}

// Read a line of bytes (up to \n) from b.
// Give up if the line exceeds maxLineLength.
// The returned bytes are owned by the bufio.Reader
// so they are only valid until the next bufio read.
func readChunkLine(b *bufio.Reader) ([]byte, []byte, error) {
	buf, err := b.ReadSlice('\n')
	if err != nil {
		// We always know when EOF is coming.
		// If the caller asked for a line, there should be a line.
		if err == io.EOF {

func truncateChunkByHalfSigv4(req *http.Request) (*http.Request, error) {
	bufReader := bufio.NewReader(req.Body)
	hexChunkSize, chunkSignature, err := readChunkLine(bufReader)
	if err != nil {
		return nil, err
	}

	newChunkHdr := []byte(fmt.Sprintf("%s"+s3ChunkSignatureStr+"%s\r\n",
		hexChunkSize, chunkSignature))
	newChunk, err := io.ReadAll(bufReader)