object Broker {
  private[cluster] case class ServerInfo(clusterResource: ClusterResource,
                                         brokerId: Int,
                                         endpoints: util.List[Endpoint],
                                         interBrokerEndpoint: Endpoint,
										 override val metrics: Metrics) extends AuthorizerServerInfo
}

case class Broker(id: Int, endPoints: Seq[EndPoint], rack: Option[String]) {
  ......
  def toServerInfo(clusterId: String, config: KafkaConfig, metrics: Metrics): AuthorizerServerInfo = {
    val clusterResource: ClusterResource = new ClusterResource(clusterId)
    val interBrokerEndpoint: Endpoint = endPoint(config.interBrokerListenerName).toJava
    val brokerEndpoints: util.List[Endpoint] = endPoints.toList.map(_.toJava).asJava
    Broker.ServerInfo(clusterResource, id, brokerEndpoints, interBrokerEndpoint, metrics)
  }
}