Jose\Encrypter::preparePayload PHP Метод

    private function preparePayload($payload, Compression\CompressionInterface $compression_method = null)
    {
        $prepared = is_string($payload) ? $payload : json_encode($payload);
        Assertion::notNull($prepared, 'The payload is empty or cannot encoded into JSON.');
        if (null === $compression_method) {
            return $prepared;
        }
        $compressed_payload = $compression_method->compress($prepared);
        Assertion::string($compressed_payload, 'Compression failed.');
        return $compressed_payload;
    }