Individual message's processing time not available as separate metric

From the PRD:

=======
The current response time is an average across all messages within a time window, alerts are based on that average but there is no way to determine if a single message failed to meet the alerting rules.

A JON alert is setup to fire if an individual message's processing time exceeds N seconds. The currently solution only looks at message averages.
=======

Individual message's processing time isn't available.