This can happen when there are audio SSRCs in the event log without any
associated events.
Issue was introduced in
https://webrtc-review.googlesource.com/c/src/+/300300
Bug: None
Change-Id: Ib0e009095bf67633812d937aa5a9e65e2cd8958a
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/300743
Reviewed-by: Björn Terelius <terelius@webrtc.org>
Commit-Queue: Jakob Ivarsson <jakobi@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#39806}