SPM-4163 introduces the ReplicatedFastCountCheckpointFlusher class which flushes updates to collection size/count to the fast_count_metadata_store. There currently exist flushTimeMsTotalCounter and flushedDocsTotalCounter , but we should consider using a histogram for flush duration and/or flushed document count.

This worked is blocked on the linked ticket, hence why it was removed from the scope of the SPM.