Rules for using init in golang

package main

import "fmt"

var age = test()

func test() int{
    
	fmt.Println("test")
	return 90
}

func init(){
    
	fmt.Println("init start")
}

func main(){
    
	fmt.Println("main start")
}

The results of the implementation are as follows

test
init start
main start

1. Execute global variable
2. perform init function , As long as it is used for initialization of global variables
3. perform main function