Не подскажете, как сделать pull down to refresh на scrollview?

import UIKit
 
class ViewController: UIViewController {
 
    @IBOutletweakvar scrollView: UIScrollView!
    var refreshControl: UIRefreshControl!
    
    func onRefresh() {
      refreshControl.endRefreshing()
    }
    
    overridefunc viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        
        
        refreshControl = UIRefreshControl()
        refreshControl.attributedTitle = NSAttributedString(string: "Pull down to reset...")
        
        refreshControl.addTarget(self, action: #selector(onRefresh), for: .valueChanged)
        scrollView.insertSubview(refreshControl, at: 0)
        
    }
 
    func run(after wait: TimeInterval, closure: @escaping () -> Void) {
        let queue = DispatchQueue.main
        queue.asyncAfter(deadline: DispatchTime.now() + wait, execute: closure)
    }
    
    func refresh() {
        run(after: 2) {
            self.refreshControl.endRefreshing()
        }
    }