kafka集群
Leader partition3
topic
Follower2 partition1
Leader partition1
Consumer1
broker1
Leader partition2
Producer
Follower2 partition3
发送消息
负载均衡（默认）
Consumer3
Consumer Group
broker2
Follower1 partition2
Follower2 partition2
Consumer2
Follower1 partition1
Follower1 partition3
