最近，我试图运行该项目，但似乎snackbar是有这样的某种错误
编译器在“上下文”消息下方显示错误
如何解决？
第一个
这里的完整的源代码的TopSnackBar

import 'dart:async';

import 'package:flutter/material.dart';
import 'package:top_snackbar_flutter/safe_area_values.dart';
import 'package:top_snackbar_flutter/tap_bounce_container.dart';

typedef ControllerCallback = void Function(AnimationController);

enum DismissType { onTap, onSwipe, none }

OverlayEntry? _previousEntry;

/// The [overlayState] argument is used to add specific overlay state.
/// If you are sure that there is a overlay state in your [BuildContext],
/// You can get it [Overlay.of(BuildContext)]
/// Displays a widget that will be passed to [child] parameter above the current
/// contents of the app, with transition animation
///
/// The [child] argument is used to pass widget that you want to show
///
/// The [animationDuration] argument is used to specify duration of
/// enter transition
///
/// The [reverseAnimationDuration] argument is used to specify duration of
/// exit transition
///
/// The [displayDuration] argument is used to specify duration displaying
///
/// The [onTap] callback of [_TopSnackBar]
///
/// The [persistent] argument is used to make snack bar persistent, so
/// [displayDuration] will be ignored. Default is false.
///
/// The [onAnimationControllerInit] callback is called on internal
/// [AnimationController] has been initialized.
///
/// The [padding] argument is used to specify amount of outer padding
///
/// [curve] and [reverseCurve] arguments are used to specify curves
/// for in and out animations respectively
///
/// The [safeAreaValues] argument is used to specify the arguments of the
/// [SafeArea] widget that wrap the snackbar.
///
/// The [dismissType] argument specify which action to trigger to
/// dismiss the snackbar. Defaults to `TopSnackBarDismissType.onTap`
///
/// The [dismissDirection] argument specify in which direction the snackbar
/// can be dismissed. This argument is only used when [dismissType] is equal
/// to `DismissType.onSwipe`. Defaults to `[DismissDirection.up]`
void showTopSnackBar(
  OverlayState overlayState,
  Widget child, {
  Duration animationDuration = const Duration(milliseconds: 1200),
  Duration reverseAnimationDuration = const Duration(milliseconds: 550),
  Duration displayDuration = const Duration(milliseconds: 3000),
  VoidCallback? onTap,
  bool persistent = false,
  ControllerCallback? onAnimationControllerInit,
  EdgeInsets padding = const EdgeInsets.all(16),
  Curve curve = Curves.elasticOut,
  Curve reverseCurve = Curves.linearToEaseOut,
  SafeAreaValues safeAreaValues = const SafeAreaValues(),
  DismissType dismissType = DismissType.onTap,
  List<DismissDirection> dismissDirection = const [DismissDirection.up],
}) {
  late OverlayEntry _overlayEntry;
  _overlayEntry = OverlayEntry(
    builder: (_) {
      return _TopSnackBar(
        onDismissed: () {
          _overlayEntry.remove();
          _previousEntry = null;
        },
        animationDuration: animationDuration,
        reverseAnimationDuration: reverseAnimationDuration,
        displayDuration: displayDuration,
        onTap: onTap,
        persistent: persistent,
        onAnimationControllerInit: onAnimationControllerInit,
        padding: padding,
        curve: curve,
        reverseCurve: reverseCurve,
        safeAreaValues: safeAreaValues,
        dismissType: dismissType,
        dismissDirections: dismissDirection,
        child: child,
      );
    },
  );

  if (_previousEntry != null && _previousEntry!.mounted) {
    _previousEntry?.remove();
  }

  overlayState.insert(_overlayEntry);
  _previousEntry = _overlayEntry;
}

/// Widget that controls all animations
class _TopSnackBar extends StatefulWidget {
  const _TopSnackBar({
    Key? key,
    required this.child,
    required this.onDismissed,
    required this.animationDuration,
    required this.reverseAnimationDuration,
    required this.displayDuration,
    required this.padding,
    required this.curve,
    required this.reverseCurve,
    required this.safeAreaValues,
    required this.dismissDirections,
    this.onTap,
    this.persistent = false,
    this.onAnimationControllerInit,
    this.dismissType = DismissType.onTap,
  }) : super(key: key);

  final Widget child;
  final VoidCallback onDismissed;
  final Duration animationDuration;
  final Duration reverseAnimationDuration;
  final Duration displayDuration;
  final VoidCallback? onTap;
  final ControllerCallback? onAnimationControllerInit;
  final bool persistent;
  final EdgeInsets padding;
  final Curve curve;
  final Curve reverseCurve;
  final SafeAreaValues safeAreaValues;
  final DismissType dismissType;
  final List<DismissDirection> dismissDirections;

  @override
  _TopSnackBarState createState() => _TopSnackBarState();
}

class _TopSnackBarState extends State<_TopSnackBar>
    with SingleTickerProviderStateMixin {
  late final Animation<Offset> _offsetAnimation;
  late final AnimationController _animationController;

  Timer? _timer;

  final _offsetTween = Tween(begin: const Offset(0, -1), end: Offset.zero);

  @override
  void initState() {
    _animationController = AnimationController(
      vsync: this,
      duration: widget.animationDuration,
      reverseDuration: widget.reverseAnimationDuration,
    );
    _animationController.addStatusListener(
      (status) {
        if (status == AnimationStatus.completed && !widget.persistent) {
          _timer = Timer(widget.displayDuration, () {
            if (mounted) {
              _animationController.reverse();
            }
          });
        }
        if (status == AnimationStatus.dismissed) {
          _timer?.cancel();
          widget.onDismissed.call();
        }
      },
    );

    widget.onAnimationControllerInit?.call(_animationController);

    _offsetAnimation = _offsetTween.animate(
      CurvedAnimation(
        parent: _animationController,
        curve: widget.curve,
        reverseCurve: widget.reverseCurve,
      ),
    );
    if (mounted) {
      _animationController.forward();
    }
    super.initState();
  }

  @override
  void dispose() {
    _animationController.dispose();
    _timer?.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Positioned(
      top: widget.padding.top,
      left: widget.padding.left,
      right: widget.padding.right,
      child: SlideTransition(
        position: _offsetAnimation,
        child: SafeArea(
          top: widget.safeAreaValues.top,
          bottom: widget.safeAreaValues.bottom,
          left: widget.safeAreaValues.left,
          right: widget.safeAreaValues.right,
          minimum: widget.safeAreaValues.minimum,
          maintainBottomViewPadding:
              widget.safeAreaValues.maintainBottomViewPadding,
          child: _buildDismissibleChild(),
        ),
      ),
    );
  }

  /// Build different type of [Widget] depending on [DismissType] value
  Widget _buildDismissibleChild() {
    switch (widget.dismissType) {
      case DismissType.onTap:
        return TapBounceContainer(
          onTap: () {
            widget.onTap?.call();
            if (!widget.persistent && mounted) {
              _animationController.reverse();
            }
          },
          child: widget.child,
        );
      case DismissType.onSwipe:
        var childWidget = widget.child;
        for (final direction in widget.dismissDirections) {
          childWidget = Dismissible(
            direction: direction,
            key: UniqueKey(),
            dismissThresholds: const {DismissDirection.up: 0.2},
            confirmDismiss: (direction) async {
              if (!widget.persistent && mounted) {
                if (direction == DismissDirection.down) {
                  await _animationController.reverse();
                } else {
                  _animationController.reset();
                }
              }
              return false;
            },
            child: childWidget,
          );
        }
        return childWidget;
      case DismissType.none:
        return widget.child;
    }
  }
}

我已经尝试在“上下文”行旁边添加一些“此”行，但仍然不起作用
我最近编辑这篇文章的一些评论要求，我显示一些职位的showtopsnackbar和一些错误消息，我得到了。
我希望这能成为解决我所有错误的方法或参考