toJson method
Implementation
core.Map<core.String, core.dynamic> toJson() => {
if (directory != null) 'directory': directory!,
if (id != null) 'id': id!,
if (kind != null) 'kind': kind!,
if (publisherName != null) 'publisherName': publisherName!,
if (title != null) 'title': title!,
};