Use sync.RWMutex to slice write jobs

gistfile1.txt

package main

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

func main() {
	rand.Seed(time.Now().UnixNano())

	const N = 9
	var vs = make([]int, N)
	var rwm sync.RWMutex

	for i := range [N]struct{}{} {
		i := i
		go func() {
			time.Sleep(time.Second * time.Duration(rand.Intn(300)) / 100)
			rwm.RLock()
			defer rwm.RUnlock()
			vs[i] = i + 1
		}()
	}

	for {
		time.Sleep(time.Second / 20)
		if ready := func() bool {
			rwm.Lock()
			defer rwm.Unlock()
			k := 0
			for i := range [N]struct{}{} {
				if vs[i] > 0 {
					k++
				}
			}
			fmt.Println(vs)
			return k == N
		}(); ready {
			break
		}
	}
}