[jerf]

"Just as you can "eliminate" the result type by explicitly handling the success and error cases, you could, theoretically, "eliminate" the async function by blocking on it"

You really can't. Shutting down the async loop doesn't just do damage to the performance of the program, it can actually affect correctness. It doesn't fix the color problem. That's why I said 'Although I will say that if your "encapsulation" is basically to run it in a non-concurrent environment, that's really not encapsulation. It isn't really "encapsulation" if you're giving up an entire major feature of the language, because that is something very visible to the rest of the program.'

Monads actually aren't really relevant, either. A monad can express something you can't escape from, but it isn't required; "Option" isn't a color because you can still deconstruct it any time you like. It's specifically IO, which traps you not because it is a "monad" but because it has no escape hatches at all. (Modulo "unsafe", which is always something we have to say, but we also always tend to ignore unsafe in these discussions because otherwise everything collapses to one big unsafe pile in all languages of note.)