public function createSession(Token $token)
    {
        $response = $this->sendInstallationPostRequest(
            '/v1/session-server',
            [
                'headers' => [
                    'X-Bunq-Client-Authentication' => $token->toString(),
                ],
                'json'    => [
                    'secret' => $this->apiKey,
                ],
            ]
        );

        $responseArray = \json_decode((string)$response->getBody(), true);

        return $responseArray['Response'][1]['Token']['token'];
    }