PROPERTY_MAP_POJO
A pojo holding a weak map from this atom's property keys (atoms) to property values. It's never nil for this descriptor class, but it may be nil in the Mutability.SHARED subclass.
A pojo holding a weak map from this atom's property keys (atoms) to property values. It's never nil for this descriptor class, but it may be nil in the Mutability.SHARED subclass.