Invoice/EventListener/AbstractInvoiceLineListener.php
public function onUpdate(ResourceEventInterface $event)
    {
        $line = $this->getInvoiceLineFromEvent($event);

        $this->preventForbiddenChange($line);

        $this->stockUnitAssigner->applyInvoiceLine($line);

        // If invoice item quantity has changed
        if ($this->persistenceHelper->isChanged($line, 'quantity')) {
            $this->scheduleInvoiceContentChangeEvent($line->getInvoice());
        }
    }
public function onUpdate(ResourceEventInterface $event)
    {
        $line = $this->getInvoiceLineFromEvent($event);

        $this->preventForbiddenChange($line);

        $this->stockUnitAssigner->applyInvoiceLine($line);

        // If invoice item quantity has changed
        if ($this->persistenceHelper->isChanged($line, 'quantity')) {
            $this->scheduleInvoiceContentChangeEvent($line->getInvoice());
        }
    }
Update event handler.

@param ResourceEventInterface $event