建立 goroutines

任何函式都可以通過在其呼叫前加上關鍵字 go 作為 goroutine 來呼叫：

func DoMultiply(x,y int) {
    // Simulate some hard work
    time.Sleep(time.Second * 1)
    fmt.Printf("Result: %d\n", x * y)
}

go DoMultiply(1,2) // first execution, non-blocking
go DoMultiply(3,4) // second execution, also non-blocking

// Results are printed after a single second only, 
// not 2 seconds because they execute concurrently:
// Result: 2
// Result: 12

請注意，忽略該函式的返回值。