diff --git a/speedtest/data_manager.go b/speedtest/data_manager.go
index 7ae2a48..21a3982 100644
--- a/speedtest/data_manager.go
+++ b/speedtest/data_manager.go
@@ -464,41 +464,20 @@ func (dc *DataChunk) GetParent() Manager {
 	return dc.manager
 }
 
-// WriteTo Used to hook all traffic.
-func (dc *DataChunk) WriteTo(w io.Writer) (written int64, err error) {
-	nw := 0
-	nr := readChunkSize
-	for {
-		dc.manager.runningRW.RLock()
-		running := dc.manager.running
-		dc.manager.runningRW.RUnlock()
-		if !running || dc.remainOrDiscardSize <= 0 {
+func (dc *DataChunk) Read(b []byte) (n int, err error) {
+	if dc.remainOrDiscardSize < readChunkSize {
+		if dc.remainOrDiscardSize <= 0 {
 			dc.endTime = time.Now()
-			return written, io.EOF
-		}
-		if dc.remainOrDiscardSize < readChunkSize {
-			nr = int(dc.remainOrDiscardSize)
-			nw, err = w.Write((*dc.manager.repeatByte)[:nr])
-		} else {
-			nw, err = w.Write(*dc.manager.repeatByte)
-		}
-		if err != nil {
-			return
-		}
-		n64 := int64(nw)
-		written += n64
-		dc.remainOrDiscardSize -= n64
-		dc.manager.AddTotalUpload(n64)
-		if nr != nw {
-			return written, io.ErrShortWrite
+			return n, io.EOF
 		}
+		n = copy(b, (*dc.manager.repeatByte)[:dc.remainOrDiscardSize])
+	} else {
+		n = copy(b, *dc.manager.repeatByte)
 	}
-}
-
-// Please don't call it, only used to wrapped by [io.NopCloser]
-// We use [DataChunk.WriteTo] that implements [io.WriterTo] to bypass this function.
-func (dc *DataChunk) Read(b []byte) (n int, err error) {
-	panic("unexpected call: only used to implement the io.Reader")
+	n64 := int64(n)
+	dc.remainOrDiscardSize -= n64
+	dc.manager.AddTotalUpload(n64)
+	return
 }
 
 // calcMAFilter Median-Averaging Filter
diff --git a/speedtest/request.go b/speedtest/request.go
index f188d56..3b7d6d1 100644
--- a/speedtest/request.go
+++ b/speedtest/request.go
@@ -185,17 +185,20 @@ func downloadRequest(ctx context.Context, s *Server, w int) error {
 
 func uploadRequest(ctx context.Context, s *Server, w int) error {
 	size := ulSizes[w]
-	dc := s.Context.NewChunk().UploadHandler(int64(size*100-51) * 10)
+	chunkSize := int64(size*100-51) * 10
+	dc := s.Context.NewChunk().UploadHandler(chunkSize)
 	req, err := http.NewRequestWithContext(ctx, http.MethodPost, s.URL, io.NopCloser(dc))
 	if err != nil {
 		return err
 	}
+	req.ContentLength = chunkSize
 	dbg.Printf("Len=%d, XulURL: %s\n", req.ContentLength, s.URL)
 	req.Header.Set("Content-Type", "application/octet-stream")
 	resp, err := s.Context.doer.Do(req)
 	if err != nil {
 		return err
 	}
+	_, _ = io.Copy(io.Discard, resp.Body)
 	defer resp.Body.Close()
 	return err
 }