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?

``` const { port1, port2 } = new MessageChannel(); const taskQueue = []; port2.start(); port2.addEventListener("message", () => { taskQueue.shift()(); });

const task = () => { return new Promise(resolve => { taskQueue.push(resolve); port1.postMessage(0); }); }

```