Returns the expiration date for the most recent monitoring period.
The current expiration date, or
nil if you have not yet begun monitoring.
This date is set when you call the
monitorKinesias(forDuration:) method. You can extend the date by calling
monitorKinesias(forDuration:) again; however, you can’t shorten the monitoring duration.
You can use the expiration date to determine whether you are currently monitoring the user.
Recording Movement Disorders