如何在不中断视频预览的情况下录制时将音频输入添加到AVCaptureSession？

I'm struggling with an issue: I have AVCaptureSession with preview layer and I also want to provide haptic feedbacks when user taps on buttons. If I add audioInput to my AVCaptureSession then I'm not able to produce haptic feedback at all. I tried to to add audioInput right before starting record and to remove immediately after stopping but modifying capture session configuration (which I did in serial queue) leads to video preview hiccups (it's disrupted for a fraction of a second). And I still have no idea how Snapchat and Instagram do this trick. One of my guesses was that they somehow configure AVAudioSession but I couldn't figure it out.I'm struggling with an issue: I have AVCaptureS