when the node is in leaving state

[aufech...@gmail.com]

func (s MemberStatus) String() string {
       switch s {
       case StatusNone:
              return "none"
       case StatusAlive:
              return "alive"
       case StatusLeaving:
              return "leaving"
       case StatusLeft:
              return "left"
       case StatusFailed:
              return "failed"
       default:
              panic(fmt.Sprintf("unknown MemberStatus: %d", s))
       }
}