Test channel bug

test.go

package main

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

func main() {
	chs := make(chan int, 10)

	var wg sync.WaitGroup
	wg.Add(10)

	for i := 0; i < 5; i++ {
		go func(r int) {
			defer wg.Done()

			num := <-chs
			fmt.Printf("Routine: %d Recv: %d\n", r, num)
		}(i)
	}

	for i := 0; i < 5; i++ {
		go func(r int) {
			defer wg.Done()

			num := rand.Intn(10)
			chs <- num
			fmt.Printf("Routine: %d Send: %d\n", r, num)
		}(i)
	}

	wg.Wait()
	fmt.Println("done")
}

test

11:14:39 λ eagle [~/demo] at  master -!?
→ go version                                                                                                                                                 [72e27fa]
go version go1.10.2 darwin/amd64

11:14:44 λ eagle [~/demo] at  master -!?
→ go run test-bug.go                                                                                                                                         [72e27fa]
Routine: 4 Send: 1
Routine: 3 Send: 7
Routine: 0 Recv: 7
Routine: 0 Send: 9
Routine: 2 Recv: 9
Routine: 1 Recv: 7
Routine: 2 Send: 7
Routine: 1 Send: 1
Routine: 4 Recv: 1
Routine: 3 Recv: 1
done

您这个是打算反应什么？多携程？