     
     
     private static let sharedInstance = WTURLSessionDelegate()
-    var shouldCache = false
     
     //网址凭据
     var credential: URLCredential?

        
        let delegate = WTURLSessionDelegate()
        delegate.completionHandler = completionHandler
        delegate.shouldCache = true
        delegate.credential = credential
        let configuration = URLSessionConfiguration.default
        configuration.urlCache = URLCache.sharedURLCacheForRequests()

        let delegate = WTURLSessionDelegate()
        delegate.completionHandler = completionHandler
        delegate.credential = credential
        
        
        let configuration = URLSessionConfiguration.default
//        configuration.urlCache = URLCache.sharedURLCacheForRequests()
