NSURLSessionDelegate and derived class

NSURLSessionDelegate
     URLSession:didBecomeInvalidWithError:
     URLSession:didReceiveChallenge:completionHandler:
     URLSessionDidFinishEventsForBackgroundURLSession:

    NSURLSessionTaskDelegate
        URLSession:task:didReceiveChallenge:completionHandler:
        URLSession:task:didSendBodyData:totalBytesSent:totalBytesExpectedToSend:
        URLSession:task:needNewBodyStream:
        URLSession:task:willPerformHTTPRedirection:newRequest:completionHandler:
        URLSession:task:didFinishCollectingMetrics:
                NSURLSessionTaskMetrics
        URLSession:task:didCompleteWithError:
        URLSession:task:willBeginDelayedRequest:completionHandler:
        URLSession:taskIsWaitingForConnectivity:

         NSURLSessionDataDelegate
            URLSession:dataTask:didReceiveResponse:completionHandler:
            URLSession:dataTask:didBecomeDownloadTask:
            URLSession:dataTask:didBecomeStreamTask:
            URLSession:dataTask:didReceiveData:
            URLSession:dataTask:willCacheResponse:completionHandler:

         NSURLSessionDownloadDelegate
            URLSession:downloadTask:didResumeAtOffset:expectedTotalBytes:
            URLSession:downloadTask:didWriteData:totalBytesWritten:totalBytesExpectedToWrite:
            URLSession:downloadTask:didFinishDownloadingToURL:

         NSURLSessionStreamDelegate
            URLSession:readClosedForStreamTask:
            URLSession:writeClosedForStreamTask:
            URLSession:betterRouteDiscoveredForStreamTask:
            URLSession:streamTask:didBecomeInputStream:outputStream: