docs: @Override
    public void close() throws SQLException {
      if (last != null) {
        last.close();
        if (!con.isClosed()) {
          if (!con.getAutoCommit()) {
            try {
              con.rollback();
            } catch (SQLException ignored) {
            }
          }
        }
      }
      try {
        con.close();
      } finally {
        con = null;
      }
    }