Implement batchSpec.StartedAt and batchSpec.FinishedAt in resolver
Created by: mrnugget
This removes two TODOs from the resolver layer by implementing batchSpec.StartedAt
and batchSpec.FinishedAt
. Part of #25962 (closed).
I implemented this through the BatchSpecStats
which were introduced in a previous PR. That saves us additional queries and also makes sense: start/end time are part of the stats. It requires a bit of shuffling around in service/resolver layer though so that we can cache and reuse the stats once fetched to compute state and the started/finished-at timestamps.