protected function _detect_and_remove_sep_row_from_data(&$data_string) {
        $sep = $this->_get_delimiter_from_sep_row($data_string);
        if ($sep === false) {
            return false;
        }

        $this->delimiter = $sep;

        // likely to be 5, but let's not assume we're always single-byte.
        $pos = 4 + strlen($sep);
        // the next characters should be a line-end
        if (substr($data_string, $pos, 1) === "\r") {
            $pos++;
        }
        if (substr($data_string, $pos, 1) === "\n") {
            $pos++;
        }

        // remove delimiter and its line-end (the data param is by-ref!)
        /** @noinspection CallableParameterUseCaseInTypeContextInspection */
        $data_string = substr($data_string, $pos);
        return true;
    }