I have created a navigationController with an upper button item so I now have a navigation bar at the top of my screen containing a 'logout' button: 

```
navigationItem.leftBarButtonItem = UIBarButtonItem(title: "logout", style: .plain, target: self, action: #selector(handleLogout))

```

I want to be able to anchor other objects in my code to the bottom of this nav bar. for example, I want to add a search bar thats topAnchor is the bottom on this navigation field that contains my 'logout' button