Question Voice Recorder in Unity.

I am using Unity for a user study and I am trying to integrate audio interview questions in the game itself. I need to record the user's input to an audio file. The closest thing I found was in this thread.

https://forum.unity.com/threads/save-microphone-recording-to-disk.378038/

It works but it tries to save a 5 minutes clip at once. So, it takes a few seconds and the whole game is stuck for a few seconds. I want to create a thread that will continuously write the shorter clips to the file. I tried using a coroutine to appending the microphone samples into the file but I am having a hard time managing the header as it is dependent on the whole clip.

Any suggestions or links to any threads I might have missed will be appreciated. Thanks!