anchor.diff:      lists:foreach(fun(Backup) -> psend(Backup, {backup, From, Key, Value}) end, Backups),
   
       %% Send the response to the caller.
  -    gen_server:reply(From, ok),
  +    preply(From, ok),
   
       %% No need to send acknowledgement back to the forwarder: 
       %%  - not needed for control flow.
  
positive.code:             {error, timeout}
      end.
  
  %%%===================================================================
  %%% gen_server callbacks
  %%%===================================================================
  
negative.code:     {ok, #state{nodes=Nodes, store=Store}}.
  
  %% @private
  handle_call(_Msg, _From, State) ->
      {reply, ok, State}.
  
  %% @private
  handle_cast({write, From, Key, Value}, #state{nodes=[Primary, Collaborator|_Rest], store=Store0}=State) ->
      case node() of 
          Primary ->
              lager:info("~p: node ~p received write for key ~p with value ~p", [?MODULE, node(), Key, Value]),
  