如何允许/等待Akka streams在JVM关闭时完成？

import akka.actor.ActorSystem;
import akka.stream.ActorMaterializer;
import akka.stream.Materializer;
import akka.stream.javadsl.Sink;
import akka.stream.javadsl.Source;

public class AkkaStreamsExample {
    public static void main(String[] args) {
        // 创建ActorSystem
        ActorSystem system = ActorSystem.create("akka-streams-example");

        // 创建Materializer
        Materializer materializer = ActorMaterializer.create(system);

        // 创建一个简单的流程
        Source.range(1, 10)
                .map(i -> i * 2)
                .runWith(Sink.foreach(System.out::println), materializer);

        // 注册JVM关闭时的钩子函数
        system.registerOnTermination(() -> {
            // 关闭Materializer，等待流程完成
            materializer.shutdown();
        });

        // 执行JVM关闭操作
        system.terminate();
    }
}