getRecipientsPayload example

    private function getPayload(Email $email, Envelope $envelope): array
    {
        $payload = [
            'key' => $this->key,
            'message' => [
                'html' => $email->getHtmlBody(),
                'text' => $email->getTextBody(),
                'subject' => $email->getSubject(),
                'from_email' => $envelope->getSender()->getAddress(),
                'to' => $this->getRecipientsPayload($email, $envelope),
            ],
        ];

        if ('' !== $envelope->getSender()->getName()) {
            $payload['message']['from_name'] = $envelope->getSender()->getName();
        }

        foreach ($email->getAttachments() as $attachment) {
            $headers = $attachment->getPreparedHeaders();
            $disposition = $headers->getHeaderBody('Content-Disposition');