redis/driver.go
func Open(URL ...string) (pubsub.Hub, error) {
	redisURL := getRedisURL(URL...)
	conn, err := redisurl.ConnectToURL(redisURL)
	if err != nil {
		return nil, err
	}
	return &hub{
		conn:     conn,
		redisURL: redisURL,
		subs:     make(map[*sub]struct{}),
	}, nil
}
func Open(URL ...string) (pubsub.Hub, error) {
	redisURL := getRedisURL(URL...)
	conn, err := redisurl.ConnectToURL(redisURL)
	if err != nil {
		return nil, err
	}
	return &hub{
		conn:     conn,
		redisURL: redisURL,
		subs:     make(map[*sub]struct{}),
	}, nil
}
// Open creates pubsub hub connected to redis server.