     }
 
     // MARK: - private
-    private static let _ioQueue = dispatch_queue_create("swift.imageloader.queues.io", DISPATCH_QUEUE_CONCURRENT)
-    private static let _Queue = dispatch_queue_create("swift.imageloader.queues.request", DISPATCH_QUEUE_SERIAL)
 
     private func imageLoader_load(URL: NSURL, completionHandler: CompletionHandler?) {
         let handler: CompletionHandler = { [weak self] URL, image, error, cacheType in

        }
    }

    // MARK: - public
    public func load(URL: URLLiteralConvertible, placeholder: UIImage? = nil, completionHandler:CompletionHandler? = nil) {
        dispatch_async(UIImageView._Queue) { [weak self] in
            guard let wSelf = self else { return }

            wSelf.cancelLoading()

            return
        }


        let identifier = hash
        let block: () -> Void = { [weak self] in
            guard let wSelf = self else { return }

            let block = Block(identifier: identifier, completionHandler: handler)
