showNotification method
Post a notification from native code (used to render foreground pushes on
Android, since FCM does not draw one while the app is open). Returns true
if it was shown. No-op / false where unsupported. payload is stashed on
the tap intent and delivered back via onNotificationTap.
Implementation
Future<bool> showNotification({
required int id,
String? title,
String? body,
required String channelId,
required String channelName,
String? payload,
String? largeIcon,
String? bigPicture,
String? smallIcon,
String? visibility,
String? accentColor,
List<Map<String, String?>>? buttons,
}) async => false;