golang 判断目录是否为空

实例：

package main

import (
    "fmt"
    "io/IoUtil"
)

func main() {
    dirname := "/root/test"
    dir,_ := IoUtil.ReadDir(dirname)
    if len(dir) == 0 {
        fmt.Println(dirname + " is empty dir!")
    } else {
        fmt.Println(dirname + " is not empty dir!")
    }
}