docs: public static MutableLongTuple apply(
          LongTuple t0, LongUnaryOperator op,
          MutableLongTuple result)
      {
          result = LongTuples.validate(t0, result);
          int n = t0.getSize();
          for (int i=0; i<n; i++)
          {
              long operand0 = t0.get(i);
              long r = op.applyAsLong(operand0);
              result.set(i, r);
          }
          return result;
      }