fmt.Println(bytes.IndexFunc([]byte("Hello, world"), f))
	// Output:
	// 7
	// -1
}

func ExampleIndexAny() {
	fmt.Println(bytes.IndexAny([]byte("chicken"), "aeiouy"))
	fmt.Println(bytes.IndexAny([]byte("crwth"), "aeiouy"))
	// Output:
	// 2
	// -1
}

func ExampleIndexRune() {
	fmt.Println(bytes.IndexRune([]byte("chicken"), 'k'))

func TestIndex(t *testing.T)     { runIndexTests(t, Index, "Index", indexTests) }
func TestLastIndex(t *testing.T) { runIndexTests(t, LastIndex, "LastIndex", lastIndexTests) }
func TestIndexAny(t *testing.T)  { runIndexAnyTests(t, IndexAny, "IndexAny", indexAnyTests) }
func TestLastIndexAny(t *testing.T) {
	runIndexAnyTests(t, LastIndexAny, "LastIndexAny", lastIndexAnyTests)
}

func TestIndexByte(t *testing.T) {
	for _, tt := range indexTests {

					return i - last
				}
			}
		}
		return -1
	}
}

// IndexAny interprets s as a sequence of UTF-8-encoded Unicode code points.
// It returns the byte index of the first occurrence in s of any of the Unicode
// code points in chars. It returns -1 if chars is empty or if there is no code
// point in common.
func IndexAny(s []byte, chars string) int {
	if chars == "" {
		// Avoid scanning all of s.
		return -1