M_ACK_VARIABLE or M_SET_VARIABLE

[Lyubomyr]

In servo actuator sketch there is a line

if (message.type==V_DIMMER) { // This could be M_ACK_VARIABLE or M_SET_VARIABLE 

I do not understand the comment at all. I searched, but I can't find any information about M_ACK_VARIABLE or M_SET_VARIABLE

Please, help me to understand how can I send these type of messages, why one would like to do that and when is it necessary to use them.

Can Domoticz sent theses messages?

[BartE]

@Lyubomyr This M_ACK_VARIABLE or M_SET_VARIABLE looks like a left over from old releases
but what is meant here:

if (message.type==V_DIMMER) {  // can be a new set dimmer value form the Gateway or an acknowledge from a previous send message

In this example there are no message send and thus not acknowledged .
In other examples this line is seen, making the distinguish between new value or ACK

  if (message.isAck()) {
     Serial.println("This is an ack from gateway");
  }

Requesting for an ACK when sending a message is done by setting the third parameter of gw.send() to true

gw.send(msg.set(state?false:true), true);

[Lyubomyr]

Thank You very much!