anchor.diff:      {noreply, #state{}} | {stop, term(), #state{}}.
   
   handle_cast({send_stun, Ip, Port, Pid}, State) ->
  -    {noreply, do_send_stun(Ip, Port, {cast, Pid}, State)};
  +    {noreply, do_send_stun(Ip, Port, {msg, Pid}, State)};
   
   handle_cast(Msg, #state{nkport=NkPort}=State) ->
       case call_protocol(listen_handle_cast, [Msg, NkPort], State) of
  
positive.code:     end.
  
  
  %% @private Sends a STUN binding request
  send_stun_async(Pid, Ip, Port) ->
      gen_server:cast(Pid, {send_stun, Ip, Port, self()}).
  
  
negative.code:                          [Ip, Port, Error]),
              case From of
                  {call, CallFrom} -> gen_server:reply(CallFrom, error);
                  {msg, MsgPid} -> MsgPid ! {stun, error}
              end,
              State
      end.
  