title: Show some UI from background in audio player or VOIP app on iOS
body: <p>I know that audio players and Voip apps can run in background on iOS. </p>
  
  <p>Is there a way to show UI from background (except LocalNotifications)? I mean full screen UI.</p>
  
  <p>A method which uses private API or other tricks are acceptable. The application will be signed with enterprise certificate and won't be deployed/reviewed by AppStore.</p>
  
  <p>A method which works only on jailbroken iOS device isn't acceptable.</p>