boolean shutdownListenerAdded = false;

        @Override
        public void addShutdownListener(ShutdownListener listener) {
            shutdownListenerAdded = true;
            // Optionally execute the listener to test its behavior
            listener.onShutdown();
        }

        @Override
        public Object execute(String scriptType, String script) {
            return null;

     */
    @Override
    public void addListener(Runnable listener, Executor exec) {
      executionList.add(listener, exec);
    }

    /**
     * Subclasses should invoke this method to set the result of the computation to {@code value}.
     * This will set the state of the future to {@link OldAbstractFuture.Sync#COMPLETED} and invoke
     * the listeners if the state was successfully changed.
     *

   * first DNS result for the first time.
   */
  @Test
  fun prefersExistingCompatible() {
    server.enqueue(MockResponse())
    server.enqueue(MockResponse())
    val connectCount = AtomicInteger()
    val listener: EventListener =
      object : EventListener() {
        override fun connectStart(
          call: Call,
          inetSocketAddress: InetSocketAddress,
          proxy: Proxy,
        ) {

pkg net, type Resolver struct, StrictErrors bool
pkg net/http, func ServeTLS(net.Listener, Handler, string, string) error
pkg net/http, method (*Server) RegisterOnShutdown(func())
pkg net/http, method (*Server) ServeTLS(net.Listener, string, string) error
pkg net/http/fcgi, func ProcessEnv(*http.Request) map[string]string

    exec.shutdown();
    exec.awaitTermination(100, MILLISECONDS);
  }

  /**
   * Tests that all listeners complete, even if they were added before or after the future was
   * finishing. Also acts as a concurrency test to make sure the locking is done correctly when a
   * future is finishing so that no listeners can be lost.
   */
  public void testAllListenersCompleteSuccessfully()

  /**
   * Value for [B1_MASK_LENGTH] which indicates the next eight bytes are the unsigned
   * length.
   */
  internal const val PAYLOAD_LONG = 127

  /** Used when an unchecked exception was thrown in a listener. */
  internal const val CLOSE_CLIENT_GOING_AWAY = 1001

  /** Used when an empty close frame was received (i.e., without a status code). */
  internal const val CLOSE_NO_STATUS_CODE = 1005

  fun toggleMask(

     */
    public fun webSocketUpgrade(listener: WebSocketListener): Builder =
      apply {
        status = "HTTP/1.1 101 Switching Protocols"
        setHeader("Connection", "Upgrade")
        setHeader("Upgrade", "websocket")
        webSocketListener = listener
      }

    /**

  // operation in the constructor.
  //
  // 1. In the listener that performs the callback. In this case it is fine since inputFuture is
  //    assigned prior to calling addListener, and addListener happens-before any invocation of the
  //    listener. Notably, this means that 'volatile' is unnecessary to make 'inputFuture' visible
  //    to the listener.
  //

        private boolean hasShutdownListener = false;

        @Override
        public void addShutdownListener(ShutdownListener listener) {
            hasShutdownListener = true;
            super.addShutdownListener(listener);
        }

        @Override
        public Object execute(String scriptType, String script) {
            return null;
        }

          throw EXCEPTION;
      }
      return outputFuture;
    }
  }

  public void testFutureGetThrowsFunctionException() throws Exception {
    inputFuture.set(EXCEPTION_DATA);
    listener.assertException(EXCEPTION);
  }

  public void testFutureGetThrowsCancellationIfInputCancelled() throws Exception {
    inputFuture.cancel(true); // argument is ignored