Help: KafkaConsumer iterator ignores consumer_timeout_ms if entire cluster is down

Hi! Forgive my poor English, but I need your help. @dpkp While stress testing Kafka, I have found that comsumer can block forever when all brokers down. After all brokers down, comsumer will fall into a loop to getting metadata from broker. This loop will never break util one or more brokers restart.
Is there a way that consumer can break this loop? I do not want block here, I want to do some other things when brokers down.

my code is like this:

consumer = KafkaConsumer(bootstrap_servers=['xxxxx','xxxxx'],
                                              group_id="test1",
                                              consumer_timeout_ms= 2000)
partition = TopicPartition("topic1", 0)
consumer.assign([partition])
consumer.seek_to_end()
for message in consumer: # it will block here when all brokers down
    print msg

After consumer block, I got this when keyboardInterrupt:

other infos: kafka_python-1.3.2 python2.6.3 kafka_2.11-0.10.2.1

[stigok]

I experience the same thing. And the loop makes CPU go to 100%.

[JamesMackerel]

After testing, I found a surprise. It will block, until the cluster is back. But I still want to know if there is any way to know if the cluster is down in consumer.