anchor.diff:            ?debug_flag(?loop, sending_kill_to_cancel),
             ets:delete(Timers, Ref),
             Pid ! {exit_signal, #message{data = kill}, self()},
  -          receive {trapping, false} -> ok end
  +          false = receive_message_ack()
         end,
         {1, Info}
     end;
  
positive.code: send_message_ack(Notify, Trapping) ->
    case Notify =/= ?notify_none of
      true ->
        Notify ! {trapping, Trapping},
        ok;
      false -> ok
    end.
  
  get_leader(#concuerror_info{processes = Processes}, P) ->
  
negative.code:           catch
              exit:{?MODULE, _} = Reason -> exit(Reason);
              throw:no_reply ->
                send_message_ack(Report, false),
                ok;
              Type:Reason ->
                Stacktrace = erlang:get_stacktrace(),
  