title: How to Extending 'backgroundTimeRemaining' more time?
body: <p>I wanna extend backgroundTimeRemaining more than 30 seconds 
  and according to Apple </p>
  
  <p>"The value is valid only after the app enters the background and has started at least one task using beginBackgroundTask(expirationHandler:) in the foreground.</p>
  
  <p>System conditions may end background execution earlier, either by calling the expiration handler, or by terminating the app."</p>
  
  <p>so I try to add and edit but it can't work </p>
  
  <p>here's what I tried</p>
  
  <pre><code>//MARK:- BeginBackgroundTask
  func registerBackgroundTask() {
    backgroundTask = UIApplication.shared.beginBackgroundTask { [weak self] in
      self?.endBackgroundTask()
      print(self!.beginTime)
    }
  
  //TODO: Add new background time ex: 60 sec
  var backgroundTimeRemaining: TimeInterval {
          get{
              return 60
          }
      }
  
  assert(backgroundTask != .invalid)
  } 
  
  //MARK:- EndBackgroundTask
  func endBackgroundTask() {
    print("Background task ended.")
    UIApplication.shared.endBackgroundTask(backgroundTask)
    backgroundTask = .invalid
  }
  </code></pre>