anchor.diff:      ?CORE:wait_needed(Id, Threshold, Store, From, ReplyFun, ?BLOCKING);
   handle_call({read, Id, Threshold}, From, #state{store=Store}=State) ->
       %% @todo Normalize this ReplyFun in the future.
  -    ReplyFun = fun({_Id, Type, Value}) ->
  -                    {reply, {ok, {_Id, Type, Value}}, State};
  +    ReplyFun = fun({_Id, Type, Metadata, Value}) ->
  +                    {reply, {ok, {_Id, Type, Metadata, Value}}, State};
                     ({error, Error}) ->
                       {reply, {error, Error}, State}
                  end,
  
positive.code: %% Broadcast record.
  -record(broadcast, {id :: id(),
                      type :: type(),
                      metadata :: metadata(),
                      value :: value()}).
  
  
negative.code: 
  %% @private
  -spec handle_call(term(), {pid(), term()}, #state{}) -> {reply, term(), #state{}}.
  handle_call({declare, Id, Type}, _From, #state{store=Store, actor=Actor, counter=Counter}=State) ->
      {ok, Id} = ?CORE:declare(Id, Type, ?CLOCK_INIT, Store),
      {reply, {ok, Id}, State#state{counter=increment_counter(Counter)}};
  handle_call({bind, Id, Value}, _From, #state{store=Store, counter=Counter}=State) ->
      Result = ?CORE:bind(Id, Value, Store),
      {reply, Result, State#state{counter=increment_counter(Counter)}};
  handle_call({bind, Id, Metadata0, Value}, _From, #state{store=Store, counter=Counter}=State) ->
      Result = ?CORE:bind(Id, Value, ?CLOCK_MERG, Store),
      {reply, Result, State#state{counter=increment_counter(Counter)}};
  handle_call({bind_to, Id, DVId}, _From, #state{store=Store}=State) ->
      {ok, _Pid} = ?CORE:bind_to(Id, DVId, Store, ?BIND, ?READ),
  