awc deadlock on some network connections

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](https://github.com/actix/actix-web/files/15474938/awc.zip)