anchor.diff:  }
   
   class _PaySampleAppState extends State<PaySampleApp> {
  -  void googlePayButtonPressed() async {
  -    var result = await _googlePayClient.showPaymentSelector(price: '99.99');
  +  void googlePayButtonPressed(paymentClient) async {
  +    var result = await paymentClient.showPaymentSelector(price: '99.99');
       debugPrint(result.toString());
  -  }
  -
  -  Widget _getPaymentButtons() {
  -    return FutureBuilder<bool>(
  -      future: _googlePayClient.userCanPay(),
  -      builder: (context, snapshot) {
  -        if (snapshot.connectionState == ConnectionState.done) {
  -          if (snapshot.data == true) {
  -            return SizedBox(
  -                width: double.infinity,
  -                child: GooglePayButton(
  -                    color: GooglePayButtonColor.flat,
  -                    type: GooglePayButtonType.pay,
  -                    onPressed: googlePayButtonPressed));
  -          } else if (snapshot.hasError) {
  -            PlatformException exc = snapshot.error;
  -            return Text(exc.message);
  -          }
  -        }
  -
  -        return CircularProgressIndicator();
  -      },
  -    );
     }
   
     @override
  
positive.code: import 'package:flutter/material.dart';
  import 'package:flutter/services.dart';
  import 'package:pay/pay.dart';
  
  Pay _googlePayClient = Pay.fromAsset('default_payment_profile.json');
  
  void main() {
    runApp(PayMaterialApp());
  
negative.code:             ),
            ),
            SizedBox(height: 15),
            Center(
              child: SizedBox(
                width: double.infinity,
                child: GooglePayButtonWidget(
                  paymentConfigurationAsset: 'default_payment_profile.json',
                  color: GooglePayButtonColor.flat,
                  type: GooglePayButtonType.pay,
                  onPressed: googlePayButtonPressed,
                  childOnError: Text('Google Pay is not available.'),
                  loadingIndicator: CircularProgressIndicator(),
                ),
              ),
            ),
            SizedBox(height: 15),
          ],
        ),
      );
    }
  }
  