gRPC-Core Release 1.27.0

[apo...@google.com]

This is 1.27.0 (guantao) release announcement for gRPC-Core and the wrapped languages C++, C#, Objective-C, Python, PHP and Ruby. Latest release notes are here.

Core

• fix build with OpenSSL1.1.1+ on Windows. (#21611)
• Add a new submodule libuv v1.34.0. (#21583)
• grpclb: Add support for balancer telling client to enter fallback mode. (#21452)
• Bare bones of the libuv EventManager. (#21216)
• Allow default use of system root certs on Android. (#21395)

C++

• Backport: Fix regression in MSVC runtime flag (for v1.27.x). (#21810)
• Add Support for Full Chain Callbacks - experimental namespace. (#21423)
• Improve documentation for building with CMake. (#21529)
• Conditionally enable OPENSSL_NO_ASM for Visual Studio. (#21427)
• Allow gRPC_INSTALL with module providers. (#21411)
• Add Findc-ares.cmake module. (#20815)
• Census client filter: use current span and tags. (#21249)
• Improve & update BUILDING.md. (#21329)

C#

• Introduce ChannelBase.ShutdownAsync() in a backward-compatible manner. (#21667)
• c# - reduce delegate allocations in the Async*Call API. (#21365)
• C# health checks watch. (#21120)

Python

• Drop manylinux1 support. Manylinux2010 is now the recommended Linux wheel format. (#21790)
• [Aio] Implement add_done_callback and time_remaining. (#21681)
• [Aio] Support SO_REUSEPORT channel option. (#21643)
• [Aio] Support metadata. (#21647)
• [Aio] Client Streaming and Bi-di Streaming. (#21517)
• [Aio] Abort mechanism for server side. (#21582)
• [Aio] Implement connectivity state related APIs. (#21621)
• [Aio] Support credentials for unary calls. (#21351)
• [Aio] Support channel argument for both client and server. (#21607)
• [Aio] Client Side Interceptor For Unary Calls. (#21455)
• [Aio] Call correctly the connect CB error when an error happens. (#21543)
• [bazel] Add more stringent check for detection of python headers. (#21477)
• [Aio] Streaming API - Server side streaming. (#21232)
• Ship grpcio-status with the actual proto file. (#21377)