With HdGp, will UpdateDependencies & Update always always always be called together (i.e., one after the other, with no changes to inputScene in between)? It looks like that is currently the case, but how future-proof is this assumption?
I find myself doing non-trivial work to dance through the scenegraph to determine all my dependencies in UpdateDependencies, and would like to cache & reuse the data in Update rather than redoing the same dance to generate the same result.