Function grant_session_cookie_path 

fn grant_session_cookie_path(callback_url: Option<&Url>) -> &str

Path attribute for the grant-session cookie. The set and removal cookies must use the same value: a cookie is only replaced (and thus removed) when its name, domain and path all match (RFC 6265 5.3), and a Set-Cookie without an explicit path defaults to the request-URI’s directory.