Use of strings.Join

package main

import (
    "fmt"
    "strings"
)

func main() {
    
    subscription := "SERVICE_NAME"
    
    var extras []string
    
    extras = append(extras, subscription)
    extras = append(extras, "LOCAL")
    extras = append(extras, "KEY")
    fmt.Println(strings.Join(extras, "_"))
    
}

Go

INFO