Preparing an iOS app for release

This guide provides a step-by-step walkthrough of releasing a Flutter app tothe [App Store][appstore] and [TestFlight][testflight].For information on obfuscating Dart code, see [Obfuscating DartCode]({{site.github}}/flutter/flutter/wiki/Obfuscating-Dart-Code).## PreliminariesBefore beginning the pr…