@Override
    protected Map<String, ConfigValue> validateSinkConnectorConfig(SinkConnector connector, ConfigDef configDef, Map<String, String> config) {
        Map<String, ConfigValue> result = super.validateSinkConnectorConfig(connector, configDef, config);
        validateSinkConnectorGroupId(config, result);
        return result;
    }
Close resources managed by this herder but which are not explicitly started.
connect/runtime/src/main/java/org/apache/kafka/connect/runtime/distributed/DistributedHerder.java