docs: private Timestamp make_localtime()
      {
          int offset = _offset != null
              ? _offset.intValue()
              : 0;
  
          // We use a Copy-Constructor that expects the time parameters to be in
          // UTC, as that's what we're supposed to have.
          // As this Copy-Constructor doesn't apply local offset to the time
          // field values (it assumes that the local offset is already applied to
          // them), we explicitly apply the local offset to the time field values
          // after we obtain the new Timestamp instance.
          Timestamp localtime = new Timestamp(_precision,
                                              _year,
                                              _month,
                                              _day,
                                              _hour,
                                              _minute,
                                              _second,
                                              _fraction,
                                              _offset,
                                              APPLY_OFFSET_NO);
          // explicitly apply the local offset to the time field values
          localtime.apply_offset(-offset);
  
          assert localtime._offset == _offset;
  
          return localtime;
      }