Merge branch 'master' into cq_create_api_changes

.pylintrc

CMakeLists.txt

Makefile

build.yaml

include/grpc/impl/codegen/sync.h

requirements.txt

src/core/lib/iomgr/tcp_server_posix.c

src/python/grpcio/grpc/_channel.py

src/python/grpcio/grpc/beta/_client_adaptations.py

src/python/grpcio/grpc/beta/_server_adaptations.py

src/python/grpcio/grpc/beta/implementations.py

src/python/grpcio/grpc/framework/interfaces/base/base.py

src/python/grpcio/grpc/framework/interfaces/face/face.py

test/core/end2end/BUILD

test/core/end2end/fixtures/h2_http_proxy.c

test/core/end2end/fixtures/http_proxy_fixture.c

test/core/end2end/fixtures/http_proxy_fixture.h

test/cpp/microbenchmarks/bm_call_create.cc

test/cpp/microbenchmarks/bm_chttp2_hpack.cc

test/cpp/microbenchmarks/bm_closure.cc