for i, sentinelAddr := range c.sentinelAddrs {
		sentinel := NewSentinelClient(c.opt.sentinelOptions(sentinelAddr))

		masterAddr, err := sentinel.GetMasterAddrByName(ctx, c.opt.MasterName).Result()
		if err != nil {
			_ = sentinel.Close()
			if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
				return "", err
			}
			internal.Logger.Printf(ctx, "sentinel: GetMasterAddrByName master=%q failed: %s",
				c.opt.MasterName, err)
			continue
		}

func (opt *FailoverOptions) sentinelOptions(addr string) *Options {
	return &Options{
		Addr:       addr,
		ClientName: opt.ClientName,

		Dialer:    opt.Dialer,
		OnConnect: opt.OnConnect,

		DB:       0,
		Username: opt.SentinelUsername,
		Password: opt.SentinelPassword,