Specifies whether location service is enabled in user settings.
You should check this property before starting location updates to
determine if the user has location services enabled for the current
On iOS, if this property is false and you start location updates anyway, the CoreLocation framework prompts the user with a confirmation panel asking whether location services should be reenabled. The user can enable or disable location services altogether from the Settings application by toggling the switch in Settings>General>LocationServices.