assertThat(sendGoAway(expectedStreamId, expectedError, EMPTY_BYTE_ARRAY))
      .isEqualTo(frame)
    reader.nextFrame(
      requireSettings = false,
      object : BaseTestHandler() {
        override fun goAway(
          lastGoodStreamId: Int,
          errorCode: ErrorCode,
          debugData: ByteString,
        ) {
          assertThat(lastGoodStreamId).isEqualTo(expectedStreamId)

        lastGoodStreamId = this.lastGoodStreamId
      }
      // TODO: propagate exception message into debugData.
      // TODO: configure a timeout on the reader so that it doesn’t block forever.
      writer.goAway(lastGoodStreamId, statusCode, EMPTY_BYTE_ARRAY)
    }
  }

  /**
   * Closes this connection. This cancels all open streams and unanswered pings. It closes the

    var debugData = ByteString.EMPTY
    if (opaqueDataLength > 0) { // Must read debug data in order to not corrupt the connection.
      debugData = source.readByteString(opaqueDataLength.toLong())
    }
    handler.goAway(lastStreamId, errorCode, debugData)
  }

  /** Unlike other `readXxx()` functions, this one must log the frame before returning. */
  @Throws(IOException::class)
  private fun readWindowUpdate(
    handler: Handler,

   * @param errorCode reason for closing the connection.
   * @param debugData only valid for HTTP/2; opaque debug data to send.
   */
  @Throws(IOException::class)
  fun goAway(
    lastGoodStreamId: Int,
    errorCode: ErrorCode,
    debugData: ByteArray,
  ) {
    withLock {
      if (closed) throw IOException("closed")