public void waitForShutdown() throws Exception {
        while (!shutdownExecutor.isShutdown()) {
            shutdownExecutor.awaitTermination(1, TimeUnit.DAYS);
        }
    }
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