1、无缓冲channel

示例：

package mainimport (	"fmt"	"time")func main() {	//创建一个无缓存的channel	ch := make(chan int, 0)	//len(ch)缓冲区剩余数据个数， cap(ch)缓冲区大小	fmt.Printf("len(ch) = %d, cap(ch)= %d\n", len(ch), cap(ch))	//新建协程	go func() {		for i := 0; i < 3; i++ {			fmt.Printf("子协程：i = %d\n", i)			ch <- i //往chan写内容		}	}()	//延时	time.Sleep(2 * time.Second)	for i := 0; i < 3; i++ {		num := <-ch //读管道中内容，没有内容前，阻塞		fmt.Println("num = ", num)	}}

执行结果：

len(ch) = 0, cap(ch)= 0子协程：i = 0num =  0子协程：i = 1    子协程：i = 2   num =  1num =  2