func clean(p string) string {
	if !strings.HasPrefix(p, "/") {
		p = "/" + p
	}
	return internalDefault(path.Clean(p))
}
func clean(p string) string {
	if !strings.HasPrefix(p, "/") {
		p = "/" + p
	}
	return internalDefault(path.Clean(p))
}
// clean canonicalizes 'path' for internal use: leading slash and no trailing
// slash. Also, clean the result with internalDefault.