return NeverScheduledFuture.create();
    }

    @Override
    public ListenableScheduledFuture<?> scheduleWithFixedDelay(
        Runnable command, long initialDelay, long delay, TimeUnit unit) {
      return NeverScheduledFuture.create();
    }

    private static final class NeverScheduledFuture<V> extends AbstractFuture<V>
        implements ListenableScheduledFuture<V> {