websocket-session-handshake-lifecycle

The order a WebSocket session has to be brought up and torn down — reader started before the first message because the answer comes back through it, the handshake settled on a deferred with a timeout, the close frame sent under a non-cancellable context, and an event buffer that suspends rather than drops. Use when a socket connects but the session never becomes usable, when a deliberate disconnect leaves the peer…