flag.Parse()
	args := flag.Args()
	if len(args) != 1 || !strings.HasSuffix(args[0], ".zip") {
		usage()
	}

	var zb bytes.Buffer
	zw := zip.NewWriter(&zb)
	seen := make(map[string]bool)
	err := filepath.WalkDir(".", func(path string, d fs.DirEntry, err error) error {
		if d.IsDir() {
			return nil
		}
		data, err := os.ReadFile(path)
		if err != nil {
			log.Fatal(err)
		}
		if strings.HasSuffix(path, ".zip") {

// It walks the directory tree starting at the root of the filesystem
// adding each file to the tar archive while maintaining the directory structure.
func (tw *Writer) AddFS(fsys fs.FS) error {
	return fs.WalkDir(fsys, ".", func(name string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}
		if d.IsDir() {
			return nil
		}
		info, err := d.Info()
		if err != nil {
			return err
		}

			var files []string
			sawErr := false
			err = fs.WalkDir(z, ".", func(path string, d fs.DirEntry, err error) error {
				if err != nil {
					if !test.wantErr {
						t.Errorf("%s: %v", path, err)
					}
					sawErr = true
					return nil
				}
				files = append(files, path)
				return nil
			})
			if err != nil {
				t.Errorf("fs.WalkDir error: %v", err)
			}
			if test.wantErr && !sawErr {

			// contains nested modules this could push a lot of unnecessary contents,
			// but for the golang.org/x repos it seems to be significantly (~2x)
			// faster than copying one file at a time (via filepath.WalkDir),
			// apparently due to high latency in 'adb' commands.
			if err := adb("push", modDir, deviceModDir); err != nil {
				return 0, err
			}
		} else {

// It walks the directory tree starting at the root of the filesystem
// adding each file to the zip using deflate while maintaining the directory structure.
func (w *Writer) AddFS(fsys fs.FS) error {
	return fs.WalkDir(fsys, ".", func(name string, d fs.DirEntry, err error) error {
		if err != nil {
			return err
		}
		if d.IsDir() {
			return nil
		}
		info, err := d.Info()
		if err != nil {
			return err
		}