if (obj instanceof Failure) {
        return ((Failure) obj).exception;
      }
    }
    return null;
  }

  /**
   * If this future has been cancelled (and possibly interrupted), cancels (and possibly interrupts)
   * the given future (if available).
   */
  final void maybePropagateCancellationTo(@CheckForNull Future<?> related) {
    if (related != null & isCancelled()) {

   * @throws CancellationException if the step was cancelled
   */
  abstract <T> T getFinalValue(ClosingFuture<T> closingFuture) throws ExecutionException;

  /** Marks the given step final, cancels it, and waits for the cancellation to happen. */
  abstract void cancelFinalStepAndWait(ClosingFuture<TestCloseable> closingFuture);

  /**

   * @throws CancellationException if the step was cancelled
   */
  abstract <T> T getFinalValue(ClosingFuture<T> closingFuture) throws ExecutionException;

  /** Marks the given step final, cancels it, and waits for the cancellation to happen. */
  abstract void cancelFinalStepAndWait(ClosingFuture<TestCloseable> closingFuture);

  /**