Invoice/EventListener/AbstractInvoiceListener.php
public function onDelete(ResourceEventInterface $event)
    {
        $invoice = $this->getInvoiceFromEvent($event);

        $this->updateCustomerBalance($invoice);

        $sale = $this->getSaleFromInvoice($invoice);

        $sale->removeInvoice($invoice);

        $this->scheduleSaleContentChangeEvent($sale);
    }
public function onDelete(ResourceEventInterface $event)
    {
        $invoice = $this->getInvoiceFromEvent($event);

        $this->updateCustomerBalance($invoice);

        $sale = $this->getSaleFromInvoice($invoice);

        $sale->removeInvoice($invoice);

        $this->scheduleSaleContentChangeEvent($sale);
    }
Delete event handler.

@param ResourceEventInterface $event