title: Override output audio port in iOS 11.3
body: <p>Is it possible to override audio port to speaker(</p>
  
  <pre><code>[[AVAudioSession sharedInstance] overrideOutputAudioPort:AVAudioSessionPortOverrideSpeaker error:nil]
  </code></pre>
  
  <p>) when device is connected to external screen via airplay, it worked on iOS 11.2 and earlier, but on iOS 11.3 it doesn't?</p>