cluster.go
func NewClusterWithHost(hosts ...*URI) *Cluster {
	cluster := DefaultCluster()
	for _, host := range hosts {
		cluster.AddHost(host)
	}
	return cluster
}
func NewClusterWithHost(hosts ...*URI) *Cluster {
	cluster := DefaultCluster()
	for _, host := range hosts {
		cluster.AddHost(host)
	}
	return cluster
}
// NewClusterWithHost returns a cluster with the given URIs.