if (future.isDone()) {
      return future;
    }
    NonCancellationPropagatingFuture<V> output = new NonCancellationPropagatingFuture<>(future);
    future.addListener(output, directExecutor());
    return output;
  }

  /** A wrapped future that does not propagate cancellation to its delegate. */
  private static final class NonCancellationPropagatingFuture<V extends @Nullable Object>

    if (future.isDone()) {
      return future;
    }
    NonCancellationPropagatingFuture<V> output = new NonCancellationPropagatingFuture<>(future);
    future.addListener(output, directExecutor());
    return output;
  }

  /** A wrapped future that does not propagate cancellation to its delegate. */
  private static final class NonCancellationPropagatingFuture<V extends @Nullable Object>