title: Why is Cache-Control attribute sent in request header (client to server)?
body: <p>After reading about the <code>Cache-Control</code> field of the HTTP header,</p>
  <p>I understand that the <code>Cache-Control</code> field in the HTTP response header (server to client) specifies the directives for the intermediate proxy servers/client browser on how to handle the response, by sending different values for the <code>Cache-Control</code> field: <code>private</code>, <code>public</code>, <code>no-cache</code>, or <code>no-store</code> in the response header.</p>
  <p>But I don't get why we need to send <code>Cache-Control</code> as a request header (client to server)?</p>