anchor.diff:  handle_cast(Msg, State) ->
       {stop, {badmsg, Msg}, State}.
   
  -handle_info(_Info, State) ->
  -    {noreply, State}.
  +handle_info(Info, State) ->
  +    {stop, {badinfo, Info}, State}.
   
   terminate(_Reason, _State) ->
       ok.
  
positive.code:     {ok, NewState} = unsubscribe(State, Topics),
      {reply, ok, NewState};
  
  handle_call(_Request, _From, State) ->
      {reply, ok, State}.
  
  handle_cast({publish, ?QOS_2, Message}, State) ->
      NewState = publish(State, {?QOS_2, Message}),
  
negative.code: %% ------------------------------------------------------------------
  
  
  