toJson method
Implementation
@override
Map<String, dynamic> toJson() => <String, dynamic>{
'total_count': totalCount,
'topics': topics.map((item) => item.toJson()).toList(),
'next_offset_date': nextOffsetDate,
'next_offset_message_id': nextOffsetMessageId,
'next_offset_forum_topic_id': nextOffsetForumTopicId,
'@type': constructor,
};