substack-concurrency-6.go

// GOOD
var wg sync.WaitGroup
for _, salutation := range []string{"hello", "greetings", "good day"} {
    wg.Add(1)
    go func(salutation string) {
        defer wg.Done()
        fmt.Println(salutation)
    }(salutation) // <-- we pass in the current iteration's variable to the closure. 
                  // a copy of the string struct is made
                  // when the goroutine is run, we'll be refering to the proper string
}
wg.Wait()

// good day
// hello
// greetings