code: public static <T> TracedParallelBatch<T> of(Iterable<? extends Promise<T>> promises) {
      return new TracedParallelBatch<>(promises);
    }
docs: Create a {@link TracedParallelBatch} for list of {@link Promise}s.
  
  @param promises an iterable of Promises
  @param <T> the type of value produced by each promise
  
  @return an instance of {@link TracedParallelBatch}.