这个是Kafka跟ZK交互的工具类，Kafka在ZK上注册了以下的节点：
val ConsumersPath ="/consumers"//这个路径用于消费者的client.id存储对应消费的offset的路径.
val ClusterIdPath ="/cluster/id" // clusterid号
val BrokerIdsPath ="/brokers/ids"//这个路径用于存储所有的broker id的路径.
val BrokerTopicsPath ="/brokers/topics"//用于存储每个broker对应的topics的信息,
val ControllerPath ="/controller" //broker leader
val ControllerEpochPath ="/controller_epoch" //周期
val ReassignPartitionsPath ="/admin/reassign_partitions" //分区的重分配
val DeleteTopicsPath ="/admin/delete_topics"//用于存储删除的topic的信息.
val PreferredReplicaLeaderElectionPath ="/admin/preferred_replica_election"
val BrokerSequenceIdPath ="/brokers/seqid"
val IsrChangeNotificationPath ="/isr_change_notification"//这个用于在kafka的副本broker发生变化时用于通知的存储路径.
val EntityConfigPath ="/config"
val EntityConfigChangesPath ="/config/changes"
