You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: tarwriter.go
    path of file: ./repos/buildkit/vendor/github.com/tonistiigi/fsutil
    
    the code of the file until where you have to start completion: package fsutil

import (
	"archive/tar"
	"context"
	"io"
	"os"
	"path/filepath"
	"strings"
	"syscall"

	"github.com/pkg/errors"
	"github.com/tonistiigi/fsutil/types"
)

func WriteTar(ctx context.Context, fs FS, w io.Writer) error {
	tw := tar.NewWriter(w)
	err := fs.Walk(ctx, "/", func(path string, entry os.DirEntry, err error) error {
		if err != nil && !errors.Is(err, os.ErrNotExist) {
			return err
		}

		fi, err := entry.Info()
		if err != nil {
			return err
		}
		stat, ok := fi.Sys().(*types.Stat)
		if !ok {
			return errors.WithStack(&os.PathError{Path: path, Err: syscall.EBADMSG, Op: "fileinfo without stat info"})
		}
		hdr, err := tar.FileInfoHeader(fi, stat.Linkname)
		if err != nil 
    
func WriteTar(ctx context.Context, fs FS, w io.Writer) error {
	tw := tar.NewWriter(w)
	err := fs.Walk(ctx, "/", func(path string, entry os.DirEntry, err error) error {
		if err != nil && !errors.Is(err, os.ErrNotExist) {
			return err
		}

		fi, err := entry.Info()
		if err != nil {
			return err
		}
		stat, ok := fi.Sys().(*types.Stat)
		if !ok {
			return errors.WithStack(&os.PathError{Path: path, Err: syscall.EBADMSG, Op: "fileinfo without stat info"})
		}
		hdr, err := tar.FileInfoHeader(fi, stat.Linkname)
		if err != nil {
			return err
		}

		name := filepath.ToSlash(path)
		if fi.IsDir() && !strings.HasSuffix(name, "/") {
			name += "/"
		}
		hdr.Name = name

		hdr.Uid = int(stat.Uid)
		hdr.Gid = int(stat.Gid)
		hdr.Devmajor = stat.Devmajor
		hdr.Devminor = stat.Devminor
		hdr.Linkname = stat.Linkname
		if hdr.Linkname != "" {
			hdr.Size = 0
			if fi.Mode()&os.ModeSymlink != 0 {
				hdr.Typeflag = tar.TypeSymlink
			} else {
				hdr.Typeflag = tar.TypeLink
			}
		}

		if len(stat.Xattrs) > 0 {
			hdr.PAXRecords = map[string]string{}
		}
		for k, v := range stat.Xattrs {
			hdr.PAXRecords["SCHILY.xattr."+k] = string(v)
		}

		if err := tw.WriteHeader(hdr); err != nil {
			return errors.Wrapf(err, "failed to write file header %s", name)
		}

		if hdr.Typeflag == tar.TypeReg && hdr.Size > 0 && hdr.Linkname == "" {
			rc, err := fs.Open(path)
			if err != nil {
				return err
			}
			if _, err := io.Copy(tw, rc); err != nil {
				return errors.WithStack(err)
			}
			if err := rc.Close(); err != nil {
				return errors.WithStack(err)
			}
		}
		return nil
	})
	if err != nil {
		return err
	}
	return tw.Close()
}