title: AVFoundation: How to write video to file in real time instead of using exportAsync?
body: <p>AVFoundation has been quite a struggle for me because most of the examples and documentation out there are in Obj-c.. As my title states, I would like to write to file in real time instead of calling exportAsync once the user has finished recording their video. </p>
  
  <p>If anyone can offer some advice or documentation on how to do this it would be greatly appreciated! </p>