private void registerDefaultConfiguration(final AnnotationMetadata metadata, final BeanDefinitionRegistry registry) {
        Map<String, Object> defaultAttrs = metadata.getAnnotationAttributes(EnableShenyuClients.class.getName(), true);

        if (MapUtils.isNotEmpty(defaultAttrs) && defaultAttrs.containsKey("defaultConfiguration")) {
            String name;
            if (metadata.hasEnclosingClass()) {
                name = "default." + metadata.getEnclosingClassName();
            } else {
                name = "default." + metadata.getClassName();
            }
            LOG.info("registerDefaultConfiguration name:{}", name);
            registerClientConfiguration(registry, name, defaultAttrs.get("defaultConfiguration"));
        }
    }
Validate fallback factory.
@param clazz the clazz
shenyu-sdk/shenyu-sdk-feign/src/main/java/org/apache/shenyu/sdk/feign/ShenyuClientsRegistrar.java