anchor.diff:     MODE is one of 'default' (use system configuration), 'custom'
      or 'none'.
      ADDRESS is in the form PROTOCOL://HOST:PORT."
  -  ;; TODO: Implement support in cl-webkit
  +  ;; TODO: Store proxy settings in BUFFER since webkit cannot return the current proxy.
     )
  
positive.code:   (setf (id buffer) (get-unique-buffer-identifier *interface*))
    (setf (gtk-object buffer)
          (make-instance 'cl-webkit2:webkit-web-view
                         :context (make-context buffer)))
    (gobject:g-signal-connect
     (gtk-object buffer) "decide-policy"
  
negative.code: 
     Note: WebKit supports three proxy 'modes': default (the system proxy),
     custom (the specified proxy) and none."
    (let* ((context (cl-webkit2:webkit-web-view-web-context (gtk-object buffer)))
           (settings (cffi:null-pointer))
           (mode :webkit-network-proxy-mode-no-proxy))
      (unless (str:emptyp proxy-uri)
        (setf mode :webkit-network-proxy-mode-custom)
        (setf settings
              (cl-webkit2:webkit-network-proxy-settings-new
               proxy-uri
               ;; TODO: Support ignore-hosts.
               (cffi:null-pointer))))
      (cl-webkit2:webkit-web-context-set-network-proxy-settings
       context
       :webkit-network-proxy-mode-custom settings)))
  
  @export
  (defmethod ipc-buffer-get-proxy ((buffer gtk-buffer))
  