The time at which the trigger will next fire.
- iOS 8.0+
- tvOS 10.0+
- watchOS 2.0+
Timer triggers are only set at the beginning of a minute. Seconds are not used and an error will be returned if the fire date includes a seconds value other than 0. When the timer fires, it will typically fire within 1 minute of the scheduled fire date or calculated recurrence fire date, depending on system power and resource management.