What bothers me, for example in Python, with the function coloring is that it creeps everywhere and you need to rewrite your functions to accommodate async. I think being able to take and return futures or promises and handle them how you wish is better ergonomics.
Yeah but to be fair, that can have adverse effects if you, say, busy wait.
The sync code might be running in an async context. Your async context might only have one thread. The task you're waiting for can never start because the thread is waiting for it to finish. Boom, you're deadlocked.
Async/await runtimes will handle this because awaiting frees the thread. So, the obvious thing to do is to await but then it gets blamed for being viral.
Obviously busy waiting in a single threaded sync context will also explode tho...
