operator+( const nsPromiseConcatenation<CharT>& lhs, const basic_nsAReadableString<CharT>& rhs )
operator+( const basic_nsAReadableString<CharT>& lhs, const basic_nsAReadableString<CharT>& rhs )
operator+( const nsPromiseConcatenation<CharT>& lhs, const basic_nsAReadableString<CharT>& rhs )  {    return nsPromiseConcatenation<CharT>(lhs, rhs, lhs.GetFragmentIdentifierMask()<<1);  }