CKModifySubscriptionsOperation
An operation for modifying one or more subscriptions.
Declaration
class CKModifySubscriptionsOperationOverview
After you create or change the configuration of a subscription, use this operation to save those changes to the server. You can also use this operation to permanently delete subscriptions.
If you assign a handler to the completionBlock property, the operation calls it after it executes and passes it the results. Use the handler to perform any housekeeping tasks for the operation. The handler you specify should manage any failures, whether due to an error or an explicit cancellation.