protected:
// ensure that our data is not shared with anybody else: if we have no
// data, it is created using CreateRefData() below, if we have shared data
// it is copied using CloneRefData(), otherwise nothing is done
void AllocExclusive();
protected:
// ensure that our data is not shared with anybody else: if we have no
// data, it is created using CreateRefData() below, if we have shared data
// it is copied using CloneRefData(), otherwise nothing is done
void AllocExclusive();