anchor.diff:  %% @end
   %%--------------------------------------------------------------------
   -spec init(Args :: term()) ->
  -    {ok, State :: #state{}} |
  -    {ok, State :: #state{}, timeout() | hibernate} |
  -    ignore |
  -    {stop, Reason :: term()}.
  +    {ok, state()} | {ok, state(), timeout() | hibernate} |
  +    {stop, Reason :: term()} | ignore.
   init([]) ->
       {ok, #state{}}.
   
  +
   %%--------------------------------------------------------------------
   %% @private
   %% @doc
  
positive.code: %%%===================================================================
  
  
  %% sends and awaits answer.
  communicate() -> ok.
  
  
  %% makes sure to put on socket.
  send_sync() -> ok.
  
  
  %% schedules sending.
  send_async() -> ok.
  
  
  %% send response.
  respond() -> ok.
  
  
  %%--------------------------------------------------------------------
  %% @doc
  %% Starts the server
  %%
  %% @end
  %%--------------------------------------------------------------------
  -spec(start_link() ->
      {ok, Pid :: pid()} | ignore | {error, Reason :: term()}).
  start_link() ->
      gen_server:start_link({local, ?SERVER}, ?MODULE, [], []).
  
  %%%===================================================================
  %%% gen_server callbacks
  %%%===================================================================
  
  %%--------------------------------------------------------------------
  %% @private
  %% @doc
  
negative.code: %% @end
  %%--------------------------------------------------------------------
  -spec handle_call(Request :: term(), From :: {pid(), Tag :: term()}, state()) ->
      {reply, Reply :: term(), NewState :: state()} |
      {reply, Reply :: term(), NewState :: state(), timeout() | hibernate} |
      {noreply, NewState :: state()} |
      {noreply, NewState :: state(), timeout() | hibernate} |
      {stop, Reason :: term(), Reply :: term(), NewState :: state()} |
      {stop, Reason :: term(), NewState :: state()}.
  handle_call(_Request, _From, State) ->
      {reply, ok, State}.
  
  
  %%--------------------------------------------------------------------
  %% @private
  %% @doc
  