anchor.diff:      gen_server:start_link(?MODULE, [], []).
   
   enqueue_message(To, Msg) ->
  -    gen_server:cast(To, {enqueue, Msg}).
  +    gen_server:call(To, {enqueue, Msg}).
   
   acknowledge_message(To, SubId, MsgId) ->
       gen_server:cast(To, {acknowledge, SubId, MsgId}).
  
positive.code:             Queue2 = Queue,
              MsgSeqs2 = MsgSeqs
      end,
      {noreply, State#state{qsize = Size, queue = Queue2,
                            next_seq = Seq + 1, msg_seqs = MsgSeqs2}};
  handle_cast({acknowledge, SubId, MsgId}, State) ->
      case gb_trees:lookup(MsgId, State#state.msg_seqs) of
          {value, Seq} ->
  
negative.code:                       {subscribers_purge_interval, SubscribersPurgeInterval}),
      {ok, #state{max_qsize = MaxQueueSize}}.
  
  handle_call({enqueue, Msg}, _From, State) ->
      Seq = State#state.next_seq,
      Queue = queue:in({Seq, Msg}, State#state.queue),
      MsgId = mumq_stomp:get_header(Msg, <<"message-id">>),
  