I tend to use type erasure technique quite a bit.
It typically looks like this:

```
class YetAnotherTypeErasure
{
public:
   // interface redirected to pImpl
private:
   // Adapting function
   template ...
   friend YetAnotherTypeErasure make_YetAnotherTypeErasure (...);

   class Interface {...};

   template <typename Adaptee>
   class Concrete final : public Interface { 
     // redirecting Interface to Adaptee
   };

   std::unique_ptr<Interface> pImpl_; // always on the heap
};

```

`std::function` does something similar, but it has a small buffer optimization, so if `Concrete<Adaptee>` is smaller than smth and has nothrow move operations, it will be stored in it. Is there some generic library solution to do it fairly easy? For enforcing small buffer only storing at compile time? Maybe something has been proposed for standardisation?