local_weak_ptr ?

I do understand that `local_shared_ptr` <=> `shared_ptr` . And that `local_shared_ptr` is basically wrap `shared_ptr`.

But which "weak counter" use `weak_ptr`? Here:
```
local_shared_ptr px(new X());
weak_ptr wp(px);
```

local or atomic? From interface described in documentation - I suppose atomic. Because it's impossible to get `local_shared_ptr` directly from `weak_ptr`.

So... Is it possible to have `local_weak_ptr`?