if si.Mode == 0 {
			// Not, set it to default.
			si.Mode = 0o600
		}
		if si.ModTime.IsZero() {
			// Set time to now.
			si.ModTime = time.Now()
		}
		header, zerr := zip.FileInfoHeader(dummyFileInfo{
			name:    filename,
			size:    si.Size,
			mode:    os.FileMode(si.Mode),
			modTime: si.ModTime,
			isDir:   si.Dir,
			sys:     nil,
		})
		if zerr != nil {