Backport of "proxysink: event_function needs to handle the event when it is disconnecetd from proxysrc" into 1.16
Backport of !1508 (merged) "proxysink: event_function needs to handle the event when it is disconnecetd from proxysrc".
Commits:
- fe3a0c2c proxysink: event_function needs to handle the event when it is disconnecetd from proxysrc