为什么一个输出有序一个输出无序？

- 代码片段一：输出结果有序 ``` package main import ( "fmt" "time" ) func main() { ch := make(chan struct{}) for i := 0; i < 10; i++ { go func(num int) { for { <-ch fmt.Println(num) } }(i) time.Sleep(time.Millisecond) } time.Sleep(time.Second) for j := 0; j < 10; j++ { ch <- struct{}{} time.Sleep(time.Millisecond) } ch <- struct{}{} time.Sleep(time.Minute) } ``` - 代码片段二：输出结果无序 ``` package main import ( "fmt" "time" ) func main() { ch := make(chan struct{}) for i := 0; i < 10; i++ { go func(num int) { for { <-ch fmt.Println(num) } }(i) time.Sleep(time.Millisecond) } time.Sleep(time.Second) for j := 0; j < 10; j++ { ch <- struct{}{} } ch <- struct{}{} time.Sleep(time.Minute) } ```