code: func newV1NodeClient(addr csiAddr) (nodeClient csipbv1.NodeClient, closer io.Closer, err error) {
  	var conn *grpc.ClientConn
  	conn, err = newGrpcConn(addr)
  	if err != nil {
  		return nil, nil, err
  	}
  
  	nodeClient = csipbv1.NewNodeClient(conn)
  	return nodeClient, conn, nil
  }
docs: // newV1NodeClient creates a new NodeClient with the internally used gRPC
  // connection set up. It also returns a closer which must to be called to close
  // the gRPC connection when the NodeClient is not used anymore.
  // This is the default implementation for the nodeV1ClientCreator, used in
  // newCsiDriverClient.