Endpoints switch cost too long time when use watch api

[pandaye]

I use following code to create an etcd client and then watch a key

	etcdCli, err := clientv3.New(clientv3.Config{
		Endpoints:        eps,
		AutoSyncInterval: DefaultSyncInterval,
		DialTimeout:      DefaultDialTimeout,
		TLS:              tlsConfig,
	})

eps have 3 avalible endpoints, syncIntrval is 60s, dialtimeout is 5s.
When program run and received some event，I close the endpoint which currently picked and keep puting new value for the watched key. I found that it cost more then 10 minute for the balancer to switch another avalible endpoint. Why？And are there any parameter settings that can shorten this time?

[pandaye]

When DialKeepAliveTime and DialKeepAliveTimeout paramenters are set this problem solved，see also tikv/pd#6059