Add a new field `Lag` in result of `show routine load` stmt.
`Lag: {"0":10, "1":0}` means kafka partition 0 has 10 msg behind and partition 1 is update-to-date.
Add a new field `Lag` in result of `show routine load` stmt.
`Lag: {"0":10, "1":0}` means kafka partition 0 has 10 msg behind and partition 1 is update-to-date.