Create a generate that iterates the whole content of the file or string, and also tells which offset is now.

        :return: An iterator iterating tuples, containing lines of the text stream,...
            separated by ``'\\n'`` or ``'\\r'``; and the offset (in bytes) of current line.

def generator_telling_position(self) -> Iterator[Tuple[str, int]]:
        """
        Create a generate that iterates the whole content of the file or string, and also tells which offset is now.

        :return: An iterator iterating tuples, containing lines of the text stream,...
            separated by ``'\\n'`` or ``'\\r'``; and the offset (in bytes) of current line.
        """
        stream = self.stream  # In case that ``self.stream`` is changed.
        stream.seek(0)
        for line in stream:
            yield line, stream.tell()