* Throwable} wrapped in an {@code ExecutionException}.
   */
  public static <V extends @Nullable Object> ListenableFuture<V> immediateFailedFuture(
      Throwable throwable) {
    checkNotNull(throwable);
    return new ImmediateFailedFuture<>(throwable);
  }

  /**
   * Creates a {@code ListenableFuture} which is cancelled immediately upon construction, so that