return ReadingIterator(fragment, startPos, *this);
return basic_nsAReadableString<CharT>::ReadingIterator(fragment, startPos, *this);
      BeginReading( PRUint32 aOffset = 0 ) const        {          ReadableFragment fragment;          const CharT* startPos = GetReadableFragment(fragment, kFragmentAt, aOffset);          return ReadingIterator(fragment, startPos, *this);        }