code: func makeForgetUpdate(files []protocol.FileInfo) []protocol.FileDownloadProgressUpdate {
  	updates := make([]protocol.FileDownloadProgressUpdate, 0, len(files))
  	for _, file := range files {
  		if file.IsSymlink() || file.IsDirectory() || file.IsDeleted() {
  			continue
  		}
  		updates = append(updates, protocol.FileDownloadProgressUpdate{
  			Name:       file.Name,
  			Version:    file.Version,
  			UpdateType: protocol.UpdateTypeForget,
  		})
  	}
  	return updates
  }
docs: // makeForgetUpdate takes an index update and constructs a download progress update
  // causing to forget any progress for files which we've just been sent.