     /* @param height - new height
      * @param animated - run default animation
      */
-    open func setParallexHeaderHeight(_ newHeight: CGFloat, animated: Bool, scrollToTop: Bool = true) {
+    open func setParallexHeaderHeight(_ newHeight: CGFloat, animated: Bool, scrollToTop: Bool = true, completion: ((Bool) -> ())? = nil) {
         
         guard parallaxHeaderHeight != newHeight else { return }
         parallaxHeaderHeight = newHeight

        case bottom
        case refresh
    }
        
    open weak var delegate: ParallaxHeaderPageTabBarControllerDelegate?
    
    open let pageTabBarController: PageTabBarController

        customView.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([customView.leadingAnchor.constraint(equalTo: parallaxHeaderContainerView.leadingAnchor),
                                     customView.trailingAnchor.constraint(equalTo: parallaxHeaderContainerView.trailingAnchor),
                                     customView.topAnchor.constraint(equalTo: parallaxHeaderContainerView.topAnchor),
                                     customView.heightAnchor.constraint(equalToConstant: height)])
        parallaxHeaderContainerView.setNeedsLayout()
        parallaxHeaderContainerView.layoutIfNeeded()
