@Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        BrokerMetadata that = (BrokerMetadata) o;
        return id == that.id && Objects.equals(rack, that.rack);
    }
@param id an integer that uniquely identifies this broker
@param rack the rack of the broker, which is used to in rack aware partition assignment for fault tolerance.
            Examples: "RACK1", "us-east-1d"
server-common/src/main/java/org/apache/kafka/admin/BrokerMetadata.java