[mplanchard]

You don’t have to make everything Send/Sync if you don’t need to. Use tokio’s local runtime and spawn_local(), or use one of the other async runtimes.

You also don’t need to spawn() futures to await them. Spawn enables parallelism on the multithreaded runtime, holding join handles, etc. If all you need is to execute concurrent code, though, the various combinators and functions in the futures crate lets you do so without having hard requirements on Send/Sync. The large majority of the concurrent code I write uses nothing specific from the tokio crate, including spawn.

As is often the case in rust, the compiler is also telling you the correct thing. If you’re using the multithreaded runtime and spawning, your code may execute in another thread, so it has to be Send/Sync, and since the ownership of the future is transferred to the executor, it must also be ‘static.

[likeabbas]

You literally can't use one of the other async run times because of the current state of async/await does not allow library authors to easily write for multiple runtimes - they were written for one runtime in mind and that is just tokio. And if you're pulling in library methods you're still stuck with the method headers they specify.

All of your arguments are just mental workarounds trying to justify how fucked the rust ecosystem is for traditional backend services.

The project I'm working on is specific to making traditional kernel threads faster (150-200 nanosecond context switches compared to 1500-2000 nano seconds for normal kernel threads). It requires a user scheduler but you can swap those out without any changes to how you write rust. In my testing, it's not only faster than async rust but also much easier to write. I hope it convinces people like you, that are hell-bent on defending the current state of async rust, that there are better paradigms and we don't have to be locked in to shitty, verbose concurrent code.

[mplanchard]

You’re moving the goalposts, and seem to have a vested interest in this that I, frankly, don’t.

Send/Sync/static is not needed on tokio’s local runtime, which doesn’t require any adjustments to your libraries.

Passing data between threads requires Send/Sync/static, except for certain cases like scoped threads, so making OS threads faster doesn’t seem to solve that issue like using a local runtime would.

Many async libraries (though certainly not all) are runtime-independent. If your library doesn’t have to spawn, it is easy to write runtime-independent code. I would like to see some spawn traits brought into std to make it easier to write libraries that have to spawn, though.

I’ll always try new ways of doing things, but you are making the assumption that the way you feel is the way everyone feels, and totally dismissing the opinions of those who don’t. It puts me off of whatever solution you might be proposing, since you clearly don’t have the empathy to understand the full range of positions of the people whose problems you’re ostensibly trying to solve.

I’m not trying to convince you the way you feel is wrong, but you are wrong that everyone thinks writing async code is miserable. There are times where it’s hard, or where the compiler emits confusing messages about async closures being not generic enough, but on the whole I enjoy writing async rust, so shoot me.

[likeabbas]

I haven’t moved any goal posts - I’ve coded async rust and is miserable compared to normal rust with threads. That has been my point which is why I started down this project.

My entire goal is to show that coding the same server with pre-async hyper vs post async hyper is nicer and more performant than async rust. I hope to show you it in just a few days.