AVAudioSession
@property(nonatomic, readonly) BOOL prefersEchoCancelledInput;
AVAudioSession
@property(nonatomic, readonly) BOOL isEchoCancelledInputEnabled;
AVAudioSession
@property(nonatomic, readonly) BOOL isEchoCancelledInputAvailable;
MicrophoneInjection
@property(atomic, readonly) AVAudioSessionMicrophoneInjectionMode preferredMicrophoneInjectionMode;
MicrophoneInjection
@property(atomic, readonly) BOOL isMicrophoneInjectionAvailable;
extern const NSNotificationName AVAudioSessionMicrophoneInjectionCapabilitiesChangeNotification
extern NSString *const AVAudioSessionMicrophoneInjectionIsAvailableKey
AVAudioApplication
@property(atomic, readonly) AVAudioApplicationMicrophoneInjectionPermission microphoneInjectionPermission;