func (hi *HostInfo) Identity() string {
	return hi.addr
}
Identity implements ringpop's Membership interface
package membership
type HostInfo struct {
	addr   string  
	labels map[string]string
}
func NewHostInfo(addr string, labels map[string]string) *HostInfo {
	if labels == nil {
		labels = make(map[string]string)
	}
	return &HostInfo{
		addr:   addr,
		labels: labels,
	}
}
func (hi *HostInfo) GetAddress() string {
	return hi.addr
}