This extension lets you use the new feature Request Review added by Apple for iOS 10.3 release, which was released on March 27, 2017.
All you need to do is call the request_review_app_store() method, and the Extension will display an Alert Dialog to rate your game or app. If the device is running a version before 10.3, the method will return 0. In the other hand, the method will return 1 if the Alert Dialog has been displayed.
Due to the Extension uses the last version of the StoreKit.framework, you'll need to build your game or app with Xcode 10.3 or later. If you try to build it with a version of Xcode before 10.3, it won't recognize the new method requestReview.