Changing volume has a slight lag on Mac using the default audio output
As directed by courmisch in #5596 (closed), separate tickets should be logged for each output plugin to implement set_volume().
So here is the one for Mac OS X, IIRC it uses CoreAudio.
Although the explanation given in #5596 (closed) seems a bit strange since it works fine in the 1.1 branch. Maybe the default cache latency change...
Anyway, it's rather annoying so I guess it should be fixed at some point... although there are much worse bugs to tackle... so priority is set to lowest.