PHP Session添加报头Pragma: no-cache

嗨，人们，我有http头请求的问题，当我测试头我得到这个响应

HTTP/1.1 200 OK
Date: Sat, 29 Oct 2016 14:24:31 GMT
Server: Apache
X-Powered-By: PHP/5.6.27
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-
    check=0
Pragma: no-cache
Set-Cookie: PHPSESSID=2d17992cfbd621c51eca940df478b89a; path=/
Vary: Accept-Encoding,User-Agent
X-Frame-Options: SAMEORIGIN
X-XSS-Protection: 1; mode=block
X-Content-Security-Policy: allow 'self';
X-Content-Type-Options: nosniff
Cache-Control: max-age=604800, must-revalidate
Connection: close
Transfer-Encoding: chunked
Content-Type: text/html; charset=UTF-8
Content-Language: it-it

只有当我在

页面上设置了session_start()时，这部分才会显示出来

Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-
    check=0
Pragma: no-cache

---

在干净的页面。php或。html页面，我得到这个响应

  HTTP/1.1 200 OK
    Date: Sat, 29 Oct 2016 14:34:27 GMT
    Server: Apache
    Last-Modified: Sat, 29 Oct 2016 13:15:00 GMT
    Accept-Ranges: bytes
    Content-Length: 314
    Vary: Accept-Encoding,User-Agent
    Cache-Control: max-age=604800, must-revalidate
    Expires: Sat, 29 Oct 2016 14:34:27 GMT
    X-Frame-Options: SAMEORIGIN
    X-XSS-Protection: 1; mode=block
    X-Content-Security-Policy: allow 'self';
    X-Content-Type-Options: nosniff
    Connection: close
    Content-Type: text/html; charset=UTF-8
    Content-Language: it-it

---

我试着到处搜索，但不知道我被封锁了有人知道为什么session_start();添加

Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-
    check=0
Pragma: no-cache

在http头????????

session_cache_limiter('private_no_expire:');
session_start();