main.go

package main

import "sync"

type receiver struct {
	sync.WaitGroup
	data chan int
}

func newReceiver() *receiver {
	r := &receiver{
		data: make(chan int, 1000000),
	}

	r.Add(1)
	go func(dataChan chan int) {
		for x := range dataChan{
			println("recv : ", x)
		}
		defer r.Done()
	}(r.data)
	return r
}

func main() {
	r := newReceiver()
	for i := 0; i < 100000; i++ {
		r.data <- i
	}

	close(r.data)
	r.Wait()
	println("Done")
}

这样写都行。