private val maskCursor: Buffer.UnsafeCursor? = if (isClient) null else Buffer.UnsafeCursor()

  interface FrameCallback {
    @Throws(IOException::class)
    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,

  /** Expose this recorder as a frame callback and shim in "ping" events.  */
  fun asFrameCallback() =
    object : WebSocketReader.FrameCallback {
      override fun onReadMessage(text: String) {
        events.add(Message(string = text))
      }

      override fun onReadMessage(bytes: ByteString) {
        events.add(Message(bytes = bytes))
      }

      override fun onReadPing(payload: ByteString) {

  @Synchronized fun receivedPongCount(): Int = receivedPongCount

  @Throws(IOException::class)
  override fun onReadMessage(text: String) {
    listener.onMessage(this, text)
  }

  @Throws(IOException::class)
  override fun onReadMessage(bytes: ByteString) {
    listener.onMessage(this, bytes)
  }

  @Synchronized override fun onReadPing(payload: ByteString) {