sync.go

package main

import (
    "fmt"
    "strconv"
    "sync"
)

func worker(wg *sync.WaitGroup, cs chan string, i int) {
    defer wg.Done()
    cs <- "worker" + strconv.Itoa(i)
}

func monitorWorker(wg *sync.WaitGroup, cs chan string) {
    wg.Wait()
    close(cs)
}

func printWorker(cs <-chan string, done chan<- bool) {
    for i := range cs {
        fmt.Println(i)
    }

    done <- true
}

func main() {
    wg := &sync.WaitGroup{}
    cs := make(chan string)

    for i := 0; i < 10; i++ {
        wg.Add(1)
        go worker(wg, cs, i)
    }

    go monitorWorker(wg, cs)

    done := make(chan bool, 1)
    go printWorker(cs, done)
    <-done
}