Rate Us Dialog
You can ask users to rate and review your app at appropriate times throughout the user experience. Make the request when users are most likely to feel satisfied with your app, such as when they’ve completed an action, level, or task. Make sure not to interrupt their activity.
See the example below:
SA.CrossPlatform.UI; ... UM_ReviewController.RequestReview();
You can't get the result of the review request, or find out how many stars user has given your app. The reason is, Apple & Google wants users to only do a fair review, and this is prohibited for app developers to give any kind of reward to users for a positive feedback.
The result will be a popup similar to the one on a picture below: