Subscribes to server's 'upgrade' event and accepts WebSocket
upgrade requests whose path matches path (or the handler's
configured path, default "/websocket"), serving any number of
concurrent RPCs per accepted connection, demultiplexed by the stream
ID on every frame. Upgrade requests for other paths are left
untouched, so multiple BidiWebSocketHandlers -- or other 'upgrade'
listeners -- can share the same http.Server. Ordinary HTTP requests
(the 'request' event) are entirely unaffected.
Optionalpath: string
Serves RPCs on an already-accepted WebSocket connection until it closes. Use this if you manage the
'upgrade'event yourself, for example to integrate with a framework that already runs its ownws.WebSocketServer.