     }
     
     private func download(_ item: Item, _ cached: IsCached, _ callback: @escaping (Result) -> ()) {
-        guard !canceled else {
+        guard !isCancelled else {
             callback(.cancel)
             return
         }

        
        contentLength(of: first) { result in
            switch result {
            case .canceled, .failure:
                callback(result)
            case let .success(headLength, headCached):
                let tail = items[(items.startIndex + 1)..<items.endIndex]

                
                self.contentLength(of: tail) { result in
                    switch result {
                    case .cancel, .failure:
                        callback(result)
                    case let .success(tailLength, tailCached):
                        guard let tailLength = tailLength else {
