modified condition for trailing metadata.
added more information to log message.

changed core logic for executing multiple ops.
added call cancellation logic
simplified the code.

V1.0.x merge into master

ASSERT vector size before directly accessing first element

Separate generated pb files from the server reflection build target, use grpc::protobuf instead of google::protobuf

General-purpose handshaker API.

Removed unused version of async_stream.h

Shutdown the listeners early when destroying the tcp_server

Regenerate template files

PHP: update package xml and composer.json

PHP: update package.xml and composer.json

Add gpr_slice_new_with_user_data.

Support server reflection in CLI

Remove non-manylinux linux .whl artifacts