anchor.diff:  
   %% @doc Get history of a xnest.
   -spec history(pid(), number())-> {ok, list()} | {error, binary()}.
  -history(_XNestPid, _Count) ->
  +history(XNestPid, Count) ->
       %%可能直接调用hisotry模块的函数
  -    FadeHistory = [[{<<"from">>, <<"<0.1.0">>}, {<<"payload">>, <<"我来了">>}, {<<"send_time">>, <<"2014-12-27">>}] 
  -		  ,[{<<"from">>, <<"<0.1.0">>}, {<<"payload">>, <<"我来了">>}, {<<"send_time">>, <<"2014-12-27">>}]
  -		  ],
  -    %%gen_server:call(XNestPid, {history, Count}).
  -    {ok, FadeHistory}.
  +    %%FadeHistory = [[{<<"from">>, <<"<0.1.0">>}, {<<"payload">>, <<"我来了">>}, {<<"send_time">>, <<"2014-12-27">>}] 
  +    %%    	  ,[{<<"from">>, <<"<0.1.0">>}, {<<"payload">>, <<"我来了">>}, {<<"send_time">>, <<"2014-12-27">>}]
  +    %%    	  ],
  +    %%{ok, FadeHistory}.
  +    gen_server:call(XNestPid, {history, Count}).
   
   
   %% gen_server.
   init([]) ->
  +    History = [],
       Clients = ets:new(xnest, [set]),
       erlang:send_after(?TTL, self(), {tick}),
  -	{ok, #state{clients=Clients, idel_time=0}}.
  +    {ok, #state{history=History, clients=Clients, idel_time=0}}.
   
   %handle_call
   handle_call({join, ClientPid}, _From, State) ->
  
positive.code:     {reply, Result, State};
  
  
  
  handle_call({leave, ClientPid}, _From, State) ->
      Clients = State#state.clients,
  
negative.code:     catch _:_ ->
          {{error, <<"Error occured when deploy message!">>}, State}
      end,
  	{noreply, NewState#state{history=NewHistory}};
  
  handle_cast(_Msg, State) ->
  	{noreply, State}.
  