UniTask === [![Readme_CN](https://camo.githubusercontent.com/d5bde5d98666bf4729701d3a41fff93990fda0f31fdb02913e395f61619b40d6/68747470733a2f2f696d672e736869656c64732e696f2f62616467652f556e695461736b2d2545342542382541442545362539362538372545362539362538372545362541312541332d726564)](https://github.com/Cysharp/UniTask/blob/master/README_CN.md) Provides an efficient allocation free async/await integration for Unity. * Struct based `UniTask` and custom AsyncMethodBuilder to achieve zero allocation * Makes all Unity AsyncOperations and Coroutines awaitable * PlayerLoop based task(`UniTask.Yield`, `UniTask.Delay`, `UniTask.DelayFrame`, etc..) that enable replacing all coroutine operations * MonoBehaviour Message Events and uGUI Events as awaitable/async-enumerable * Runs completely on Unity's PlayerLoop so doesn't use threads and runs on WebGL, wasm, etc. * Asynchronous LINQ, with Channel and AsyncReactiveProperty * TaskTracker window to prevent memory leaks * Highly compatible behaviour with Task/ValueTask/IValueTaskSource For technical details, see blog post: [UniTask v2 — Zero Allocation async/await for Unity, with Asynchronous LINQ ](https://medium.com/@neuecc/unitask-v2-zero-allocation-async-await-for-unity-with-asynchronous-linq-1aa9c96aa7dd) For advanced tips, see blog post: [Extends UnityWebRequest via async decorator pattern — Advanced Techniques of UniTask](https://medium.com/@neuecc/extends-unitywebrequest-via-async-decorator-pattern-advanced-techniques-of-unitask-ceff9c5ee846) ## Table of Contents - [Getting started](https://github.com/Cysharp/UniTask/raw/master/#getting-started) - [Basics of UniTask and AsyncOperation](https://github.com/Cysharp/UniTask/raw/master/#basics-of-unitask-and-asyncoperation) - [Cancellation and Exception handling](https://github.com/Cysharp/UniTask/raw/master/#cancellation-and-exception-handling) - [Timeout handling](https://github.com/Cysharp/UniTask/raw/master/#timeout-handling) - [Progress](https://github.com/Cysharp/UniTask/raw/master/#progress) - [PlayerLoop](https://github.com/Cysharp/UniTask/raw/master/#playerloop) - [async void vs async UniTaskVoid](https://github.com/Cysharp/UniTask/raw/master/#async-void-vs-async-unitaskvoid) - [UniTaskTracker](https://github.com/Cysharp/UniTask/raw/master/#unitasktracker) - [External Assets](https://github.com/Cysharp/UniTask/raw/master/#external-assets) - [AsyncEnumerable and Async LINQ](https://github.com/Cysharp/UniTask/raw/master/#asyncenumerable-and-async-linq) - [Awaitable Events](https://github.com/Cysharp/UniTask/raw/master/#awaitable-events) - [Channel](https://github.com/Cysharp/UniTask/raw/master/#channel) - [For Unit Testing](https://github.com/Cysharp/UniTask/raw/master/#for-unit-testing) - [ThreadPool limitation](https://github.com/Cysharp/UniTask/raw/master/#threadpool-limitation) - [IEnumerator.ToUniTask limitation](https://github.com/Cysharp/UniTask/raw/master/#ienumeratortounitask-limitation) - [For UnityEditor](https://github.com/Cysharp/UniTask/raw/master/#for-unityeditor) - [Compare with Standard Task API](https://github.com/Cysharp/UniTask/raw/master/#compare-with-standard-task-api) - [Pooling Configuration](https://github.com/Cysharp/UniTask/raw/master/#pooling-configuration) - [Allocation on Profiler](https://github.com/Cysharp/UniTask/raw/master/#allocation-on-profiler) - [UniTaskSynchronizationContext](https://github.com/Cysharp/UniTask/raw/master/#unitasksynchronizationcontext) - [API References](https://github.com/Cysharp/UniTask/raw/master/#api-references) - [UPM Package](https://github.com/Cysharp/UniTask/raw/master/#upm-package) - [Install via git URL](https://github.com/Cysharp/UniTask/raw/master/#install-via-git-url) - [.NET Core](https://github.com/Cysharp/UniTask/raw/master/#net-core) - [License](https://github.com/Cysharp/UniTask/raw/master/#license) Getting started --- Install via [UPM package](https://github.com/Cysharp/UniTask/raw/master/#upm-package) or asset package(`UniTask.*.*.*.unitypackage`) available in [UniTask/releases](https://github.com/Cysharp/UniTask/releases) page. ```csharp // extension awaiter/methods can be used by this namespace using Cysharp.Threading.Tasks; // You can return type as struct UniTask(or UniTask), it is unity specialized lightweight alternative of Task // zero allocation and fast excution for zero overhead async/await integrate with Unity async UniTask DemoAsync() { // You can await Unity's AsyncObject var asset = await Resources.LoadAsync("foo"); var txt = (await UnityWebRequest.Get("https://...").SendWebRequest()).downloadHandler.text; await SceneManager.LoadSceneAsync("scene2"); // .WithCancellation enables Cancel, GetCancellationTokenOnDestroy synchornizes with lifetime of GameObject var asset2 = await Resources.LoadAsync("bar").WithCancellation(this.GetCancellationTokenOnDestroy()); // .ToUniTask accepts progress callback(and all options), Progress.Create is a lightweight alternative of IProgress var asset3 = await Resources.LoadAsync("baz").ToUniTask(Progress.Create(x => Debug.Log(x))); // await frame-based operation like a coroutine await UniTask.DelayFrame(100); // replacement of yield return new WaitForSeconds/WaitForSecondsRealtime await UniTask.Delay(TimeSpan.FromSeconds(10), ignoreTimeScale: false); // yield any playerloop timing(PreUpdate, Update, LateUpdate, etc...) await UniTask.Yield(PlayerLoopTiming.PreLateUpdate); // replacement of yield return null await UniTask.Yield(); await UniTask.NextFrame(); // replacement of WaitForEndOfFrame #if UNITY_2023_1_OR_NEWER await UniTask.WaitForEndOfFrame(); #else // requires MonoBehaviour(CoroutineRunner)) await UniTask.WaitForEndOfFrame(this); // this is MonoBehaviour #endif // replacement of yield return new WaitForFixedUpdate(same as UniTask.Yield(PlayerLoopTiming.FixedUpdate)) await UniTask.WaitForFixedUpdate(); // replacement of yield return WaitUntil await UniTask.WaitUntil(() => isActive == false); // special helper of WaitUntil await UniTask.WaitUntilValueChanged(this, x => x.isActive); // You can await IEnumerator coroutines await FooCoroutineEnumerator(); // You can await a standard task await Task.Run(() => 100); // Multithreading, run on ThreadPool under this code await UniTask.SwitchToThreadPool(); /* work on ThreadPool */ // return to MainThread(same as `ObserveOnMainThread` in UniRx) await UniTask.SwitchToMainThread(); // get async webrequest async UniTask 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 results easily by tuple syntax var (google, bing, yahoo) = await UniTask.WhenAll(task1, task2, task3); // shorthand of WhenAll, tuple can await directly var (google2, bing2, yahoo2) = await (task1, task2, task3); // 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"); } ``` Basics of UniTask and AsyncOperation --- UniTask features rely on C# 7.0([task-like custom async method builder feature](https://github.com/dotnet/roslyn/blob/master/docs/features/task-types.md)) so the required Unity version is after `Unity 2018.3`, the official lowest version supported is `Unity 2018.4.13f1`. Why is UniTask(custom task-like object) required? Because Task is too heavy and not matched to Unity threading (single-thread). UniTask does not use threads and SynchronizationContext/ExecutionContext because Unity's asynchronous object is automaticaly dispatched by Unity's engine layer. It achieves faster and lower allocation, and is completely integrated with Unity. You can await `AsyncOperation`, `ResourceRequest`, `AssetBundleRequest`, `AssetBundleCreateRequest`, `UnityWebRequestAsyncOperation`, `AsyncGPUReadbackRequest`, `IEnumerator` and others when `using Cysharp.Threading.Tasks;`. UniTask provides three pattern of extension methods. ```csharp * await asyncOperation; * .WithCancellation(CancellationToken); * .ToUniTask(IProgress, PlayerLoopTiming, CancellationToken); ``` `WithCancellation` is a simple version of `ToUniTask`, both return `UniTask`. For details of cancellation, see: [Cancellation and Exception handling](https://github.com/Cysharp/UniTask/raw/master/#cancellation-and-exception-handling) section. > Note: await directly is returned from native timing of PlayerLoop but WithCancellation and ToUniTask are returned from specified PlayerLoopTiming. For details of timing, see: [PlayerLoop](https://github.com/Cysharp/UniTask/raw/master/#playerloop) section. > Note: AssetBundleRequest has `asset` and `allAssets`, default await returns `asset`. If you want to get `allAssets`, you can use `AwaitForAllAssets()` method. The type of `UniTask` can use utilities like `UniTask.WhenAll`, `UniTask.WhenAny`. They are like `Task.WhenAll`/`Task.WhenAny` but the return type is more useful. They return value tuples so you can deconstruct each result and pass multiple types. ```csharp public async UniTaskVoid LoadManyAsync() { // parallel load. var (a, b, c) = await UniTask.WhenAll( LoadAsSprite("foo"), LoadAsSprite("bar"), LoadAsSprite("baz")); } async UniTask LoadAsSprite(string path) { var resource = await Resources.LoadAsync(path); return (resource as Sprite); } ``` If you want to convert a callback to UniTask, you can use `UniTaskCompletionSource` which is a lightweight edition of `TaskCompletionSource`. ```csharp public UniTask WrapByUniTaskCompletionSource() { var utcs = new UniTaskCompletionSource(); // when complete, call utcs.TrySetResult(); // when failed, call utcs.TrySetException(); // when cancel, call utcs.TrySetCanceled(); return utcs.Task; //return UniTask } ``` You can convert Task -> UniTask: `AsUniTask`, `UniTask` -> `UniTask`: `AsAsyncUnitUniTask`, `UniTask` -> `UniTask`: `AsUniTask`. `UniTask` -> `UniTask`'s conversion cost is free. If you want to convert async to coroutine, you can use `.ToCoroutine()`, this is useful if you want to only allow using the coroutine system. UniTask can not await twice. This is a similar constraint to the [ValueTask/IValueTaskSource](https://docs.microsoft.com/en-us/dotnet/api/system.threading.tasks.valuetask-1?view=netcore-3.1) introduced in .NET Standard 2.1. > The following operations should never be performed on a ValueTask instance: > > * Awaiting the instance multiple times. > * Calling AsTask multiple times. > * Using .Result or .GetAwaiter().GetResult() when the operation hasn't yet completed, or using them multiple times. > * Using more than one of these techniques to consume the instance. > > If you do any of the above, the results are undefined. ```csharp var task = UniTask.DelayFrame(10); await task; await task; // NG, throws Exception ``` Store to the class field, you can use `UniTask.Lazy` that supports calling multiple times. `.Preserve()` allows for multiple calls (internally cached results). This is useful when there are multiple calls in a function scope. Also `UniTaskCompletionSource` can await multiple times and await from many callers. Cancellation and Exception handling --- Some UniTask factory methods have a `CancellationToken cancellationToken = default` parameter. Also some async operations for Unity have `WithCancellation(CancellationToken)` and `ToUniTask(..., CancellationToken cancellation = default)` extension methods. You can pass `CancellationToken` to parameter by standard [`CancellationTokenSource`](https://docs.microsoft.com/en-us/dotnet/api/system.threading.cancellationtokensource). ```csharp var cts = new CancellationTokenSource(); cancelButton.onClick.AddListener(() => { cts.Cancel(); }); await UnityWebRequest.Get("http://google.co.jp").SendWebRequest().WithCancellation(cts.Token); await UniTask.DelayFrame(1000, cancellationToken: cts.Token); ``` CancellationToken can be created by `CancellationTokenSource` or MonoBehaviour's extension method `GetCancellationTokenOnDestroy`. ```csharp // this CancellationToken lifecycle is same as GameObject. await UniTask.DelayFrame(1000, cancellationToken: this.GetCancellationTokenOnDestroy()); ``` For propagate Cancellation, all async method recommend to accept `CancellationToken cancellationToken` at last argument, and pass `CancellationToken` from root to end. ```csharp await FooAsync(this.GetCancellationTokenOnDestroy()); // --- async UniTask FooAsync(CancellationToken cancellationToken) { await BarAsync(cancellationToken); } async UniTask BarAsync(CancellationToken cancellationToken) { await UniTask.Delay(TimeSpan.FromSeconds(3), cancellationToken); } ``` `CancellationToken` means lifecycle of async. You can hold your own lifecycle insteadof default CancellationTokenOnDestroy. ```csharp public class MyBehaviour : MonoBehaviour { CancellationTokenSource disableCancellation = new CancellationTokenSource(); CancellationTokenSource destroyCancellation = new CancellationTokenSource(); private void OnEnable() { if (disableCancellation != null) { disableCancellation.Dispose(); } disableCancellation = new CancellationTokenSource(); } private void OnDisable() { disableCancellation.Cancel(); } private void OnDestroy() { destroyCancellation.Cancel(); destroyCancellation.Dispose(); } } ``` When cancellation is detected, all methods throw `OperationCanceledException` and propagate upstream. When exception(not limited to `OperationCanceledException`) is not handled in async method, it is propagated finally to `UniTaskScheduler.UnobservedTaskException`. The default behaviour of received unhandled exception is to write log as exception. Log level can be changed using `UniTaskScheduler.UnobservedExceptionWriteLogType`. If you want to use custom behaviour, set an action to `UniTaskScheduler.UnobservedTaskException.` Andalso `OperationCanceledException` is a special exception, this is silently ignored at `UnobservedTaskException`. If you want to cancel behaviour in an async UniTask method, throw `OperationCanceledException` manually. ```csharp public async UniTask FooAsync() { await UniTask.Yield(); throw new OperationCanceledException(); } ``` If you handle an exception but want to ignore(propagate to global cancellation handling), use an exception filter. ```csharp public async UniTask BarAsync() { try { var x = await FooAsync(); return x * 2; } catch (Exception ex) when (!(ex is OperationCanceledException)) // when (ex is not OperationCanceledException) at C# 9.0 { return -1; } } ``` throws/catch `OperationCanceledException` is slightly heavy, so if performance is a concern, use `UniTask.SuppressCancellationThrow` to avoid OperationCanceledException throw. It returns `(bool IsCanceled, T Result)` instead of throwing. ```csharp var (isCanceled, _) = await UniTask.DelayFrame(10, cancellationToken: cts.Token).SuppressCancellationThrow(); if (isCanceled) { // ... } ``` Note: Only suppress throws if you call directly into the most source method. Otherwise, the return value will be converted, but the entire pipeline will not suppress throws. Timeout handling --- Timeout is a variation of cancellation. You can set timeout by `CancellationTokenSouce.CancelAfterSlim(TimeSpan)` and pass CancellationToken to async methods. ```csharp var cts = new CancellationTokenSource(); cts.CancelAfterSlim(TimeSpan.FromSeconds(5)); // 5sec timeout. try { await UnityWebRequest.Get("http://foo").SendWebRequest().WithCancellation(cts.Token); } catch (OperationCanceledException ex) { if (ex.CancellationToken == cts.Token) { UnityEngine.Debug.Log("Timeout"); } } ``` > `CancellationTokenSouce.CancelAfter` is a standard api. However in Unity you should not use it because it depends threading timer. `CancelAfterSlim` is UniTask's extension methods, it uses PlayerLoop instead. If you want to use timeout with other source of cancellation, use `CancellationTokenSource.CreateLinkedTokenSource`. ```csharp var cancelToken = new CancellationTokenSource(); cancelButton.onClick.AddListener(()=> { cancelToken.Cancel(); // cancel from button click. }); var timeoutToken = new CancellationTokenSource(); timeoutToken.CancelAfterSlim(TimeSpan.FromSeconds(5)); // 5sec timeout. try { // combine token var linkedTokenSource = CancellationTokenSource.CreateLinkedTokenSource(cancelToken.Token, timeoutToken.Token); await UnityWebRequest.Get("http://foo").SendWebRequest().WithCancellation(linkedTokenSource.Token); } catch (OperationCanceledException ex) { if (timeoutToken.IsCancellationRequested) { UnityEngine.Debug.Log("Timeout."); } else if (cancelToken.IsCancellationRequested) { UnityEngine.Debug.Log("Cancel clicked."); } } ``` Optimize for reduce allocation of CancellationTokenSource for timeout per call async method, you can use UniTask's `TimeoutController`. ```csharp TimeoutController timeoutController = new TimeoutController(); // setup to field for reuse. async UniTask FooAsync() { try { // you can pass timeoutController.Timeout(TimeSpan) to cancellationToken. await UnityWebRequest.Get("http://foo").SendWebRequest() .WithCancellation(timeoutController.Timeout(TimeSpan.FromSeconds(5))); timeoutController.Reset(); // call Reset(Stop timeout timer and ready for reuse) when succeed. } catch (OperationCanceledException ex) { if (timeoutController.IsTimeout()) { UnityEngine.Debug.Log("timeout"); } } } ``` If you want to use timeout with other source of cancellation, use `new TimeoutController(CancellationToken)`. ```csharp TimeoutController timeoutController; CancellationTokenSource clickCancelSource; void Start() { this.clickCancelSource = new CancellationTokenSource(); this.timeoutController = new TimeoutController(clickCancelSource); } ``` Note: UniTask has `.Timeout`, `.TimeoutWithoutException` methods however, if possible, do not use these, please pass `CancellationToken`. Because `.Timeout` work from external of task, can not stop timeoutted task. `.Timeout` means ignore result when timeout. If you pass a `CancellationToken` to the method, it will act from inside of the task, so it is possible to stop a running task. Progress --- Some async operations for unity have `ToUniTask(IProgress progress = null, ...)` extension methods. ```csharp var progress = Progress.Create(x => Debug.Log(x)); var request = await UnityWebRequest.Get("http://google.co.jp") .SendWebRequest() .ToUniTask(progress: progress); ``` You should not use standard `new System.Progress`, because it causes allocation every time. Use `Cysharp.Threading.Tasks.Progress` instead. This progress factory has two methods, `Create` and `CreateOnlyValueChanged`. `CreateOnlyValueChanged` calls only when the progress value has changed. Implementing IProgress interface to caller is better as there is no lambda allocation. ```csharp public class Foo : MonoBehaviour, IProgress { public void Report(float value) { UnityEngine.Debug.Log(value); } public async UniTaskVoid WebRequest() { var request = await UnityWebRequest.Get("http://google.co.jp") .SendWebRequest() .ToUniTask(progress: this); // pass this } } ``` PlayerLoop --- UniTask is run on a custom [PlayerLoop](https://docs.unity3d.com/ScriptReference/LowLevel.PlayerLoop.html). UniTask's playerloop based methods (such as `Delay`, `DelayFrame`, `asyncOperation.ToUniTask`, etc...) accept this `PlayerLoopTiming`. ```csharp public enum PlayerLoopTiming { Initialization = 0, LastInitialization = 1, EarlyUpdate = 2, LastEarlyUpdate = 3, FixedUpdate = 4, LastFixedUpdate = 5, PreUpdate = 6, LastPreUpdate = 7, Update = 8, LastUpdate = 9, PreLateUpdate = 10, LastPreLateUpdate = 11, PostLateUpdate = 12, LastPostLateUpdate = 13 #if UNITY_2020_2_OR_NEWER TimeUpdate = 14, LastTimeUpdate = 15, #endif } ``` It indicates when to run, you can check [PlayerLoopList.md](https://gist.github.com/neuecc/bc3a1cfd4d74501ad057e49efcd7bdae) to Unity's default playerloop and injected UniTask's custom loop. `PlayerLoopTiming.Update` is similar to `yield return null` in a coroutine, but it is called before Update(Update and uGUI events(button.onClick, etc...) are called on `ScriptRunBehaviourUpdate`, yield return null is called on `ScriptRunDelayedDynamicFrameRate`). `PlayerLoopTiming.FixedUpdate` is similar to `WaitForFixedUpdate`. > `PlayerLoopTiming.LastPostLateUpdate` is not equivalent to coroutine's `yield return new WaitForEndOfFrame()`. Coroutine's WaitForEndOfFrame seems to run after the PlayerLoop is done. Some methods that require coroutine's end of frame(`Texture2D.ReadPixels`, `ScreenCapture.CaptureScreenshotAsTexture`, `CommandBuffer`, etc) do not work correctly when replaced with async/await. In these cases, pass MonoBehaviour(coroutine runnner) to `UniTask.WaitForEndOfFrame`. For example, `await UniTask.WaitForEndOfFrame(this);` is lightweight allocation free alternative of `yield return new WaitForEndOfFrame()`. > > Note: In Unity 2023.1 or newer, `await UniTask.WaitForEndOfFrame();` no longer requires MonoBehaviour. It uses `UnityEngine.Awaitable.EndOfFrameAsync`. `yield return null` and `UniTask.Yield` are similar but different. `yield return null` always returns next frame but `UniTask.Yield` returns next called. That is, call `UniTask.Yield(PlayerLoopTiming.Update)` on `PreUpdate`, it returns same frame. `UniTask.NextFrame()` guarantees return next frame, you can expect this to behave exactly the same as `yield return null`. > UniTask.Yield(without CancellationToken) is a special type, returns `YieldAwaitable` and runs on YieldRunner. It is the most lightweight and fastest. `AsyncOperation` is returned from native timing. For example, await `SceneManager.LoadSceneAsync` is returned from `EarlyUpdate.UpdatePreloading` and after being called, the loaded scene's `Start` is called from `EarlyUpdate.ScriptRunDelayedStartupFrame`. Also `await UnityWebRequest` is returned from `EarlyUpdate.ExecuteMainThreadJobs`. In UniTask, await directly uses native timing, while `WithCancellation` and `ToUniTask` use specified timing. This is usually not a particular problem, but with `LoadSceneAsync`, it causes a different order of Start and continuation after await. So it is recommended not to use `LoadSceneAsync.ToUniTask`. In the stacktrace, you can check where it is running in playerloop. ![image](https://user-images.githubusercontent.com/46207/83735571-83caea80-a68b-11ea-8d22-5e22864f0d24.png) By default, UniTask's PlayerLoop is initialized at `[RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]`. The order in which methods are called in BeforeSceneLoad is nondeterministic, so if you want to use UniTask in other BeforeSceneLoad methods, you should try to initialize it before this. ```csharp // AfterAssembliesLoaded is called before BeforeSceneLoad [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.AfterAssembliesLoaded)] public static void InitUniTaskLoop() { var loop = PlayerLoop.GetCurrentPlayerLoop(); Cysharp.Threading.Tasks.PlayerLoopHelper.Initialize(ref loop); } ``` If you import Unity's `Entities` package, that resets the custom player loop to default at `BeforeSceneLoad` and injects ECS's loop. When Unity calls ECS's inject method after UniTask's initialize method, UniTask will no longer work. To solve this issue, you can re-initialize the UniTask PlayerLoop after ECS is initialized. ```csharp // Get ECS Loop. var playerLoop = ScriptBehaviourUpdateOrder.CurrentPlayerLoop; // Setup UniTask's PlayerLoop. PlayerLoopHelper.Initialize(ref playerLoop); ``` You can diagnose whether UniTask's player loop is ready by calling `PlayerLoopHelper.IsInjectedUniTaskPlayerLoop()`. And also `PlayerLoopHelper.DumpCurrentPlayerLoop` logs all current playerloops to console. ```csharp void Start() { UnityEngine.Debug.Log("UniTaskPlayerLoop ready? " + PlayerLoopHelper.IsInjectedUniTaskPlayerLoop()); PlayerLoopHelper.DumpCurrentPlayerLoop(); } ``` You can optimize loop cost slightly by remove unuse PlayerLoopTiming injection. You can call `PlayerLoopHelper.Initialize(InjectPlayerLoopTimings)` on initialize. ```csharp var loop = PlayerLoop.GetCurrentPlayerLoop(); PlayerLoopHelper.Initialize(ref loop, InjectPlayerLoopTimings.Minimum); // minimum is Update | FixedUpdate | LastPostLateUpdate ``` `InjectPlayerLoopTimings` has three preset, `All` and `Standard`(All without last except LastPostLateUpdate), `Minimum`(`Update | FixedUpdate | LastPostLateUpdate`). Default is All and you can combine custom inject timings like `InjectPlayerLoopTimings.Update | InjectPlayerLoopTimings.FixedUpdate | InjectPlayerLoopTimings.PreLateUpdate`. You can make error to use uninjected `PlayerLoopTiming` by [Microsoft.CodeAnalysis.BannedApiAnalyzers](https://github.com/dotnet/roslyn-analyzers/blob/master/src/Microsoft.CodeAnalysis.BannedApiAnalyzers/BannedApiAnalyzers.Help.md). For example, you can setup `BannedSymbols.txt` like this for `InjectPlayerLoopTimings.Minimum`. ```txt F:Cysharp.Threading.Tasks.PlayerLoopTiming.Initialization; Isn't injected this PlayerLoop in this project. F:Cysharp.Threading.Tasks.PlayerLoopTiming.LastInitialization; Isn't injected this PlayerLoop in this project. F:Cysharp.Threading.Tasks.PlayerLoopTiming.EarlyUpdate; Isn't injected this PlayerLoop in this project. F:Cysharp.Threading.Tasks.PlayerLoopTiming.LastEarlyUpdate; Isn't injected this PlayerLoop in this project.d F:Cysharp.Threading.Tasks.PlayerLoopTiming.LastFixedUpdate; Isn't injected this PlayerLoop in this project. F:Cysharp.Threading.Tasks.PlayerLoopTiming.PreUpdate; Isn't injected this PlayerLoop in this project. F:Cysharp.Threading.Tasks.PlayerLoopTiming.LastPreUpdate; Isn't injected this PlayerLoop in this project. F:Cysharp.Threading.Tasks.PlayerLoopTiming.LastUpdate; Isn't injected this PlayerLoop in this project. F:Cysharp.Threading.Tasks.PlayerLoopTiming.PreLateUpdate; Isn't injected this PlayerLoop in this project. F:Cysharp.Threading.Tasks.PlayerLoopTiming.LastPreLateUpdate; Isn't injected this PlayerLoop in this project. F:Cysharp.Threading.Tasks.PlayerLoopTiming.PostLateUpdate; Isn't injected this PlayerLoop in this project. F:Cysharp.Threading.Tasks.PlayerLoopTiming.TimeUpdate; Isn't injected this PlayerLoop in this project. F:Cysharp.Threading.Tasks.PlayerLoopTiming.LastTimeUpdate; Isn't injected this PlayerLoop in this project. ``` You can configure `RS0030` severity to error. ![image](https://user-images.githubusercontent.com/46207/109150837-bb933880-77ac-11eb-85ba-4fd15819dbd0.png) async void vs async UniTaskVoid --- `async void` is a standard C# task system so it does not run on UniTask systems. It is better not to use it. `async UniTaskVoid` is a lightweight version of `async UniTask` because it does not have awaitable completion and reports errors immediately to `UniTaskScheduler.UnobservedTaskException`. If you don't require awaiting (fire and forget), using `UniTaskVoid` is better. Unfortunately to dismiss warning, you're required to call `Forget()`. ```csharp public async UniTaskVoid FireAndForgetMethod() { // do anything... await UniTask.Yield(); } public void Caller() { FireAndForgetMethod().Forget(); } ``` Also UniTask has the `Forget` method, it is similar to `UniTaskVoid` and has the same effects. However `UniTaskVoid` is more efficient if you completely don't use `await`。 ```csharp public async UniTask DoAsync() { // do anything... await UniTask.Yield(); } public void Caller() { DoAsync().Forget(); } ``` To use an async lambda registered to an event, don't use `async void`. Instead you can use `UniTask.Action` or `UniTask.UnityAction`, both of which create a delegate via `async UniTaskVoid` lambda. ```csharp Action actEvent; UnityAction unityEvent; // especially used in uGUI // Bad: async void actEvent += async () => { }; unityEvent += async () => { }; // Ok: create Action delegate by lambda actEvent += UniTask.Action(async () => { await UniTask.Yield(); }); unityEvent += UniTask.UnityAction(async () => { await UniTask.Yield(); }); ``` `UniTaskVoid` can also be used in MonoBehaviour's `Start` method. ```csharp class Sample : MonoBehaviour { async UniTaskVoid Start() { // async init code. } } ``` UniTaskTracker --- useful for checking (leaked) UniTasks. You can open tracker window in `Window -> UniTask Tracker`. ![image](https://user-images.githubusercontent.com/46207/83527073-4434bf00-a522-11ea-86e9-3b3975b26266.png) * Enable AutoReload(Toggle) - Reload automatically. * Reload - Reload view. * GC.Collect - Invoke GC.Collect. * Enable Tracking(Toggle) - Start to track async/await UniTask. Performance impact: low. * Enable StackTrace(Toggle) - Capture StackTrace when task is started. Performance impact: high. UniTaskTracker is intended for debugging use only as enabling tracking and capturing stacktraces is useful but has a heavy performance impact. Recommended usage is to enable both tracking and stacktraces to find task leaks and to disable them both when done. External Assets --- By default, UniTask supports TextMeshPro(`BindTo(TMP_Text)` and `TMP_InputField` event extensions like standard uGUI `InputField`), DOTween(`Tween` as awaitable) and Addressables(`AsyncOperationHandle` and `AsyncOperationHandle` as awaitable). There are defined in separated asmdefs like `UniTask.TextMeshPro`, `UniTask.DOTween`, `UniTask.Addressables`. TextMeshPro and Addressables support are automatically enabled when importing their packages from package manager. However for DOTween support, after importing from the [DOTWeen assets](https://assetstore.unity.com/packages/tools/animation/dotween-hotween-v2-27676r) and define the scripting define symbol `UNITASK_DOTWEEN_SUPPORT` to enable it. ```csharp // sequential await transform.DOMoveX(2, 10); await transform.DOMoveZ(5, 20); // parallel with cancellation var ct = this.GetCancellationTokenOnDestroy(); await UniTask.WhenAll( transform.DOMoveX(10, 3).WithCancellation(ct), transform.DOScale(10, 3).WithCancellation(ct)); ``` DOTween support's default behaviour(`await`, `WithCancellation`, `ToUniTask`) awaits tween is killed. It works on both Complete(true/false) and Kill(true/false). But if you want to reuse tweens (`SetAutoKill(false)`), it does not work as expected. If you want to await for another timing, the following extension methods exist in Tween, `AwaitForComplete`, `AwaitForPause`, `AwaitForPlay`, `AwaitForRewind`, `AwaitForStepComplete`. AsyncEnumerable and Async LINQ --- Unity 2020.2 supports C# 8.0 so you can use `await foreach`. This is the new Update notation in the async era. ```csharp // Unity 2020.2, C# 8.0 await foreach (var _ in UniTaskAsyncEnumerable.EveryUpdate(token)) { Debug.Log("Update() " + Time.frameCount); } ``` In a C# 7.3 environment, you can use the `ForEachAsync` method to work in almost the same way. ```csharp // C# 7.3(Unity 2018.3~) await UniTaskAsyncEnumerable.EveryUpdate(token).ForEachAsync(_ => { Debug.Log("Update() " + Time.frameCount); }); ``` UniTaskAsyncEnumerable implements asynchronous LINQ, similar to LINQ in `IEnumerable` or Rx in `IObservable`. All standard LINQ query operators can be applied to asynchronous streams. For example, the following code shows how to apply a Where filter to a button-click asynchronous stream that runs once every two clicks. ```csharp await okButton.OnClickAsAsyncEnumerable().Where((x, i) => i % 2 == 0).ForEachAsync(_ => { }); ``` Fire and Forget style(for example, event handling), you can also use `Subscribe`. ```csharp okButton.OnClickAsAsyncEnumerable().Where((x, i) => i % 2 == 0).Subscribe(_ => { }); ``` Async LINQ is enabled when `using Cysharp.Threading.Tasks.Linq;`, and `UniTaskAsyncEnumerable` is defined in `UniTask.Linq` asmdef. It's closer to UniRx (Reactive Extensions), but UniTaskAsyncEnumerable is a pull-based asynchronous stream, whereas Rx was a push-based asynchronous stream. Note that although similar, the characteristics are different and the details behave differently along with them. `UniTaskAsyncEnumerable` is the entry point like `Enumerable`. In addition to the standard query operators, there are other generators for Unity such as `EveryUpdate`, `Timer`, `TimerFrame`, `Interval`, `IntervalFrame`, and `EveryValueChanged`. And also added additional UniTask original query operators like `Append`, `Prepend`, `DistinctUntilChanged`, `ToHashSet`, `Buffer`, `CombineLatest`,`Merge` `Do`, `Never`, `ForEachAsync`, `Pairwise`, `Publish`, `Queue`, `Return`, `SkipUntil`, `TakeUntil`, `SkipUntilCanceled`, `TakeUntilCanceled`, `TakeLast`, `Subscribe`. The method with Func as an argument has three additional overloads, `***Await`, `***AwaitWithCancellation`. ```csharp Select(Func selector) SelectAwait(Func> selector) SelectAwaitWithCancellation(Func> selector) ``` If you want to use the `async` method inside the func, use the `***Await` or `***AwaitWithCancellation`. How to create an async iterator: C# 8.0 supports async iterator(`async yield return`) but it only allows `IAsyncEnumerable` and of course requires C# 8.0. UniTask supports `UniTaskAsyncEnumerable.Create` method to create custom async iterator. ```csharp // IAsyncEnumerable, C# 8.0 version of async iterator. ( do not use this style, IAsyncEnumerable is not controled in UniTask). public async IAsyncEnumerable MyEveryUpdate([EnumeratorCancellation]CancellationToken cancelationToken = default) { var frameCount = 0; await UniTask.Yield(); while (!token.IsCancellationRequested) { yield return frameCount++; await UniTask.Yield(); } } // UniTaskAsyncEnumerable.Create and use `await writer.YieldAsync` instead of `yield return`. public IUniTaskAsyncEnumerable MyEveryUpdate() { // writer(IAsyncWriter) has `YieldAsync(value)` method. return UniTaskAsyncEnumerable.Create(async (writer, token) => { var frameCount = 0; await UniTask.Yield(); while (!token.IsCancellationRequested) { await writer.YieldAsync(frameCount++); // instead of `yield return` await UniTask.Yield(); } }); } ``` Awaitable Events --- All uGUI component implements `***AsAsyncEnumerable` to convert asynchronous streams of events. ```csharp async UniTask TripleClick() { // In default, used button.GetCancellationTokenOnDestroy to manage lieftime of async await button.OnClickAsync(); await button.OnClickAsync(); await button.OnClickAsync(); Debug.Log("Three times clicked"); } // more efficient way async UniTask TripleClick() { using (var handler = button.GetAsyncClickEventHandler()) { await handler.OnClickAsync(); await handler.OnClickAsync(); await handler.OnClickAsync(); Debug.Log("Three times clicked"); } } // use async LINQ async UniTask TripleClick(CancellationToken token) { await button.OnClickAsAsyncEnumerable().Take(3).Last(); Debug.Log("Three times clicked"); } // use async LINQ2 async UniTask TripleClick(CancellationToken token) { await button.OnClickAsAsyncEnumerable().Take(3).ForEachAsync(_ => { Debug.Log("Every clicked"); }); Debug.Log("Three times clicked, complete."); } ``` All MonoBehaviour message events can convert async-streams by `AsyncTriggers` that can be enabled by `using Cysharp.Threading.Tasks.Triggers;`. AsyncTrigger can be created using `GetAsync***Trigger` and triggers itself as UniTaskAsyncEnumerable. ```csharp var trigger = this.GetOnCollisionEnterAsyncHandler(); await trigger.OnCollisionEnterAsync(); await trigger.OnCollisionEnterAsync(); await trigger.OnCollisionEnterAsync(); // every moves. await this.GetAsyncMoveTrigger().ForEachAsync(axisEventData => { }); ``` `AsyncReactiveProperty`, `AsyncReadOnlyReactiveProperty` is UniTask's version of ReactiveProperty. `BindTo` extension method of `IUniTaskAsyncEnumerable` for binding asynchronous stream values to Unity components(Text/Selectable/TMP/Text). ```csharp var rp = new AsyncReactiveProperty(99); // AsyncReactiveProperty itself is IUniTaskAsyncEnumerable, you can query by LINQ rp.ForEachAsync(x => { Debug.Log(x); }, this.GetCancellationTokenOnDestroy()).Forget(); rp.Value = 10; // push 10 to all subscriber rp.Value = 11; // push 11 to all subscriber // WithoutCurrent ignore initial value // BindTo bind stream value to unity components. rp.WithoutCurrent().BindTo(this.textComponent); await rp.WaitAsync(); // wait until next value set // also exists ToReadOnlyAsyncReactiveProperty var rp2 = new AsyncReactiveProperty(99); var rorp = rp.CombineLatest(rp2, (x, y) => (x, y)).ToReadOnlyAsyncReactiveProperty(CancellationToken.None); ``` A pull-type asynchronous stream does not get the next values until the asynchronous processing in the sequence is complete. This could spill data from push-type events such as buttons. ```csharp // can not get click event during 3 seconds complete. await button.OnClickAsAsyncEnumerable().ForEachAwaitAsync(async x => { await UniTask.Delay(TimeSpan.FromSeconds(3)); }); ``` It is useful (prevent double-click) but not useful sometimes. Using the `Queue()` method will also queue events during asynchronous processing. ```csharp // queued message in asynchronous processing await button.OnClickAsAsyncEnumerable().Queue().ForEachAwaitAsync(async x => { await UniTask.Delay(TimeSpan.FromSeconds(3)); }); ``` Or use `Subscribe`, fire and forget style. ```csharp button.OnClickAsAsyncEnumerable().Subscribe(async x => { await UniTask.Delay(TimeSpan.FromSeconds(3)); }); ``` Channel --- `Channel` is the same as [System.Threading.Tasks.Channels](https://docs.microsoft.com/en-us/dotnet/api/system.threading.channels?view=netcore-3.1) which is similar to a GoLang Channel. Currently it only supports multiple-producer, single-consumer unbounded channels. It can create by `Channel.CreateSingleConsumerUnbounded()`. For producer(`.Writer`), use `TryWrite` to push value and `TryComplete` to complete channel. For consumer(`.Reader`), use `TryRead`, `WaitToReadAsync`, `ReadAsync`, `Completion` and `ReadAllAsync` to read queued messages. `ReadAllAsync` returns `IUniTaskAsyncEnumerable` so query LINQ operators. Reader only allows single-consumer but uses `.Publish()` query operator to enable multicast message. For example, make pub/sub utility. ```csharp public class AsyncMessageBroker : IDisposable { Channel channel; IConnectableUniTaskAsyncEnumerable multicastSource; IDisposable connection; public AsyncMessageBroker() { channel = Channel.CreateSingleConsumerUnbounded(); multicastSource = channel.Reader.ReadAllAsync().Publish(); connection = multicastSource.Connect(); // Publish returns IConnectableUniTaskAsyncEnumerable. } public void Publish(T value) { channel.Writer.TryWrite(value); } public IUniTaskAsyncEnumerable Subscribe() { return multicastSource; } public void Dispose() { channel.Writer.TryComplete(); connection.Dispose(); } } ``` For Unit Testing --- Unity's `[UnityTest]` attribute can test coroutine(IEnumerator) but can not test async. `UniTask.ToCoroutine` bridges async/await to coroutine so you can test async methods. ```csharp [UnityTest] public IEnumerator DelayIgnore() => UniTask.ToCoroutine(async () => { var time = Time.realtimeSinceStartup; Time.timeScale = 0.5f; try { await UniTask.Delay(TimeSpan.FromSeconds(3), ignoreTimeScale: true); var elapsed = Time.realtimeSinceStartup - time; Assert.AreEqual(3, (int)Math.Round(TimeSpan.FromSeconds(elapsed).TotalSeconds, MidpointRounding.ToEven)); } finally { Time.timeScale = 1.0f; } }); ``` UniTask's own unit tests are written using Unity Test Runner and [Cysharp/RuntimeUnitTestToolkit](https://github.com/Cysharp/RuntimeUnitTestToolkit) to integrate with CI and check if IL2CPP is working. ThreadPool limitation --- Most UniTask methods run on a single thread (PlayerLoop), with only `UniTask.Run`(`Task.Run` equivalent) and `UniTask.SwitchToThreadPool` running on a thread pool. If you use a thread pool, it won't work with WebGL and so on. `UniTask.Run` is now deprecated. You can use `UniTask.RunOnThreadPool` instead. And also consider whether you can use `UniTask.Create` or `UniTask.Void`. IEnumerator.ToUniTask limitation --- You can convert coroutine(IEnumerator) to UniTask(or await directly) but it has some limitations. * `WaitForEndOfFrame`/`WaitForFixedUpdate`/`Coroutine` is not supported. * Consuming loop timing is not the same as `StartCoroutine`, it uses the specified `PlayerLoopTiming` and the default `PlayerLoopTiming.Update` is run before MonoBehaviour's `Update` and `StartCoroutine`'s loop. If you want fully compatible conversion from coroutine to async, use the `IEnumerator.ToUniTask(MonoBehaviour coroutineRunner)` overload. It executes StartCoroutine on an instance of the argument MonoBehaviour and waits for it to complete in UniTask. For UnityEditor --- UniTask can run on Unity Editor like an Editor Coroutine. However, there are some limitations. * UniTask.Delay's DelayType.DeltaTime, UnscaledDeltaTime do not work correctly because they can not get deltaTime in editor. Therefore run on EditMode, automatically change DelayType to `DelayType.Realtime` that wait for the right time. * All PlayerLoopTiming run on the timing `EditorApplication.update`. * `-batchmode` with `-quit` does not work because Unity does not run `EditorApplication.update` and quit after a single frame. Instead, don't use `-quit` and quit manually with `EditorApplication.Exit(0)`. Compare with Standard Task API --- UniTask has many standard Task-like APIs. This table shows what the alternative apis are. Use standard type. | .NET Type | UniTask Type | | --- | --- | | `IProgress` | --- | | `CancellationToken` | --- | | `CancellationTokenSource` | --- | Use UniTask type. | .NET Type | UniTask Type | | --- | --- | | `Task`/`ValueTask` | `UniTask` | | `Task`/`ValueTask` | `UniTask` | | `async void` | `async UniTaskVoid` | | `+= async () => { }` | `UniTask.Void`, `UniTask.Action`, `UniTask.UnityAction` | | --- | `UniTaskCompletionSource` | | `TaskCompletionSource` | `UniTaskCompletionSource`/`AutoResetUniTaskCompletionSource` | | `ManualResetValueTaskSourceCore` | `UniTaskCompletionSourceCore` | | `IValueTaskSource` | `IUniTaskSource` | | `IValueTaskSource` | `IUniTaskSource` | | `ValueTask.IsCompleted` | `UniTask.Status.IsCompleted()` | | `ValueTask.IsCompleted` | `UniTask.Status.IsCompleted()` | | `new Progress` | `Progress.Create` | | `CancellationToken.Register(UnsafeRegister)` | `CancellationToken.RegisterWithoutCaptureExecutionContext` | | `CancellationTokenSource.CancelAfter` | `CancellationTokenSource.CancelAfterSlim` | | `Channel.CreateUnbounded(false){ SingleReader = true }` | `Channel.CreateSingleConsumerUnbounded` | | `IAsyncEnumerable` | `IUniTaskAsyncEnumerable` | | `IAsyncEnumerator` | `IUniTaskAsyncEnumerator` | | `IAsyncDisposable` | `IUniTaskAsyncDisposable` | | `Task.Delay` | `UniTask.Delay` | | `Task.Yield` | `UniTask.Yield` | | `Task.Run` | `UniTask.RunOnThreadPool` | | `Task.WhenAll` | `UniTask.WhenAll` | | `Task.WhenAny` | `UniTask.WhenAny` | | `Task.CompletedTask` | `UniTask.CompletedTask` | | `Task.FromException` | `UniTask.FromException` | | `Task.FromResult` | `UniTask.FromResult` | | `Task.FromCanceled` | `UniTask.FromCanceled` | | `Task.ContinueWith` | `UniTask.ContinueWith` | | `TaskScheduler.UnobservedTaskException` | `UniTaskScheduler.UnobservedTaskException` | Pooling Configuration --- UniTask aggressively caches async promise objects to achieve zero allocation (for technical details, see blog post [UniTask v2 — Zero Allocation async/await for Unity, with Asynchronous LINQ](https://medium.com/@neuecc/unitask-v2-zero-allocation-async-await-for-unity-with-asynchronous-linq-1aa9c96aa7dd)). By default, it caches all promises but you can configure `TaskPool.SetMaxPoolSize` to your value, the value indicates cache size per type. `TaskPool.GetCacheSizeInfo` returns currently cached objects in pool. ```csharp foreach (var (type, size) in TaskPool.GetCacheSizeInfo()) { Debug.Log(type + ":" + size); } ``` Allocation on Profiler --- In UnityEditor the profiler shows allocation of compiler generated AsyncStateMachine but it only occurs in debug(development) build. C# Compiler generates AsyncStateMachine as class on Debug build and as struct on Release build. Unity supports Code Optimization option starting in 2020.1 (right, footer). ![](https://user-images.githubusercontent.com/46207/89967342-2f944600-dc8c-11ea-99fc-0b74527a16f6.png) You can change C# compiler optimization to release to remove AsyncStateMachine allocation in development builds. This optimization option can also be set via `Compilation.CompilationPipeline-codeOptimization`, and `Compilation.CodeOptimization`. UniTaskSynchronizationContext --- Unity's default SynchronizationContext(`UnitySynchronizationContext`) is a poor implementation for performance. UniTask bypasses `SynchronizationContext`(and `ExecutionContext`) so it does not use it but if exists in `async Task`, still used it. `UniTaskSynchronizationContext` is a replacement of `UnitySynchronizationContext` which is better for performance. ```csharp public class SyncContextInjecter { [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)] public static void Inject() { SynchronizationContext.SetSynchronizationContext(new UniTaskSynchronizationContext()); } } ``` This is an optional choice and is not always recommended; `UniTaskSynchronizationContext` is less performant than `async UniTask` and is not a complete UniTask replacement. It also does not guarantee full behavioral compatibility with the `UnitySynchronizationContext`. API References --- UniTask's API References are hosted at [cysharp.github.io/UniTask](https://cysharp.github.io/UniTask/api/Cysharp.Threading.Tasks.html) by [DocFX](https://dotnet.github.io/docfx/) and [Cysharp/DocfXTemplate](https://github.com/Cysharp/DocfxTemplate). For example, UniTask's factory methods can be seen at [UniTask#methods](https://cysharp.github.io/UniTask/api/Cysharp.Threading.Tasks.UniTask.html#methods-1). UniTaskAsyncEnumerable's factory/extension methods can be seen at [UniTaskAsyncEnumerable#methods](https://cysharp.github.io/UniTask/api/Cysharp.Threading.Tasks.Linq.UniTaskAsyncEnumerable.html#methods-1). UPM Package --- ### Install via git URL Requires a version of unity that supports path query parameter for git packages (Unity >= 2019.3.4f1, Unity >= 2020.1a21). You can add `https://github.com/Cysharp/UniTask.git?path=src/UniTask/Assets/Plugins/UniTask` to Package Manager ![image](https://user-images.githubusercontent.com/46207/79450714-3aadd100-8020-11ea-8aae-b8d87fc4d7be.png) ![image](https://user-images.githubusercontent.com/46207/83702872-e0f17c80-a648-11ea-8183-7469dcd4f810.png) or add `"com.cysharp.unitask": "https://github.com/Cysharp/UniTask.git?path=src/UniTask/Assets/Plugins/UniTask"` to `Packages/manifest.json`. If you want to set a target version, UniTask uses the `*.*.*` release tag so you can specify a version like `#2.1.0`. For example `https://github.com/Cysharp/UniTask.git?path=src/UniTask/Assets/Plugins/UniTask#2.1.0`. .NET Core --- For .NET Core, use NuGet. > PM> Install-Package [UniTask](https://www.nuget.org/packages/UniTask) UniTask of .NET Core version is a subset of Unity UniTask with PlayerLoop dependent methods removed. It runs at higher performance than the standard Task/ValueTask, but you should be careful to ignore the ExecutionContext/SynchronizationContext when using it. `AsyncLocal` also does not work because it ignores ExecutionContext. If you use UniTask internally, but provide ValueTask as an external API, you can write it like the following(Inspired by [PooledAwait](https://github.com/mgravell/PooledAwait)). ```csharp public class ZeroAllocAsyncAwaitInDotNetCore { public ValueTask DoAsync(int x, int y) { return Core(this, x, y); static async UniTask Core(ZeroAllocAsyncAwaitInDotNetCore self, int x, int y) { // do anything... await Task.Delay(TimeSpan.FromSeconds(x + y)); await UniTask.Yield(); return 10; } } } // UniTask does not return to original SynchronizationContext but you can use helper `ReturnToCurrentSynchronizationContext`. public ValueTask TestAsync() { await using (UniTask.ReturnToCurrentSynchronizationContext()) { await UniTask.SwitchToThreadPool(); // do anything.. } } ``` .NET Core version is intended to allow users to use UniTask as an interface when sharing code with Unity (such as [Cysharp/MagicOnion](https://github.com/Cysharp/MagicOnion/)). .NET Core version of UniTask enables smooth code sharing. Utility methods such as WhenAll which are equivalent to UniTask are provided as [Cysharp/ValueTaskSupplement](https://github.com/Cysharp/ValueTaskSupplement). License --- This library is under the MIT License.