viewController property

UiKitViewController viewController

The unique identifier of the UIView controlled by this controller.

Typically generated by PlatformViewsRegistry.getNextPlatformViewId, the UIView must have been created by calling PlatformViewsService.initUiKitView.

Implementation 

UiKitViewController get viewController => _viewController;
void viewController= (UiKitViewController viewId)

Implementation 

set viewController(UiKitViewController viewId) {
  assert(viewId != null);
  _viewController = viewId;
  markNeedsPaint();
}