stepper.dart

Stepper(
  type: stepperType,
  ... "continue" ...
  onStepContinue: ()async { 
    
    var data = await onClickSave();
    
     pet = data;
     print(pet);
                
  setState(() {                
    print('entrouuuuuuuu');    
  });

    
  },
  onStepCancel: () {},
  onStepTapped: (step) {
     setState(() {
        this._currentStep = step;
     });
  },
);

Future<User> onClickSave() async {

    Future<User> user = User.get();
  
    user.then((user) async {
      // Save User
      setState(() {
        _showProgress = true;
      });

      await Future.delayed(Duration(seconds: 3));

      ApiResponse<User> response = await UserApi.save(c);

      setState(() {
        _showProgress = false;
      });

      if (response != null) {
         //Usuario salvo retornado
         print('retornou o usuário');
         return response;
      } else {
        return null;
      }
    }, onError: (error){
        print(error);
    }
);