The GRPCCall.h file is already correctly imported in the
GRPCRequestHeaders.m implementation file. This header shouldn’t need to
import GRPCCall and should specify a class forward declaration for
reference.

Prevent failed docker builds from accumulating

By default docker does not clean up temporary images when the build
fails to allow the user to inspect the state of the container to
determine what went wrong. Those images don't help us at all and just
accumulate until disk usage is 100%.

Fix mutex bug

It is a bad idea to have a map with string_refs as output params.

This is very much unsafe as the string_ref could point on a stack
variable of the callee.

Fix parameter types in function definition.

Fixed typo in channel_args.h docstring

Fix windows build

Client now swallows content-type on receive

remove connectivity watcher from interested party early

Security connector refactoring

Credentials plugin fixes (after the branch was merged).

Removed spurious predicate from if branch

Add --use_docker flag support for run_tests.py

the channeld->content_type->key is already consumed by the preceding if.

Fix portserver on Win and Mac

Add empty_stream test case

Design and implementation of the core credentials plugin API.

Rename the TCP server callback arguments to be more descriptive.

This reverts commit 784db97a.

Swallow content-type at the client.

Round Robin LB Policy