String()用法

package mainimport(    "fmt")type State intconst (    Running State = iota    Stopped    Rebooting    Terminated)func main() {    state := Running    // print: "state 0"    fmt.Println("state ", state)}func (s State) String() string {    switch s {    case Running:        return "Running"    case Stopped:        return "Stopped"    case Rebooting:        return "Rebooting"    case Terminated:        return "Terminated"    default:        return "Unknown"    }}