Demo for use AudioUnit of type kAudioUnitSubType_VoiceProcessingIO on Mac
kAudioUnitSubType_VoiceProcessingIO is Supported on Mac, but it'is a little different。
- kAudioOutputUnitProperty_EnableIO can't be set。 On Mac, input and output is both open，and can't be modified。
- The Sample Rate for input and output must be same.
- The method to set buffer size is different。 On Mac use kAudioDevicePropertyBufferFrameSize property, instead of kAudioSessionProperty_PreferredHardwareIOBufferDuration.
- When I test , I found the StreamFromat kAudioFormatFlagIsSignedInteger could be used for record, but when use in playback, you can't hear anything.