Code review comment for lp:~yuningdodo/unity-control-center/unity-control-center.lp1396464-prevent-update-sink-input-in-parallel

Sebastien, in my own test this patch works for myself, and my explanation to the patch can be found in previous comments. However I'm not an audio expert and don't have a deep enough understanding to u-c-c, I hope the patch can be reviewed by experienced expert.