anchor.diff:      case Recipient =:= Self of
         true ->
           %% Instant delivery to self
  -        Self ! {trapping, element(2, Instant)},
  +        send_message_ack(Self, element(2, Instant)),
           ?notify_none;
         false -> Self
       end,
     Recipient ! {Type, Message, Notify},
     receive
  -    {trapping, Trapping} ->
  +    {message_ack, Trapping} ->
         NewMessageEvent = MessageEvent#message_event{trapping = Trapping},
         NewSpecial =
           case already_known_delivery(Message, Special) of
  
positive.code:           catch
              exit:{?MODULE, _} = Reason -> exit(Reason);
              throw:no_reply ->
                Report ! {trapping, false},
                ok;
              Type:Reason ->
                Stacktrace = erlang:get_stacktrace(),
  
negative.code:           ?debug_flag(?loop, sending_kill_to_cancel),
            ets:delete(Timers, Ref),
            Pid ! {exit_signal, #message{data = kill}, self()},
            false = receive_message_ack()
        end,
        {1, Info}
    end;
  