anchor.diff:  
       {noreply, State#state{refs_pub=NewRefs}};
   
  -handle_cast({unsubscribe_exchange, UserId, ExchangeName, From}, State=#state{refs_sub=Refs}) ->
  +handle_cast({unsubscribe_exchange, _UserId, _ExchangeName, From}, State=#state{refs_sub=Refs}) ->
       NewRefs = case dict:find(From, Refs) of
           error -> Refs;
           {ok, Ref} -> erlang:demonitor(Ref, [flush]),
  
positive.code:     NewRefsSub = case dict:find(Pid, RefsSub) of
                    error -> Refs;
                       {ok, RefSub} -> erlang:demonitor(RefSub, [flush]),
                                       dict:erase(Pid)
                end,
  
      F2 = fun() -> mnesia:delete({subscribers, Pid}) end,
  
negative.code:     NewRefs = case dict:find(Pid, Refs) of
                    error -> Refs;
                    {ok, Ref} -> erlang:demonitor(Ref, [flush]),
                                 dict:erase(Pid, Refs)
                end,
  
      F = fun() -> mnesia:delete({publishers, Pid}) end,
  