title: What's the best approach to prefill Core Data store when using NSPersistentCloudKitContainer?
body: <p>I'm having the following scenario where I'm parsing objects from a JSON file and store them into my Core Data store. Now I'm using <code>NSPersistentCloudKitContainer</code> and when I'm running the app on a different device, it also parses the JSON file and adds objects to Core Data. That results in duplicate objects.</p>
  
  <p>Now I'm wondering if there is:</p>
  
  <ul>
  <li>An easy way if I can check that an entity already exists remotely?</li>
  <li>Any other way to avoid objects being saved twice in CloudKit?</li>
  <li>Getting notified when fetching data from remote has finished?</li>
  </ul>