I'm referring to runtime_context.h. The Attach method returns a Token but wrapped in a unique_ptr. At the same time the Token just contains a Context which is in fact just a shared_ptr to some data. I guess Token is supposed to be some kind of guard that ensures that a context is eventually detached.

Are my assumptions correct?

If so, then we don't need an allocation of a Token for that. Instead make Token a proper guard type, that semantically behaves like a unique_ptr. Is it possible to change that or am I missing something? Would this be considered a breaking api change?

I'm happy to provide a patch.