addRefund example

$this->ids,
            'refund',
            $this->ids->get('capture')
        ))
            ->add('stateId', $this->getStateMachineState(
                OrderTransactionCaptureRefundStates::STATE_MACHINE,
                OrderTransactionCaptureRefundStates::STATE_OPEN
            ))
            ->build();

        $capture = (new OrderTransactionCaptureBuilder($this->ids, 'capture', $this->ids->get('transaction')))
            ->addRefund('refund', $refund)
            ->build();

        $transaction = (new OrderTransactionBuilder($this->ids, '10000'))
            ->addCapture('capture', $capture)
            ->add('paymentMethod', [
                'id' => $this->ids->get('payment_method'),
                // this enables refund handling for the payment method                 'handlerIdentifier' => RefundPaymentHandlerInterface::class,
                'translations' => [
                    Defaults::LANGUAGE_SYSTEM => [
                        'name' => 'foo',
                    ],