server.go
func ListenAndServeUNIX(addr string, mode os.FileMode, handler RequestHandler) error {
	s := &Server{
		Handler: handler,
	}
	return s.ListenAndServeUNIX(addr, mode)
}
func ListenAndServeUNIX(addr string, mode os.FileMode, handler RequestHandler) error {
	s := &Server{
		Handler: handler,
	}
	return s.ListenAndServeUNIX(addr, mode)
}
// ListenAndServeUNIX serves HTTP requests from the given UNIX addr
// using the given handler.
//
// The function deletes existing file at addr before starting serving.
//
// The server sets the given file mode for the UNIX addr.