I expaned my tests a bit and your version does indeed queue a task and not a micro task. I did find it to be somewhat less reliable than setTimeout, is there a particular reason why you used this scheme instead of a setTimeout based solution to queue tasks? Why did you choose this method in particular to queue tasks?
Also, AsyncTask and MicroTask are not fully equivalent. MicroTask is equivalent to a bare `await 0;`, but because AsyncTask wraps that in another async function it will queue a second micro task when the first one resolves, and resolve the promise when the second micro task resolves :)
Why do you think it's less reliable? setTimeout gets clamped by the browser to a minimum of 4ms, so you waste a lot of time when all you want is a task boundary.
I tried so many janky different ways that I don't quite remember how to reproduce it, but I found that setTimeout was more likely to always execute once per animationFrame, where using MessageChannel would sometimes execute more than once per frame. I guess the minimum timeout added to setTimeout makes it more likely to not hit twice between paints. The test setup I have now gets pretty clean results.
One final question would be why you have this uid system with attaching and removing event listeners? I think MessageChannels are order preserving, so you can do with a single EventListener that consumes events off a queue, or am I missing something?
I expaned my tests a bit and your version does indeed queue a task and not a micro task. I did find it to be somewhat less reliable than setTimeout, is there a particular reason why you used this scheme instead of a setTimeout based solution to queue tasks? Why did you choose this method in particular to queue tasks?
Also, AsyncTask and MicroTask are not fully equivalent. MicroTask is equivalent to a bare `await 0;`, but because AsyncTask wraps that in another async function it will queue a second micro task when the first one resolves, and resolve the promise when the second micro task resolves :)