Golang：同步功能呼叫http发布请求

I need to call multiple URL at the same time. My functions get called at the same time (in milli seconds) but the moment I add a Http post request to the code it gets called one after the other. Below is the code:

Check(url1)
Check(url2)

func Check(xurl string) {

    nowstartx    := time.Now()
    startnanos   := nowstartx.UnixNano()
    nowstart := startnanos / 1000000
    fmt.Println(nowstart)

    json = {"name" : "test"}
    req, err := http.NewRequest("POST", xurl, bytes.NewBuffer(json))
    req.Header.Set("X-Custom-Header", "myvalue")
    req.Header.Set("Content-Type", "application/json")
    client := &http.Client{}
    resp, err := client.Do(req)

    if err != nil {
        panic(err)

    } else {
        defer resp.Body.Close()
        body, _ = ioutil.ReadAll(resp.Body)
    }

}

Appreciate help, I need to get the same time (in milliseconds) when I run the program.

This is achieved by using Goroutines

go Check(url1)
go Check(url2)

func Check(xurl string) {

    nowstartx    := time.Now()
    startnanos   := nowstartx.UnixNano()
    nowstart := startnanos / 1000000
    fmt.Println(nowstart)

    json = {"name" : "test"}
    req, err := http.NewRequest("POST", xurl, bytes.NewBuffer(json))
    req.Header.Set("X-Custom-Header", "myvalue")
    req.Header.Set("Content-Type", "application/json")
    client := &http.Client{}
    resp, err := client.Do(req)

    if err != nil {
        panic(err)

    } else {
        defer resp.Body.Close()
        body, _ = ioutil.ReadAll(resp.Body)
    }

}