- When audio is muted, server injects silence frames which moves the
time stamp forward and adjusts offset. That cannot be used against
publisher side sender report. Use a pinned version.
- Ignore small changes to propagation delay even while checking for
sharp increase. That is spamming a lot for small changes, i.e.
existing delta is 100 micro seconds or so and the new one is 300 micro
seconds. Also rename to `longTerm` from `smoothed` as it is a slow
varying long term estimate of propagation delay delta. And slow down
that adaptation more.