Getting single zone

[Algirdas-Z]

https://github.com/outini/python-powerdns/blob/173763c11bb4fe9f3017625847be5c1f65125ceb/powerdns/interface.py#L221

Shouldn't this method have some kind of flag to skip caching "all zones" if not desired? I can understand benefit of this caching in small environment, however in huge setup it wouldn't likely complete, or, would cause huge impact on PDNS/DB when trying to fetch lets say million zones. (when you actually need 1 )