anchor.diff:              %% Write value locally.
               Store = dict:store(Key, Value, Store0),
   
  -            %% Forward to replicas and wait for reply, then write locally and return.
  +            %% Forward to collaboration message.
               FromNode = partisan_peer_service_manager:myself(),
               Manager = partisan_config:get(partisan_peer_service_manager),
  -
  -            lists:foreach(fun(N) ->
  -                ok = Manager:forward_message(N, undefined, ?MODULE, {update, From, FromNode, Key, Value}, [])
  -            end, Rest),
  +            ok = Manager:forward_message(Collaborator, undefined, ?MODULE, {collaborate, From, FromNode, Key, Value}, []),
               lager:info("~p: node ~p sent replication request for key ~p with value ~p", [?MODULE, node(), Key, Value]),
   
               {noreply, State#state{store=Store}};
  
positive.code:     {ok, #state{nodes=Nodes, store=Store}}.
  
  %% @private
  handle_call({write, Key, Value}, From, #state{nodes=[Node|Rest], store=Store0}=State) ->
      case node() of 
          Node ->
              lager:info("~p: node ~p received write for key ~p with value ~p", [?MODULE, node(), Key, Value]),
  
negative.code:     {noreply, State}.
  
  %% @private
  handle_info({collaborate_ack, From, Key, Value}, State) ->
      lager:info("~p: node ~p ack received for key ~p value ~p", [?MODULE, node(), Key, Value]),
  
      %% On ack, reply to caller.
      gen_server:reply(From, ok),
  
      {noreply, State};
  handle_info({collaborate, From, FromNode, Key, Value}, #state{store=Store0}=State) ->
      %% Write value locally.
      Store = dict:store(Key, Value, Store0),
      lager:info("~p: node ~p storing updated value key ~p value ~p", [?MODULE, node(), Key, Value]),
  
      %% Send write acknowledgement.
      Manager = partisan_config:get(partisan_peer_service_manager),
      ok = Manager:forward_message(FromNode, undefined, ?MODULE, {collaborate_ack, From, Key, Value}, []),
      lager:info("~p: node ~p acknowledging value for key ~p value ~p", [?MODULE, node(), Key, Value]),
  
      {noreply, State#state{store=Store}};
  