title: Stream audio to a phone call Android
body: <p>I am attempting to send an audio stream out over a phone call on Android.</p>
  
  <p>For example, to create an app which would play some custom on-hold music, or answer a call and play a recording/audio file. I know it is possible to have an app automatically answer a call, but can it send audio to the caller?</p>
  
  <p>If it is possible, please let me know what classes/functions handle this.</p>