pg_stat_get_wal_senders(OUT pid integer, OUT state text, OUT sent_lsn pg_lsn, OUT write_lsn pg_lsn, OUT flush_lsn pg_lsn, OUT replay_lsn pg_lsn, OUT write_lag interval, OUT flush_lag interval, OUT replay_lag interval, OUT sync_priority integer, OUT sync_state text, OUT reply_time timestamp with time zone)