getPendingMessages method
Implementation
@override
Future<ChatResult<List<PendingChatMessage>>> getPendingMessages(
String roomId,
) async {
final list = _pendingMessages[roomId];
if (list == null) return const ChatSuccess(<PendingChatMessage>[]);
final sorted = [...list]
..sort((a, b) => a.message.timestamp.compareTo(b.message.timestamp));
return ChatSuccess(List.unmodifiable(sorted));
}