Storing and retrieving data with CloudKit
CloudKit is meant to be used as a backend for your app that syncs across devices and provides a seamless experience for users. This section will go over the principles that you should keep in mind when implementing CloudKit in your app. By the end of this section, you will know precisely how storing, retrieving, and updating data in CloudKit works. You will then go on to implement CloudKit in the MustC app by combining it with the existing Core Data database.
Communicating with CloudKit for the first time
When your app launches for the very first time, it should immediately make itself known to CloudKit so it can subscribe to changes. Technically you don't have to do this because you can implement your own logic to retrieve data from CloudKit as you need it. However, an efficient CloudKit implementation will work flawlessly when there is no internet connection, which means that it's probably a good idea to store all data locally by writing it to a...
