Comment by osigurdson

Agree that with something like go, there is truly no function coloring at all. However, since most real world async things require cancellation, a context parameter is always present so there is some "coloring" do to that. Still, it is much less viral than C# style async await as if you don't have a context in your call stack you can still create one when needed and call the function. I don't think it is reasonable to abstract cancellation in a way that nothing has to be passed in so perhaps the approach presented here is realistically as good as it gets.