Adjust Screen when keyboard shows or hide

KeyboardObserver.swift

extension HellViewController {
    func startObservers() {
        let nc = NotificationCenter.default
        nc.addObserver(self, selector: #selector(showKeyboard), name: NSNotification.Name.UIKeyboardWillShow, object: nil)
        nc.addObserver(self, selector: #selector(hideKeyboard), name: NSNotification.Name.UIKeyboardWillHide, object: nil)
    }
    
    func stopObservers() {
        let nc = NotificationCenter.default
        nc.removeObserver(self, name: NSNotification.Name.UIKeyboardWillShow, object: nil)
        nc.removeObserver(self, name: NSNotification.Name.UIKeyboardWillHide, object: nil)
    }
    
    func showKeyboard(notification:Notification) {
        if let frame = notification.userInfo?["UIKeyboardBoundsUserInfoKey"] as? NSValue {
            let finalFrame = frame.cgRectValue
            let offset = finalFrame.height
            let chatViewOffset = chatView.bounds.height
            
            bottomSpace.constant = offset
            tableview.contentInset = UIEdgeInsets(top: 0, left: 0, bottom: offset + chatViewOffset, right: 0)
            
            view.setNeedsUpdateConstraints()
            UIView.animate(withDuration: 0.2, animations: {[unowned self] in
                self.view.layoutIfNeeded()
            })
        }
    }
    
    func hideKeyboard(notification:Notification) {
        bottomSpace.constant = 0.0
        view.setNeedsUpdateConstraints()
        resetTableViewInsets()
        
        UIView.animate(withDuration: 0.2, animations: {[unowned self] in
            self.view.layoutIfNeeded()
        })
    }
}