private void wakeupForTask() {
        final Worker worker = this.worker;
        if (worker != null) {
            worker.notifyIfNeeded();
        }
    }
Add a task to the task queue, or throws a {@link RejectedExecutionException} if
this instance was shutdown before.
jraft-core/src/main/java/com/alipay/sofa/jraft/util/concurrent/MpscSingleThreadExecutor.java