collapseIDKey
A value that the system uses to coalesce unseen push notifications.
Declaration
var collapseIDKey: String? { get set }Discussion
When CloudKit generates a push notification, it sets the notification’s apns-collapse-id header to this property’s value. The system uses this header to coalesce unseen notifications.
See Sending notification requests to APNs for more information about sending notifications using the Apple Push Notification service.