Combine/KVO Compliance

[bilalb]

First of all, thanks for the great work on that library.

It would be great if the objects used in project (especially FSAudioController & FSAudioStream) would be KVO compliant.
That would enable Combine support and make the library more convenient to use.
I'd be glad to help with that.

Thanks in advance :)

[muhku]

Sure, this would be a good thing. I can take a look at any PRs.

[bilalb]

I don't have much experience with Objective-C and it's been a while I haven't used it.
Also, KVO compliance doesn't look that trivial.

If someone could provide an example applied to the library that I could follow and apply to the other classes that'd be great.