@Override
    public void connectors(final Callback<Collection<String>> callback) {
        log.trace("Submitting connector listing request");

        addRequest(
            () -> {
                if (!checkRebalanceNeeded(callback))
                    callback.onCompletion(null, configState.connectors());
                return null;
            },
            forwardErrorAndTickThreadStages(callback)
        );
    }
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