Support HTTP2

[c-antin]

Any plans on supporting an HTTP2 connection especially for the client?

See https://deno.com/blog/v1.38#websockets-improvements

Use case: rust client connecting to deno server over h2

[c-antin]

An alternative would be deno gRPC server support + rust tonic client for bidirectional binary streams.
See denoland/deno#17308 (comment)

[littledivy]

You can perform the handshake yourself using h2 and pass the stream to WebSocket::after_handshake. This is how it's implemented in Deno right now.