Snapchat like tableview scrolling over header - ios

Question

i have been trying to implement scrolling behaviour like snapchat tableview where on scrolling down the tableview moves behind top header and the lists scrolls.
I have tried below code :
But it is not as smooth as snapchat, if anyone has any idea please share.
func scrollViewDidScroll(_ scrollView: UIScrollView)
{
let CONTAINER_HEIGHT:CGFloat = 44
let translation = scrollView.panGestureRecognizer.translation(in: scrollView.panGestureRecognizer.view!)
if(translation.y <= 0)
{
//UP DIRECTION
let percent = -translation.y / scrollView.panGestureRecognizer.view!.bounds.size.height
print("PERCENT : \(percent)")
switch (scrollView.panGestureRecognizer.state)
{
case .began:
break;
case .changed:
if(percent <= 1.0 && percent >= 0)
{
var panSize = (CONTAINER_HEIGHT)*percent
panSize = CONTAINER_HEIGHT-panSize
print("Pan Value : \(panSize) -- Percent : \(percent)" )
//panSize += 44
self.bottomSlideTopConstraint.constant = panSize
self.view.layoutIfNeeded()
}
break;
// User is currently dragging the scroll view
case .ended,.cancelled:
let velocity = scrollView.panGestureRecognizer.velocity(in: scrollView.panGestureRecognizer.view)
if (percent > 0.5 && velocity.y == 0) || velocity.y > 0
{
print("ENDED TRUE")
self.bottomSlideTopConstraint.constant = 0
UIView.animate(withDuration: 0.2, animations: {
self.view.layoutIfNeeded()
})
}
else
{
print("CANCELLED")
self.bottomSlideTopConstraint.constant = 44
UIView.animate(withDuration: 0.2, animations: {
self.view.layoutIfNeeded()
})
}
default:
break;
}
}
}