inline size_t Distance( const nsReadingIterator<char>& start, const nsReadingIterator<char>& end )
inline size_t Distance( const nsReadingIterator<PRUnichar>& start, const nsReadingIterator<PRUnichar>& end )
inline size_t Distance( const nsReadingIterator<char>& start, const nsReadingIterator<char>& end )  {    return end.get() - start.get();  }