title: How to use Notification service extension with UNNotification in iOS
body: <p>Apple introduce new extension names <a href="https://developer.apple.com/reference/usernotifications/unnotificationserviceextension" rel="noreferrer">"UNNotificationServiceExtension"</a>, but how to launch it from push notification ?</p>
  
  <p>I read that service extension provide end to end encryption for payload.</p>
  
  <p>Which key is required to set payload of push notification ?</p>
  
  <p>How to identify payload and how to launch service extension from push notification ?</p>