protected function removeXmlFirstLine($str)
    {
        $first = '<?xml version="1.0"?>';
        if (Str::startsWith($str, $first)) {
            return trim(substr($str, strlen($first)));
        }

        return $str;
    }
protected function removeXmlFirstLine($str)
    {
        $first = '<?xml version="1.0"?>';
        if (Str::startsWith($str, $first)) {
            return trim(substr($str, strlen($first)));
        }

        return $str;
    }
protected function removeXmlFirstLine ( $ str ) { $ first = '<?xml version="1.0"?>' ; if ( Str :: startsWith ( $ str , $ first ) ) { return trim ( substr ( $ str , strlen ( $ first ) ) ) ; } return $ str ; }
remove the first line of xml string
@param string $str
@return string
remove the first line of xml string