fetchMessages method
Fetches all existing messages for the conversation at path, ordered
oldest first.
Implementation
@override
Future<List<ChatBackendMessage>> fetchMessages(String path) async {
final rows = await _client.from(path).select().order("timestamp");
return rows.map((row) {
final data = Map<String, dynamic>.from(row);
final id = data.remove("id").toString();
return ChatBackendMessage(id: id, data: _normalize(data));
}).toList();
}