Count events that are read by not written because there's no sink defined for that route

[christopheranderson]

Is your feature request related to a problem? Please describe.
I want to ensure that eventsRead and eventsWritten match, but if I'm using routes to filter events by not specifying sink, I cannot tell what part of the delta is from my route specific issues vs potential data loss from the writers.

Describe the solution you'd like
Emit a metric for events that are no-op'd from an empty route

Describe alternatives you've considered (Optional)
Don't emit eventsread for these scenarios. This is less desirable because I want to match eventsRead to the number of writes/records in my source system.

Emit as eventsWritten. This solves the problem of "correctness", but could be confusing if the number of items in OpenSearch actually differs from this amount.

Additional context
N/A

[kkondaka]

Sounds like a good idea.