go调用函数时，不能打印不带返回值的函数否则报used as value，不带返回值的函数直接函数即可

package main

import "fmt"

var i int = 100

func TestInt()  {
   defer func() {
      i+=100
   }()
   fmt.Println(i)
   //return

}

func main() {
   fmt.Println(TestInt())
   //fmt.Println(i)

}

报错：.\test19.go:17:21: TestInt() used as value