public ApiMessageAndVersion toRecord() {
        return new ApiMessageAndVersion(
            new ZkMigrationStateRecord().setZkMigrationState(value()),
            (short) 0
        );
    }
The controller is a ZK controller. No migration has been performed. This state is never persisted
and is only used by KafkaController in order to have a unified metric that indicates what kind of
metadata state the controller is in.
metadata/src/main/java/org/apache/kafka/metadata/migration/ZkMigrationState.java