title: iOS 10 don't call Notification Service Extension
body: <p>I tried to implement the new Notification Service Extension, but I have a problem.</p>
  
  <p>In my NotificationService.swift file I have this code:</p>
  
  <pre><code>class NotificationService: UNNotificationServiceExtension {
  
  var contentHandler: ((UNNotificationContent) -&gt; Void)?
  var bestAttemptContent: UNMutableNotificationContent?
  
  override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -&gt; Void) {
      self.contentHandler = contentHandler
      bestAttemptContent = (request.content.mutableCopy() as? UNMutableNotificationContent)
  
      if let bestAttemptContent = bestAttemptContent {
          // Modify the notification content here...
          bestAttemptContent.title = "\(bestAttemptContent.title) [modified]"
  
          print(bestAttemptContent.body)
  
          contentHandler(bestAttemptContent)
      }
  }
  
  override func serviceExtensionTimeWillExpire() {
      // Called just before the extension will be terminated by the system.
      // Use this as an opportunity to deliver your "best attempt" at modified content, otherwise the original push payload will be used.
      if let contentHandler = contentHandler, let bestAttemptContent =  bestAttemptContent {
          contentHandler(bestAttemptContent)
      }
  }
  }
  </code></pre>
  
  <p>When I got a push notification the <em>didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void)</em> method never called. </p>
  
  <p>Maybe I misunderstood how this extension is working?</p>