* listeners will not be invoked.
   */
  private static class ListenableFutureAdapter<V extends @Nullable Object>
      extends ForwardingFuture<V> implements ListenableFuture<V> {

    private static final ThreadFactory threadFactory =
        new ThreadFactoryBuilder()
            .setDaemon(true)

                return new ThrowingScheduledFuture<>();
              }
            },
            testRunnable);
    assertTrue(called);
  }

  private static final class ThrowingScheduledFuture<V> extends ForwardingFuture<V>
      implements ScheduledFuture<V> {
    @Override
    protected Future<V> delegate() {
      throw new UnsupportedOperationException("test should not care about this");
    }

    @Override

                return new ThrowingScheduledFuture<>();
              }
            },
            testRunnable);
    assertTrue(called);
  }

  private static final class ThrowingScheduledFuture<V> extends ForwardingFuture<V>
      implements ScheduledFuture<V> {
    @Override
    protected Future<V> delegate() {
      throw new UnsupportedOperationException("test should not care about this");
    }

    @Override