Esc.cpp : esc_status_sub_cb(const uavcan::ReceivedDataStructure<uavcan::equipment::esc::Status> &msg) functionality

I am new to c++ and I am trying to make modifications to understand how

void UavcanEscController::esc_status_sub_cb(const uavcan::ReceivedDataStructureuavcan::equipment::esc::Status &msg)

the above function works. I could see it is been called from uavcan_main.cpp but i could not see any execution for this method when i run my code in qgroundcontrol. I went through the documentation but still could not figure out what i am missing over here. Can someone tell me how to access this function?

It has been made as a “private method” but I wanted to understand whats is actually happening inside this function. I wont be able to do it unless this function executes.
Any pointers would be helpful
Thank you

Thanks and Regards