Async disposal of a firebase Admob banner in dart.

main.dart

import 'dart:io';

import 'package:firebase_admob/firebase_admob.dart';
import 'package:flutter/material.dart';
import 'package:sabnzbdplusrewrite/retrofit/models/history.dart';
import 'package:sabnzbdplusrewrite/retrofit/models/queue.dart';
import 'package:sabnzbdplusrewrite/retrofit/models/status.dart' as prefix0;
import './screens/main_activity.dart';
import 'package:shared_preferences/shared_preferences.dart';

SharedPreferences prefs;

Future<prefix0.Status> mStatus;
Future<History> mHistory;
Future<Queue> mQueue;
MobileAdTargetingInfo targetingInfo;

Queue mQueueData;
History mHistoryData;
prefix0.Status mStatusData;

int qStart;
int hStart;

double bottomNavCoordinateX;
double bottomNavCoordinateY;
double upperBotNavCoordinateX;
double upperBotNavCoordinateY;

void main() async {
  qStart = 0;
  hStart = 0;
  prefs = await SharedPreferences.getInstance();
  runApp(new MyApp());
}

class MyApp extends StatefulWidget {
  // This widget is the root of your application.
  @override
  State<StatefulWidget> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  @override
  void initState() {
    try {
      mQueue = QueueModel().getQueueData();
      mHistory = HistoryModel().getHistoryData();
      mStatus = prefix0.StatusModel().getStatusData();
    } catch (Exception) {}

    String appId = "ca-app-pub-0000000000000000~0000000000";

    if (Platform.isAndroid) {
          // Android-specific code
          appId = "ca-app-pub-0000000000000000~0000000000";
        } else if (Platform.isIOS) {
          // iOS-specific code
          appId = "ca-app-pub-1111111111111111~1111111111";
        } else {
          appId = "ca-app-pub-2222222222222222~2222222222";
        }

    FirebaseAdMob.instance
        .initialize(appId: appId);
        
    targetingInfo = MobileAdTargetingInfo(
      keywords: <String>['flutterio', 'beautiful apps'],
      contentUrl: 'https://flutter.io',
      childDirected: false,
      testDevices: <String>[], // Android emulators are considered test devices
    );

    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'SabNzbd Remote 2.0',
      theme: ThemeData(
        primarySwatch: Colors.orange,
      ),
      home: MainActivity(title: 'SabNzbd Remote 2.0'),
    );
  }
}

void disposeBanner(BannerAd banner) {
  try {
    banner.isLoaded().then((isloaded) {
      if (isloaded)
        complete(banner);
      else
        Future.delayed(Duration(seconds: 1), (){
          disposeBanner(banner);
        });
    }, onError: (e){
      print(e);
    });
  } catch (e) {
    print("it broke partially with $e");
  }
}

void disposeBannerBlock(BannerAd banner) async {
  try {
    await banner.isLoaded();
    completeBlocked(banner);
  } catch (e) {
    print("it broke partially with $e");
    try {
      completeBlocked(banner);
    } catch (ex) {
      print("it broke partially some more with $ex");
    }
  }
}

void completeBlocked(BannerAd banner) async {
 try {
    await banner.dispose();
  } catch (e) {
    print("it broke properly with $e");
  }
}

void complete(BannerAd banner) {
  try {
    banner.dispose();
  } catch (e) {
    print("it broke properly with $e");
  }
}