booming example session

$data_string = json_encode([
    'game_id' => '55f2dc09ba36f81816000001',
    'balance' => '123',
    'currency' => 'EUR',
    'locale' => 'en',
    'player_id' => 'asdf',
    'callback' => $this->callBackUrl,
    'rollback_callback' => $this->rollBackCallBackUrl,
    'bonus_callback' => $this->bonusCallBackUrl,
    'demo' => false,
    'variant' => 'desktop',
]);

$nonce = rand() << 32 | rand();
$message = '/v2/session' . $nonce . hash('sha256', $data_string);
    $signature = hash_hmac('sha512', $message, $this->apiSecret);

$ch = curl_init($this->apiUrl . 'v2/session');
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'POST');
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $data_string);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, [
    'Content-Type: application/json',
    'Content-Length: ' . strlen($data_string),
    'X-Bg-Api-Key: ' . $this->apiKey,
    'X-Bg-Nonce: ' . $nonce,
    'X-Bg-Signature: ' . $signature
]);

$result = curl_exec($ch);

echo '<pre>'; print_r($result);