将FBFlutterViewContainer的实例对象的view添加到原生VC的view 上，FBFlutterViewContainer的view不展示

flutterBoost 3.0 iOS真机
现在出现了这样的情况，我在自定义转场动画的原生VC里面，将FBFlutterViewContainer的实例对象的view添加到原生VC的view
上，这时候FBFlutterViewContainer的view不展示，我想知道我如果想把FBFlutterViewContainer添加到原生的vc上展示的时候，应该取FBFlutterViewContainer的哪个属性来展示？

The report concerns FBFlutterViewContainer inside a custom-transition native view controller on a real iOS device. Start by reproducing the missing view and inspecting the container and native view hierarchy; done means identifying the supported property or integration path that makes the Flutter view render when attached to the native controller.

Written by the indexing model from the issue text.