anchor.diff:      gen_server:start_link({local, ?MODULE}, ?MODULE, DriverMod, []).
   
   msgs([Adr | Msgs]) ->
  -    do_msgs(Adr, Msgs).
  +    EncodedMsgs = do_msgs(Adr, Msgs),
  +    gen_server:call(?MODULE, {msgs, EncodedMsgs}).
  +
   
   %--- Callbacks -----------------------------------------------------------------
   
  
positive.code:     {ok, #state{driver = {DriverMod, Ref}}}.
  
  % @private
  handle_call({msgs, Enc_msgs}, _From, State) ->
      {DriverMod, Ref} = State#state.driver,
      Resp = DriverMod:command(Ref, Enc_msgs),
      {reply, Resp, State}.
  
  % @private
  handle_cast(Request, _State) -> error({unknown_cast, Request}).
  
negative.code:     Data_len = byte_size(W),
      Msg_count = byte_size(M) div 8,
      <<Data_len:16, W/binary, Msg_count:16, M/binary>>.
  
  maybe_send_msgs({sleep, Time}, _DriverMod, _Ref) ->
      timer:sleep(Time);
  maybe_send_msgs(Msg, DriverMod, Ref) ->
      DriverMod:command(Ref, Msg).
  