For a beginner to intrusive_ptr, we won’t be too far off to remember that a pointee class could (not required) implement a java-style interface with 2 public methods addRef and delRef(). The pointee class typically uses these methods to change a private field refCount.
In Boost, the intrusive_ptr actually uses 2 stipulated free functions, but they could (and often do) call methods of the pointee class, like our 2 methods.
