src/Serializer/JsonSerializer.php
public function serialize(Message $message, array $options = [])
    {
        if (isset($options['json_encode_options'])) {
            return json_encode(parent::serialize($message, $options), $options['json_encode_options']);
        }

        return json_encode(parent::serialize($message, $options));
    }
public function serialize(Message $message, array $options = [])
    {
        if (isset($options['json_encode_options'])) {
            return json_encode(parent::serialize($message, $options), $options['json_encode_options']);
        }

        return json_encode(parent::serialize($message, $options));
    }
{@inheritdoc}