Send pvol metadata on mute

[mill1000]

We discussed the possibility of sending mute state via MQTT a while ago here https://github.com/mikebrady/shairport-sync/discussions/1646

It seems the path of least resistance is to emit the same volume messages with the special muted volume value of -144.0.

This is in order to support implementing mute support in a Home Assistant custom integration: https://github.com/parautenbach/hass-shairport-sync/pull/14

Leaving as a draft as I have yet to fully test.

[mikebrady]

Thanks for this, and it looks like a good idea.

One little thing is that we have managed to avoid using bool so far — we use 0 for false and 1 for true.

unfortunately, I am away from machines until around October 8, so can’t test extensively until then.

But certainly, IMHO the concept is good.

[mill1000]

Gave this a quick test and it seems to work as expected.

[mikebrady]

Many thanks -- let's give it a try.