This example shows how it works for one trait, Debug, but what if you have a type that (might) implement multiple traits A, B, and/or C? It isn't clear to me if that is possible, unless the type implements all of those traits. What I'd like to do is have some base trait object and query it to see if it supports other interfaces, but also not have to have stub "I don't actually implement this" trait impls for the unsupported ones. A bit like how I might use dynamic_cast in c++.<p>(I believe I understand that in rust this has not historically been possible because rust doesn't have inheritance, so, there can be only one vtable for a type, rather than an chain like you might have in c++.)