How to get TTURLRequest to return expired cached data, while queing HTTP request which would asynchroniously update cache for next time?

Question

I'm looking for a way to get TTURLRequest to always return data from the cache (assuming it exists for the URL) even if it has expired. In the case that is has expired, I want to add the request to a TTURLRequestQueue that would cache the updated version for the next access.

What would be my best approach to implementing this? Should I override -(BOOL)loadRequestFromCache:(TTURLRequest*)request in TTURLRequestQueue with my own custom implementation?