func mountServer(token, mountpoint string) (*fuse.Server, error) {
	if err := os.MkdirAll(filepath.Dir(mountpoint), 0755); err != nil {
		return nil, err
	}

	client, err := vault.Client(token)
	if err != nil {
		return nil, err
	}

	kwfs, root := fs.NewFs(client)

	mountOptions := &fuse.MountOptions{
		AllowOther: true,
		Name:       kwfs.String(),
		Options:    []string{"default_permissions"},
	}

	// Empty Options struct avoids setting a global uid/gid override.
	conn := nodefs.NewFileSystemConnector(root, &nodefs.Options{})
	server, err := fuse.NewServer(conn.RawFS(), mountpoint, mountOptions)
	if err != nil {
		log.Printf("Mount fail: %v\n", err)
		return nil, err
	}

	go server.Serve()

	return server, nil
}
func (d *driver) client() (*api.Client, error) {
	return vault.Client(d.token)
}