public function download()
    {
        $connection = $this->connection();
        $client = $connection->connect();

        $headers = [
            'Accept' => 'application/pdf',
            'Content-Type' => 'application/pdf',
            'Authorization' => 'Bearer ' . $connection->getAccessToken(),
        ];

        $endpoint = 'https://moneybird.com/' . $connection->getAdministrationId() . '/' . $this->endpoint . '/' . $this->id . '.pdf';
        $body = '';

        $request = new Request('GET', $endpoint, $headers, $body);
        $response = $client->send($request);

        return $response->getBody()->getContents();
    }