If the replicator is in an offline or error state, the appliedLatency will show a value of -1. This property will reflect the last known applied latency prior to the offline event.
When the service is online, this will reflect the same values as appliedLatency.
The value is written to disk every 10 secs so as not to overload
the replicator. This can be adjusted by setting the following
property svc-applier-last-applied-write-interval=20