If you are using threads you wouldn't use nested callbacks in the first place. In a proper threaded model you can use exactly the same syntax that you would us

If you are using threads you wouldn't use nested callbacks in the first place. In a proper threaded model you can use exactly the same syntax that you would use with async/await (futures, future combinators, message passing what have you) except you do not have to randomly annotate your code with awaits.