void instantiate_ptr_serialization(Serializable* s, int, adl_tag) {
    instantiate_ptr_serialization(s, counter<20>());
}
 void export_guid(mpl::false_) const {
     // generates the statically-initialized objects whose constructors
     // register the information allowing serialization of T objects
     // through pointers to their base classes.
     instantiate_ptr_serialization((T*)0, 0, adl_tag());
 }