public static void addPublicConfig(ConfigDef configDef) {
        addInternalConfig(configDef);
        configDef
                .define(
                        REST_EXTENSION_CLASSES_CONFIG,
                        ConfigDef.Type.LIST,
                        "",
                        ConfigDef.Importance.LOW, REST_EXTENSION_CLASSES_DOC
                ).define(ADMIN_LISTENERS_CONFIG,
                        ConfigDef.Type.LIST,
                        null,
                        new AdminListenersValidator(),
                        ConfigDef.Importance.LOW,
                        ADMIN_LISTENERS_DOC);
    }
Add the properties related to a user-facing server to the given {@link ConfigDef}.
</p>
This automatically adds the properties for intra-cluster communication; it is not necessary to
invoke both {@link #addInternalConfig(ConfigDef)} and this method on the same {@link ConfigDef}.
@param configDef the {@link ConfigDef} to add the properties to; may not be null
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/rest/RestServerConfig.java