if w.compressors == nil {
		w.compressors = make(map[uint16]Compressor)
	}
	w.compressors[method] = comp
}

// AddFS adds the files from fs.FS to the archive.
// 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 {

	// Determine package files.
	dir := w.importDir[name]
	if dir == "" {
		dir = filepath.Join(w.root, filepath.FromSlash(name))
	}
	if fi, err := os.Stat(dir); err != nil || !fi.IsDir() {
		log.Panicf("no source in tree for import %q (from import %s in %s): %v", name, fromPath, fromDir, err)
	}

	context := w.context
	if context == nil {
		context = &build.Default
	}

	// Look in cache.