hasCallbackConstructor method
Whether the API has a method that callbacks to Dart to add a new instance to the InstanceManager.
This is possible as long as no callback methods are required to instantiate the class.
Implementation
bool hasCallbackConstructor() {
return flutterMethods
.followedBy(flutterMethodsFromSuperClasses())
.followedBy(flutterMethodsFromInterfaces())
.every((Method method) => !method.isRequired);
}