Don't set the JSESSIONID cookie for static files

[denprog]

For caching my site (its static files) on Cloudflare I need to send some responses without JSESSIONID. I use sessions, but for sending static I don't need this cookie, otherwise Cloudflare will not cache these files.
So, how can I turn it off, but still using sessions? As far I understand it doesn't need in every response, it set in the beginning and after is the same, so we don't need to repeate it?
Deleting this cookie manually doesn't help:

    std::string r = HttpAppFramework::instance().getDocumentRoot();
    auto resp = HttpResponse::newFileResponse(r + param);

    drogon::Cookie cookie("JSESSIONID", "deleted");
    cookie.setPath("/");
    cookie.setExpiresDate(trantor::Date(0));
    resp->addCookie(cookie);

    callback(resp);

[an-tao]

We need to add a method (e.g. disableSession()) in the HttpResponse class to achieve this. I'll add it when I have time.