Swift Download image asynchronously with completion handler

Asynchronous Download

dowloadImage("link", completion: {(var image) in
                    if image {
                    // downloaded successfully
                    }
                })


// dowload image with completion handler
func dowloadImage(link: String, completion:(image: UIImage) -> Void){
        dispatch_async(dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), {
            if let url = NSURL(string: link){
                if let data = NSData(contentsOfURL: url){
                    if let image = UIImage(data: data){
                        completion(image: image)
                    }
                }
            }

        })
    
    }