上传文件完成后一直卡住无法断开连接，代码该如何改呢？

```go package main import ( "crypto/rand" "fmt" ruisUtil "github.com/mgr9525/go-ruisutil" "io" "net/http" "os" "strconv" "time" "context" ) func randomBoundarys() string { var buf [30]byte _, err := io.ReadFull(rand.Reader, buf[:]) if err != nil { panic(err) } return fmt.Sprintf("%x", buf[:]) } func uploadss(url,flpath string){ ctx, _ := context.WithCancel(context.Background()) body := ruisUtil.NewCircleByteBuffer(ctx,10240000) boundary:=randomBoundarys() boundarybytes := []byte("\r\n--" + boundary + "\r\n") endbytes := []byte("\r\n--" + boundary + "--\r\n") reqest, err := http.NewRequest("POST", url, body) if err != nil { panic(err) } reqest.Header.Add("Connection", "keep-alive") reqest.Header.Add("Content-Type", "multipart/form-data; charset=utf-8; boundary="+boundary) go func() { //defer ruisRecovers("upload.run") f, err := os.OpenFile(flpath, os.O_RDONLY, 0666) //其实这里的 O_RDWR应该是 O_RDWR|O_CREATE，也就是文件不存在的情况下就建一个空文件，但是因为windows下还有BUG，如果使用这个O_CREATE，就会直接清空文件，所以这里就不用了这个标志，你自己事先建立好文件。 if err != nil { panic(err) } stat, err := f.Stat() //获取文件状态 if err != nil { panic(err) } defer f.Close() header:=fmt.Sprintf("Content-Disposition: form-data; name=\"upfile\"; filename=\"%s\"\r\nContent-Type: application/octet-stream\r\n\r\n",stat.Name()) body.Write(boundarybytes) body.Write([]byte(header)) fsz:=float64(stat.Size()) fupsz:=float64(0) buf:=make([]byte,10240000) for { time.Sleep(10*time.Microsecond)//减缓上传速度，看进度效果 n,err:=f.Read(buf) fmt.Println(err) if err==io.EOF { break } if n>0{ nz,_:=body.Write(buf[0:n]) fupsz+=float64(nz) progress := strconv.Itoa(int((fupsz / fsz) * 100))+"%" fmt.Println("upload:",progress,"|",strconv.FormatFloat(fupsz,'f',0,64),"/",stat.Size()) } } body.Write(endbytes) body.Write(nil)//输入EOF,表示数据写完了 }() resp,err:=http.DefaultClient.Do(reqest) fmt.Println(resp) if err != nil { panic(err) } defer resp.Body.Close() if resp.StatusCode==200{ fmt.Println("上传成功") }else{ fmt.Println("上传失败,StatusCode:",resp.StatusCode) } } // sample usage func main() { uploadss("http://103.18.10.5:8080/PutFile","D:\\go1.14.3.windows-amd64.zip") } ```