試圖理解 goroutine 的流程，所以我寫了這段代碼，只有一件我無法理解的事情是，routine-end 如何在其他 go 例程之間運(yùn)行并完成單個 go 例程并在最后打印來自通道的輸出.import(    "fmt")func add(dataArr []int,dataChannel chan int,i int ){    var sum int    fmt.Println("GOROUTINE",i+1)    for i:=0;i<len(dataArr);i++{        sum += dataArr[i]    }    fmt.Println("wRITING TO CHANNEL.....")    dataChannel <- sum    fmt.Println("routine-end")}func main(){    fmt.Println("main() started")    dataChannel := make(chan int)    dataArr := []int{1,2,3,4,5,6,7,8,9}    for i:=0;i<len(dataArr);i+=3{        go add(dataArr[i:i+3],dataChannel,i)    }       fmt.Println("came to blocking statement ..........")    fmt.Println(<-dataChannel)    fmt.Println("main() end")}outputmain() startedcame to blocking statement ..........GOROUTINE 1wRITING TO CHANNEL.....routine-endGOROUTINE 4wRITING TO CHANNEL.....6main() end