import 'package:sample_sdk/sdk/services/category.dart'; import 'package:sample_sdk/sdk/services/product.dart'; class ClientSDK { static var _instance; static ClientSDK getInstance() { if (_instance == null) { ClientSDK(); } return _instance; } ProductService productService = ProductService(); CategoryService categoryService = CategoryService(); ClientSDK() { _instance = this; } void dispose() { _instance = null; } }