code: public Stream max(Comparator<TridentTuple> comparator) {
          Aggregator<ComparisonAggregator.State> max = new MaxWithComparator<>(comparator);
          return comparableAggregateStream(null, max);
      }
docs: This aggregator operation computes the maximum of tuples in a stream by using the given {@code comparator} with
  {@code TridentTuple}s.
  
  @param comparator comparator used in for finding maximum of two tuple values.
  @return the new stream with this operation.