docs: @Override
      public List<Future<Boolean>> getPendingFutures() {
          final List<Future<Boolean>> returnFutures = new ArrayList<Future<Boolean>>(expectedCompleteCount);
          for (Future<Boolean> future : futures) {
              if (!future.isDone()) {
                  returnFutures.add(future);
              }
          }
          return returnFutures;
      }