UNNotification
The data for a local or remote notification the system delivers to your app.
Declaration
class UNNotificationOverview
A UNNotification object contains the initial notification request, which contains the notification’s payload, and the date that the system delivered the notification.
Don’t create notification objects directly. When handling notifications, the system delivers notification objects to your UNUserNotificationCenterDelegate object. The UNUserNotificationCenter object also maintains the list of notifications that the system delivers, and you use the getDeliveredNotifications(completionHandler:) method to retrieve those objects.