code: @SafeVarargs
      public static <T> ContinuableFuture<List<T>> allOf(final Future<? extends T>... cfs) {
          return allOf2(Arrays.asList(cfs));
      }
docs: Returns a new Future that is completed when all of
  the given Futures complete. If any of the given
  Futures complete exceptionally, then the returned
  Future also does so.
  
  @param cfs
  @return