anchor.diff:            .subtitle1;
   
     OverlayEntry? entry;
  +  void close() {
  +    if (entry != null && entry.mounted) {
  +      entry.remove();
  +    }
  +  }
  +
     entry = OverlayEntry(builder: (context) {
       return Align(
         alignment: Alignment.bottomCenter,
  
positive.code:           duration,
            backgroundColor: backgroundColor,
            textStyle: textStyle,
            onComplete: () {
              entry!.remove();
            },
          ),
        ),
      );
  
negative.code:   Timer.run(() {
      Overlay.of(context)!.insert(entry!);
    });
  
    return close;
  }
  