$dummy = new class {
            #[\Symfony\Component\Serializer\Annotation\SerializedName('@test')]
            public bool $foo = false;
            public bool $bar = false;
        };

        $classMetadataFactory = new ClassMetadataFactory(new AnnotationLoader(new AnnotationReader()));
        $metadataAwareNameConverter = new MetadataAwareNameConverter($classMetadataFactory);

        $serializer = new Symfony\Component\Serializer\Serializer([
            new ObjectNormalizer($classMetadataFactory, $metadataAwareNameConverter)
        ], [
            new \Symfony\Component\Serializer\Encoder\XmlEncoder()
    ]);
        var_dump($serializer->serialize($dummy, 'xml'));