOKORO_KEYSTORE_DIR}/4321_grpc-testing-service
 
 temp_dir=$(mktemp -d)
-ln -f "${KOKORO_GFILE_DIR}/bazel-release-0.12.0" ${temp_dir}/bazel
-chmod 755 "${KOKORO_GFILE_DIR}/bazel-release-0.12.0"
+ln -f "${KOKORO_GFILE_DIR}/bazel-rc-0.14.0rc5" ${temp_dir}/bazel
+chmod 755 "${KOKORO_GFILE_DIR}/bazel-rc-0.14.0rc5"
 export PATH="${temp_dir}:${PATH}"
 # This should show ${temp_dir}/bazel
 which bazel
@@ -50,13 +50,16 @@ source tools/internal_ci/helper_scripts/prepare_build_linux_rc
   --strategy=Closure=remote  \
   --genrule_strategy=remote  \
   --experimental_strict_action_env=true \
-  --experimental_remote_platform_override='properties:{name:"container-image" value:"docker://gcr.io/cloud-marketplace/google/rbe-debian8@sha256:1ede2a929b44d629ec5abe86eee6d7ffea1d5a4d247489a8867d46cfde3e38bd" }' \
+  --experimental_remote_platform_override='properties:{name:"container-image" value:"docker://gcr.io/cloud-marketplace/google/rbe-ubuntu16-04@sha256:59bf0e191a6b5cc1ab62c2224c810681d1326bad5a27b1d36c9f40113e79da7f" }' \
   --define GRPC_PORT_ISOLATED_RUNTIME=1 \
   --copt=-gmlt \
   --strip=never \
   --copt=-fsanitize=undefined \
   --linkopt=-fsanitize=undefined \
-  --crosstool_top=@com_github_bazelbuild_bazeltoolchains//configs/experimental/debian8_clang/0.3.0/bazel_0.12.0/ubsan:toolchain \
+  --crosstool_top=@com_github_bazelbuild_bazeltoolchains//configs/experimental/ubuntu16_04_clang/1.0/bazel_0.13.0/ubsan:toolchain \
+  --action_env=BAZEL_DO_NOT_DETECT_CPP_TOOLCHAIN=1 \
+  --extra_toolchains=@com_github_bazelbuild_bazeltoolchains//configs/ubuntu16_04_clang/1.0/bazel_0.13.0/cpp:cc-toolchain-clang-x86_64-default \
+  --extra_execution_platforms=@com_github_bazelbuild_bazeltoolchains//configs/ubuntu16_04_clang/1.0:rbe_ubuntu1604 \
   -- //test/... || FAILED="true"
 
 # Sleep to let ResultStore finish writing results before querying
diff --git a/tools/interop_matrix/client_matrix.py b/tools/interop_matrix/client_matrix.py
index 2d43e3ea12..d6a704681a 100644
--- a/tools/interop_matrix/client_matrix.py
+++ b/tools/interop_matrix/client_matrix.py
@@ -326,7 +326,14 @@ LANG_RELEASE_MATRIX = {
         },
     ],
     'csharp': [
-        #{'v1.0.1': None},
+        {
+            'v1.0.1': {
+                'patch': [
+                    'tools/dockerfile/interoptest/grpc_interop_csharp/Dockerfile',
+                    'tools/dockerfile/interoptest/grpc_interop_csharpcoreclr/Dockerfile',
+                ]
+            }
+        },
         {
             'v1.1.4': None
         },
@@ -377,6 +384,7 @@ TESTCASES_VERSION_MATRIX = {
     'node_v1.4.2': 'node__v1.1.4',
     'node_v1.6.6': 'node__v1.1.4',
     'ruby_v1.0.1': 'ruby__v1.0.1',
+    'csharp_v1.0.1': 'csharp__v1.1.4',
     'csharp_v1.1.4': 'csharp__v1.1.4',
     'csharp_v1.2.5': 'csharp__v1.1.4',
     'python_v1.0.x': 'python__v1.0.x',
diff --git a/tools/interop_matrix/create_matrix_images.py b/tools/interop_matrix/create_matrix_images.py
index ef9f6a5990..c2568efba0 100755
--- a/tools/interop_matrix/create_matrix_images.py
+++ b/tools/interop_matrix/create_matrix_images.py
@@ -97,6 +97,12 @@ argp.add_argument(
     'reusing the repo can cause git checkout error if you switch '
     'between releases.')
 
+argp.add_argument(
+    '--upload_images',
+    action='store_true',
+    help='If set, images will be uploaded to container registry after building.'
+)
+
 args = argp.parse_args()
 
 
@@ -166,8 +172,10 @@ def build_all_images_for_lang(lang):
     """Build all docker images for a language across releases and runtimes."""
     if not args.git_checkout:
         if args.release != 'master':
-            print('WARNING: --release is set but will be ignored\n')
-        releases = ['master']
+            print(
+                'Cannot use --release without also enabling --git_checkout.\n')
+            sys.exit(1)
+        releases = [args.release]
     else:
         if args.release == 'all':
             releases = client_matrix.get_release_tags(lang)
@@ -268,6 +276,13 @@ def maybe_apply_patches_on_git_tag(stack_base, lang, release):
         sys.exit(1)
     subprocess.check_output(
         ['git', 'apply', patch_file], cwd=stack_base, stderr=subprocess.STDOUT)
+
+    # TODO(jtattermusch): this really would need simplification and refactoring
+    # - "git add" and "git commit" can easily be done in a single command
+    # - it looks like the only reason for the existence of the "files_to_patch"
+    #   entry is to perform "git add" - which is clumsy and fragile.
+    # - we only allow a single patch with name "git_repo.patch". A better design
+    #   would be to allow multiple patches that can have more descriptive names.
     for repo_relative_path in files_to_patch:
         subprocess.check_output(
             ['git', 'add', repo_relative_path],
@@ -334,8 +349,12 @@ languages = args.language if args.language != ['all'] else _LANGUAGES
 for lang in languages:
     docker_images = build_all_images_for_lang(lang)
     for image in docker_images:
-        jobset.message('START', 'Uploading %s' % image, do_newline=True)
-        # docker image name must be in the format <gcr_path>/<image>:<gcr_tag>
-        assert image.startswith(args.gcr_path) and image.find(':') != -1
-
-        subprocess.call(['gcloud', 'docker', '--', 'push', image])
+        if args.upload_images:
+            jobset.message('START', 'Uploading %s' % image, do_newline=True)
+            # docker image name must be in the format <gcr_path>/<image>:<gcr_tag>
+            assert image.startswith(args.gcr_path) and image.find(':') != -1
+            subprocess.call(['gcloud', 'docker', '--', 'push', image])
+        else:
+            # Uploading (and overwriting images) by default can easily break things.
+            print('Not uploading image %s, run with --upload_images to upload.'
+                  % image)
diff --git a/tools/interop_matrix/patches/csharp_v1.0.1/git_repo.patch b/tools/interop_matrix/patches/csharp_v1.0.1/git_repo.patch
new file mode 100644
index 0000000000..e07b9c80f8
--- /dev/null
+++ b/tools/interop_matrix/patches/csharp_v1.0.1/git_repo.patch
@@ -0,0 +1,81 @@
+diff --git a/third_party/boringssl b/third_party/boringssl
+index c880e42ba1..70ef9596bb 160000
+--- a/third_party/boringssl
++++ b/third_party/boringssl
+@@ -1 +1 @@
+-Subproject commit c880e42ba1c8032d4cdde2aba0541d8a9d9fa2e9
++Subproject commit 70ef9596bbcc11353b9bb8d4e91478694dd21439
+diff --git a/third_party/gflags b/third_party/gflags
+index 05b155ff59..30dbc81fb5 160000
+--- a/third_party/gflags
++++ b/third_party/gflags
+@@ -1 +1 @@
+-Subproject commit 05b155ff59114735ec8cd089f669c4c3d8f59029
++Subproject commit 30dbc81fb5ffdc98ea9b14b1918bfe4e8779b26e
+diff --git a/third_party/googletest b/third_party/googletest
+index c99458533a..ec44c6c167 160000
+--- a/third_party/googletest
++++ b/third_party/googletest
+@@ -1 +1 @@
+-Subproject commit c99458533a9b4c743ed51537e25989ea55944908
++Subproject commit ec44c6c1675c25b9827aacd08c02433cccde7780
+diff --git a/third_party/protobuf b/third_party/protobuf
+index 1a58673508..b5fbb742af 160000
+--- a/third_party/protobuf
++++ b/third_party/protobuf
+@@ -1 +1 @@
+-Subproject commit 1a586735085e817b1f52e53feec92ce418049f69
++Subproject commit b5fbb742af122b565925987e65c08957739976a7
+diff --git a/third_party/zlib b/third_party/zlib
+index 5089329162..cacf7f1d4e 160000
+--- a/third_party/zlib
++++ b/third_party/zlib
+@@ -1 +1 @@
+-Subproject commit 50893291621658f355bc5b4d450a8d06a563053d
++Subproject commit cacf7f1d4e3d44d871b605da3b647f07d718623f
+diff --git a/tools/dockerfile/interoptest/grpc_interop_csharp/Dockerfile b/tools/dockerfile/interoptest/grpc_interop_csharp/Dockerfile
+index da1d2c645e..f405994293 100644
+--- a/tools/dockerfile/interoptest/grpc_interop_csharp/Dockerfile
++++ b/tools/dockerfile/interoptest/grpc_interop_csharp/Dockerfile
+@@ -67,11 +67,10 @@ RUN apt-get update && apt-get install -y time && apt-get clean
+ # C# dependencies
+ 
+ # Update to a newer version of mono
+-RUN apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
+-RUN echo "deb http://download.mono-project.com/repo/debian wheezy main" | tee /etc/apt/sources.list.d/mono-xamarin.list
++RUN apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
++RUN echo "deb http://download.mono-project.com/repo/debian wheezy/snapshots/4.6 main" | tee /etc/apt/sources.list.d/official.list
+ RUN echo "deb http://download.mono-project.com/repo/debian wheezy-apache24-compat main" | tee -a /etc/apt/sources.list.d/mono-xamarin.list
+ RUN echo "deb http://download.mono-project.com/repo/debian wheezy-libjpeg62-compat main" | tee -a /etc/apt/sources.list.d/mono-xamarin.list
+-RUN echo "deb http://download.mono-project.com/repo/debian wheezy-libtiff-compat main" | tee -a /etc/apt/sources.list.d/mono-xamarin.list
+ 
+ # Install dependencies
+ RUN apt-get update && apt-get -y dist-upgrade && apt-get install -y \
+diff --git a/tools/dockerfile/interoptest/grpc_interop_csharpcoreclr/Dockerfile b/tools/dockerfile/interoptest/grpc_interop_csharpcoreclr/Dockerfile
+index 65f67d3650..26223753ed 100644
+--- a/tools/dockerfile/interoptest/grpc_interop_csharpcoreclr/Dockerfile
++++ b/tools/dockerfile/interoptest/grpc_interop_csharpcoreclr/Dockerfile
+@@ -82,11 +82,10 @@ RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.0.0a2
+ # C# dependencies
+ 
+ # Update to a newer version of mono
+-RUN apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
+-RUN echo "deb http://download.mono-project.com/repo/debian wheezy main" | tee /etc/apt/sources.list.d/mono-xamarin.list
++RUN apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
++RUN echo "deb http://download.mono-project.com/repo/debian jessie main" | tee /etc/apt/sources.list.d/mono-official.list
+ RUN echo "deb http://download.mono-project.com/repo/debian wheezy-apache24-compat main" | tee -a /etc/apt/sources.list.d/mono-xamarin.list
+ RUN echo "deb http://download.mono-project.com/repo/debian wheezy-libjpeg62-compat main" | tee -a /etc/apt/sources.list.d/mono-xamarin.list
+-RUN echo "deb http://download.mono-project.com/repo/debian wheezy-libtiff-compat main" | tee -a /etc/apt/sources.list.d/mono-xamarin.list
+ 
+ # Install dependencies
+ RUN apt-get update && apt-get -y dist-upgrade && apt-get install -y \
+@@ -99,7 +98,8 @@ RUN nuget update -self
+ 
+ # Install dotnet SDK based on https://www.microsoft.com/net/core#debian
+ RUN apt-get update && apt-get install -y curl libunwind8 gettext
+-RUN curl -sSL -o dotnet.tar.gz https://go.microsoft.com/fwlink/?LinkID=809130
++# https://github.com/dotnet/core/blob/master/release-notes/download-archives/1.0.1-preview2-download.md
++RUN curl -sSL -o dotnet.tar.gz https://go.microsoft.com/fwlink/?LinkID=827530
+ RUN mkdir -p /opt/dotnet && tar zxf dotnet.tar.gz -C /opt/dotnet
+ RUN ln -s /opt/dotnet/dotnet /usr/local/bin
+ 
diff --git a/tools/interop_matrix/run_interop_matrix_tests.py b/tools/interop_matrix/run_interop_matrix_tests.py
index eb8b7d6944..9d442346a7 100755
--- a/tools/interop_matrix/run_interop_matrix_tests.py
+++ b/tools/interop_matrix/run_interop_matrix_tests.py
@@ -116,6 +116,10 @@ def find_all_images_for_lang(lang):
             return {}
         releases = [args.release]
 
+    # TODO(jtattermusch): why do we need to query the existing images/tags?
+    # From LANG_RUNTIME_MATRIX and LANG_RELEASE_MATRIX it should be obvious
+    # which tags we want to test - and it should be an error if they are
+    # missing.
     # Images tuples keyed by runtime.
     images = {}
     for runtime in client_matrix.LANG_RUNTIME_MATRIX[lang]:
diff --git a/tools/profiling/ios_bin/binary_diff.py b/tools/profiling/ios_bin/binary_diff.py
new file mode 100755
index 0000000000..6d5ae65e46
--- /dev/null
+++ b/tools/profiling/ios_bin/binary_diff.py
@@ -0,0 +1,127 @@
+#!/usr/bin/env python2.7
+#
+# Copyright 2018 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import argparse
+import glob
+import multiprocessing
+import os
+import shutil
+import subprocess
+import sys
+from parse_link_map import parse_link_map
+
+sys.path.append(
+    os.path.join(
+        os.path.dirname(sys.argv[0]), '..', '..', 'run_tests', 'python_utils'))
+import comment_on_pr
+
+size_labels = ('Core', 'ObjC', 'BoringSSL', 'Protobuf', 'Total')
+
+argp = argparse.ArgumentParser(
+    description='Binary size diff of gRPC Objective-C sample')
+
+argp.add_argument(
+    '-d',
+    '--diff_base',
+    type=str,
+    help='Commit or branch to compare the current one to')
+
+args = argp.parse_args()
+
+
+def dir_size(dir):
+    total = 0
+    for dirpath, dirnames, filenames in os.walk(dir):
+        for f in filenames:
+            fp = os.path.join(dirpath, f)
+            total += os.stat(fp).st_size
+    return total
+
+
+def get_size(where, frameworks):
+    build_dir = 'src/objective-c/examples/Sample/Build-%s/' % where
+    if not frameworks:
+        link_map_filename = 'Build/Intermediates.noindex/Sample.build/Release-iphoneos/Sample.build/Sample-LinkMap-normal-arm64.txt'
+        return parse_link_map(build_dir + link_map_filename)
+    else:
+        framework_dir = 'Build/Products/Release-iphoneos/Sample.app/Frameworks/'
+        boringssl_size = dir_size(
+            build_dir + framework_dir + 'openssl.framework')
+        core_size = dir_size(build_dir + framework_dir + 'grpc.framework')
+        objc_size = dir_size(build_dir + framework_dir + 'GRPCClient.framework') + \
+                    dir_size(build_dir + framework_dir + 'RxLibrary.framework') + \
+                    dir_size(build_dir + framework_dir + 'ProtoRPC.framework')
+        protobuf_size = dir_size(
+            build_dir + framework_dir + 'Protobuf.framework')
+        app_size = dir_size(
+            build_dir + 'Build/Products/Release-iphoneos/Sample.app')
+        return core_size, objc_size, boringssl_size, protobuf_size, app_size
+
+
+def build(where, frameworks):
+    shutil.rmtree(
+        'src/objective-c/examples/Sample/Build-%s' % where, ignore_errors=True)
+    subprocess.check_call(
+        'CONFIG=opt EXAMPLE_PATH=src/objective-c/examples/Sample SCHEME=Sample FRAMEWORKS=%s ./build_one_example.sh'
+        % ('YES' if frameworks else 'NO'),
+        shell=True,
+        cwd='src/objective-c/tests')
+    os.rename('src/objective-c/examples/Sample/Build',
+              'src/objective-c/examples/Sample/Build-%s' % where)
+
+
+text = ''
+for frameworks in [False, True]:
+    build('new', frameworks)
+    new_size = get_size('new', frameworks)
+    old_size = None
+
+    if args.diff_base:
+        old = 'old'
+        where_am_i = subprocess.check_output(
+            ['git', 'rev-parse', '--abbrev-ref', 'HEAD']).strip()
+        subprocess.check_call(['git', 'checkout', '--', '.'])
+        subprocess.check_call(['git', 'checkout', args.diff_base])
+        subprocess.check_call(['git', 'submodule', 'update'])
+        try:
+            build('old', frameworks)
+            old_size = get_size('old', frameworks)
+        finally:
+            subprocess.check_call(['git', 'checkout', '--', '.'])
+            subprocess.check_call(['git', 'checkout', where_am_i])
+            subprocess.check_call(['git', 'submodule', 'update'])
+
+    text += ('****************FRAMEWORKS*****************\n'
+             if frameworks else '******************STATIC*******************\n')
+    row_format = "{:>10}{:>15}{:>15}" + '\n'
+    text += row_format.format('New size', '', 'Old size')
+    for i in range(0, len(size_labels)):
+        if old_size == None:
+            diff_sign = ' '
+        elif new_size[i] == old_size[i]:
+            diff_sign = ' (=)'
+        elif new_size[i] > old_size[i]:
+            diff_sign = ' (>)'
+        else:
+            diff_sign = ' (<)'
+        text += ('\n' if i == len(size_labels) - 1 else '') + row_format.format(
+            '{:,}'.format(new_size[i]), size_labels[i] + diff_sign,
+            '{:,}'.format(old_size[i]) if old_size != None else '')
+    text += '\n'
+
+print text
+
+comment_on_pr.comment_on_pr('```\n%s\n```' % text)
diff --git a/tools/profiling/ios_bin/parse_link_map.py b/tools/profiling/ios_bin/parse_link_map.py
new file mode 100755
index 0000000000..eaa1d6e060
--- /dev/null
+++ b/tools/profiling/ios_bin/parse_link_map.py
@@ -0,0 +1,104 @@
+#!/usr/bin/python
+# Copyright 2018 gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# This script analyzes link map file generated by Xcode. It calculates and
+# prints out the sizes of each dependent library and the total sizes of the
+# symbols.
+# The script takes one parameter, which is the path to the link map file.
+
+import sys
+import re
+
+
+def parse_link_map(filename):
+    table_tag = {}
+    state = "start"
+
+    table_stats_symbol = {}
+    table_stats_dead = {}
+    section_total_size = 0
+    symbol_total_size = 0
+
+    boringssl_size = 0
+    core_size = 0
+    objc_size = 0
+    protobuf_size = 0
+
+    lines = list(open(filename))
+    for line in lines:
+        line_stripped = line[:-1]
+        if "# Object files:" == line_stripped:
+            state = "object"
+            continue
+        elif "# Sections:" == line_stripped:
+            state = "section"
+            continue
+        elif "# Symbols:" == line_stripped:
+            state = "symbol"
+            continue
+        elif "# Dead Stripped Symbols:" == line_stripped:
+            state = "dead"
+            continue
+
+        if state == "object":
+            segs = re.search('(\[ *[0-9]*\]) (.*)', line_stripped)
+            table_tag[segs.group(1)] = segs.group(2)
+
+        if state == "section":
+            if len(line_stripped) == 0 or line_stripped[0] == '#':
+                continue
+            segs = re.search('^(.+?)\s+(.+?)\s+.*', line_stripped)
+            section_total_size += int(segs.group(2), 16)
+
+        if state == "symbol":
+            if len(line_stripped) == 0 or line_stripped[0] == '#':
+                continue
+            segs = re.search('^.+?\s+(.+?)\s+(\[.+?\]).*', line_stripped)
+            target = table_tag[segs.group(2)]
+            target_stripped = re.search('^(.*?)(\(.+?\))?$', target).group(1)
+            size = int(segs.group(1), 16)
+            if not target_stripped in table_stats_symbol:
+                table_stats_symbol[target_stripped] = 0
+            table_stats_symbol[target_stripped] += size
+            if 'BoringSSL' in target_stripped:
+                boringssl_size += size
+            elif 'libgRPC-Core' in target_stripped:
+                core_size += size
+            elif 'libgRPC-RxLibrary' in target_stripped or \
+                 'libgRPC' in target_stripped or \
+                 'libgRPC-ProtoLibrary' in target_stripped:
+                objc_size += size
+            elif 'libProtobuf' in target_stripped:
+                protobuf_size += size
+
+    for target in table_stats_symbol:
+        symbol_total_size += table_stats_symbol[target]
+
+    return core_size, objc_size, boringssl_size, protobuf_size, symbol_total_size
+
+
+def main():
+    filename = sys.argv[1]
+    core_size, objc_size, boringssl_size, protobuf_size, total_size = parse_link_map(
+        filename)
+    print('Core size:{:,}'.format(core_size))
+    print('ObjC size:{:,}'.format(objc_size))
+    print('BoringSSL size:{:,}'.format(boringssl_size))
+    print('Protobuf size:{:,}\n'.format(protobuf_size))
+    print('Total size:{:,}'.format(total_size))
+
+
+if __name__ == "__main__":
+    main()
diff --git a/tools/run_tests/artifacts/build_artifact_csharp.bat b/tools/run_tests/artifacts/build_artifact_csharp.bat
index a84bc54157..ac2c92b716 100644
--- a/tools/run_tests/artifacts/build_artifact_csharp.bat
+++ b/tools/run_tests/artifacts/build_artifact_csharp.bat
@@ -19,11 +19,12 @@ set GRPC_SKIP_DOTNET_RESTORE=true
 @call tools\run_tests\helper_scripts\pre_build_csharp.bat %ARCHITECTURE% || goto :error
 
 cd cmake\build\%ARCHITECTURE%
-cmake --build . --target grpc_csharp_ext --config Release
+cmake --build . --target grpc_csharp_ext --config RelWithDebInfo
 cd ..\..\..
 
 mkdir -p %ARTIFACTS_OUT%
-copy /Y cmake\build\Win32\Release\grpc_csharp_ext.dll %ARTIFACTS_OUT% || copy /Y cmake\build\x64\Release\grpc_csharp_ext.dll %ARTIFACTS_OUT% || goto :error
+copy /Y cmake\build\Win32\RelWithDebInfo\grpc_csharp_ext.dll %ARTIFACTS_OUT% || copy /Y cmake\build\x64\RelWithDebInfo\grpc_csharp_ext.dll %ARTIFACTS_OUT% || goto :error
+copy /Y cmake\build\Win32\RelWithDebInfo\grpc_csharp_ext.pdb %ARTIFACTS_OUT% || copy /Y cmake\build\x64\RelWithDebInfo\grpc_csharp_ext.pdb %ARTIFACTS_OUT% || goto :error
 
 goto :EOF
 
diff --git a/tools/run_tests/artifacts/distribtest_targets.py b/tools/run_tests/artifacts/distribtest_targets.py
index 213325439e..e02f4bffcd 100644
--- a/tools/run_tests/artifacts/distribtest_targets.py
+++ b/tools/run_tests/artifacts/distribtest_targets.py
@@ -303,7 +303,6 @@ def targets():
         CppDistribTest('linux', 'x64', 'jessie', 'cmake_as_submodule'),
         CppDistribTest('windows', 'x86', testcase='cmake'),
         CppDistribTest('windows', 'x86', testcase='cmake_as_externalproject'),
-        CSharpDistribTest('linux', 'x64', 'wheezy'),
         CSharpDistribTest('linux', 'x64', 'jessie'),
         CSharpDistribTest('linux', 'x86', 'jessie'),
         CSharpDistribTest('linux', 'x64', 'centos7'),
diff --git a/tools/run_tests/generated/sources_and_headers.json b/tools/run_tests/generated/sources_and_headers.json
index 0af4e19a1a..585f68140a 100644
--- a/tools/run_tests/generated/sources_and_headers.json
+++ b/tools/run_tests/generated/sources_and_headers.json
@@ -8746,6 +8746,7 @@
       "test/core/end2end/tests/max_message_length.cc", 
       "test/core/end2end/tests/negative_deadline.cc", 
       "test/core/end2end/tests/network_status_change.cc", 
+      "test/core/end2end/tests/no_error_on_hotpath.cc", 
       "test/core/end2end/tests/no_logging.cc", 
       "test/core/end2end/tests/no_op.cc", 
       "test/core/end2end/tests/payload.cc", 
@@ -8845,6 +8846,7 @@
       "test/core/end2end/tests/max_message_length.cc", 
       "test/core/end2end/tests/negative_deadline.cc", 
       "test/core/end2end/tests/network_status_change.cc", 
+      "test/core/end2end/tests/no_error_on_hotpath.cc", 
       "test/core/end2end/tests/no_logging.cc", 
       "test/core/end2end/tests/no_op.cc", 
       "test/core/end2end/tests/payload.cc", 
@@ -9747,6 +9749,32 @@
   {
     "deps": [
       "gpr", 
+      "gpr_base_headers", 
+      "grpc_base_headers"
+    ], 
+    "headers": [
+      "src/core/lib/iomgr/cfstream_handle.h", 
+      "src/core/lib/iomgr/endpoint_cfstream.h", 
+      "src/core/lib/iomgr/error_cfstream.h"
+    ], 
+    "is_filegroup": true, 
+    "language": "c", 
+    "name": "grpc_cfstream", 
+    "src": [
+      "src/core/lib/iomgr/cfstream_handle.cc", 
+      "src/core/lib/iomgr/cfstream_handle.h", 
+      "src/core/lib/iomgr/endpoint_cfstream.cc", 
+      "src/core/lib/iomgr/endpoint_cfstream.h", 
+      "src/core/lib/iomgr/error_cfstream.cc", 
+      "src/core/lib/iomgr/error_cfstream.h", 
+      "src/core/lib/iomgr/tcp_client_cfstream.cc"
+    ], 
+    "third_party": false, 
+    "type": "filegroup"
+  }, 
+  {
+    "deps": [
+      "gpr", 
       "grpc_base"
     ], 
     "headers": [
diff --git a/tools/run_tests/generated/tests.json b/tools/run_tests/generated/tests.json
index 00604f181c..902ddbf257 100644
--- a/tools/run_tests/generated/tests.json
+++ b/tools/run_tests/generated/tests.json
@@ -7798,6 +7798,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_census_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -9550,6 +9573,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_compress_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -11243,6 +11289,28 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_fakesec_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -12813,6 +12881,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [
+      "uv"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_fd_test", 
+    "platforms": [
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -14151,6 +14242,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_full_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -15755,6 +15869,25 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [
+      "uv"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_full+pipe_test", 
+    "platforms": [
+      "linux"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -17324,6 +17457,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_full+trace_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_op"
     ], 
     "ci_platforms": [
@@ -19053,6 +19209,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_full+workarounds_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -20837,6 +21016,30 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [
+      "uv"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_http_proxy_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -22653,6 +22856,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_load_reporting_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -24437,6 +24663,30 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [
+      "uv"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_oauth2_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -27293,6 +27543,30 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [
+      "uv"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_sockpair_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -28517,6 +28791,30 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [
+      "uv"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_sockpair+trace_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_op"
     ], 
     "ci_platforms": [
@@ -29777,6 +30075,32 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [
+      "msan"
+    ], 
+    "exclude_iomgrs": [
+      "uv"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_sockpair_1byte_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -31155,6 +31479,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_ssl_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -34033,6 +34380,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [
+      "uv"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_uds_test", 
+    "platforms": [
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -35505,6 +35875,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "inproc_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -36705,6 +37098,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_census_nosec_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -38434,6 +38850,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_compress_nosec_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -39998,6 +40437,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [
+      "uv"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_fd_nosec_test", 
+    "platforms": [
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -41313,6 +41775,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_full_nosec_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -42898,6 +43383,25 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "linux"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [
+      "uv"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_full+pipe_nosec_test", 
+    "platforms": [
+      "linux"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -44444,6 +44948,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_full+trace_nosec_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_op"
     ], 
     "ci_platforms": [
@@ -46150,6 +46677,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_full+workarounds_nosec_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -47910,6 +48460,30 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [
+      "uv"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_http_proxy_nosec_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -49703,6 +50277,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_load_reporting_nosec_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -52471,6 +53068,30 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [
+      "uv"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_sockpair_nosec_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -53671,6 +54292,30 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [
+      "uv"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_sockpair+trace_nosec_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_op"
     ], 
     "ci_platforms": [
@@ -54905,6 +55550,32 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [
+      "msan"
+    ], 
+    "exclude_iomgrs": [
+      "uv"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_sockpair_1byte_nosec_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -56210,6 +56881,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [
+      "uv"
+    ], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "h2_uds_nosec_test", 
+    "platforms": [
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
@@ -57659,6 +58353,29 @@
   }, 
   {
     "args": [
+      "no_error_on_hotpath"
+    ], 
+    "ci_platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "language": "c", 
+    "name": "inproc_nosec_test", 
+    "platforms": [
+      "windows", 
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
       "no_logging"
     ], 
     "ci_platforms": [
diff --git a/tools/run_tests/python_utils/upload_rbe_results.py b/tools/run_tests/python_utils/upload_rbe_results.py
index 5955b3792f..a2dd0bc39d 100644
--- a/tools/run_tests/python_utils/upload_rbe_results.py
+++ b/tools/run_tests/python_utils/upload_rbe_results.py
@@ -175,8 +175,8 @@ if __name__ == "__main__":
                     'build_id':
                     os.getenv('KOKORO_BUILD_NUMBER'),
                     'build_url':
-                    'https://sponge.corp.google.com/invocation?id=%s' %
-                    os.getenv('KOKORO_BUILD_ID'),
+                    'https://source.cloud.google.com/results/invocations/%s' %
+                    invocation_id,
                     'test_target':
                     action['id']['targetId'],
                     'test_case':
diff --git a/tools/run_tests/run_tests.py b/tools/run_tests/run_tests.py
index ea4c7c3c65..67aa641e2d 100755
--- a/tools/run_tests/run_tests.py
+++ b/tools/run_tests/run_tests.py
@@ -1114,6 +1114,12 @@ class ObjCLanguage(object):
                     'SCHEME': 'SwiftSample',
                     'EXAMPLE_PATH': 'src/objective-c/examples/SwiftSample'
                 }),
+            self.config.job_spec(
+                ['test/core/iomgr/ios/CFStreamTests/run_tests.sh'],
+                timeout_seconds=10 * 60,
+                shortname='cfstream-tests',
+                cpu_cost=1e6,
+                environ=_FORCE_ENVIRON_FOR_WRAPPERS),
         ]
 
     def pre_build_steps(self):
@@ -1126,7 +1132,10 @@ class ObjCLanguage(object):
         return []
 
     def build_steps(self):
-        return [['src/objective-c/tests/build_tests.sh']]
+        return [
+            ['src/objective-c/tests/build_tests.sh'],
+            ['test/core/iomgr/ios/CFStreamTests/build_tests.sh'],
+        ]
 
     def post_tests_steps(self):
         return []
diff --git a/tools/run_tests/sanity/check_sources_and_headers.py b/tools/run_tests/sanity/check_sources_and_headers.py
deleted file mode 100755
index 57ae5c5acc..0000000000
--- a/tools/run_tests/sanity/check_sources_and_headers.py
+++ /dev/null
@@ -1,126 +0,0 @@
-#!/usr/bin/env python
-# Copyright 2015 gRPC authors.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-from __future__ import print_function
-
-import json
-import os
-import re
-import sys
-
-root = os.path.abspath(os.path.join(os.path.dirname(sys.argv[0]), '../../..'))
-with open(
-        os.path.join(root, 'tools', 'run_tests', 'generated',
-                     'sources_and_headers.json')) as f:
-    js = json.loads(f.read())
-
-re_inc1 = re.compile(r'^#\s*include\s*"([^"]*)"')
-assert re_inc1.match('#include "foo"').group(1) == 'foo'
-re_inc2 = re.compile(r'^#\s*include\s*<((grpc|grpc\+\+)/[^"]*)>')
-assert re_inc2.match('#include <grpc++/foo>').group(1) == 'grpc++/foo'
-
-
-def get_target(name):
-    for target in js:
-        if target['name'] == name:
-            return target
-    assert False, 'no target %s' % name
-
-
-def get_headers_transitive():
-    """Computes set of headers transitively provided by each target"""
-    target_headers_transitive = {}
-    for target in js:
-        target_name = target['name']
-        assert not target_headers_transitive.has_key(target_name)
-        target_headers_transitive[target_name] = set(target['headers'])
-
-    # Make sure each target's transitive headers contain those
-    # of their dependencies. If not, add them and continue doing
-    # so until we get a full pass over all targets without any updates.
-    closure_changed = True
-    while closure_changed:
-        closure_changed = False
-        for target in js:
-            target_name = target['name']
-            for dep in target['deps']:
-                headers = target_headers_transitive[target_name]
-                old_count = len(headers)
-                headers.update(target_headers_transitive[dep])
-                if old_count != len(headers):
-                    closure_changed = True
-    return target_headers_transitive
-
-
-# precompute transitive closure of headers provided by each target
-target_headers_transitive = get_headers_transitive()
-
-
-def target_has_header(target, name):
-    if name in target_headers_transitive[target['name']]:
-        return True
-    if name.startswith('absl/'):
-        return True
-    if name in [
-            'src/core/lib/profiling/stap_probes.h',
-            'src/proto/grpc/reflection/v1alpha/reflection.grpc.pb.h'
-    ]:
-        return True
-    return False
-
-
-def produces_object(name):
-    return os.path.splitext(name)[1] in ['.c', '.cc']
-
-
-c_ish = {}
-obj_producer_to_source = {'c': c_ish, 'c++': c_ish, 'csharp': {}}
-
-errors = 0
-for target in js:
-    if not target['third_party']:
-        for fn in target['src']:
-            with open(os.path.join(root, fn)) as f:
-                src = f.read().splitlines()
-            for line in src:
-                m = re_inc1.match(line)
-                if m:
-                    if not target_has_header(target, m.group(1)):
-                        print(
-                            'target %s (%s) does not name header %s as a dependency'
-                            % (target['name'], fn, m.group(1)))
-                        errors += 1
-                m = re_inc2.match(line)
-                if m:
-                    if not target_has_header(target, 'include/' + m.group(1)):
-                        print(
-                            'target %s (%s) does not name header %s as a dependency'
-                            % (target['name'], fn, m.group(1)))
-                        errors += 1
-    if target['type'] in ['lib', 'filegroup']:
-        for fn in target['src']:
-            language = target['language']
-            if produces_object(fn):
-                obj_base = os.path.splitext(os.path.basename(fn))[0]
-                if obj_base in obj_producer_to_source[language]:
-                    if obj_producer_to_source[language][obj_base] != fn:
-                        print(
-                            'target %s (%s) produces an aliased object file with %s'
-                            % (target['name'], fn,
-                               obj_producer_to_source[language][obj_base]))
-                else:
-                    obj_producer_to_source[language][obj_base] = fn
-
-assert errors == 0
diff --git a/tools/run_tests/sanity/core_banned_functions.py b/tools/run_tests/sanity/core_banned_functions.py
index 1d3f2eba8a..8afd826453 100755
--- a/tools/run_tests/sanity/core_banned_functions.py
+++ b/tools/run_tests/sanity/core_banned_functions.py
@@ -30,7 +30,8 @@ BANNED_EXCEPT = {
     ['src/core/lib/slice/slice_buffer.cc'],
     'grpc_slice_ref(': ['src/core/lib/slice/slice.cc'],
     'grpc_slice_unref(': ['src/core/lib/slice/slice.cc'],
-    'grpc_error_create(': ['src/core/lib/iomgr/error.cc'],
+    'grpc_error_create(':
+    ['src/core/lib/iomgr/error.cc', 'src/core/lib/iomgr/error_cfstream.cc'],
     'grpc_error_ref(': ['src/core/lib/iomgr/error.cc'],
     'grpc_error_unref(': ['src/core/lib/iomgr/error.cc'],
     'grpc_os_error(': ['src/core/lib/iomgr/error.cc'],
diff --git a/tools/run_tests/sanity/sanity_tests.yaml b/tools/run_tests/sanity/sanity_tests.yaml
index a15473db0f..ac0d4c70e5 100644
--- a/tools/run_tests/sanity/sanity_tests.yaml
+++ b/tools/run_tests/sanity/sanity_tests.yaml
@@ -2,7 +2,6 @@
 - script: tools/run_tests/sanity/check_bazel_workspace.py
 - script: tools/run_tests/sanity/check_cache_mk.sh
 - script: tools/run_tests/sanity/check_owners.sh
-- script: tools/run_tests/sanity/check_sources_and_headers.py
 - script: tools/run_tests/sanity/check_shellcheck.sh
 - script: tools/run_tests/sanity/check_submodules.sh
 - script: tools/run_tests/sanity/check_test_filtering.py