Net： ConnectionDebug

protocol DownloadConnectionDelegate: NSObjectProtocol {
    func DownloadConnection(downloader: DownloadConnection , failWithError error: NSError)
    func DownloadConnection(downloader: DownloadConnection , 
finishWithData data: NSData)
}

//UseOfUnclaredType 'DownloadConnection'    ,换一个名字，就好了。



class DownloadConnection: NSObject , NSURLConnectionDelegate , NSURLConnectionDataDelegate {
  
    
    
    var delegateConnection: DownloadConnectionDelegate?
    
    ```