code: public Table sortOn(Comparator<Row> rowComparator) {
          Row row1 = new Row(this);
          Row row2 = new Row(this);
          return sortOn((IntComparator) (k1, k2) -> {
              row1.at(k1);
              row2.at(k2);
              return rowComparator.compare(row1, row2);
          });
      }
docs: Returns a copy of this table sorted using the given comparator