* including adding URLs to the queue, filtering URLs, managing crawler threads,
 * and handling the overall crawling lifecycle.
 *
 * <p>It implements the Runnable interface to be executed in a separate thread,
 * and the AutoCloseable interface to ensure resources are properly released after use.
 *
 * <p>The crawler uses several services and components, such as UrlQueueService, DataService,

  private final ListenableFuture<V> delegate;

  ForwardingFluentFuture(ListenableFuture<V> delegate) {
    this.delegate = checkNotNull(delegate);
  }

  @Override
  public void addListener(Runnable listener, Executor executor) {
    delegate.addListener(listener, executor);
  }

  @Override
  public boolean cancel(boolean mayInterruptIfRunning) {
    return delegate.cancel(mayInterruptIfRunning);
  }

    return task;
  }

  /**
   * Executes {@code runnable} on the specified {@code executor}, returning a {@code Future} that
   * will complete after execution.
   *
   * @throws RejectedExecutionException if the task cannot be scheduled for execution
   * @since 28.2
   */
  public static ListenableFuture<@Nullable Void> submit(Runnable runnable, Executor executor) {
    TrustedListenableFutureTask<@Nullable Void> task =

              return 25;
            }
          });

  @Override
  protected void setUp() throws Exception {
    super.setUp();

    exec = newCachedThreadPool();

    task.addListener(
        new Runnable() {
          @Override
          public void run() {
            listenerLatch.countDown();
          }
        },
        directExecutor());
  }

  @Override

    private val exceptions: BlockingQueue<Exception> = LinkedBlockingQueue()

    override fun execute(runnable: Runnable) {
      super.execute {
        try {
          runnable.run()
        } catch (e: Exception) {
          exceptions.add(e)
        }
      }
    }

    fun takeException(): Exception = exceptions.take()
  }

  private Thread executionThread;
  private Throwable thrownByExecutionThread;
  private final Executor exceptionCatchingExecutor =
      new Executor() {
        @Override
        public void execute(Runnable command) {
          executionThread = new Thread(command);
          executionThread.setUncaughtExceptionHandler(
              new UncaughtExceptionHandler() {
                @Override

    /** List of initialization processes to run after container initialization. */
    private static List<Runnable> initProcesses = new ArrayList<>();

    /**
     * Private constructor to prevent instantiation.
     */
    private ComponentUtil() {
    }

    /**
     * Processes a runnable after container initialization.
     * @param process The process to run after container init.
     */

        };
    addCallback(f, callback, directExecutor());
  }

  private class CountingSameThreadExecutor implements Executor {
    int runCount = 0;

    @Override
    public void execute(Runnable command) {
      command.run();
      runCount++;
    }
  }

  private final class MockCallback implements FutureCallback<String> {
    @Nullable private String value = null;

        ExecutorService executor = Executors.newFixedThreadPool(threadCount);

        for (int i = 0; i < threadCount; i++) {
            final int threadId = i;
            executor.submit(new Runnable() {
                @Override
                public void run() {
                    try {
                        startLatch.await();
                        for (int j = 0; j < operationsPerThread; j++) {

    Service service =
        new TestService() {
          @Override
          protected Executor executor() {
            return new Executor() {
              @Override
              public void execute(Runnable command) {}
            };
          }

          @Override
          protected String serviceName() {
            return "Foo";
          }
        };
    TimeoutException e =