type Migrator struct {
	cfg           *EtcdMigrateCfg // TODO: don't wire this directly in
	dataDirectory *DataDirectory
	client        EtcdMigrateClient
}

// MigrateIfNeeded upgrades or downgrades the etcd data directory to the given target version.
func (m *Migrator) MigrateIfNeeded(target *EtcdVersionPair) error {
	klog.Infof("Starting migration to %s", target)
	err := m.dataDirectory.Initialize(target)
	if err != nil {

	}
	client, err := NewEtcdMigrateClient(cfg)
	if err != nil {
		klog.Fatalf("Migration failed: %v", err)
	}
	defer client.Close()

	migrator := &Migrator{cfg, dataDir, client}

	err = migrator.MigrateIfNeeded(target)
	if err != nil {
		klog.Fatalf("Migration failed: %v", err)
	}