anchor.diff:      lager:info("~p: node ~p acknowledging value for key ~p value ~p", [?MODULE, node(), Key, Value]),
   
       %% Send backup message to backups.
  -    lists:foreach(fun(Backup) ->
  -        forward_message(Backup, {backup, From, Key, Value})
  -    end, Backups),
  +    lists:foreach(fun(Backup) -> forward_message(Backup, {backup, From, Key, Value}) end, Backups),
   
       %% On ack, reply to caller.
       gen_server:reply(From, ok),
  
positive.code:                     lager:info("~p: node ~p ack received for key ~p value ~p", [?MODULE, node(), Key, Value]),
                      {reply, ok, State#state{store=Store}}
              after
                  ?PB_RETRY_TIMEOUT ->
                      {reply, {error, timeout}, State}
              end;
          _ ->
              {reply, {error, {primary, Primary}}, State}
      end;
  handle_call({read, Key}, _From, #state{nodes=[Primary|_Rest], store=Store}=State) ->
      case node() of 
          Primary ->
              Value = case dict:find(Key, Store) of 
                  {ok, V} ->
                      V;
                  error ->
                      not_found
              end,
              lager:info("~p: node ~p received read for key ~p and returning value ~p", [?MODULE, node(), Key, Value]),
              {reply, {ok, Value}, State};
          _ ->
              {reply, {error, {primary, Primary}}, State}
      end;
  handle_call(_Msg, _From, State) ->
      {reply, ok, State}.
  
negative.code:     lager:info("~p: node ~p storing updated value key ~p value ~p", [?MODULE, node(), Key, Value]),
  
      {noreply, State#state{store=Store}};
  handle_info({forwarded_read, From, FromNode, Key}, #state{store=Store}=State) ->
      Value = read(Key, Store),
  
      lager:info("~p: node ~p received forwarded read for key ~p and returning value ~p", [?MODULE, node(), Key, Value]),
  
      %% Notify forwarder that read was serviced.
      forward_message(FromNode, {forwarded_read_ack, From, Key, Value}),
      lager:info("~p: node ~p acknowledging forwarded read for key ~p value ~p", [?MODULE, node(), Key, Value]),
  
      %% Reply to caller.
      gen_server:reply(From, {ok, Value}),
  
      {noreply, State};
  handle_info(_Msg, State) ->
      {noreply, State}.
  
  