UniRx.Async Demo.cs

// extension awaiter/methods can be used by this namespace
using UniRx.Async;

// You can return type as struct UniTask<T>, it is unity specialized lightweight alternative of Task<T>
// no(or less) allocation and fast excution for zero overhead async/await integrate with Unity
async UniTask<string> DemoAsync()
{
    // You can await Unity's AsyncObject
    var asset = await Resources.LoadAsync<TextAsset>("foo");

    // .ConfigureAwait accepts progress callback
    await SceneManager.LoadSceneAsync("scene2").ConfigureAwait(new Progress<float>(x => Debug.Log(x)));

    // await frame-based operation(you can also await frame count by DelayFrame)
    await UniTask.Delay(TimeSpan.FromSeconds(3));

    // like 'yield return WaitForEndOfFrame', or Rx's ObserveOn(scheduler)
    await UniTask.Yield(PlayerLoopTiming.PostLateUpdate);

    // You can await standard task
    await Task.Run(() => 100);

    // You can await IEnumerator coroutine
    await ToaruCoroutineEnumerator();

    // get async webrequest
    async UniTask<string> GetTextAsync(UnityWebRequest req)
    {
        var op = await req.SendWebRequest();
        return op.downloadHandler.text;
    }

    var task1 = GetTextAsync(UnityWebRequest.Get("http://google.com"));
    var task2 = GetTextAsync(UnityWebRequest.Get("http://bing.com"));
    var task3 = GetTextAsync(UnityWebRequest.Get("http://yahoo.com"));

    // concurrent async-wait and get result easily by tuple syntax
    var (google, bing, yahoo) = await UniTask.WhenAll(task1, task2, task3);

    // You can handle timeout easily
    await GetTextAsync(UnityWebRequest.Get("http://unity.com")).Timeout(TimeSpan.FromMilliseconds(300));

    // return async-value.(or you can use `UniTask`(no result), `UniTaskVoid`(fire and forget)).
    return (asset as TextAsset)?.text ?? throw new InvalidOperationException("Asset not found");
}