code: @Override
    public void watch(@Service DatabaseWatch watch, String sql, 
                      Result<Cancel> result,
                      Object ...args)
    {
      _kraken.query(sql, 
                          result.then((x,r)->{ x.watch(watch, r, args); }));
    }
docs: Registers a watch listener for updates to a row.
  
  @param watch the watch service receiving updates
  @param sql query specifying the rows to watch
  @param args parameters to the query
  
  @return true if successful