Go中构建Http请求参数

func createMultipartRequest() *http.Request {
    boundary := "--testboundary"
    body := new(bytes.Buffer)
    mw := multipart.NewWriter(body)
    defer mw.Close()

    must(mw.SetBoundary(boundary))
    must(mw.WriteField("foo", "bar"))
    must(mw.WriteField("bar", "10"))
    must(mw.WriteField("bar", "foo2"))
    must(mw.WriteField("array", "first"))
    must(mw.WriteField("array", "second"))
    must(mw.WriteField("id", ""))
    must(mw.WriteField("time_local", "31/12/2016 14:55"))
    must(mw.WriteField("time_utc", "31/12/2016 14:55"))
    must(mw.WriteField("time_location", "31/12/2016 14:55"))
    must(mw.WriteField("names[a]", "thinkerou"))
    must(mw.WriteField("names[b]", "tianou"))
    req, err := http.NewRequest("POST", "/", body)
    must(err)
    req.Header.Set("Content-Type", MIMEMultipartPOSTForm+"; boundary="+boundary)
    return req
}