Offline corsarotrace takes a long time to quit

```
[17:03:17.478] corsarotrace: all threads have joined, exiting.
[17:05:47.238] corsarotrace: error while reading message on faux control socket: Context was terminated
```
This isn't a super big deal, but when trying to do offline processing in series (e.g., for different filters) it does waste some precious time.