Spawning from looking at a couple traces and wanting a little more info.
Follow-up to github.com/element-hq/synapse/pull/17501
The changes in this PR allow you to find slow Sliding Sync traces ignoring the
`wait_for_events` time. In Jaeger, you can now filter for the `current_sync_for_user`
operation with `RESULT.result=true` indicating that it actually returned non-empty results.
If you want to find traces for your own user, you can use
`RESULT.result=true ARG.sync_config.user="@madlittlemods:matrix.org"`
