Is the automatic cleanup after the process exits really working?

The README says:

```
By default, you have to cleanup the files by yourself, however, you can tell Temp to track the temporary files. You just need to call Temp.track (or the bang version Temp.track!) and you are done. Temporary files will be cleaned up automatically when the process exits
```

From my testing this doesn't seem to be the case and the files are still around after the process exits. Looking in the code I also don't see any place, where the current process will be monitored and the files cleaned up when it exits.