I think the promise-based model is the ideal model. After reading [1], I'm convinced that it's very close to realizing the underlying state machine ([2]) of the

I think the promise-based model is the ideal model. After reading [1], I'm convinced that it's very close to realizing the underlying state machine ([2]) of the program, and I find that valuable. I agree that fibers are easier to use, but not simpler. I understand that my hard-line approach is not practical everywhere, but at least the async model used by Rust is not just a concession to the C ABI and whatnot, but an important model in its own right. So I think that it is quite sensible, if not practical for most programmers to make sense of :). Add fiber abstractions on top if appropriate, of course. [1] https://glyph.twistedmatrix.com/2014/02/unyielding.html https://glyph.twistedmatrix.com/2014/02/unyielding.html [2] https://lamport.azurewebsites.net/pubs/state-machine.pdf https://lamport.azurewebsites.net/pubs/state-machine.pdf (read the introduction)