Hello. I've noticed the package does two things: it has widgets integrated with the once and also does the timer logic thing. This mean the package has a unnecessary dependency on Flutter, those running Dart only can't use it. So, it would be nice to split into once and once_flutter, something like that.

Steps to reproduce:

1. Use the default flutter app
2. Convert stateless into statefull widget
3. Insert the following code into the class _MyAppState

  @override
  void initState() {
    super.initState();

    Once.runOnNewDay(
      'testonce',
      callback: () {
        debugPrint("Once is running");
        return true;
      },
        debugCallback: true,
      fallback: () {
        debugPrint("Fallback triggered");
      }
    );
  }

After starting the app for the first time the console shows

I/flutter (26773): Once is running

After stopping the app and running it again the console shows:

I/flutter (27127): Once is running

Expected behavior: I would expect to get the log message the first time the app is running but not the second time.

Running on Android Emulator.

Output of flutter doctor -v

[✓] Flutter (Channel stable, 3.0.5, on Ubuntu 20.04.4 LTS 5.13.0-52-generic, locale de_DE.UTF-8)
    • Flutter version 3.0.5 at /home/olf/snap/flutter/common/flutter
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision f1875d570e (vor 5 Wochen), 2022-07-13 11:24:16 -0700
    • Engine revision e85ea0e79c
    • Dart version 2.17.6
    • DevTools version 2.12.2

[!] Android toolchain - develop for Android devices (Android SDK version 31.0.0)
    • Android SDK at /home/olf/Android/Sdk
    • Platform android-31, build-tools 31.0.0
    • Java binary at: /opt/android-studio-2021.2.1/android-studio/jre/bin/java
    • Java version OpenJDK Runtime Environment (build 11.0.12+0-b1504.28-7817840)
    ✗ Android license status unknown.
      Run `flutter doctor --android-licenses` to accept the SDK licenses.
      See https://flutter.dev/docs/get-started/install/linux#android-setup for more details.

[✓] Chrome - develop for the web
    • Chrome at google-chrome

[✓] Linux toolchain - develop for Linux desktop
    • clang version 6.0.0-1ubuntu2 (tags/RELEASE_600/final)
    • cmake version 3.10.2
    • ninja version 1.8.2
    • pkg-config version 0.29.1

[✓] Android Studio (version 2021.2)
    • Android Studio at /opt/android-studio-2021.2.1/android-studio
    • Flutter plugin version 69.0.2
    • Dart plugin version 212.5744
    • Java version OpenJDK Runtime Environment (build 11.0.12+0-b1504.28-7817840)

[✓] Android Studio
    • Android Studio at /opt/android-studio
    • Flutter plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
      🔨 https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.12+0-b1504.28-7817840)

[✓] Connected device (3 available)
    • sdk gphone64 x86 64 (mobile) • emulator-5554 • android-x64    • Android 12 (API 31) (emulator)
    • Linux (desktop)              • linux         • linux-x64      • Ubuntu 20.04.4 LTS 5.13.0-52-generic
    • Chrome (web)                 • chrome        • web-javascript • Google Chrome 104.0.5112.101

[✓] HTTP Host Availability
    • All required HTTP hosts are available

! Doctor found issues in 1 category.

One of the most important features of Once java impl is the Todo API.

Have you thought about including it?

For example, suppose that you want to display the rate app modal after some conditions are met on a specific screen. You can achieve that easily using the todo API

Hello,

Is it possible to add the APP_AT_INSTALL like the java library ? It will fired only at the first launch to show an introduction screens slider. NewVersion will not work in this case.

Thks V.

2.0.0

• all periodic functions now are returning a nullable generic typed Future Future<T?>
• you can now use FutureBuilder to return a widget from once like so

  • FutureBuilder<Widget?>(
        future: Once.runDaily<Widget?>(
            "MyKey",
            (){/* handling the callback to return a [Widget] or [null] */},
        ),
        builder: (_, snapshot) {
            if (snapshot.hasData) {
                return snapshot.data!;
            } else {
                /* handling a fallback widget if [myNullableWidget] returns null */
            }
        },
    )