@Override
    public void stop() {
        log.info("Herder stopping");

        stopping.set(true);
        member.wakeup();
        ThreadUtils.shutdownExecutorServiceQuietly(herderExecutor, herderExecutorTimeoutMs(), TimeUnit.MILLISECONDS);
        ThreadUtils.shutdownExecutorServiceQuietly(forwardRequestExecutor, FORWARD_REQUEST_SHUTDOWN_TIMEOUT_MS, TimeUnit.MILLISECONDS);
        ThreadUtils.shutdownExecutorServiceQuietly(startAndStopExecutor, START_AND_STOP_SHUTDOWN_TIMEOUT_MS, TimeUnit.MILLISECONDS);
        log.info("Herder stopped");
    }
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