anchor.diff:  -define(BP_QUEUE,    5).
   -define(BP_STEPPED,  6).
   -define(BP_STEPPER,  7).
  +-define(EXC_SUBS,    8).
   
   %% userdevguide-begin gen_component:behaviour
   -ifdef(have_callback_support).
  
positive.code: %     Options, _Slowest = 0.0,
       _BPs = [], _BPActive = false,
       _BPHoldbackQueue = [], _BPStepped = false,
       _BPStepperPid = unknown
      }.
  gc_mod(State) ->                element(?MOD, State).
  gc_hand(State) ->               element(?HAND, State).
  gc_set_hand(State, Handler) ->  setelement(?HAND, State, Handler).
  %% opts
  %% slowest
  -spec gc_bps(gc_state()) -> [bp()].
  
negative.code:                           UState ->
                                DefaultHandler
                        end,
              T2State = case lists:keyfind(exception_subscription, 1, Options) of
                            {exception_subscription, Subs} ->
                                gc_set_exc_subs(T1State, Subs);
                            _ ->
                                T1State
                        end,
              {UState, gc_set_hand(T2State, Handler)}
          catch
              % If init throws up, send 'started' to the supervisor but exit.
              % The supervisor will try to restart the process as it is watching
  