* 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)
            .setNameFormat("ListenableFutureAdapter-thread-%d")
            .build();

   * 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)
            .setNameFormat("ListenableFutureAdapter-thread-%d")
            .build();