netty: Port client and server handler to frame codec.

[buchgr]

Port the netty layer to use the Http2FrameCodec. This change requires netty/netty#5914, which is currently under reviews.

Performance has yet to be evaluated. I currentlly don't have hardware to run benchmarks on.

The plan is to maintain this in a separate branch, until the Http2FrameCodec API is mature and released and performance is on bar with the Http2ConnectionHandler API.

[ejona86]

I updated this to current Netty and reduced the diff size in https://github.com/ejona86/grpc-java/tree/netty_http2_framecodec . Grep for FIXMEs. It currently will leak all streams, as it keeps them in a map and never removes them (since managedState isn't available). To remove them, it looks like we should override Abstract{Server,Client}Stream.TransportState.deframerClosed() but that's not available at the version of gRPC being modified here. It could be added fairly easily to this without upgrading grpc (see a446b53 where it was added), but meh.

I looked through the conflicts to update to grpc master, and there didn't appear to be anything too hard in the non-test code to merge such that we would want to go with a different approach. There were some non-trivial conflicts in the Handlers, but they also seems pretty self-contained and mostly clear what is going on.

[thelinuxfoundation]

Thank you for your pull request. Before we can look at your contribution, we need to ensure all contributors are covered by a Contributor License Agreement.

After the following items are addressed, please respond with a new comment here, and the automated system will re-verify.

• User @buchgr isn't covered by a CLA. They will need to complete the form at https://identity.linuxfoundation.org/projects/cncf

Regards,
CLA GitHub bot

[ejona86]

This need to propagate the messages or make sure to release them (reference counting). Right now any unknown message is leaked.