awc deadlock on some network connections

[lovasoa]

Hello and thank you for this project !

I am reporting a bug that is hard to reproduce, so feel free to close it if needed.
I have a build script that downloads data using awc: https://github.com/lovasoa/SQLpage/blob/v0.21.0/build.rs
It works well most of the time. But on some network connections, it systematically falls into a deadlock. No timeout is ever reached, awc simply never returns. It really depends only on the network connection being used, and on the networks that fail, I can download the same files using a web browser or curl without issues.
I'm joining a network packet capture realized while awc was locked: awc.zip

[robjtede]

Some reproduction steps would be hugely helpful, otherwise I fear this issue will not go anywhere. Or maybe at lease some description of the network condition's characteristics?

[lovasoa]

I'm sorry, but it's hard to reproduce for me without physically going to the places where I know the network produces this. It has happened to me on only two distinct WiFi networks. Once on the network, the issue is reproducible 100% of the time. I hoped the packet capture would help.

[pchemguy]

I would like to report a similar issue, except I also observed similar problems when tried to browse and download the resources via the browser.

The problem might be location specific, but may not be application/library specific. It very well might be related to the state activities aimed at filtering/eavesdropping the traffic. If true, application/library developers cannot do much about the cause, but finding a robust approach to handling the issue might be good idea. Perhaps setting a reasonable response timeout, so that even if no timeout is returned from the upstream code, the library could still detect a poor connection and return a timeout error.

[lovasoa]

awc already has a timeout, but when I experienced the problem, it was not respected.

[pchemguy]

I see