the lost of "BEGIN" in mariadb server's binlog result in our lots of projects not working

we have developed lots of projects based on mysql/mariadb Binlog, but in newest version of mariadb server, the BEGIN event have lost in row based binlog, which result in our projects not working at all. but in Oracle's mysql, the BEGIN event still been there.

what happened on Mariadb? is it a bug? this issue is very critical to our projects, if it can not included in, we have only one choice: choose to use Oracle/MySQL.

in attachments, WechatIMG230.jpeg is Mariadb, the BEGIN is included to GTID event, so there have lost the BEGIN event info, such as thread id..., detailed info as 1523853247199.jpg, WechatIMG228.jpeg is Oracle/MySQL, the BEGIN is still an alone event, I can read the thread id from it, detailed info as 1523853121489.jpg