[iOS Issue] NotificationCenter 사용

 NotificationCenter를 사용 시 실행할 observer를 closure로 지정할 경우 deinit에서 remove해줘야 하지만 selector로 함수로 지정해주면 제거할 필요가 없다.

 

If your app targets iOS 9.0 and later or macOS 10.11 and later, and you used addObserver:selector:name:object:, you do not need to unregister the observer. If you forget or are unable to remove the observer, the system cleans up the next time it would have posted to it.