Multiple HTTP connections accessing one session #1971

Trying to fix the WPT WebDriver client behaviour, I've realised this isn't clearly specified anywhere.

Relatedly: w3c/webdriver-bidi#47

A remote end has a list of active sessions.

When a connection is established, and the URL contains a session ID, it is looked up in the list of active sessions, per the processing model.

The only occasions when we remove something from the list of active sessions is in close the session.

This gets invoked only from Delete Session and Close Window.

Given the list of active sessions isn't local to the connection (and can't be, given we want to forbid multiple sessions with a single endpoint), this implies you can have multiple connections dealing with the same active session, modulo "the exact details of how this connection works and how it is established are out of scope".

This leeway I think can be used to justify disallowing multiple simultaneous HTTP connections (i.e., it is valid for the connection can only accept one socket at a time).

But I don't think that forbids making two sequential connections; web-platform-tests/wpt#62028 seems to imply that everyone already allows this.