title: iOS: UIBackgroundFetch - PerformFetch not called
body: <p>I want to update my app in background, so I added Required background modes "fetch" to my info.plist.
  In my FinishedLaunching I added:</p>
  
  <pre><code>UIApplication.SharedApplication.SetMinimumBackgroundFetchInterval (UIApplication.BackgroundFetchIntervalMinimum);
  </code></pre>
  
  <p>And overwriting the method PerformFetch:</p>
  
  <pre><code>public override void PerformFetch (UIApplication application, Action&lt;UIBackgroundFetchResult&gt; completionHandler)
  {
      Console.WriteLine ("PerformFetch called...");
  
  //Return no new data by default
  var result = UIBackgroundFetchResult.NoData;
  ...
  
  completionHandler (result);
  }
  </code></pre>
  
  <p>But the method never get called... :(</p>
  
  <p>What's the problem, I can't find any mistakes? Thank you for help.</p>