goroutine with channels life cycle

goroutine.go

package main

import "fmt"

func do_stuff(done chan bool) {
	fmt.Println("2")
	done <- true
	fmt.Println("3")
}

func main() {
	done := make(chan bool)
	go do_stuff(done)
	fmt.Println("1")
	<-done 			// forces `do_stuff` to do job
	fmt.Println("4")
}