Golang concurrency - await first returned

awaitfirst.go

package main

import (
	"fmt"
	"math/rand"
	"time"
)

func main() {
	ch := make(chan struct{})

	for i := 0; i < 3; i++ {
		go slowRunning(ch)
	}

	<-ch

	fmt.Println("Finishing.")
}

func slowRunning(ch chan<- struct{}) {
	sleepLen := rand.Intn(5)

	fmt.Printf("Sleeping for %d seconds.\n", sleepLen)
	time.Sleep(time.Duration(sleepLen) * time.Second)

	fmt.Println("Waking up...")
	ch <- struct{}{}
}