code: func NewEtcdMigrateServer(cfg *EtcdMigrateCfg, client EtcdMigrateClient) *EtcdMigrateServer {
  	return &EtcdMigrateServer{cfg: cfg, client: client}
  }
docs: // NewEtcdMigrateServer creates a EtcdMigrateServer for starting and stopping a etcd server at the given version.