hasLargeIcon property
icon of the notification which setted by setSmallIcon, at most time this is icon of the application package. So no need to set this, use a method to take from android. To display as a image use the Image.memory widget. Example:
Image.memory(evt.icon)
if we have the large icon
Implementation
// Uint8List? icon;
/// if we have the large icon
bool? hasLargeIcon;