Need a way to separate the retries for Read, Write and Sync activities

[jet]

Need a way to separate the retries for Read, Write and Sync activities

[bartelink]

@sbose2k17 master now has a clearer implementation of the metrics events - there's one wart causing the extra logging config which I hope can be removed, see serilog/serilog#1124
I'm working on adding tests which will assert correct rery and logging behavior, which will, as a side-effect add extra items into the EventStore.Log.Events union, which will give us the info needed in a consistent fashion (as it happens, the withLoggedRetries mechanism already affords us a way to to it that is messy, but our wiring does not actually trigger it at the present time due to how we have wired up our retry policy)
cc @reuveniy

[bartelink]

@sbose2k17 do we feel there still is a need to separate out this metric or should be close this for now?

I'm intending to revisit this soon wrt surfacing each attempt/load/retry as an xray span, but the basic mechanism wrt how we surface events/metrics will remain - so if the desire is to trap retries via events in the log stream, we may still have some work to do.

[bartelink]

Closing on the assumption you'll reopen if/hen you need any more detail added to the presently exposed metrics