title: applicationMusicPlayer volume notification
body: <p>I am using an applicationMusicPlayer and when i try to change the volume appear the visual notification, as shown in the picture.
  Here the code I am using:</p>
  
  <pre><code>[MPMusicPlayerController applicationMusicPlayer] setVolume:newVolune];
  </code></pre>
  
  <p>Anyone knows how to hide this notification?</p>
  
  <p><img src="https://i.stack.imgur.com/NprK2.jpg" alt="enter image description here"></p>