Tells the delegate that the Watch app is now visible and processing events.
- watchOS 2.0+
WatchKit calls this method to let you know that your app transitioned from the inactive to the active state. Use this method to start any tasks that were paused or not yet started while the app was inactive. For example, you could use it to start timers. You can also use it to gather information needed to configure your app’s initial user interface.