synchronized(this@RealWebSocket) {
      if (failed) {
        return false // Failed web socket.
      }

      writer = this.writer
      pong = pongQueue.poll()
      if (pong == null) {
        messageOrClose = messageAndCloseQueue.poll()
        if (messageOrClose is Close) {
          receivedCloseCode = this.receivedCloseCode
          receivedCloseReason = this.receivedCloseReason