Swift: load images Async in UITableViewCell

I have a tableview that I created with code (without storyboard):

class MSContentVerticalList: MSContent,UITableViewDelegate,UITableViewDataSource {
var tblView:UITableView!
var dataSource:[MSC_VCItem]=[]

init(Frame: CGRect,DataSource:[MSC_VCItem]) {
    super.init(frame: Frame)
    self.dataSource = DataSource
    tblView = UITableView(frame: Frame, style: .Plain)
    tblView.delegate = self
    tblView.dataSource = self
    self.addSubview(tblView)
}

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return dataSource.count
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = UITableViewCell(style: .Subtitle, reuseIdentifier: nil)

    let record = dataSource[indexPath.row]
    cell.textLabel!.text = record.Title
    cell.imageView!.downloadFrom(link: record.Icon, contentMode: UIViewContentMode.ScaleAspectFit)
    cell.imageView!.frame = CGRect(x: 0, y: 0, width: 100, height: 100)
    print(cell.imageView!.frame)
    cell.detailTextLabel!.text = record.SubTitle
    return cell
}
}

and in other class I have an extension method for download images Async:

   extension UIImageView
{
    func downloadFrom(link link:String?, contentMode mode: UIViewContentMode)
    {
        contentMode = mode
        if link == nil
        {
            self.image = UIImage(named: "default")
            return
        }
        if let url = NSURL(string: link!)
        {
            print("\nstart download: \(url.lastPathComponent!)")
            NSURLSession.sharedSession().dataTaskWithURL(url, completionHandler: { (data, _, error) -> Void in
                guard let data = data where error == nil else {
                    print("\nerror on download \(error)")
                    return
                }
                dispatch_async(dispatch_get_main_queue()) { () -> Void in
                    print("\ndownload completed \(url.lastPathComponent!)")
                    self.image = UIImage(data: data)
                }
            }).resume()
        }
        else
        {
            self.image = UIImage(named: "default")
        }
    }
}

I used this function in other places and worked correctly, Based on my logs I understand that images downloaded without problem (when the cell is rendered) and after download of image, The cell UI not updated.

Also I tried to use caching library like Haneke but problem is exist and not change.

Please help me to understand mistakes

Thanks

After setting the image you should call self.layoutSubviews()

edit: corrected from setNeedsLayout to layoutSubviews