feat(extensions/websocket): implement websocketstream

[crowlKats]

Needed for #10359.

Implements the WebSocketStream spec.

Resources:
https://docs.google.com/document/d/1La1ehXw76HP6n1uUeks-WJGFgAnpX2tCjKts7QFJ57Y/edit
https://docs.google.com/document/d/1XuxEshh5VYBYm1qRVKordTamCOsR-uGQBCYFcHXP4L0/edit
https://github.com/ricea/websocketstream-explainer
https://chromestatus.com/feature/5189728691290112

Closes #8831

[bnoordhuis]

@crowlKats Is this ready for review?

[crowlKats]

@bnoordhuis there are leaking async ops, and not sure how those can be fixed. i think it might have to do with the pull on the readable stream, but not sure. that aside, it would be ready

[bnoordhuis]

Some comments but mostly LGTM. Good set of regressions tests, too.

I'm trying to understand your remark about leaking ops. Can you go in more detail?

[crowlKats]

I'm trying to understand your remark about leaking ops. Can you go in more detail?

Well when running the tests they fail due to leaking async ops. i have no clue what exactly the cause is, buut the only async stuff that i can see that could be causing this is the readable stream loop. i guess we somehow have to close the streams when close (or any other method to close the websocket) is called

[lucacasonato]

Can you change this to only be registered when --unstable is passed? I think typeof WebSocketStream === "undefined" should be true when user does not pass --unstable.

[bartlomieju]

Please update UNSTABLE_DENO_PROPS in cli/diagnostics.rs

[lucacasonato]

LGTM. Thanks @crowlKats for seeing this through.

API is --unstable for now as spec has not yet been finalized.

[sanfusu]

@bnoordhuis there are leaking async ops, and not sure how those can be fixed. i think it might have to do with the pull on the readable stream, but not sure. that aside, it would be ready

Does this problem still exist? I have some problems about leaking async ops, but I'm not sure if it's related to websocket.