ToastrConfig constructor
      const
      ToastrConfig({ 
    
- required ToastrType type,
 - required String message,
 - String? title,
 - Duration duration = const Duration(seconds: 5),
 - Duration? extendedTimeout,
 - bool dismissible = true,
 - bool showCloseButton = false,
 - Widget? customIcon,
 - Color? backgroundColor,
 - Color? textColor,
 - Duration showDuration = const Duration(milliseconds: 300),
 - Duration hideDuration = const Duration(milliseconds: 1000),
 - ToastrPosition position = ToastrPosition.topRight,
 - ToastrShowMethod showMethod = ToastrShowMethod.fadeIn,
 - ToastrHideMethod hideMethod = ToastrHideMethod.fadeOut,
 - Curve showEasing = Curves.easeOut,
 - Curve hideEasing = Curves.easeIn,
 - bool showProgressBar = false,
 - bool preventDuplicates = false,
 - String? duplicateKey,
 
Creates a new ToastrConfig with the specified parameters.
The type and message parameters are required.
All other parameters have sensible defaults.
Implementation
const ToastrConfig({
  required this.type,
  required this.message,
  this.title,
  this.duration = const Duration(seconds: 5),
  this.extendedTimeout,
  this.dismissible = true,
  this.showCloseButton = false,
  this.customIcon,
  this.backgroundColor,
  this.textColor,
  this.showDuration = const Duration(milliseconds: 300),
  this.hideDuration = const Duration(milliseconds: 1000),
  this.position = ToastrPosition.topRight,
  this.showMethod = ToastrShowMethod.fadeIn,
  this.hideMethod = ToastrHideMethod.fadeOut,
  this.showEasing = Curves.easeOut,
  this.hideEasing = Curves.easeIn,
  this.showProgressBar = false,
  this.preventDuplicates = false,
  this.duplicateKey,
});