Golang sync.WaitGroup example https://play.golang.org/p/NIRRu05m4Ub

sync.WaitGroup.go

package main

import (
	"fmt"
	"sync"
)

func main() {
	var workers = 4
	var wg sync.WaitGroup
	var chains = make([]chan int, workers)
	for i := 0; i < workers; i++ {
		chains[i] = make(chan int)
		wg.Add(1)
		go func(c chan int) {
			defer wg.Done()
			for {
				n, more := <-c
				if more {
					fmt.Println(n)
				} else {
					fmt.Println("close")
					return
				}

			}

		}(chains[i])
	}

	for i := 0; i < 1000; i++ {
		chains[i%workers] <- i
	}

	for i := 0; i < workers; i++ {
		close(chains[i])
	}

	wg.Wait()

	fmt.Println("Hello, playground")
}