Problem with Will Topic in arduino IDE.

[joko2020]

Hi There,
I need to use Will Topic on sketch but
I have experiencing problem when using Will topic on example mqtt esp8266.ino
The problem arise when I added
mqtt.will("/feed/test","offline");
I added those code before mqtt.connect
error log

and I try to change the code like this
Adafruit_MQTT.will("/feed/test","offline");

error log

I'm Using :
Arduino IDE : 1.8.12
Adafruit Mqtt Library : 2.1.0
Library installed from Library Manager

Please help to get ride from this problem , or maybe example sketch for using Will topic

Note :
I have Already test as given in https://learn.adafruit.com/mqtt-adafruit-io-and-you/qos-and-wills?view=all
with the same error