生成会话
Session会自动保存cookie信息, 其实现是浏览器级别完备的
$session = Saber::session([
'base_uri' => 'http://httpbin.org',
'redirect' => 0
]);
$session->get('/cookies/set?foo=bar&k=v&apple=banana');
$session->get('/cookies/delete?k');
echo $session->get('/cookies')->body;