if HasSuffix(s, suffix) {
		return s[:len(s)-len(suffix)]
	}
	return s
}

// IndexFunc interprets s as a sequence of UTF-8-encoded code points.
// It returns the byte index in s of the first Unicode
// code point satisfying f(c), or -1 if none do.
func IndexFunc(s []byte, f func(r rune) bool) int {
	return indexFunc(s, f, true)
}

// LastIndexFunc interprets s as a sequence of UTF-8-encoded code points.