Handle a sleep event.
- iOS 9.0+
- macOS 10.11+
- Mac Catalyst 13.0+
Implementations of this method must execute this block when the provider is finished handling the sleep event.
This method is called by the system when the device is about to go to sleep.
NEProvider subclasses should override this method if the provider needs to perform any tasks before the device sleeps, such as disconnecting a tunnel connection.