BTW I think some anti-Rust people are more annoying than the worst Rust evangelists - seen some of them calling people not using Rust as "murderers", because "memory leakage can kill at the right time" - but that's due to them being evangelists to right-wing politics.
A lot of the time it's not about options. It's about not messing up the async pattern.
If you have something that either:
If not, just use future polling tricks like the futures::join!() macro or a stream with .buffered(). It won't be slower. The bottle neck is IO. Not the program.
Personally I even try to replace the heavy reqwest library with ureq + blocking, and it works perfectly and compiles faster (you can see that in the api_bindium crate)