void shutdown(int timeout) {
        shutdownAndAwaitTermination(executorService, timeout);
        shutdownAndAwaitTermination(leaseExtendExecutorService, timeout);
        leaseExtendMap.clear();
    }
Manages the threadpool used by the workers for execution and server communication (polling and
task update).
client/src/main/java/com/netflix/conductor/client/automator/TaskPollExecutor.java