clear the bad connection
        :param reason:
        :param idle_pool:
        :param using_pool:
        :param channel_pool:
        :param conn_id:
        :return:

def _clear(reason, idle_pool, using_pool, channel_pool, conn_id):
        """
        clear the bad connection
        :param reason:
        :param idle_pool:
        :param using_pool:
        :param channel_pool:
        :param conn_id:
        :return:
        """
        with _lock():
            try:
                idle_pool.pop(conn_id)
                logger.info('a connection lost when not using')
            except KeyError:
                if using_pool.pop(conn_id, None):
                    logger.warn('connection lost when using, should be handled later')
                    return reason
            finally:
                channel_pool.pop(conn_id, None)