@Override
        public Void call() throws Exception {
            log.info("{}: Shutting down WorkerManager.", nodeName);
            try {
                stateChangeExecutor.submit(new DestroyAllWorkers()).get();
                log.info("{}: Waiting for shutdownManager quiescence...", nodeName);
                shutdownManager.waitForQuiescence();
                workerCleanupExecutor.shutdownNow();
                stateChangeExecutor.shutdownNow();
                log.info("{}: Waiting for workerCleanupExecutor to terminate...", nodeName);
                workerCleanupExecutor.awaitTermination(1, TimeUnit.DAYS);
                log.info("{}: Waiting for stateChangeExecutor to terminate...", nodeName);
                stateChangeExecutor.awaitTermination(1, TimeUnit.DAYS);
                log.info("{}: Shutting down shutdownExecutor.", nodeName);
                shutdownExecutor.shutdown();
            } catch (Exception e) {
                log.info("{}: Caught exception while shutting down WorkerManager", nodeName, e);
                throw e;
            }
            return null;
        }
Cleans up the resources associated with a worker.  Processed by the worker
cleanup thread pool.
trogdor/src/main/java/org/apache/kafka/trogdor/agent/WorkerManager.java