NSURLSessionDelegatefailingforlargefileson4G&iOS10only

I'm having strange problem with NSURLSessionDelegate. Here's my code first:

我对NSURLSessionDelegate有一些奇怪的问题。这是我的代码：

    class NetworkHandler: NSObject,NSURLSessionDelegate,NSURLSessionDownloadDelegate {

    lazy var downloadsSession: NSURLSession = {
        let cOnfiguration= NSURLSessionConfiguration.backgroundSessionConfigurationWithIdentifier("abc")
        let session = NSURLSession(configuration: configuration, delegate: self, delegateQueue: nil)
        return session
    }()

    func URLSession(session: NSURLSession, downloadTask: NSURLSessionDownloadTask, didFinishDownloadingToURL location: NSURL) {

        print("finished")
    }

    func URLSession(session: NSURLSession, downloadTask: NSURLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) {

       print("\(String(format: "%.1f%% of %@",  progress * 100, totalSize))" )
}

    func URLSession(session: NSURLSession, downloadTask: NSURLSessionDownloadTask, didResumeAtOffset fileOffset: Int64, expectedTotalBytes: Int64) {
        print("didResumeAtOffset: \(fileOffset)")
    }

    func URLSession(session: NSURLSession, task: NSURLSessionTask, didCompleteWithError error: NSError?) {
        print("didCompleteWithError error=\(error)");
    }

    func URLSessionDidFinishEventsForBackgroundURLSession(session: NSURLSession) {
        if let appDelegate = UIApplication.sharedApplication().delegate as? AppDelegate {
            if let completiOnHandler= appDelegate.backgroundSessionCompletionHandler {
                appDelegate.backgroundSessiOnCompletionHandler= nil
                dispatch_async(dispatch_get_main_queue(), {
                    completionHandler()
                })
            }
        }
    }
}

Here's my output when my file is ~20MB and I'm on 4G/LTE:

这是我的输出，当我的文件大约是20MB并且我在4G / LTE时：

didCompleteWithError error=Optional(Error Domain=NSURLErrorDomain Code=-1002 "unsupported URL" UserInfo={NSLocalizedDescription=unsupported URL})

I've already checked my url has http and its a valid url. This code works 100% of the time when I'm on wifi or when file size is <~10MB or NOT iOS10. The file downloads till about 60% and then fail everytime. I'm just out of ideas to even justify myself what could go wrong.

我已经检查过我的网址有http和它的有效网址。当我在wifi上或文件大小<~10MB或不是iOS10时，此代码可以100％正常工作。文件下载到大约60％，然后每次都失败。我只是出于想法，甚至为自己辩解可能出错的地方。

The problem happens when it's iOS10 File size ~20MB 4G/LTE ONLY If I change any of the above 3 criteria, it works.

问题发生在它的iOS10文件大小~20MB 4G / LTE ONLY如果我改变上述3个标准中的任何一个，它就有效。

I tried Apple code and the problem is same

我试过Apple代码，问题是一样的

1 个解决方案