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0 pointssimias5y ago0 comments

You answered jgilias better than I could, I feel exactly the same way. Async is deceptively simple in my opinion, because while it looks arguably even simpler than an explicit state machine, it makes your program flow nonlinear and I find that a lot harder to work with. With blocking code I can mentally step through the code follow causes and consequences easily, with async I feel like I'm watching a scifi movie involving time travel and parallel universes.

And the loss of control is also an issue for me. I write code for memory-constrained environments, with blocking code and OS threads I can usually bound my memory consumption fairly easily. If I surrender the control to a scheduler runtime I feel like it becomes a lot harder, although here I'm willing to concede that it might have more to do with my lack of experience with Tokio than an objective issue.

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jstrong5y ago

agree 100%. it honestly kind of baffles me, "async" is like the programming community's white whale, and all of us get to come along for the chase. meanwhile, I long ago grew accustomed to the paradigm of an "event loop" in my programs. after a certain point it becomes very natural. on the subject of memory, recently there was an issue where the async dyn futures were blowing up stacks because a resolved future was > 2mb - what!? I mean, look at the signatures in the aturon article - we are going from this

    fn read(&mut self, buf: &mut [u8]) -> Result<usize, io::Error>

... to this ...

    fn read<T: AsMut<[u8]>>(self, buf: T) ->
        impl Future<Item = (Self, T, usize), Error = (Self, T, io::Error)>

is that supposed to be easier?

I recently tried writing a small program that would manually poll a future to get a feel for it - utter disaster. conflicting versions of tokio, compiles but crashes because something is called outside of the tokio runtime context, etc. all the examples have #[tokio::main]-decorated main - it's like, I'm not giving you my #$(&#@(&ing main function! the programs I write have tons of stuff going on! I can't just give some library my entire control flow!

sorry for the rant! felt good to write it though.

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