If I had to guess, what they wanted was to sample from a finite set you're only allowed to stream ("unbounded" just means you don't know the bound). Or if it re

If I had to guess, what they wanted was to sample from a finite set you're only allowed to stream ("unbounded" just means you don't know the bound). Or if it really is unbounded, they still just want a uniform sample up to that point (i.e., still bounded).