我找到了一些帶有“從 Goroutines 中獲取值”的示例->鏈接有展示如何獲取值，但如果我想從多個 goroutines 返回值，它就不會工作。那么，有人知道該怎么做嗎？ package mainimport (    "fmt"    "io/ioutil"    "log"    "net/http"    "sync")// WaitGroup is used to wait for the program to finish goroutines.var wg sync.WaitGroupfunc responseSize(url string, nums chan int) {    // Schedule the call to WaitGroup's Done to tell goroutine is completed.    defer wg.Done()    response, err := http.Get(url)    if err != nil {        log.Fatal(err)    }    defer response.Body.Close()    body, err := ioutil.ReadAll(response.Body)    if err != nil {        log.Fatal(err)    }    // Send value to the unbuffered channel    nums <- len(body)}func main() {    nums := make(chan int) // Declare a unbuffered channel    wg.Add(1)    go responseSize("https://www.golangprograms.com", nums)    go responseSize("https://gobyexample.com/worker-pools", nums)    go responseSize("https://stackoverflow.com/questions/ask", nums)    fmt.Println(<-nums) // Read the value from unbuffered channel    wg.Wait()    close(nums) // Closes the channel    // >> loading forever另外，這個例子，工作池是否可以從結果中獲取值：fmt.Println(<-results)<- 將出錯。