halokid/codeBox: book_sample/Concurrency-in-Go/c5.go; 8 LoC

Found a possible issue in [halokid/codeBox](https://www.github.com/halokid/codeBox) at [book_sample/Concurrency-in-Go/c5.go](https://github.com/halokid/codeBox/blob/c28908b9968c264515dded12d146171c74b8f07f/book_sample/Concurrency-in-Go/c5.go#L19-L26)

Below is the message reported by the analyzer for this snippet of code. Beware that the analyzer only reports the first
issue it finds, so please do not limit your consideration to the contents of the below message.

> range-loop variable j used in defer or goroutine at line 24

[Click here to see the code in its original context.](https://github.com/halokid/codeBox/blob/c28908b9968c264515dded12d146171c74b8f07f/book_sample/Concurrency-in-Go/c5.go#L19-L26)

Click here to show the 8 line(s) of Go which triggered the analyzer.

```go
for j := range is {
wg4.Add(1)

go func() {
defer wg4.Done()
fmt.Println(j) // 当 fork 的 groutine 执行输出 j 的时候， main groutine 给 j 赋值是什么，就输出什么
}()
}

```

Leave a reaction on this issue to contribute to the project by classifying this instance as a **Bug** :-1:, **Mitigated** :+1:, or **Desirable Behavior** :rocket:
See the descriptions of the classifications [here](https://github.com/github-vet/rangeclosure-findings#how-can-i-help) for more information.

commit ID: c28908b9968c264515dded12d146171c74b8f07f