// list with an empty final value but stops at the token "STOP".
func ExampleScanner_earlyStop() {
	onComma := func(data []byte, atEOF bool) (advance int, token []byte, err error) {
		i := bytes.IndexByte(data, ',')
		if i == -1 {
			if !atEOF {
				return 0, nil, nil
			}
			// If we have reached the end, return the last token.
			return 0, data, bufio.ErrFinalToken
		}

	fmt.Println(bytes.Index([]byte("chicken"), []byte("dmr")))
	// Output:
	// 4
	// -1
}

func ExampleIndexByte() {
	fmt.Println(bytes.IndexByte([]byte("chicken"), byte('k')))
	fmt.Println(bytes.IndexByte([]byte("chicken"), byte('g')))
	// Output:
	// 4
	// -1
}

func ExampleIndexFunc() {
	f := func(c rune) bool {
		return unicode.Is(unicode.Han, c)
	}