loadContacts example

    public function flush(): void
    {
        if (empty($this->entries) || $this->flushError) {
            return;
        }

        $this->connection->beginTransaction();

        try {
            $contacts = $this->loadContacts();

            foreach ($this->entries as $entry) {
                $this->connection->insert('s_mail_log', [
                    'type_id' => $entry->getType() ? $entry->getType()->getId() : null,
                    'order_id' => $entry->getOrder() ? $entry->getOrder()->getId() : null,
                    'shop_id' => $entry->getShop() ? $entry->getShop()->getId() : null,
                    'subject' => $entry->getSubject(),
                    'sender' => (string) $entry->getSender(),
                    'sent_at' => $entry->getSentAt()->format('Y-m-d H:i:s'),
                    'content_html' => $entry->getContentHtml(),
                    'content_text' => $entry->getContentText(),
                ]);