Future<V> future) {
    if (future instanceof ListenableFuture) {
      return (ListenableFuture<V>) future;
    }
    return new ListenableFutureAdapter<>(future);
  }

  /**
   * Submits a blocking task for the given {@link Future} to provide {@link ListenableFuture}
   * functionality.
   *
   * <p><b>Warning:</b> If the input future does not already implement {@code ListenableFuture}, the

    return delegate.awaitTermination(timeout, unit);
  }

  @Override
  public <T> ListenableFuture<T> submit(Callable<T> task) {
    Preconditions.checkNotNull(task, "task must not be null!");
    return delegate.submit(task);
  }

  @Override
  public <T> ListenableFuture<T> submit(Runnable task, T result) {
    Preconditions.checkNotNull(task, "task must not be null!");

    return delegate.awaitTermination(timeout, unit);
  }

  @Override
  public <T> ListenableFuture<T> submit(Callable<T> task) {
    Preconditions.checkNotNull(task, "task must not be null!");
    return delegate.submit(task);
  }

  @Override
  public <T> ListenableFuture<T> submit(Runnable task, T result) {
    Preconditions.checkNotNull(task, "task must not be null!");

  @SafeVarargs
  public static <V extends @Nullable Object> ListenableFuture<List<V>> allAsList(
      ListenableFuture<? extends V>... futures) {
    ListenableFuture<List<@Nullable V>> nullable =
        new ListFuture<V>(ImmutableList.copyOf(futures), true);
    // allAsList ensures that it fills the output list with V instances.
    @SuppressWarnings("nullness")
    ListenableFuture<List<V>> nonNull = nullable;
    return nonNull;
  }

          public Class<?> loadClass(String name) throws ClassNotFoundException {
            if (name.startsWith(concurrentPackage)
                // Use other classloader for ListenableFuture, so that the objects can interact
                && !ListenableFuture.class.getName().equals(name)) {
              synchronized (loadedClasses) {
                Class<?> toReturn = loadedClasses.get(name);
                if (toReturn == null) {

          public Class<?> loadClass(String name) throws ClassNotFoundException {
            if (name.startsWith(concurrentPackage)
                // Use other classloader for ListenableFuture, so that the objects can interact
                && !ListenableFuture.class.getName().equals(name)) {
              synchronized (loadedClasses) {
                Class<?> toReturn = loadedClasses.get(name);
                if (toReturn == null) {

  private static final class TestCallable implements AsyncCallable<@Nullable Void> {

    private final ListenableFuture<@Nullable Void> future;
    private boolean called = false;

    private TestCallable(ListenableFuture<@Nullable Void> future) {
      this.future = future;
    }

    @Override
    public ListenableFuture<@Nullable Void> call() throws Exception {
      called = true;
      return future;
    }
  }

   *   <li>Return a {@code ClosingFuture}. To turn a {@link ListenableFuture} into a {@code
   *       ClosingFuture} call {@link #from(ListenableFuture)}.
   *   <li>In case this step doesn't create new closeables, you can adapt an API that returns a
   *       {@link ListenableFuture} to return a {@code ClosingFuture} by wrapping it with a call to
   *       {@link #withoutCloser(AsyncFunction)}

      extends InterruptibleTask<ListenableFuture<V>> {
    private final AsyncCallable<V> callable;

    TrustedFutureInterruptibleAsyncTask(AsyncCallable<V> callable) {
      this.callable = checkNotNull(callable);
    }

    @Override
    final boolean isDone() {
      return TrustedListenableFutureTask.this.isDone();
    }

    @Override
    ListenableFuture<V> runInterruptibly() throws Exception {

  }

  FluentFuture() {}

  /**
   * Converts the given {@code ListenableFuture} to an equivalent {@code FluentFuture}.
   *
   * <p>If the given {@code ListenableFuture} is already a {@code FluentFuture}, it is returned
   * directly. If not, it is wrapped in a {@code FluentFuture} that delegates all calls to the
   * original {@code ListenableFuture}.
   */