Swift 5.4 - 키보드 올라올라올 때 애니메이션 정확히 동일한 curve 알기.

NotificationCenter.default.publisher(for: UIResponder.keyboardWillHideNotification)
    .receive(on: RunLoop.main)
    .sink { [weak self] (notification) in
                
        let curve = notification.userInfo?[UIResponder.keyboardAnimationCurveUserInfoKey] as! UInt
        let duration = notification.userInfo?[UIResponder.keyboardAnimationDurationUserInfoKey] as! Double;

        let curveOpt = UIView.AnimationOptions(rawValue: curve << 16)
            
        UIView.animate(withDuration: duration, delay: 0, options: [curveOpt]) {
            self?.constBottom.constant = 0;
            self!.layoutIfNeeded()
        }
    }