import 'dart:async';

import 'package:flutter/material.dart';


ScaffoldFeatureController<SnackBar, SnackBarClosedReason> notifyUserX(
  ScaffoldMessengerState sm, 
  String message, 
  { int delaySeconds = 3 }
) => sm.showSnackBar(SnackBar(content: Text(message), duration: Duration(seconds: delaySeconds)));

ScaffoldFeatureController<SnackBar, SnackBarClosedReason> notifyUser(
  BuildContext context, 
  String message, 
  { int delaySeconds = 3 }
) => notifyUserX(ScaffoldMessenger.of(context), message, delaySeconds: delaySeconds);

Future<ScaffoldFeatureController<SnackBar, SnackBarClosedReason>> postNotifyUser(
  BuildContext context, String message, {int delaySeconds = 3}) {

  final completer = Completer<ScaffoldFeatureController<SnackBar, SnackBarClosedReason>>();

  WidgetsBinding.instance.addPostFrameCallback((_) {
    final controller = notifyUser(context, message, delaySeconds: delaySeconds);
    completer.complete(controller);
  });

  return completer.future;
}