How to animate UITableView header view

Question

I need to animate the insertion of a tableview header view. I want that the table rows to slide down while the header view expands its frame.
So far the best result I go

Answer 1

Use below code this works

extension UITableView {

 func hideTableHeaderView() -> Void {
    self.beginUpdates()
    UIView.animate(withDuration: 0.2, animations: {
        self.tableHeaderView = nil
    })
    self.endUpdates()
}

func showTableHeaderView(header: UIView) -> Void {
    let headerView = header
    self.beginUpdates()
    let headerFrame = headerView.frame
    headerView.frame = CGRect()
    self.tableHeaderView = headerView
    UIView.animate(withDuration: 0.2, animations: {
        self.tableHeaderView?.frame = headerFrame
        self.tableHeaderView?.alpha = 0
        self.endUpdates()
    }, completion: { (ok) in
        self.tableHeaderView?.alpha = 1
    })
   }
}