Swap Tabley Valeurs dans des indices spécifiques?

Je crée asynchrone NSURLConnections code> pour les images hors d'un tableau de dictionnaires, chacun avec leur propre URL de l'image:

var allPosts:Array<Dictionary<String, AnyObject>> = [
    ["imageURL": "http://i.imgur.com/aLsnGqn.jpg", "postTitle":"0"],
    ["imageURL": "http://i.imgur.com/vgTXEYY.png", "postTitle":"1"],
    ["imageURL": "http://i.imgur.com/OXzDEA6.jpg", "postTitle":"2"],
    ["imageURL": "http://i.imgur.com/ilOKOx5.jpg", "postTitle":"3"],
]

var lastIndex = 0
var threshold = 4
var activeConnections = Dictionary<NSURLConnection, Dictionary<String, AnyObject?>>()

func loadBatchInForwardDirection(){
    func createConnection(i: Int){
        allPosts[i]["calledIndex"] = i
        var post = allPosts[i]
        let imageURL = NSURL(string: post["imageURL"] as! String)
        if imageURL != nil {
            let request = NSMutableURLRequest(URL: imageURL!, cachePolicy: .ReloadIgnoringLocalCacheData, timeoutInterval: 60)
            let connection = NSURLConnection(request: request, delegate: self, startImmediately: true)
            if connection != nil {
                activeConnections[connection!] = post
            }
        }
    }
    let startingIndex = lastIndex;
    for (var i = startingIndex; i < startingIndex + threshold; i++){
        createConnection(i)
        lastIndex++
    }
}

func connection(connection: NSURLConnection, didReceiveData data: NSData) {
    if activeConnections[connection] != nil {
        let dataDict = activeConnections[connection]!["data"]
        if dataDict == nil {
            activeConnections[connection]!["data"] = NSMutableData(data: data)
        } else {
            (activeConnections[connection]!["data"] as! NSMutableData).appendData(data)
        }
    }
}

var loadedIndex = 0
func connectionDidFinishLoading(connection: NSURLConnection) {
    let loadedPost = activeConnections[connection]!
    activeConnections.removeValueForKey(connection)
    let data = loadedPost["data"] as? NSData
    let calledIndex = loadedPost["calledIndex"] as! Int
    println(calledIndex)

    swap(&allPosts[calledIndex], &allPosts[loadedIndex])
    //(allPosts[calledIndex], allPosts[loadedIndex]) = (allPosts[loadedIndex], allPosts[calledIndex])

    loadedIndex++
    done(loadedIndex)
}

func done(index: Int){
    if index == 4 {
        println()
        println("Actual: ")
        println(allPosts[0]["postTitle"] as! String)
        println(allPosts[1]["postTitle"] as! String)
        println(allPosts[2]["postTitle"] as! String)
        println(allPosts[3]["postTitle"] as! String)
    }
}

func applicationDidFinishLaunching(aNotification: NSNotification) {
    loadBatchInForwardDirection()
    println("Loaded: ")
}

func applicationWillTerminate(aNotification: NSNotification) {
    // Insert code here to tear down your application
}