MySensors send message with ACK and wait for confirmation message

SendWithACK.cpp

bool magAck;
MyMessage msgBtn(PIN_BUTTON_1, V_TRIPPED);

void loop()
{
    int8_t btn = sleep(0, CHANGE, 1, CHANGE, 3600000);
    if (btn >= 0) 
    {
        delay(20);
        msgBtn.sensor = PIN_BUTTON_1 + btn;
        msgAck = false;
        for (int i = 0; msgAck == false && i < 3; i++)
        {
            send(msgBtn.set(digitalRead(PIN_BUTTON_1 + btn) == LOW), true);
            wait(500, C_SET, V_TRIPPED);
		}
	}
}

void receive(const MyMessage& msg)
{
	if (msg.isAck() && msg.sensor == PIN_BUTTON && msg.type == V_TRIPPED)
	{ 
		msgAck = true;
	}
}