req.Header.Set("x-amz-decoded-content-length", strconv.FormatInt(dataLength, 10))
	req.Header.Set("content-length", strconv.FormatInt(contentLength, 10))

	// Seek back to beginning.
	body.Seek(0, 0)

	// Add body
	req.Body = io.NopCloser(body)
	req.ContentLength = contentLength

	return req, nil
}

	// Verify it is a regular file, otherwise subsequent Seek is
	// undefined.
	if !st.Mode().IsRegular() {
		file.Close()
		return nil, errIsNotRegular
	}

	if st.Size() < offset+length {
		// Expected size cannot be satisfied for
		// requested offset and length
		file.Close()
		return nil, errFileCorrupt
	}

	if offset > 0 {
		if _, err = file.Seek(offset, io.SeekStart); err != nil {

	defer os.Remove(tf.Name())
	defer tf.Close()

	const text = "Hello, fd 3!"
	_, err = tf.Write([]byte(text))
	if err != nil {
		t.Fatalf("Write: %v", err)
	}
	_, err = tf.Seek(0, io.SeekStart)
	if err != nil {
		t.Fatalf("Seek: %v", err)
	}

	tempdir := t.TempDir()
	exe := filepath.Join(tempdir, "read3.exe")

	c := testenv.Command(t, testenv.GoToolPath(t), "build", "-o", exe, "read3.go")

// writeParallel handles scheduling parallel execution of data write functions.
func writeParallel(wg *sync.WaitGroup, fn writeFn, ctxt *Link, seek, vaddr, length uint64) {
	if out, err := ctxt.Out.View(seek); err != nil {
		ctxt.Out.SeekSet(int64(seek))
		fn(ctxt, ctxt.Out, int64(vaddr), int64(length))
	} else {
		wg.Add(1)
		go func() {
			defer wg.Done()
			fn(ctxt, out, int64(vaddr), int64(length))

		if _, err := io.CopyN(f, rand.Reader, nBytes); err != nil {
			return nil, nil, fmt.Errorf("failed to write data to file: %v", err)
		}
		if _, err := f.Seek(0, 0); err != nil {
			return nil, nil, fmt.Errorf("failed to seek to front: %v", err)
		}

		done = func() {
			f.Close()
			os.Remove(f.Name())
		}

		return f, done, nil
	}

			bestPos = b.Pos
			for _, v := range b.Values {
				if v.LackingPos() {
					continue
				}
				if v.Pos != src.NoXPos {
					// Assume values are still in roughly textual order;
					// TODO: could also seek minimum position?
					bestPos = v.Pos
					break
				}
			}
		}
		p.Pos = bestPos
		s.updateUnsetPredPos(p) // We do not expect long chains of these, thus recursion is okay.
	}
}