Tells the delegate that the region displayed by the map view is about to change.
- iOS 3.0+
- macOS 10.9+
- Mac Catalyst 13.0+
- tvOS 9.2+
The map view whose visible region is about to change.
true, the change to the new region will be animated. If
false, the change will be made immediately.
This method is called at the beginning of a change to the map's visible region.