anchor.diff:  handle_call({join, {_Name, _, _}=Node}, _From, State) ->
       gen_server:cast(?MODULE, {join, Node}),
       {reply, ok, State};
  +
  +handle_call(state, _From, State) ->
  +    {reply, {ok, State}, State};
   
   handle_call({send_message, Name, Message}, _From,
               #state{connections=Connections}=State) ->
  
positive.code: leave(Node) ->
      gen_server:call(?MODULE, {leave, Node}, infinity).
  
  %% @doc Decode state.
  decode(Active) ->
      sets:to_list(Active).
  
negative.code:          receive_message/1,
           decode/1]).
  
  %% debug.
  -export([state/0]).
  
  %% gen_server callbacks
  -export([init/1,
           handle_call/3,
  