title: Converting AVSpeechSynthesizer text to audio file (.CAF)
body: <p>I would like to programmatically convert a string file, which would be spoken using AVSpeechSynthesizer into an audio file, a .CAF file if possible (to use with local notifications).</p>
  
  <p>I would like to do this in the background, upon app initialisation without the user being aware.</p>
  
  <p>Is this at all possible?</p>