   private struct Metrics {
     static let defaultAnimationDuration: TimeInterval = 0.4
     static let buttonBarHeight: CGFloat = 88
-    static let landscapeBarTopInset: CGFloat = ViewConstants.toolbarHeight
   }
 
   let navController: UINavigationController = {

    detailNavController.didMove(toParent: self)

    view.addSubview(buttonBar)
    layoutConstraints[.portrait] = preparePortraitLayout(buttonBar: buttonBar, view: view)
    layoutConstraints[.landscape] = prepareLandscapeLayout(buttonBar: buttonBar, view: view)

    updateCurrentLayout(for: view.bounds.size)
  }

  private func preparePortraitLayout(buttonBar: MDCButtonBar, view: UIView) -> LayoutConstraints {

    }
  }

  private var currentConstraints: LayoutConstraints! { // set in viewDidLoad
    didSet {
      currentConstraints.enable(showBar: false)
    }
  }

  override func viewDidLoad() {
    super.viewDidLoad()
