Sometimes, there are use-cases where you want to entirely pause processing of some tasks, and then later scale back up. CapacityLimiter is basically perfect for this kind of thing, except that it currently raises an error if you pass total_tokens=0:

It's already possible to get the desired effect just by deliberately "leaking" one of the tokens, but it would be much nicer to simply allow zero as the intended capacity, by editing the numbers in the setter above.