I started looking into it but was interrupted (this is the Sprint Of Interruptions) and ran out of time - it looks like you can create an object to pass to Response as the "response" arg which is an iterator. Iterators all the way down, baby. As long as it doesn't subclass str types, list or tuple it'll be treated as a dumb iterator and that'll give you the ability to perform the lazy content creation cleanly in the __iter__ call and whatever you want to do in __next__.