go :如何优雅地超时退出

package main

import (
    "fmt"
    "time"

    "k8s.io/apimachinery/pkg/util/wait"
    "k8s.io/klog"
)

func main() {
    for {
        a := wait.Poll(time.Second, time.Second*5, func() (done bool, err error) {
            fmt.Println(time.Now())
            return false, nil
        })
        if a != nil {
            klog.Error(a)
            break
        }
    }

}