A Boolean value indicating whether another app is currently playing audio.
- iOS 6.0+
- tvOS 9.0+
- watchOS 2.0+
In iOS 8.0 and later applications should use
secondary instead of this property.
This property will be true if any other audio (including audio from an app using
AVAudio is playing, whereas the
secondary property is more restrictive in its consideration of whether primary audio from another application is playing.