I am setting the `AVAudioSessionCategoryPlayback` and then running the Voice Processing IO AudioUnit. In my test, when I am checking the AVAudioSession's currentRoute.inputs.count, it is not returning the consistent result. Following is my observation -
Returns 0 for iPhone 7 plus running iOS 12 Beta
Returns 0 for iPhone 6s running iOS 11.0
Returns 1 for iPhone 6 running iOS 11.4.1
Returns 1 for iPad pro running iOS 11
I was expecting when the category is set to `AVAudioSessionCategoryPlayback`, AVAudioSession's currentRoute.inputs.count should always return 0. Is this an incorrect expectation?