Log Message:
grpc: updated to 1.19.1

Release v1.19.1
Core
Backport 18201 to fix "symbol not found: _ares_library_init" error in \ 
C++ Bazel build on MacOS.

Python
Backport "Add the missing grpc_cfstream dependency" to v1.19.x.

Release v1.19.0
Core
Fix c-ares on Windows "DNS resolution failure" triggered by logging.
Disable c-ares on Android.
Ignore reserved bit in WINDOW_UPDATE frame.
Set c-ares as the default resolver.
Add period at end of metadata.google.internal to prevent unnecessary DNS lookups.
Decrease verbosity of ALTS platform check to avoid a spam log message.
Fix windows localhost address sorting bug.
Re-enable c-ares as the default resolver; but don't turn on SRV queries.
Remove filters from subchannel args.

C++
Register for cq avalanching when interceptors are going to be run.
Add a caching interceptor to the keyvaluestore example.
Enable per-channel subchannel pool.
Fix build with bazel 0.21.
Switch the default DNS resolver from native to c-ares.
Modifying semantics for GetSendMessage and GetSerializedSendMessage. Also adding \ 
ModifySendMessage.
Add interceptor methods to fail recv msg for hijacked rpcs and set recv message \ 
to nullptr on failure.
Add interceptor method to fail hijacked send messages and get status on \ 
POST_SEND_MESSAGE.
New Experimental Interception API - GetSendMessage and GetSerializedSendMessage.

C#
Upgrade System.Interactive.Async to 3.2.0.
Refactor ServerServiceDefinition and move it to Grpc.Core.Api nuget.
Allow passing null implementation to generated BindService overload using \ 
ServiceBinderBase.
Move public types needed for server implementation to Grpc.Core.Api.

Objective-C
Disable c-ares on iOS.
Added support for tvOS.
Fixing a few thread safety issues in gRPC Objective-C library.
Rolling out new API for gRPC Objective-C library.

Python
grpc_prefork(): check grpc_is_initialized before creating execctx.
[gRPC] Enable Python 3 for Bazel to Run Tests.
Escalate the failure of protoc execution.
Remove dependency of grpc.framework.foundation.callable_util.

Ruby
Disable service config resolution with c-ares by default, for now.
Ruby: refactor init/shutdown logic to avoid using atexit; fix windows.
Ruby tooling: respect user toolchain overrides.