请问java消费rabbitmq队列消息,如何实现多线程并发消费消息呢?

java11
没有使用springboot

     channel.exchangeDeclare(exchangeName, exchangeType, true);
//        4.监听队列
        channel.queueBind("click", exchangeName, routingKey);

        MyConsumer myConsumer = new MyConsumer(channel);

        int prefetchCount = 100; // 设置每个消费者预取的消息数量
        channel.basicQos(prefetchCount); // 设置消费者的 QoS

        // 启动多个线程处理消息
        for (int i = 0; i < 100; i++) {
            Thread thread = new Thread(() -> {
                try {
                    channel.basicConsume("bookmark_click", false, myConsumer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            });
            thread.start();
        }
    }

    static class MyConsumer extends DefaultConsumer {
        // 其他代码...

        public MyConsumer(Channel channel) {
            super(channel);
        }

        @Override
        public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }
            LocalDateTime currentTime = LocalDateTime.now();
            System.out.println("Current time: " + currentTime);
            getChannel().basicAck(envelope.getDeliveryTag(), false);
        }
    }

为什么以上代码.是一个个消息执行,每个消息需要一秒,为什么不能每一秒100个消息并发执行呢? 为什么会出现阻塞呢?