WebSocket and WebTransport support

[mxinden]

Should we make HappyEyeballs aware of whether this is a WebSocket connection? That way we could e.g. track EXTENDED CONNECT support, or fallback to a different connection in case WebSocket doesn't work?

• https://datatracker.ietf.org/doc/html/rfc6455
• https://datatracker.ietf.org/doc/html/rfc8441
• Waiting for the Extended CONNECT HTTP setting on http/2
• Having to wait for the 200 OK on both HTTP/2 and HTTP/1.

Should we make HappyEyeballs aware of whether this is a WebTransport connection? That way we could e.g. track EXTENDED CONNECT support, or fallback to a different connection in case WebTransport doesn't work?

• https://www.ietf.org/archive/id/draft-ietf-webtrans-overview-12.html

• Taking the extended connect HTTP setting http/3 into account?

• Optimistically establish session on connection?

• We need to differentiate between a connection being established and a websocket and webtransport establishment (lack of a better word) being successful.

• User should be able to request websocket or webtransport at HEv3 state machine construction time.