@Override
    public void execute(final Runnable task) {
        this.singleThreadExecutor.execute(task);
    }
Anti-gentleman is not against villains, we believe that you are
providing a single-thread executor.

@param singleThreadExecutorService a {@link ExecutorService} instance
jraft-core/src/main/java/com/alipay/sofa/jraft/util/concurrent/DefaultSingleThreadExecutor.java