anchor.diff:      {noreply, State};
   
   
  -handle_cast({consume}, #state{id                     = Id,
  -                              module                 = Mod,
  -                              num_of_batch_processes = NumOfBatchProc,
  -                              max_interval           = MaxInterval,
  -                              min_interval           = MinInterval,
  -                              backend_index          = BackendIndex,
  -                              backend_message        = BackendMessage} = State) ->
  +handle_cast(consume, #state{id                     = Id,
  +                            module                 = Mod,
  +                            num_of_batch_processes = NumOfBatchProc,
  +                            max_interval           = MaxInterval,
  +                            min_interval           = MinInterval,
  +                            backend_index          = BackendIndex,
  +                            backend_message        = BackendMessage} = State) ->
       case consume_fun(Id, Mod, BackendIndex, BackendMessage, NumOfBatchProc) of
           not_found ->
               defer_consume(Id, ?DEF_AFTER_NOT_FOUND_INTERVAL_MAX,
  
positive.code: -spec(status(atom()) ->
               {ok, list()}).
  status(Id) ->
      gen_server:call(Id, {status}, ?DEF_TIMEOUT).
  
  
  %%--------------------------------------------------------------------
  
negative.code: %%
  -spec(consume(atom()) -> ok | {error, any()}).
  consume(Id) ->
      gen_server:cast(Id, consume).
  
  
  %% @doc get state from the queue.
  