We are using debezium mysql connector in our company. We need to have a metric that will say how far "slave(debezium) is behind master".
We could compare master binlog position and file with slave(debezium) position.
Debezium is using https://github.com/shyiko/mysql-binlog-connector-java which have feature Exposing BinaryLogClient through JMX.
It would be very useful to have this metric for monitoring purposes.