anchor.diff:  (define-ffi-method ffi-buffer-get-proxy ((buffer gtk-buffer))
     "Return the proxy URL and list of ignored hosts (a list of strings) as second value."
     (the (values (or quri:uri null) list-of-strings)
  -       (values (proxy-url buffer)
  +       (values (gtk-proxy-url buffer)
                  (proxy-ignored-hosts buffer))))
   
   (define-ffi-method ffi-buffer-set-zoom-level ((buffer gtk-buffer) value)
  
positive.code: Note: WebKit supports three proxy 'modes': default (the system proxy),
  custom (the specified proxy) and none."
    (declare (type quri:uri proxy-url))
    (setf (proxy-url buffer) proxy-url)
    (setf (proxy-ignored-hosts buffer) ignore-hosts)
    (let* ((context (webkit:webkit-web-view-web-context (gtk-object buffer)))
           (settings (cffi:null-pointer))
  
negative.code: 
  (define-class gtk-buffer ()
    ((gtk-object)
     (gtk-proxy-url (quri:uri ""))
     (proxy-ignored-hosts '())
     (data-manager-path (make-instance 'data-manager-data-path
                                       :dirname (uiop:xdg-cache-home +data-root+))
  