How to solve timeout issues caused by bad HTTP persistent connection?

Question

I\'ve been struggling with an HTTP timeout issue recently. After more than one month of investigation I\'m quite sure that it is caused by bad HTTP persistent connections. Detai

Answer 1

After 2 weeks of research, I can give answers to question 3 and 4:

3. nginx's persistent connection timeout is set to 5s on server, which should not be the cause. Server engineers found those timed-out requests are actually normally received and responded. So it is more likely a client side issue. Since I have a minimal reproducible code to rule out my code as the cause, the cause should be in iOS.
4. The only way I found is to use CFNetwork. Higher level API such as NSURLConnection or NSURLSession's Connection header will be overwritten by system.