changefeedccl: improve test coverage for metrics #111042
Description
There is not enough test coverage for metrics. Most of these SLI metrics have no test coverage.
- EmittedMessages changefeedccl: emittedmessages metric resolved messages semantics aren't consistent #111043
- FilteredMessages
- MessageSize
- EmittedBytes
- FlushedBytes
- BatchHistNanos
- Flushes
- FlushHistNanos
- SizeBasedFlushes
- ParallelIOQueueNanos
- SinkIOInflight
- CommitLatency
- ErrorRetries
- AdmitLatency
- BackfillCount
- BackfillPendingRanges
- RunningCount
- BatchReductionCount
- InternalRetryMessageCount
- [ ]
There likely isn't much test coverage for non-sli metrics either.
Jira issue: CRDB-31738