anchor.diff:  get_service(Bus, ServiceName) ->
       gen_server:call(Bus, {get_service, ServiceName, self()}).
   
  +release_service(Bus, Service) ->
  +    gen_server:call(Bus, {release_service, Service, self()}).
  +
   cast(Bus, Header) ->
       gen_server:cast(Bus, {cast, Header}).
   
  
positive.code: %% gen_server callbacks
  %%
  init([BusId, Owner]) ->
      process_flag(trap_exit, true),
      self() ! {setup, BusId},
      {ok, #state{owner=Owner}}.
  
  
negative.code: 	 export_service/2,
  	 unexport_service/2,
  	 get_service/2,
  	 release_service/2,
  	 cast/2
  	]).
  
  