Use the CocoaPods dependency manager and installed Flutter SDK.
  In this case, the flutter_module is compiled from
  the source each time the app is built. (Recommended.)

Create frameworks for the Flutter engine, your compiled Dart code,
  and all Flutter plugins. Here, you manually embed the frameworks,
  and update your existing application’s build settings in Xcode.
  This can be useful for teams that don’t want to require every developer
  to have the Flutter SDK and Cocoapods installed locally.

Create frameworks for your compiled Dart code,
  and all Flutter plugins. Use CocoaPods for the Flutter engine. 
  With this option, embed the frameworks for your application
  and the plugins in Xcode, but distribute the
  Flutter engine as a CocoaPods podspec.
  This is similar to the second option, but it provides
  an alternative to distributing the large Flutter.xcframework.