protected function getQueryString(?array $query) : ?string
    {
        if (empty($query)) {
            return null;
        }

        return '?' . http_build_query($query, null, '&', PHP_QUERY_RFC3986);
    }
protected function getQueryString(?array $query) : ?string
    {
        if (empty($query)) {
            return null;
        }

        return '?' . http_build_query($query, null, '&', PHP_QUERY_RFC3986);
    }
protected function getQueryString ( ? array $ query ) : ? string { if ( empty ( $ query ) ) { return null ; } return '?' . http_build_query ( $ query , null , '&' , PHP_QUERY_RFC3986 ) ; }
Build query string

@param array|null $query
@return null|string
Build query string