> The alternatives are callbacks, which everybody hates and for a good reason. Then you have callbacks wrapped by Futures/Promises. And then you have some form of coroutines.
The event loop model is arguably equivalent to coroutines. Just replace yield with return and have the underlying runtime decide which functions to call next by looping through them in a list. You can even stall the event loop and increase latency if you take too long to return. It's cooperative multitasking by another name.
Coroutines/resumable functions are not restricted to yielding to a single runtime or event loop, they can simply "resume" each other directly. There are also extensions of coroutines that are more than one-shot (a resumable function where the current state can be copied and invoked more than once) and/or are allowed to provide values when "resuming" other code, which also goes beyond the common "event loop" model.
It's all the same concept, it's just a matter who/what is managing the state while you are waiting for I/O. When you yield, it's the compiler/runtime making sure the context is saved. When you return, it's your responsibility.
The event loop model is arguably equivalent to coroutines. Just replace yield with return and have the underlying runtime decide which functions to call next by looping through them in a list. You can even stall the event loop and increase latency if you take too long to return. It's cooperative multitasking by another name.