func ExampleFrom() {
	fs1 := fstest.MapFS{
		"dir1/dir00": &fstest.MapFile{
			Mode: fs.ModeDir,
		},
		"dir1/dir11/f111.txt": &fstest.MapFile{
			Data: []byte(`hello 1`),
			Mode: 0644,
		},
		"dir1/dir11/f112.txt": &fstest.MapFile{
			Data: []byte(`hello 2`),
			Mode: 0644,
		},
	}
	fs2 := fstest.MapFS{
		"dir1/dir22": &fstest.MapFile{
			Mode: fs.ModeDir,
		},
		"dir1/dir11/f111.txt": &fstest.MapFile{
			Data: []byte(`hello 1 from f2`),
			Mode: 0644,
		},
		"dir1/dir11/f113.txt": &fstest.MapFile{
			Data: []byte(`hello 3`),
			Mode: 0644,
		},
	}

	ovfs := overlayfs.From(fs1, fs2)

	f1, err := fs.ReadFile(ovfs, "dir1/dir11/f111.txt")
	if err != nil {
		log.Fatalf("could not read file: %v", err)
	}
	fmt.Printf("f1: %q\n", f1)

	f2, err := fs.ReadFile(ovfs, "dir1/dir11/f112.txt")
	if err != nil {
		log.Fatalf("could not read file: %v", err)
	}
	fmt.Printf("f2: %q\n", f2)

	f3, err := fs.ReadFile(ovfs, "dir1/dir11/f113.txt")
	if err != nil {
		log.Fatalf("could not read file: %v", err)
	}
	fmt.Printf("f3: %q\n", f3)

	// Output:
	// f1: "hello 1 from f2"
	// f2: "hello 2"
	// f3: "hello 3"
}```

## License

- `overlayfs` is released under the `BSD-3` license.