fun onReadMessage(text: String)

    @Throws(IOException::class)
    fun onReadMessage(bytes: ByteString)

    fun onReadPing(payload: ByteString)

    fun onReadPong(payload: ByteString)

    fun onReadClose(
      code: Int,
      reason: String,
    )
  }

  /**
   * Process the next protocol frame.
   *
   *  * If it is a control frame this will result in a single call to [FrameCallback].

        events.add(Ping(payload))
      }

      override fun onReadPong(payload: ByteString) {
        events.add(Pong(payload))
      }

      override fun onReadClose(
        code: Int,
        reason: String,
      ) {
        events.add(Closing(code, reason))
      }
    }

  internal class Open(
    val webSocket: WebSocket,
    val response: Response,

    receivedPingCount++
  }

  @Synchronized override fun onReadPong(payload: ByteString) {
    // This API doesn't expose pings.
    receivedPongCount++
    awaitingPong = false
  }

  override fun onReadClose(
    code: Int,
    reason: String,
  ) {
    require(code != -1)

    synchronized(this) {
      check(receivedCloseCode == -1) { "already closed" }
      receivedCloseCode = code