messageAndCloseQueue.add(Message(formatOpcode, data))
    runWriter()
    return true
  }

  @Synchronized fun pong(payload: ByteString): Boolean {
    // Don't send pongs after we've failed or sent the close frame.
    if (failed || enqueuedClose && messageAndCloseQueue.isEmpty()) return false

    pongQueue.add(payload)
    runWriter()
    return true
  }

  override fun close(
    code: Int,