unity-unitask-design

UniTask is a struct whose backing source is recycled after the first await, so awaiting the same variable twice throws InvalidOperationException. Call .Preserve() once to get a memoized copy that can be awaited multiple times, or invoke the async method again for a fresh UniTask.

Use this.GetCancellationTokenOnDestroy(), available on MonoBehaviour, GameObject, and Component, and pass the token through your async call chain. Plain C# classes must own and dispose their own CancellationTokenSource instead.

No. UniTask.SwitchToThreadPool and UniTask.RunOnThreadPool throw NotSupportedException on WebGL because the platform is single-threaded. Guard those calls with #if UNITY_WEBGL && !UNITY_EDITOR and fall back to synchronous or Yield-based cooperative work.

UniTask.Yield may resume on the same frame if awaited from an earlier PlayerLoop phase than the target timing, while NextFrame guarantees continuation on a subsequent frame. Use NextFrame to split work across frames and Yield(timing) to target a specific phase.

A returned UniTask that is neither awaited nor .Forget()ed drops its result, routing exceptions only to UniTaskScheduler.UnobservedTaskException. Always await the UniTask or call .Forget() with an exception handler for fire-and-forget work.

Call .ToUniTask() on the operation, passing an IProgress<float> and CancellationToken as needed. For UnityWebRequest, wrap the await in try/catch for UnityWebRequestException, since plain await does not throw on HTTP errors.