Async Image download with Swift 2.2

AsyncImageSwift

import UIKit
import Foundation

class ViewController: UIViewController {

    @IBOutlet var mainTitle: UILabel!
    @IBOutlet var mainPoster: UIImageView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        
        
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        
        if let checkedUrl = NSURL(string: "http://www.apple.com/euro/ios/ios8/a/generic/images/og.png") {
            mainPoster.contentMode = .ScaleAspectFit
            downloadImage(checkedUrl)
        }
        
    }
    
    func downloadImage(url: NSURL){
        print("Download Started")
        print("lastPathComponent: " + (url.lastPathComponent ?? ""))
        getDataFromUrl(url) { (data, response, error)  in
            dispatch_async(dispatch_get_main_queue()) { () -> Void in
                guard let data = data where error == nil else { return }
                print(response?.suggestedFilename ?? "")
                print("Download Finished")
                self.mainPoster.image = UIImage(data: data)
            }
        }
    }
    
    func getDataFromUrl(url:NSURL, completion: ((data: NSData?, response: NSURLResponse?, error: NSError? ) -> Void)) {
        NSURLSession.sharedSession().dataTaskWithURL(url) { (data, response, error) in
            completion(data: data, response: response, error: error)
            }.resume()
    }
    
}

extension UIImageView {
    func downloadedFrom(link link:String, contentMode mode: UIViewContentMode) {
        guard
            let url = NSURL(string: link)
            else {return}
        contentMode = mode
        NSURLSession.sharedSession().dataTaskWithURL(url, completionHandler: { (data, response, error) -> Void in
            guard
                let httpURLResponse = response as? NSHTTPURLResponse where httpURLResponse.statusCode == 200,
                let mimeType = response?.MIMEType where mimeType.hasPrefix("image"),
                let data = data where error == nil,
                let image = UIImage(data: data)
                else { return }
            dispatch_async(dispatch_get_main_queue()) { () -> Void in
                self.image = image
            }
        }).resume()
    }
}