Lint for replication lag

[chasers]

Need a lint for replication lag.

Something like:

SELECT
    pid,
    usename,
    application_name,
    client_addr,
    state,
    sync_state,
    replay_lag,
    flush_lag,
    write_lag,
    pg_size_pretty(pg_wal_lsn_diff(pg_current_wal_lsn(), sent_lsn))      AS sent_lag_size,
    pg_size_pretty(pg_wal_lsn_diff(pg_current_wal_lsn(), write_lsn))     AS write_lag_size,
    pg_size_pretty(pg_wal_lsn_diff(pg_current_wal_lsn(), flush_lsn))     AS flush_lag_size,
    pg_size_pretty(pg_wal_lsn_diff(pg_current_wal_lsn(), replay_lsn))    AS replay_lag_size
FROM pg_stat_replication;

Could probably do something different on the primary vs a replica.