Map<String, String> transform(Map<String, String> props) {
        // transform worker config according to config.providers
        List<String> providerNames = configProviders();
        Map<String, ConfigProvider> providers = new HashMap<>();
        for (String name : providerNames) {
            ConfigProvider configProvider = plugins.newConfigProvider(
                    this,
                    CONFIG_PROVIDERS_CONFIG + "." + name,
                    Plugins.ClassLoaderUsage.PLUGINS
            );
            providers.put(name, configProvider);
        }
        ConfigTransformer transformer = new ConfigTransformer(providers);
        Map<String, String> transformed = transformer.transform(props).data();
        providers.values().forEach(x -> Utils.closeQuietly(x, "config provider"));
        return transformed;
    }
Construct a MirrorClientConfig from properties of the form cluster.x.y.z.
Use to connect to a cluster based on the MirrorMaker top-level config file.
connect/mirror/src/main/java/org/apache/kafka/connect/mirror/MirrorMakerConfig.java