             cachedViewControllers[page] = vc
         }
     }
-    
-    var isTracking = false
 }
 
 extension PagingContentViewController: UIScrollViewDelegate {
     public func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
-        isTracking = true
+        isExplicityScrolling = true
         delegate?.contentViewController(viewController: self, willBeginScrollFrom: leftSidePageIndex)
     }
     

        lastContentOffset = scrollView.contentOffset
        leftSidePageIndex = Int(scrollView.contentOffset.x / scrollView.bounds.width)
        
        if isTracking {
            let leftSideContentOffset = CGFloat(leftSidePageIndex) * scrollView.bounds.width
            let percent = (scrollView.contentOffset.x - leftSideContentOffset) / scrollView.bounds.width
            let normalizedPercent = min(max(0, percent), 1)

    
    fileprivate var lastContentOffset = CGPoint.zero
    fileprivate var leftSidePageIndex = 0
    fileprivate var isExplicityScrolling = false
    
    fileprivate let scrollView: UIScrollView = {
        let scrollView = UIScrollView()
