A more accurate way to look at this based on your example is that, sometimes listAnimals returns [cat, dog, mouse], and sometimes it returns null. It’s not tha

A more accurate way to look at this based on your example is that, sometimes listAnimals returns [cat, dog, mouse], and sometimes it returns null. It’s not that the result is nondeterministic, it’s that _whether or not the result is returned within the timeout of the polling mechanism_ is deterministic.