anchor.diff:  state_set_crashed_after(State, Val) -> setelement(4, State, Val).
   -spec state_get_table(state()) -> atom().
   state_get_table(State)              -> element(5, State).
  --spec state_get_monitors(state()) -> [{comm:mypid(), reference()}].
  +-spec state_get_monitors(state())   -> [{comm:mypid(), reference()}].
   state_get_monitors(State)           -> element(6, State).
   -spec state_set_monitors(state(), [{comm:mypid(), reference()}]) -> state().
   state_set_monitors(State, Val)      -> setelement(6, State, Val).
  
positive.code:         unchanged -> S1
      end;
  
  on({add_watching_of, WatchedPid} = _Msg, State) ->
      ?TRACE("fd_hbs add_watching_of ~.0p~n", [_Msg]),
      %% request from remote fd_hbs: watch a pid locally and forward
  
negative.code:     erlang:unlink(FD),
      _ = try
              lists:foldl(fun(X, S) -> on({crashed, X}, S) end,
                          State, [ rempid_get_rempid(RemPidEntry)
                                   || RemPidEntry <- state_get_rem_pids(State)])
          catch _:_ -> ignore_exception
          end,
      kill.
  