class Emoji { const Emoji({ required this.char, required this.shortName, required this.unicode, }); final String char; final String shortName; final String unicode; } class Hashtag { const Hashtag({ required this.name, required this.weight, required this.description, required this.image, }); final String name; final int weight; final String description; final String image; } class User { const User({ required this.id, required this.name, required this.avatar, }); final String id; final String name; final String avatar; } class ChatMessage { const ChatMessage({ required this.text, required this.createdAt, required this.sender, }); final String text; final DateTime createdAt; final User sender; }