diff --git a/src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.AssetBundleRequestAllAssets.cs b/src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.AssetBundleRequestAllAssets.cs
index 95f00b2..f6fccc0 100644
--- a/src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.AssetBundleRequestAllAssets.cs
+++ b/src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.AssetBundleRequestAllAssets.cs
@@ -24,17 +24,24 @@ namespace Cysharp.Threading.Tasks
             return AwaitForAllAssets(asyncOperation, null, PlayerLoopTiming.Update, cancellationToken: cancellationToken);
         }
 
-        public static UniTask<UnityEngine.Object[]> AwaitForAllAssets(this AssetBundleRequest asyncOperation, CancellationToken cancellationToken, bool cancelImmediately)
+        public static UniTask<UnityEngine.Object[]> AwaitForAllAssets(this AssetBundleRequest asyncOperation, bool handleImmediately, CancellationToken cancellationToken)
         {
-            return AwaitForAllAssets(asyncOperation, null, PlayerLoopTiming.Update, cancellationToken: cancellationToken, cancelImmediately: cancelImmediately);
+            if (handleImmediately)
+            {
+                Error.ThrowArgumentNullException(asyncOperation, nameof(asyncOperation));
+                if (cancellationToken.IsCancellationRequested) return UniTask.FromCanceled<UnityEngine.Object[]>(cancellationToken);
+                if (asyncOperation.isDone) return UniTask.FromResult(asyncOperation.allAssets);
+                return new UniTask<UnityEngine.Object[]>(AssetBundleRequestAllAssetsCallbackHandlerSource.Create(asyncOperation, cancellationToken, out var token), token);
+            }
+            return AwaitForAllAssets(asyncOperation, progress: null, cancellationToken: cancellationToken);
         }
 
-        public static UniTask<UnityEngine.Object[]> AwaitForAllAssets(this AssetBundleRequest asyncOperation, IProgress<float> progress = null, PlayerLoopTiming timing = PlayerLoopTiming.Update, CancellationToken cancellationToken = default(CancellationToken), bool cancelImmediately = false)
+        public static UniTask<UnityEngine.Object[]> AwaitForAllAssets(this AssetBundleRequest asyncOperation, IProgress<float> progress = null, PlayerLoopTiming timing = PlayerLoopTiming.Update, CancellationToken cancellationToken = default(CancellationToken))
         {
             Error.ThrowArgumentNullException(asyncOperation, nameof(asyncOperation));
             if (cancellationToken.IsCancellationRequested) return UniTask.FromCanceled<UnityEngine.Object[]>(cancellationToken);
             if (asyncOperation.isDone) return UniTask.FromResult(asyncOperation.allAssets);
-            return new UniTask<UnityEngine.Object[]>(AssetBundleRequestAllAssetsConfiguredSource.Create(asyncOperation, timing, progress, cancellationToken, cancelImmediately, out var token), token);
+            return new UniTask<UnityEngine.Object[]>(AssetBundleRequestAllAssetsConfiguredSource.Create(asyncOperation, timing, progress, cancellationToken, out var token), token);
         }
 
         public struct AssetBundleRequestAllAssetsAwaiter : ICriticalNotifyCompletion
@@ -85,6 +92,108 @@ namespace Cysharp.Threading.Tasks
                 asyncOperation.completed += continuationAction;
             }
         }
+                
+        sealed class AssetBundleRequestAllAssetsCallbackHandlerSource : IUniTaskSource<UnityEngine.Object[]>, ITaskPoolNode<AssetBundleRequestAllAssetsCallbackHandlerSource>
+        {
+            static TaskPool<AssetBundleRequestAllAssetsCallbackHandlerSource> pool;
+            AssetBundleRequestAllAssetsCallbackHandlerSource nextNode;
+            public ref AssetBundleRequestAllAssetsCallbackHandlerSource NextNode => ref nextNode;
+
+            static AssetBundleRequestAllAssetsCallbackHandlerSource()
+            {
+                TaskPool.RegisterSizeGetter(typeof(AssetBundleRequestConfiguredSource), () => pool.Size);
+            }
+
+            AssetBundleRequest asyncOperation;
+            CancellationToken cancellationToken;
+            CancellationTokenRegistration cancellationTokenRegistration;
+
+            UniTaskCompletionSourceCore<UnityEngine.Object[]> core;
+
+            AssetBundleRequestAllAssetsCallbackHandlerSource()
+            {
+            }
+
+            public static IUniTaskSource<UnityEngine.Object[]> Create(AssetBundleRequest asyncOperation, CancellationToken cancellationToken, out short token)
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    return AutoResetUniTaskCompletionSource<UnityEngine.Object[]>.CreateFromCanceled(cancellationToken, out token);
+                }
+
+                if (!pool.TryPop(out var result))
+                {
+                    result = new AssetBundleRequestAllAssetsCallbackHandlerSource();
+                }
+
+                result.asyncOperation = asyncOperation;
+                result.cancellationToken = cancellationToken;
+
+                asyncOperation.completed += result.AsyncOperationCompletedHandler;
+                
+                if (cancellationToken.CanBeCanceled)
+                {
+                    result.cancellationTokenRegistration = cancellationToken.RegisterWithoutCaptureExecutionContext(state =>
+                    {
+                        var source = (AssetBundleRequestAllAssetsCallbackHandlerSource)state;
+                        source.core.TrySetCanceled(source.cancellationToken);
+                    }, result);
+                }
+
+                TaskTracker.TrackActiveTask(result, 3);
+
+                token = result.core.Version;
+                return result;
+            }
+
+            public UnityEngine.Object[] GetResult(short token)
+            {
+                try
+                {
+                    return core.GetResult(token);
+                }
+                finally
+                {
+                    TryReturn();
+                }
+            }
+
+            void IUniTaskSource.GetResult(short token)
+            {
+                GetResult(token);
+            }
+
+            public UniTaskStatus GetStatus(short token)
+            {
+                return core.GetStatus(token);
+            }
+
+            public UniTaskStatus UnsafeGetStatus()
+            {
+                return core.UnsafeGetStatus();
+            }
+
+            public void OnCompleted(Action<object> continuation, object state, short token)
+            {
+                core.OnCompleted(continuation, state, token);
+            }
+
+            bool TryReturn()
+            {
+                TaskTracker.RemoveTracking(this);
+                core.Reset();
+                asyncOperation.completed -= AsyncOperationCompletedHandler;
+                asyncOperation = default;
+                cancellationToken = default;
+                cancellationTokenRegistration.Dispose();
+                return pool.TryPush(this);
+            }
+            
+            void AsyncOperationCompletedHandler(AsyncOperation _)
+            {
+                core.TrySetResult(asyncOperation.allAssets);
+            }
+        }
 
         sealed class AssetBundleRequestAllAssetsConfiguredSource : IUniTaskSource<UnityEngine.Object[]>, IPlayerLoopItem, ITaskPoolNode<AssetBundleRequestAllAssetsConfiguredSource>
         {
@@ -100,7 +209,6 @@ namespace Cysharp.Threading.Tasks
             AssetBundleRequest asyncOperation;
             IProgress<float> progress;
             CancellationToken cancellationToken;
-            CancellationTokenRegistration cancellationTokenRegistration;
 
             UniTaskCompletionSourceCore<UnityEngine.Object[]> core;
 
@@ -108,7 +216,7 @@ namespace Cysharp.Threading.Tasks
             {
             }
 
-            public static IUniTaskSource<UnityEngine.Object[]> Create(AssetBundleRequest asyncOperation, PlayerLoopTiming timing, IProgress<float> progress, CancellationToken cancellationToken, bool cancelImmediately, out short token)
+            public static IUniTaskSource<UnityEngine.Object[]> Create(AssetBundleRequest asyncOperation, PlayerLoopTiming timing, IProgress<float> progress, CancellationToken cancellationToken, out short token)
             {
                 if (cancellationToken.IsCancellationRequested)
                 {
@@ -123,15 +231,6 @@ namespace Cysharp.Threading.Tasks
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
                 result.cancellationToken = cancellationToken;
-                
-                if (cancelImmediately && cancellationToken.CanBeCanceled)
-                {
-                    result.cancellationTokenRegistration = cancellationToken.RegisterWithoutCaptureExecutionContext(state =>
-                    {
-                        var promise = (AssetBundleRequestAllAssetsConfiguredSource)state;
-                        promise.core.TrySetCanceled(promise.cancellationToken);
-                    }, result);
-                }
 
                 TaskTracker.TrackActiveTask(result, 3);
 
@@ -202,7 +301,6 @@ namespace Cysharp.Threading.Tasks
                 asyncOperation = default;
                 progress = default;
                 cancellationToken = default;
-                cancellationTokenRegistration.Dispose();
                 return pool.TryPush(this);
             }
         }
diff --git a/src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.cs b/src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.cs
index 235faa0..069ee5a 100644
--- a/src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.cs
+++ b/src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.cs
@@ -15,32 +15,35 @@ namespace Cysharp.Threading.Tasks
     {
         #region AsyncOperation
 
-#if !UNITY_2023_1_OR_NEWER
-        // from Unity2023.1.0a15, AsyncOperationAwaitableExtensions.GetAwaiter is defined in UnityEngine.
-
         public static AsyncOperationAwaiter GetAwaiter(this AsyncOperation asyncOperation)
         {
             Error.ThrowArgumentNullException(asyncOperation, nameof(asyncOperation));
             return new AsyncOperationAwaiter(asyncOperation);
         }
-#endif
 
         public static UniTask WithCancellation(this AsyncOperation asyncOperation, CancellationToken cancellationToken)
         {
             return ToUniTask(asyncOperation, cancellationToken: cancellationToken);
         }
-        
-        public static UniTask WithCancellation(this AsyncOperation asyncOperation, CancellationToken cancellationToken, bool cancelImmediately)
+
+        public static UniTask WithCancellation(this AsyncOperation asyncOperation, bool handleImmediately, CancellationToken cancellationToken)
         {
-            return ToUniTask(asyncOperation, cancellationToken: cancellationToken, cancelImmediately: cancelImmediately);
+            if (handleImmediately)
+            {
+                Error.ThrowArgumentNullException(asyncOperation, nameof(asyncOperation));
+                if (cancellationToken.IsCancellationRequested) return UniTask.FromCanceled(cancellationToken);
+                if (asyncOperation.isDone) return UniTask.CompletedTask;
+                return new UniTask(AsyncOperationCallbackHandlerSource.Create(asyncOperation, cancellationToken, out var token), token);
+            }
+            return ToUniTask(asyncOperation, cancellationToken: cancellationToken);
         }
 
-        public static UniTask ToUniTask(this AsyncOperation asyncOperation, IProgress<float> progress = null, PlayerLoopTiming timing = PlayerLoopTiming.Update, CancellationToken cancellationToken = default(CancellationToken), bool cancelImmediately = false)
+        public static UniTask ToUniTask(this AsyncOperation asyncOperation, IProgress<float> progress = null, PlayerLoopTiming timing = PlayerLoopTiming.Update, CancellationToken cancellationToken = default(CancellationToken))
         {
             Error.ThrowArgumentNullException(asyncOperation, nameof(asyncOperation));
             if (cancellationToken.IsCancellationRequested) return UniTask.FromCanceled(cancellationToken);
             if (asyncOperation.isDone) return UniTask.CompletedTask;
-            return new UniTask(AsyncOperationConfiguredSource.Create(asyncOperation, timing, progress, cancellationToken, cancelImmediately, out var token), token);
+            return new UniTask(AsyncOperationConfiguredSource.Create(asyncOperation, timing, progress, cancellationToken, out var token), token);
         }
 
         public struct AsyncOperationAwaiter : ICriticalNotifyCompletion
@@ -83,6 +86,106 @@ namespace Cysharp.Threading.Tasks
             }
         }
 
+        sealed class AsyncOperationCallbackHandlerSource : IUniTaskSource, ITaskPoolNode<AsyncOperationCallbackHandlerSource>
+        {
+            static TaskPool<AsyncOperationCallbackHandlerSource> pool;
+            AsyncOperationCallbackHandlerSource nextNode;
+            public ref AsyncOperationCallbackHandlerSource NextNode => ref nextNode;
+
+            static AsyncOperationCallbackHandlerSource()
+            {
+                TaskPool.RegisterSizeGetter(typeof(AsyncOperationCallbackHandlerSource), () => pool.Size);
+            }
+
+            AsyncOperation asyncOperation;
+            IProgress<float> progress;
+            CancellationToken cancellationToken;
+            CancellationTokenRegistration cancellationTokenRegistration;
+
+            UniTaskCompletionSourceCore<AsyncUnit> core;
+
+            AsyncOperationCallbackHandlerSource()
+            {
+            }
+
+            public static IUniTaskSource Create(AsyncOperation asyncOperation, CancellationToken cancellationToken, out short token)
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    return AutoResetUniTaskCompletionSource.CreateFromCanceled(cancellationToken, out token);
+                }
+
+                if (!pool.TryPop(out var result))
+                {
+                    result = new AsyncOperationCallbackHandlerSource();
+                }
+
+                result.asyncOperation = asyncOperation;
+                result.cancellationToken = cancellationToken;
+
+                asyncOperation.completed += result.AsyncOperationCompletedHandler;
+
+                if (cancellationToken.CanBeCanceled)
+                {
+                    result.cancellationTokenRegistration = cancellationToken.RegisterWithoutCaptureExecutionContext(state =>
+                    {
+                        var source = (AsyncOperationCallbackHandlerSource)state;
+                        source.core.TrySetCanceled(source.cancellationToken);
+                    }, result);
+                }
+
+                TaskTracker.TrackActiveTask(result, 3);
+
+                token = result.core.Version;
+                return result;
+            }
+
+            public void GetResult(short token)
+            {
+                try
+                {
+                    core.GetResult(token);
+                }
+                finally
+                {
+                    TryReturn();
+                }
+            }
+
+
+            public UniTaskStatus GetStatus(short token)
+            {
+                return core.GetStatus(token);
+            }
+
+            public UniTaskStatus UnsafeGetStatus()
+            {
+                return core.UnsafeGetStatus();
+            }
+
+            public void OnCompleted(Action<object> continuation, object state, short token)
+            {
+                core.OnCompleted(continuation, state, token);
+            }
+
+            bool TryReturn()
+            {
+                TaskTracker.RemoveTracking(this);
+                core.Reset();
+                asyncOperation.completed -= AsyncOperationCompletedHandler;
+                asyncOperation = default;
+                progress = default;
+                cancellationToken = default;
+                cancellationTokenRegistration.Dispose();
+                return pool.TryPush(this);
+            }
+
+            void AsyncOperationCompletedHandler(AsyncOperation _)
+            {
+                core.TrySetResult(AsyncUnit.Default);
+            }
+        }
+
         sealed class AsyncOperationConfiguredSource : IUniTaskSource, IPlayerLoopItem, ITaskPoolNode<AsyncOperationConfiguredSource>
         {
             static TaskPool<AsyncOperationConfiguredSource> pool;
@@ -97,7 +200,6 @@ namespace Cysharp.Threading.Tasks
             AsyncOperation asyncOperation;
             IProgress<float> progress;
             CancellationToken cancellationToken;
-            CancellationTokenRegistration cancellationTokenRegistration;
 
             UniTaskCompletionSourceCore<AsyncUnit> core;
 
@@ -105,7 +207,7 @@ namespace Cysharp.Threading.Tasks
             {
             }
 
-            public static IUniTaskSource Create(AsyncOperation asyncOperation, PlayerLoopTiming timing, IProgress<float> progress, CancellationToken cancellationToken, bool cancelImmediately, out short token)
+            public static IUniTaskSource Create(AsyncOperation asyncOperation, PlayerLoopTiming timing, IProgress<float> progress, CancellationToken cancellationToken, out short token)
             {
                 if (cancellationToken.IsCancellationRequested)
                 {
@@ -116,16 +218,6 @@ namespace Cysharp.Threading.Tasks
                 {
                     result = new AsyncOperationConfiguredSource();
                 }
-                
-                
-                if (cancelImmediately && cancellationToken.CanBeCanceled)
-                {
-                    result.cancellationTokenRegistration = cancellationToken.RegisterWithoutCaptureExecutionContext(state =>
-                    {
-                        var promise = (AsyncOperationConfiguredSource)state;
-                        promise.core.TrySetCanceled(promise.cancellationToken);
-                    }, result);
-                }
 
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
@@ -151,6 +243,7 @@ namespace Cysharp.Threading.Tasks
                 }
             }
 
+
             public UniTaskStatus GetStatus(short token)
             {
                 return core.GetStatus(token);
@@ -195,7 +288,6 @@ namespace Cysharp.Threading.Tasks
                 asyncOperation = default;
                 progress = default;
                 cancellationToken = default;
-                cancellationTokenRegistration.Dispose();
                 return pool.TryPush(this);
             }
         }
@@ -215,17 +307,24 @@ namespace Cysharp.Threading.Tasks
             return ToUniTask(asyncOperation, cancellationToken: cancellationToken);
         }
 
-        public static UniTask<UnityEngine.Object> WithCancellation(this ResourceRequest asyncOperation, CancellationToken cancellationToken, bool cancelImmediately)
+        public static UniTask<UnityEngine.Object> WithCancellation(this ResourceRequest asyncOperation, bool handleImmediately, CancellationToken cancellationToken)
         {
-            return ToUniTask(asyncOperation, cancellationToken: cancellationToken, cancelImmediately: cancelImmediately);
+            if (handleImmediately)
+            {
+                Error.ThrowArgumentNullException(asyncOperation, nameof(asyncOperation));
+                if (cancellationToken.IsCancellationRequested) return UniTask.FromCanceled<UnityEngine.Object>(cancellationToken);
+                if (asyncOperation.isDone) return UniTask.FromResult(asyncOperation.asset);
+                return new UniTask<UnityEngine.Object>(ResourceRequestCallbackHandlerSource.Create(asyncOperation, cancellationToken, out var token), token);
+            }
+            return ToUniTask(asyncOperation, cancellationToken: cancellationToken);
         }
 
-        public static UniTask<UnityEngine.Object> ToUniTask(this ResourceRequest asyncOperation, IProgress<float> progress = null, PlayerLoopTiming timing = PlayerLoopTiming.Update, CancellationToken cancellationToken = default(CancellationToken), bool cancelImmediately = false)
+        public static UniTask<UnityEngine.Object> ToUniTask(this ResourceRequest asyncOperation, IProgress<float> progress = null, PlayerLoopTiming timing = PlayerLoopTiming.Update, CancellationToken cancellationToken = default(CancellationToken))
         {
             Error.ThrowArgumentNullException(asyncOperation, nameof(asyncOperation));
             if (cancellationToken.IsCancellationRequested) return UniTask.FromCanceled<UnityEngine.Object>(cancellationToken);
             if (asyncOperation.isDone) return UniTask.FromResult(asyncOperation.asset);
-            return new UniTask<UnityEngine.Object>(ResourceRequestConfiguredSource.Create(asyncOperation, timing, progress, cancellationToken, cancelImmediately, out var token), token);
+            return new UniTask<UnityEngine.Object>(ResourceRequestConfiguredSource.Create(asyncOperation, timing, progress, cancellationToken, out var token), token);
         }
 
         public struct ResourceRequestAwaiter : ICriticalNotifyCompletion
@@ -272,6 +371,110 @@ namespace Cysharp.Threading.Tasks
             }
         }
 
+        sealed class ResourceRequestCallbackHandlerSource : IUniTaskSource<UnityEngine.Object>, ITaskPoolNode<ResourceRequestCallbackHandlerSource>
+        {
+            static TaskPool<ResourceRequestCallbackHandlerSource> pool;
+            ResourceRequestCallbackHandlerSource nextNode;
+            public ref ResourceRequestCallbackHandlerSource NextNode => ref nextNode;
+
+            static ResourceRequestCallbackHandlerSource()
+            {
+                TaskPool.RegisterSizeGetter(typeof(ResourceRequestCallbackHandlerSource), () => pool.Size);
+            }
+
+            ResourceRequest asyncOperation;
+            IProgress<float> progress;
+            CancellationToken cancellationToken;
+            CancellationTokenRegistration cancellationTokenRegistration;
+
+            UniTaskCompletionSourceCore<UnityEngine.Object> core;
+
+            ResourceRequestCallbackHandlerSource()
+            {
+            }
+
+            public static IUniTaskSource<UnityEngine.Object> Create(ResourceRequest asyncOperation, CancellationToken cancellationToken, out short token)
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    return AutoResetUniTaskCompletionSource<UnityEngine.Object>.CreateFromCanceled(cancellationToken, out token);
+                }
+
+                if (!pool.TryPop(out var result))
+                {
+                    result = new ResourceRequestCallbackHandlerSource();
+                }
+
+                result.asyncOperation = asyncOperation;
+                result.cancellationToken = cancellationToken;
+
+                asyncOperation.completed += result.AsyncOperationCompletedHandler;
+
+                if (cancellationToken.CanBeCanceled)
+                {
+                    result.cancellationTokenRegistration = cancellationToken.RegisterWithoutCaptureExecutionContext(state =>
+                    {
+                        var source = (ResourceRequestCallbackHandlerSource)state;
+                        source.core.TrySetCanceled(source.cancellationToken);
+                    }, result);
+                }
+
+                TaskTracker.TrackActiveTask(result, 3);
+
+                token = result.core.Version;
+                return result;
+            }
+
+            public UnityEngine.Object GetResult(short token)
+            {
+                try
+                {
+                    return core.GetResult(token);
+                }
+                finally
+                {
+                    TryReturn();
+                }
+            }
+
+            void IUniTaskSource.GetResult(short token)
+            {
+                GetResult(token);
+            }
+
+            public UniTaskStatus GetStatus(short token)
+            {
+                return core.GetStatus(token);
+            }
+
+            public UniTaskStatus UnsafeGetStatus()
+            {
+                return core.UnsafeGetStatus();
+            }
+
+            public void OnCompleted(Action<object> continuation, object state, short token)
+            {
+                core.OnCompleted(continuation, state, token);
+            }
+
+            bool TryReturn()
+            {
+                TaskTracker.RemoveTracking(this);
+                core.Reset();
+                asyncOperation.completed -= AsyncOperationCompletedHandler;
+                asyncOperation = default;
+                progress = default;
+                cancellationToken = default;
+                cancellationTokenRegistration.Dispose();
+                return pool.TryPush(this);
+            }
+
+            void AsyncOperationCompletedHandler(AsyncOperation _)
+            {
+                core.TrySetResult(asyncOperation.asset);
+            }
+        }
+
         sealed class ResourceRequestConfiguredSource : IUniTaskSource<UnityEngine.Object>, IPlayerLoopItem, ITaskPoolNode<ResourceRequestConfiguredSource>
         {
             static TaskPool<ResourceRequestConfiguredSource> pool;
@@ -286,7 +489,6 @@ namespace Cysharp.Threading.Tasks
             ResourceRequest asyncOperation;
             IProgress<float> progress;
             CancellationToken cancellationToken;
-            CancellationTokenRegistration cancellationTokenRegistration;
 
             UniTaskCompletionSourceCore<UnityEngine.Object> core;
 
@@ -294,7 +496,7 @@ namespace Cysharp.Threading.Tasks
             {
             }
 
-            public static IUniTaskSource<UnityEngine.Object> Create(ResourceRequest asyncOperation, PlayerLoopTiming timing, IProgress<float> progress, CancellationToken cancellationToken, bool cancelImmediately, out short token)
+            public static IUniTaskSource<UnityEngine.Object> Create(ResourceRequest asyncOperation, PlayerLoopTiming timing, IProgress<float> progress, CancellationToken cancellationToken, out short token)
             {
                 if (cancellationToken.IsCancellationRequested)
                 {
@@ -309,15 +511,6 @@ namespace Cysharp.Threading.Tasks
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
                 result.cancellationToken = cancellationToken;
-                
-                if (cancelImmediately && cancellationToken.CanBeCanceled)
-                {
-                    result.cancellationTokenRegistration = cancellationToken.RegisterWithoutCaptureExecutionContext(state =>
-                    {
-                        var source = (ResourceRequestConfiguredSource)state;
-                        source.core.TrySetCanceled(source.cancellationToken);
-                    }, result);
-                }
 
                 TaskTracker.TrackActiveTask(result, 3);
 
@@ -388,7 +581,6 @@ namespace Cysharp.Threading.Tasks
                 asyncOperation = default;
                 progress = default;
                 cancellationToken = default;
-                cancellationTokenRegistration.Dispose();
                 return pool.TryPush(this);
             }
         }
@@ -409,17 +601,24 @@ namespace Cysharp.Threading.Tasks
             return ToUniTask(asyncOperation, cancellationToken: cancellationToken);
         }
 
-        public static UniTask<UnityEngine.Object> WithCancellation(this AssetBundleRequest asyncOperation, CancellationToken cancellationToken, bool cancelImmediately)
+        public static UniTask<UnityEngine.Object> WithCancellation(this AssetBundleRequest asyncOperation, bool handleImmediately, CancellationToken cancellationToken)
         {
-            return ToUniTask(asyncOperation, cancellationToken: cancellationToken, cancelImmediately: cancelImmediately);
+            if (handleImmediately)
+            {
+                Error.ThrowArgumentNullException(asyncOperation, nameof(asyncOperation));
+                if (cancellationToken.IsCancellationRequested) return UniTask.FromCanceled<UnityEngine.Object>(cancellationToken);
+                if (asyncOperation.isDone) return UniTask.FromResult(asyncOperation.asset);
+                return new UniTask<UnityEngine.Object>(AssetBundleRequestCallbackHandlerSource.Create(asyncOperation, cancellationToken, out var token), token);
+            }
+            return ToUniTask(asyncOperation, cancellationToken: cancellationToken);
         }
 
-        public static UniTask<UnityEngine.Object> ToUniTask(this AssetBundleRequest asyncOperation, IProgress<float> progress = null, PlayerLoopTiming timing = PlayerLoopTiming.Update, CancellationToken cancellationToken = default(CancellationToken), bool cancelImmediately = false)
+        public static UniTask<UnityEngine.Object> ToUniTask(this AssetBundleRequest asyncOperation, IProgress<float> progress = null, PlayerLoopTiming timing = PlayerLoopTiming.Update, CancellationToken cancellationToken = default(CancellationToken))
         {
             Error.ThrowArgumentNullException(asyncOperation, nameof(asyncOperation));
             if (cancellationToken.IsCancellationRequested) return UniTask.FromCanceled<UnityEngine.Object>(cancellationToken);
             if (asyncOperation.isDone) return UniTask.FromResult(asyncOperation.asset);
-            return new UniTask<UnityEngine.Object>(AssetBundleRequestConfiguredSource.Create(asyncOperation, timing, progress, cancellationToken, cancelImmediately, out var token), token);
+            return new UniTask<UnityEngine.Object>(AssetBundleRequestConfiguredSource.Create(asyncOperation, timing, progress, cancellationToken, out var token), token);
         }
 
         public struct AssetBundleRequestAwaiter : ICriticalNotifyCompletion
@@ -466,6 +665,110 @@ namespace Cysharp.Threading.Tasks
             }
         }
 
+        sealed class AssetBundleRequestCallbackHandlerSource : IUniTaskSource<UnityEngine.Object>, ITaskPoolNode<AssetBundleRequestCallbackHandlerSource>
+        {
+            static TaskPool<AssetBundleRequestCallbackHandlerSource> pool;
+            AssetBundleRequestCallbackHandlerSource nextNode;
+            public ref AssetBundleRequestCallbackHandlerSource NextNode => ref nextNode;
+
+            static AssetBundleRequestCallbackHandlerSource()
+            {
+                TaskPool.RegisterSizeGetter(typeof(AssetBundleRequestCallbackHandlerSource), () => pool.Size);
+            }
+
+            AssetBundleRequest asyncOperation;
+            IProgress<float> progress;
+            CancellationToken cancellationToken;
+            CancellationTokenRegistration cancellationTokenRegistration;
+
+            UniTaskCompletionSourceCore<UnityEngine.Object> core;
+
+            AssetBundleRequestCallbackHandlerSource()
+            {
+            }
+
+            public static IUniTaskSource<UnityEngine.Object> Create(AssetBundleRequest asyncOperation, CancellationToken cancellationToken, out short token)
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    return AutoResetUniTaskCompletionSource<UnityEngine.Object>.CreateFromCanceled(cancellationToken, out token);
+                }
+
+                if (!pool.TryPop(out var result))
+                {
+                    result = new AssetBundleRequestCallbackHandlerSource();
+                }
+
+                result.asyncOperation = asyncOperation;
+                result.cancellationToken = cancellationToken;
+
+                asyncOperation.completed += result.AsyncOperationCompletedHandler;
+
+                if (cancellationToken.CanBeCanceled)
+                {
+                    result.cancellationTokenRegistration = cancellationToken.RegisterWithoutCaptureExecutionContext(state =>
+                    {
+                        var source = (AssetBundleRequestCallbackHandlerSource)state;
+                        source.core.TrySetCanceled(source.cancellationToken);
+                    }, result);
+                }
+
+                TaskTracker.TrackActiveTask(result, 3);
+
+                token = result.core.Version;
+                return result;
+            }
+
+            public UnityEngine.Object GetResult(short token)
+            {
+                try
+                {
+                    return core.GetResult(token);
+                }
+                finally
+                {
+                    TryReturn();
+                }
+            }
+
+            void IUniTaskSource.GetResult(short token)
+            {
+                GetResult(token);
+            }
+
+            public UniTaskStatus GetStatus(short token)
+            {
+                return core.GetStatus(token);
+            }
+
+            public UniTaskStatus UnsafeGetStatus()
+            {
+                return core.UnsafeGetStatus();
+            }
+
+            public void OnCompleted(Action<object> continuation, object state, short token)
+            {
+                core.OnCompleted(continuation, state, token);
+            }
+
+            bool TryReturn()
+            {
+                TaskTracker.RemoveTracking(this);
+                core.Reset();
+                asyncOperation.completed -= AsyncOperationCompletedHandler;
+                asyncOperation = default;
+                progress = default;
+                cancellationToken = default;
+                cancellationTokenRegistration.Dispose();
+                return pool.TryPush(this);
+            }
+
+            void AsyncOperationCompletedHandler(AsyncOperation _)
+            {
+                core.TrySetResult(asyncOperation.asset);
+            }
+        }
+
         sealed class AssetBundleRequestConfiguredSource : IUniTaskSource<UnityEngine.Object>, IPlayerLoopItem, ITaskPoolNode<AssetBundleRequestConfiguredSource>
         {
             static TaskPool<AssetBundleRequestConfiguredSource> pool;
@@ -480,7 +783,6 @@ namespace Cysharp.Threading.Tasks
             AssetBundleRequest asyncOperation;
             IProgress<float> progress;
             CancellationToken cancellationToken;
-            CancellationTokenRegistration cancellationTokenRegistration;
 
             UniTaskCompletionSourceCore<UnityEngine.Object> core;
 
@@ -488,7 +790,7 @@ namespace Cysharp.Threading.Tasks
             {
             }
 
-            public static IUniTaskSource<UnityEngine.Object> Create(AssetBundleRequest asyncOperation, PlayerLoopTiming timing, IProgress<float> progress, CancellationToken cancellationToken, bool cancelImmediately, out short token)
+            public static IUniTaskSource<UnityEngine.Object> Create(AssetBundleRequest asyncOperation, PlayerLoopTiming timing, IProgress<float> progress, CancellationToken cancellationToken, out short token)
             {
                 if (cancellationToken.IsCancellationRequested)
                 {
@@ -503,15 +805,6 @@ namespace Cysharp.Threading.Tasks
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
                 result.cancellationToken = cancellationToken;
-                
-                if (cancelImmediately && cancellationToken.CanBeCanceled)
-                {
-                    result.cancellationTokenRegistration = cancellationToken.RegisterWithoutCaptureExecutionContext(state =>
-                    {
-                        var source = (AssetBundleRequestConfiguredSource)state;
-                        source.core.TrySetCanceled(source.cancellationToken);
-                    }, result);
-                }
 
                 TaskTracker.TrackActiveTask(result, 3);
 
@@ -582,7 +875,6 @@ namespace Cysharp.Threading.Tasks
                 asyncOperation = default;
                 progress = default;
                 cancellationToken = default;
-                cancellationTokenRegistration.Dispose();
                 return pool.TryPush(this);
             }
         }
@@ -604,17 +896,24 @@ namespace Cysharp.Threading.Tasks
             return ToUniTask(asyncOperation, cancellationToken: cancellationToken);
         }
 
-        public static UniTask<AssetBundle> WithCancellation(this AssetBundleCreateRequest asyncOperation, CancellationToken cancellationToken, bool cancelImmediately)
+        public static UniTask<AssetBundle> WithCancellation(this AssetBundleCreateRequest asyncOperation, bool handleImmediately, CancellationToken cancellationToken)
         {
-            return ToUniTask(asyncOperation, cancellationToken: cancellationToken, cancelImmediately: cancelImmediately);
+            if (handleImmediately)
+            {
+                Error.ThrowArgumentNullException(asyncOperation, nameof(asyncOperation));
+                if (cancellationToken.IsCancellationRequested) return UniTask.FromCanceled<AssetBundle>(cancellationToken);
+                if (asyncOperation.isDone) return UniTask.FromResult(asyncOperation.assetBundle);
+                return new UniTask<AssetBundle>(AssetBundleCreateRequestCallbackHandlerSource.Create(asyncOperation, cancellationToken, out var token), token);
+            }
+            return ToUniTask(asyncOperation, cancellationToken: cancellationToken);
         }
 
-        public static UniTask<AssetBundle> ToUniTask(this AssetBundleCreateRequest asyncOperation, IProgress<float> progress = null, PlayerLoopTiming timing = PlayerLoopTiming.Update, CancellationToken cancellationToken = default(CancellationToken), bool cancelImmediately = false)
+        public static UniTask<AssetBundle> ToUniTask(this AssetBundleCreateRequest asyncOperation, IProgress<float> progress = null, PlayerLoopTiming timing = PlayerLoopTiming.Update, CancellationToken cancellationToken = default(CancellationToken))
         {
             Error.ThrowArgumentNullException(asyncOperation, nameof(asyncOperation));
             if (cancellationToken.IsCancellationRequested) return UniTask.FromCanceled<AssetBundle>(cancellationToken);
             if (asyncOperation.isDone) return UniTask.FromResult(asyncOperation.assetBundle);
-            return new UniTask<AssetBundle>(AssetBundleCreateRequestConfiguredSource.Create(asyncOperation, timing, progress, cancellationToken, cancelImmediately, out var token), token);
+            return new UniTask<AssetBundle>(AssetBundleCreateRequestConfiguredSource.Create(asyncOperation, timing, progress, cancellationToken, out var token), token);
         }
 
         public struct AssetBundleCreateRequestAwaiter : ICriticalNotifyCompletion
@@ -661,6 +960,110 @@ namespace Cysharp.Threading.Tasks
             }
         }
 
+        sealed class AssetBundleCreateRequestCallbackHandlerSource : IUniTaskSource<AssetBundle>, ITaskPoolNode<AssetBundleCreateRequestCallbackHandlerSource>
+        {
+            static TaskPool<AssetBundleCreateRequestCallbackHandlerSource> pool;
+            AssetBundleCreateRequestCallbackHandlerSource nextNode;
+            public ref AssetBundleCreateRequestCallbackHandlerSource NextNode => ref nextNode;
+
+            static AssetBundleCreateRequestCallbackHandlerSource()
+            {
+                TaskPool.RegisterSizeGetter(typeof(AssetBundleCreateRequestCallbackHandlerSource), () => pool.Size);
+            }
+
+            AssetBundleCreateRequest asyncOperation;
+            IProgress<float> progress;
+            CancellationToken cancellationToken;
+            CancellationTokenRegistration cancellationTokenRegistration;
+
+            UniTaskCompletionSourceCore<AssetBundle> core;
+
+            AssetBundleCreateRequestCallbackHandlerSource()
+            {
+            }
+
+            public static IUniTaskSource<AssetBundle> Create(AssetBundleCreateRequest asyncOperation, CancellationToken cancellationToken, out short token)
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    return AutoResetUniTaskCompletionSource<AssetBundle>.CreateFromCanceled(cancellationToken, out token);
+                }
+
+                if (!pool.TryPop(out var result))
+                {
+                    result = new AssetBundleCreateRequestCallbackHandlerSource();
+                }
+
+                result.asyncOperation = asyncOperation;
+                result.cancellationToken = cancellationToken;
+
+                asyncOperation.completed += result.AsyncOperationCompletedHandler;
+
+                if (cancellationToken.CanBeCanceled)
+                {
+                    result.cancellationTokenRegistration = cancellationToken.RegisterWithoutCaptureExecutionContext(state =>
+                    {
+                        var source = (AssetBundleCreateRequestCallbackHandlerSource)state;
+                        source.core.TrySetCanceled(source.cancellationToken);
+                    }, result);
+                }
+
+                TaskTracker.TrackActiveTask(result, 3);
+
+                token = result.core.Version;
+                return result;
+            }
+
+            public AssetBundle GetResult(short token)
+            {
+                try
+                {
+                    return core.GetResult(token);
+                }
+                finally
+                {
+                    TryReturn();
+                }
+            }
+
+            void IUniTaskSource.GetResult(short token)
+            {
+                GetResult(token);
+            }
+
+            public UniTaskStatus GetStatus(short token)
+            {
+                return core.GetStatus(token);
+            }
+
+            public UniTaskStatus UnsafeGetStatus()
+            {
+                return core.UnsafeGetStatus();
+            }
+
+            public void OnCompleted(Action<object> continuation, object state, short token)
+            {
+                core.OnCompleted(continuation, state, token);
+            }
+
+            bool TryReturn()
+            {
+                TaskTracker.RemoveTracking(this);
+                core.Reset();
+                asyncOperation.completed -= AsyncOperationCompletedHandler;
+                asyncOperation = default;
+                progress = default;
+                cancellationToken = default;
+                cancellationTokenRegistration.Dispose();
+                return pool.TryPush(this);
+            }
+
+            void AsyncOperationCompletedHandler(AsyncOperation _)
+            {
+                core.TrySetResult(asyncOperation.assetBundle);
+            }
+        }
+
         sealed class AssetBundleCreateRequestConfiguredSource : IUniTaskSource<AssetBundle>, IPlayerLoopItem, ITaskPoolNode<AssetBundleCreateRequestConfiguredSource>
         {
             static TaskPool<AssetBundleCreateRequestConfiguredSource> pool;
@@ -675,7 +1078,6 @@ namespace Cysharp.Threading.Tasks
             AssetBundleCreateRequest asyncOperation;
             IProgress<float> progress;
             CancellationToken cancellationToken;
-            CancellationTokenRegistration cancellationTokenRegistration;
 
             UniTaskCompletionSourceCore<AssetBundle> core;
 
@@ -683,7 +1085,7 @@ namespace Cysharp.Threading.Tasks
             {
             }
 
-            public static IUniTaskSource<AssetBundle> Create(AssetBundleCreateRequest asyncOperation, PlayerLoopTiming timing, IProgress<float> progress, CancellationToken cancellationToken, bool cancelImmediately, out short token)
+            public static IUniTaskSource<AssetBundle> Create(AssetBundleCreateRequest asyncOperation, PlayerLoopTiming timing, IProgress<float> progress, CancellationToken cancellationToken, out short token)
             {
                 if (cancellationToken.IsCancellationRequested)
                 {
@@ -698,15 +1100,6 @@ namespace Cysharp.Threading.Tasks
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
                 result.cancellationToken = cancellationToken;
-                
-                if (cancelImmediately && cancellationToken.CanBeCanceled)
-                {
-                    result.cancellationTokenRegistration = cancellationToken.RegisterWithoutCaptureExecutionContext(state =>
-                    {
-                        var source = (AssetBundleCreateRequestConfiguredSource)state;
-                        source.core.TrySetCanceled(source.cancellationToken);
-                    }, result);
-                }
 
                 TaskTracker.TrackActiveTask(result, 3);
 
@@ -777,7 +1170,6 @@ namespace Cysharp.Threading.Tasks
                 asyncOperation = default;
                 progress = default;
                 cancellationToken = default;
-                cancellationTokenRegistration.Dispose();
                 return pool.TryPush(this);
             }
         }
@@ -799,12 +1191,26 @@ namespace Cysharp.Threading.Tasks
             return ToUniTask(asyncOperation, cancellationToken: cancellationToken);
         }
 
-        public static UniTask<UnityWebRequest> WithCancellation(this UnityWebRequestAsyncOperation asyncOperation, CancellationToken cancellationToken, bool cancelImmediately)
+        public static UniTask<UnityWebRequest> WithCancellation(this UnityWebRequestAsyncOperation asyncOperation, bool handleImmediately, CancellationToken cancellationToken)
         {
-            return ToUniTask(asyncOperation, cancellationToken: cancellationToken, cancelImmediately: cancelImmediately);
+            if (handleImmediately)
+            {
+                Error.ThrowArgumentNullException(asyncOperation, nameof(asyncOperation));
+                if (cancellationToken.IsCancellationRequested) return UniTask.FromCanceled<UnityWebRequest>(cancellationToken);
+                if (asyncOperation.isDone)
+                {
+                    if (asyncOperation.webRequest.IsError())
+                    {
+                        return UniTask.FromException<UnityWebRequest>(new UnityWebRequestException(asyncOperation.webRequest));
+                    }
+                    return UniTask.FromResult(asyncOperation.webRequest);
+                }
+                return new UniTask<UnityWebRequest>(UnityWebRequestAsyncOperationCallbackHandlerSource.Create(asyncOperation, cancellationToken, out var token), token);
+            }
+            return ToUniTask(asyncOperation, cancellationToken: cancellationToken);
         }
 
-        public static UniTask<UnityWebRequest> ToUniTask(this UnityWebRequestAsyncOperation asyncOperation, IProgress<float> progress = null, PlayerLoopTiming timing = PlayerLoopTiming.Update, CancellationToken cancellationToken = default(CancellationToken), bool cancelImmediately = false)
+        public static UniTask<UnityWebRequest> ToUniTask(this UnityWebRequestAsyncOperation asyncOperation, IProgress<float> progress = null, PlayerLoopTiming timing = PlayerLoopTiming.Update, CancellationToken cancellationToken = default(CancellationToken))
         {
             Error.ThrowArgumentNullException(asyncOperation, nameof(asyncOperation));
             if (cancellationToken.IsCancellationRequested) return UniTask.FromCanceled<UnityWebRequest>(cancellationToken);
@@ -816,7 +1222,7 @@ namespace Cysharp.Threading.Tasks
                 }
                 return UniTask.FromResult(asyncOperation.webRequest);
             }
-            return new UniTask<UnityWebRequest>(UnityWebRequestAsyncOperationConfiguredSource.Create(asyncOperation, timing, progress, cancellationToken, cancelImmediately, out var token), token);
+            return new UniTask<UnityWebRequest>(UnityWebRequestAsyncOperationConfiguredSource.Create(asyncOperation, timing, progress, cancellationToken, out var token), token);
         }
 
         public struct UnityWebRequestAsyncOperationAwaiter : ICriticalNotifyCompletion
@@ -871,6 +1277,118 @@ namespace Cysharp.Threading.Tasks
             }
         }
 
+        sealed class UnityWebRequestAsyncOperationCallbackHandlerSource : IUniTaskSource<UnityWebRequest>, ITaskPoolNode<UnityWebRequestAsyncOperationCallbackHandlerSource>
+        {
+            static TaskPool<UnityWebRequestAsyncOperationCallbackHandlerSource> pool;
+            UnityWebRequestAsyncOperationCallbackHandlerSource nextNode;
+            public ref UnityWebRequestAsyncOperationCallbackHandlerSource NextNode => ref nextNode;
+
+            static UnityWebRequestAsyncOperationCallbackHandlerSource()
+            {
+                TaskPool.RegisterSizeGetter(typeof(UnityWebRequestAsyncOperationCallbackHandlerSource), () => pool.Size);
+            }
+
+            UnityWebRequestAsyncOperation asyncOperation;
+            IProgress<float> progress;
+            CancellationToken cancellationToken;
+            CancellationTokenRegistration cancellationTokenRegistration;
+
+            UniTaskCompletionSourceCore<UnityWebRequest> core;
+
+            UnityWebRequestAsyncOperationCallbackHandlerSource()
+            {
+            }
+
+            public static IUniTaskSource<UnityWebRequest> Create(UnityWebRequestAsyncOperation asyncOperation, CancellationToken cancellationToken, out short token)
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    return AutoResetUniTaskCompletionSource<UnityWebRequest>.CreateFromCanceled(cancellationToken, out token);
+                }
+
+                if (!pool.TryPop(out var result))
+                {
+                    result = new UnityWebRequestAsyncOperationCallbackHandlerSource();
+                }
+
+                result.asyncOperation = asyncOperation;
+                result.cancellationToken = cancellationToken;
+
+                asyncOperation.completed += result.AsyncOperationCompletedHandler;
+
+                if (cancellationToken.CanBeCanceled)
+                {
+                    result.cancellationTokenRegistration = cancellationToken.RegisterWithoutCaptureExecutionContext(state =>
+                    {
+                        var source = (UnityWebRequestAsyncOperationCallbackHandlerSource)state;
+                        source.asyncOperation.webRequest.Abort();
+                        source.core.TrySetCanceled(source.cancellationToken);
+                    }, result);
+                }
+
+                TaskTracker.TrackActiveTask(result, 3);
+
+                token = result.core.Version;
+                return result;
+            }
+
+            public UnityWebRequest GetResult(short token)
+            {
+                try
+                {
+                    return core.GetResult(token);
+                }
+                finally
+                {
+                    TryReturn();
+                }
+            }
+
+            void IUniTaskSource.GetResult(short token)
+            {
+                GetResult(token);
+            }
+
+            public UniTaskStatus GetStatus(short token)
+            {
+                return core.GetStatus(token);
+            }
+
+            public UniTaskStatus UnsafeGetStatus()
+            {
+                return core.UnsafeGetStatus();
+            }
+
+            public void OnCompleted(Action<object> continuation, object state, short token)
+            {
+                core.OnCompleted(continuation, state, token);
+            }
+
+            bool TryReturn()
+            {
+                TaskTracker.RemoveTracking(this);
+                core.Reset();
+                asyncOperation.completed -= AsyncOperationCompletedHandler;
+                asyncOperation = default;
+                progress = default;
+                cancellationToken = default;
+                cancellationTokenRegistration.Dispose();
+                return pool.TryPush(this);
+            }
+
+            void AsyncOperationCompletedHandler(AsyncOperation _)
+            {
+                if (asyncOperation.webRequest.IsError())
+                {
+                    core.TrySetException(new UnityWebRequestException(asyncOperation.webRequest));
+                }
+                else
+                {
+                    core.TrySetResult(asyncOperation.webRequest);
+                }
+            }
+        }
+
         sealed class UnityWebRequestAsyncOperationConfiguredSource : IUniTaskSource<UnityWebRequest>, IPlayerLoopItem, ITaskPoolNode<UnityWebRequestAsyncOperationConfiguredSource>
         {
             static TaskPool<UnityWebRequestAsyncOperationConfiguredSource> pool;
@@ -885,7 +1403,6 @@ namespace Cysharp.Threading.Tasks
             UnityWebRequestAsyncOperation asyncOperation;
             IProgress<float> progress;
             CancellationToken cancellationToken;
-            CancellationTokenRegistration cancellationTokenRegistration;
 
             UniTaskCompletionSourceCore<UnityWebRequest> core;
 
@@ -893,7 +1410,7 @@ namespace Cysharp.Threading.Tasks
             {
             }
 
-            public static IUniTaskSource<UnityWebRequest> Create(UnityWebRequestAsyncOperation asyncOperation, PlayerLoopTiming timing, IProgress<float> progress, CancellationToken cancellationToken, bool cancelImmediately, out short token)
+            public static IUniTaskSource<UnityWebRequest> Create(UnityWebRequestAsyncOperation asyncOperation, PlayerLoopTiming timing, IProgress<float> progress, CancellationToken cancellationToken, out short token)
             {
                 if (cancellationToken.IsCancellationRequested)
                 {
@@ -908,15 +1425,6 @@ namespace Cysharp.Threading.Tasks
                 result.asyncOperation = asyncOperation;
                 result.progress = progress;
                 result.cancellationToken = cancellationToken;
-                
-                if (cancelImmediately && cancellationToken.CanBeCanceled)
-                {
-                    result.cancellationTokenRegistration = cancellationToken.RegisterWithoutCaptureExecutionContext(state =>
-                    {
-                        var promise = (UnityWebRequestAsyncOperationConfiguredSource)state;
-                        promise.core.TrySetCanceled(promise.cancellationToken);
-                    }, result);
-                }
 
                 TaskTracker.TrackActiveTask(result, 3);
 
@@ -974,11 +1482,7 @@ namespace Cysharp.Threading.Tasks
 
                 if (asyncOperation.isDone)
                 {
-                    if (asyncOperation.webRequest == null)
-                    {
-                        core.TrySetException(new ObjectDisposedException("The webRequest has been destroyed."));
-                    }
-                    else if (asyncOperation.webRequest.IsError())
+                    if (asyncOperation.webRequest.IsError())
                     {
                         core.TrySetException(new UnityWebRequestException(asyncOperation.webRequest));
                     }
@@ -999,7 +1503,6 @@ namespace Cysharp.Threading.Tasks
                 asyncOperation = default;
                 progress = default;
                 cancellationToken = default;
-                cancellationTokenRegistration.Dispose();
                 return pool.TryPush(this);
             }
         }
diff --git a/src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.tt b/src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.tt
index 65dac9e..f74fa0b 100644
--- a/src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.tt
+++ b/src/UniTask/Assets/Plugins/UniTask/Runtime/UnityAsyncExtensions.tt
@@ -54,6 +54,29 @@ namespace Cysharp.Threading.Tasks
             return ToUniTask(asyncOperation, cancellationToken: cancellationToken);
         }
 
+        public static <#= ToUniTaskReturnType(t.returnType) #> WithCancellation(this <#= t.typeName #> asyncOperation, bool handleImmediately, CancellationToken cancellationToken)
+        {
+            if (handleImmediately)
+            {
+                Error.ThrowArgumentNullException(asyncOperation, nameof(asyncOperation));
+                if (cancellationToken.IsCancellationRequested) return UniTask.FromCanceled<#= IsVoid(t) ? "" : "<" + t.returnType + ">" #>(cancellationToken);
+<# if(IsUnityWebRequest(t)) { #>
+                if (asyncOperation.isDone)
+                {
+                    if (asyncOperation.webRequest.IsError())
+                    {
+                        return UniTask.FromException<UnityWebRequest>(new UnityWebRequestException(asyncOperation.webRequest));
+                    }
+                    return UniTask.FromResult(asyncOperation.webRequest);
+                }
+<# } else { #>
+                if (asyncOperation.isDone) return <#= IsVoid(t) ? "UniTask.CompletedTask" : $"UniTask.FromResult(asyncOperation.{t.returnField})" #>;
+<# } #>
+                return new <#= ToUniTaskReturnType(t.returnType) #>(<#= t.typeName #>CallbackHandlerSource.Create(asyncOperation, cancellationToken, out var token), token);
+            }
+            return ToUniTask(asyncOperation, cancellationToken: cancellationToken);
+        }
+
         public static <#= ToUniTaskReturnType(t.returnType) #> ToUniTask(this <#= t.typeName #> asyncOperation, IProgress<float> progress = null, PlayerLoopTiming timing = PlayerLoopTiming.Update, CancellationToken cancellationToken = default(CancellationToken))
         {
             Error.ThrowArgumentNullException(asyncOperation, nameof(asyncOperation));
@@ -137,6 +160,130 @@ namespace Cysharp.Threading.Tasks
             }
         }
 
+        sealed class <#= t.typeName #>CallbackHandlerSource : <#= ToIUniTaskSourceReturnType(t.returnType) #>, ITaskPoolNode<<#= t.typeName #>CallbackHandlerSource>
+        {
+            static TaskPool<<#= t.typeName #>CallbackHandlerSource> pool;
+            <#= t.typeName #>CallbackHandlerSource nextNode;
+            public ref <#= t.typeName #>CallbackHandlerSource NextNode => ref nextNode;
+
+            static <#= t.typeName #>CallbackHandlerSource()
+            {
+                TaskPool.RegisterSizeGetter(typeof(<#= t.typeName #>CallbackHandlerSource), () => pool.Size);
+            }
+
+            <#= t.typeName #> asyncOperation;
+            IProgress<float> progress;
+            CancellationToken cancellationToken;
+            CancellationTokenRegistration cancellationTokenRegistration;
+
+            UniTaskCompletionSourceCore<<#= IsVoid(t) ? "AsyncUnit" : t.returnType #>> core;
+
+            <#= t.typeName #>CallbackHandlerSource()
+            {
+            }
+
+            public static <#= ToIUniTaskSourceReturnType(t.returnType) #> Create(<#= t.typeName #> asyncOperation, CancellationToken cancellationToken, out short token)
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    return AutoResetUniTaskCompletionSource<#= IsVoid(t) ? "" : $"<{t.returnType}>" #>.CreateFromCanceled(cancellationToken, out token);
+                }
+
+                if (!pool.TryPop(out var result))
+                {
+                    result = new <#= t.typeName #>CallbackHandlerSource();
+                }
+
+                result.asyncOperation = asyncOperation;
+                result.cancellationToken = cancellationToken;
+
+                asyncOperation.completed += result.AsyncOperationCompletedHandler;
+
+                if (cancellationToken.CanBeCanceled)
+                {
+                    result.cancellationTokenRegistration = cancellationToken.RegisterWithoutCaptureExecutionContext(state =>
+                    {
+                        var source = (<#= t.typeName #>CallbackHandlerSource)state;
+<# if(IsUnityWebRequest(t)) { #>
+                        source.asyncOperation.webRequest.Abort();
+<# } #>
+                        source.core.TrySetCanceled(source.cancellationToken);
+                    }, result);
+                }
+
+                TaskTracker.TrackActiveTask(result, 3);
+
+                token = result.core.Version;
+                return result;
+            }
+
+            public <#= t.returnType #> GetResult(short token)
+            {
+                try
+                {
+<# if (!IsVoid(t)) { #>
+                    return core.GetResult(token);
+<# } else { #>
+                    core.GetResult(token);
+<# } #>
+                }
+                finally
+                {
+                    TryReturn();
+                }
+            }
+
+<# if (!IsVoid(t)) { #>
+            void IUniTaskSource.GetResult(short token)
+            {
+                GetResult(token);
+            }
+<# } #>
+
+            public UniTaskStatus GetStatus(short token)
+            {
+                return core.GetStatus(token);
+            }
+
+            public UniTaskStatus UnsafeGetStatus()
+            {
+                return core.UnsafeGetStatus();
+            }
+
+            public void OnCompleted(Action<object> continuation, object state, short token)
+            {
+                core.OnCompleted(continuation, state, token);
+            }
+
+            bool TryReturn()
+            {
+                TaskTracker.RemoveTracking(this);
+                core.Reset();
+                asyncOperation.completed -= AsyncOperationCompletedHandler;
+                asyncOperation = default;
+                progress = default;
+                cancellationToken = default;
+                cancellationTokenRegistration.Dispose();
+                return pool.TryPush(this);
+            }
+
+            void AsyncOperationCompletedHandler(AsyncOperation _)
+            {
+<# if(IsUnityWebRequest(t)) { #>
+                if (asyncOperation.webRequest.IsError())
+                {
+                    core.TrySetException(new UnityWebRequestException(asyncOperation.webRequest));
+                }
+                else
+                {
+                    core.TrySetResult(asyncOperation.webRequest);
+                }
+<# } else { #>
+                core.TrySetResult(<#= IsVoid(t) ? "AsyncUnit.Default" : $"asyncOperation.{t.returnField}" #>);
+<# } #>
+            }
+        }
+
         sealed class <#= t.typeName #>ConfiguredSource : <#= ToIUniTaskSourceReturnType(t.returnType) #>, IPlayerLoopItem, ITaskPoolNode<<#= t.typeName #>ConfiguredSource>
         {
             static TaskPool<<#= t.typeName #>ConfiguredSource> pool;
@@ -156,7 +303,6 @@ namespace Cysharp.Threading.Tasks
 
             <#= t.typeName #>ConfiguredSource()
             {
-
             }
 
             public static <#= ToIUniTaskSourceReturnType(t.returnType) #> Create(<#= t.typeName #> asyncOperation, PlayerLoopTiming timing, IProgress<float> progress, CancellationToken cancellationToken, out short token)