Common/EventListener/AbstractSaleAddressListener.php
public function onUpdate(ResourceEventInterface $event)
    {
        $address = $this->getAddressFromEvent($event);

        if ($this->persistenceHelper->isChanged($address, 'country')) {
            $this->scheduleSaleAddressChangeEvent($address);
        }
    }
public function onUpdate(ResourceEventInterface $event)
    {
        $address = $this->getAddressFromEvent($event);

        if ($this->persistenceHelper->isChanged($address, 'country')) {
            $this->scheduleSaleAddressChangeEvent($address);
        }
    }
Update event handler.

@param ResourceEventInterface $event