Code review comment for lp:~cemil-azizoglu/mir/add-create-module-context-fn

> I was about to suggest using mir::UniqueModulePtr<void> instead - it would
> keep the module alive at least as long as the context object from the platform
> is alive. But unique_ptr does not allow void.

As with the branch Alexandros proposed yesterday there's an advantage to an "empty" type with a vtab - it can be used with RTTI to safely downcast at the receiving end.