WebSocketService.prototype.peek(name: string): WebSocketRoom | undefined
Returns the named room if one already exists, without creating it.
The non-allocating counterpart to WebSocketService.room. A
presence endpoint reading size for a request-supplied name must use this:
room() registers one room per distinct name polled, and a room nobody
joined is reclaimed only on the next disconnection.
WebSocketRoom | undefined
The room, or undefined when no room of that name exists