[kragen]

i'm not underestimating efficiency; i'm well aware that in many situations it's more important than correctness. but i think it's important to distinguish between decisions made for the sake of efficiency and decisions that tend to make your code more modular, flexible, comprehensible, verifiable, or maintainable. promises originated as a way to make highly concurrent code more modular, flexible, comprehensible, verifiable, and maintainable. halstead's futures did, too. so did rust itself

async in rust is the opposite, and to me it looks like such an expensive way to get that efficiency that it strongly undermines the reasons for adopting rust