If `Capability.MARIADB_CLIENT_EXTENDED_TYPE_INFO` is set, the [Column Definition Packet](https://mariadb.com/kb/en/result-set-packets/#column-definition-packet) will contain an [extend type info](https://mariadb.com/kb/en/result-set-packets/#extended-type-info) MariaDB returns `JSON` data as `VARCHAR` (`MYSQL_TYPE_STRING`), so reading the extend type info is useful to identify the correct `MySqlType`.