flutter tindercard swipe up

i am using this plugin here to swipe up, down, left right. my problem is, if i swipe up it remove from the list. let assume i have 4 item in a list [1,2,3,4].

i want it in a way that if i swipe up i dont want it to remove from the list. i have been looking at the plugin code but i cant figure out where is calling index to remove.

sample code..

import 'package:flutter/material.dart';
import 'package:flutter_tindercard/flutter_tindercard.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: ExampleHomePage(),
    );
  }
}

class ExampleHomePage extends StatefulWidget {
  @override
  _ExampleHomePageState createState() => _ExampleHomePageState();
}

class _ExampleHomePageState extends State<ExampleHomePage>
    with TickerProviderStateMixin {
  List<String> welcomeImages = [
    "assets/welcome0.png",
    "assets/welcome1.png",
    "assets/welcome2.png",
    "assets/welcome2.png",
    "assets/welcome1.png",
    "assets/welcome1.png"
  ];

  @override
  Widget build(BuildContext context) {
    CardController controller; //Use this to trigger swap.

    return new Scaffold(
      body: new Center(
          child: Container(
              height: MediaQuery.of(context).size.height * 0.6,
              child: new TinderSwapCard(
                  swipeUp: true,
                  swipeDown: true,
                  orientation: AmassOrientation.BOTTOM,
                  totalNum: welcomeImages.length,
                  stackNum: 3,
                  swipeEdge: 4.0,
                  maxWidth: MediaQuery.of(context).size.width * 0.9,
                  maxHeight: MediaQuery.of(context).size.width * 0.9,
                  minWidth: MediaQuery.of(context).size.width * 0.8,
                  minHeight: MediaQuery.of(context).size.width * 0.8,
                  cardBuilder: (context, index) => Card(
                        child: Image.asset('${welcomeImages[index]}'),
                      ),
                  cardController: controller = CardController(),
                  swipeUpdateCallback:
                      (DragUpdateDetails details, Alignment align) {
                    /// Get swiping card's alignment
                    if (align.x < 0) {
                      //Card is LEFT swiping
                    } else if (align.x > 0) {
                      //Card is RIGHT swiping
                    }
                  },
                  swipeCompleteCallback:
                      (CardSwipeOrientation orientation, int index) {
                    /// Get orientation & index of swiped card!
                  },
              ),
          ),
      ),
    );
  }
}