mysql have table t(a Int, b Int), 2 records: (1,1) and (2, 2), then in ck count
`select count(1) from ckdb.t ` -- 2, that's ok.
then, mysql  delete (2,2) and ck count
`select count(1) from ckdb.t ` -- still 2, that's not correct .
{
        binlog_pos = binlog_pos_;
        binlog_name = binlog_name_;
        gtid_sets.parse(gtid_sets_);
    }
    void Position::dump(std::ostream & out) const