如何使用Swift在iOS中同时录制和播放音频？

In Objective-C, recording and playing audio simultaneously is fairly simple. And there are tonnes of sample code on the internet. But I want to record and play audio simultaneously using Audio Unit/Core Audio in Swift. There are vary small amount of help and sample code on this using Swift. And i couldn't find any help which could show how to achieve this. In Objective-C, recording and playing audio sim