anchor.diff:  start_link() ->
       gen_server:start_link({local, ?MODULE}, ?MODULE, [], []).
   
  +stop() ->
  +    %% only call after all application that call INTO a
  +    %% plugin are stopped...
  +    gen_server:call(?MODULE, stop, infinity).
  +
   -spec enable_plugin(atom()) -> ok | {error, _}.
   enable_plugin(Plugin) ->
       enable_plugin(Plugin, auto).
  
positive.code: %%                                   {stop, Reason, State}
  %% @end
  %%--------------------------------------------------------------------
  handle_call(Call, _From, #state{ready=true} = State) ->
      handle_plugin_call(Call, State);
  handle_call(Call, From, #state{defered_calls=DeferedCalls} = State) ->
  
negative.code: 
  %% API
  -export([start_link/0,
           stop/0,
           enable_plugin/1,
           enable_plugin/2,
           enable_module_plugin/3,
  