如何自定义HTTP响应的协议说明符？

I have the requirement to send HTTP packets with a protocol specifier other than HTTP/... I use the http.Response to create packets

resp := new(http.Response)
resp.Status = "200 OK"
resp.StatusCode = http.StatusOK
resp.ProtoMajor = 1
resp.ProtoMinor = 0
resp.Proto = "EVENT/1.0"

I set the Proto field, but at the end the written bytes still contains HTTP/1.0 200 OK because that's hardcoded in response.go

216 if _, err := io.WriteString(w, "HTTP/"+protoMajor+"."+protoMinor+" "+statusCode+text+"
"); err != nil {
217 return err
218 }

Is there a reason why the Proto field is ignored?