setItem<T extends StorableModel> method
Creates or updates an item in a specified collection.
This method retrieves the current data for the given tag,
updates the item if it exists, or adds a new one if it doesn't.
The updated data is then saved to persistent storage.
Parameters:
tag: A unique identifier for the collection where the item is stored.item: An object of typeTthat extends StorableModel, representing the item to be created or updated.
Returns:
- A Future that completes when the item is successfully stored.
Implementation
Future<void> setItem<T extends StorableModel>(
final String tag,
final T item,
) async {
final Map<String, dynamic> data = await _loadData(tag);
data[item.id] = item.toJson();
await _saveData(tag, data);
}