code: @Beta
    @SafeVarargs
    public static <V> FutureCombiner<V> whenAllSucceed(ListenableFuture<? extends V>... futures) {
      return new FutureCombiner<V>(true, ImmutableList.copyOf(futures));
    }
docs: Creates a {@link FutureCombiner} requiring that all passed in futures are successful.
  
  <p>If any input fails, the returned future fails immediately.
  
  @since 20.0