diff --git a/Assets/UniRx.Async/UniTask.Bridge.cs b/Assets/UniRx.Async/UniTask.Bridge.cs
index 814bd02..a9ecbf6 100644
--- a/Assets/UniRx.Async/UniTask.Bridge.cs
+++ b/Assets/UniRx.Async/UniTask.Bridge.cs
@@ -8,6 +8,14 @@ namespace UniRx.Async
 {
     // UnityEngine Bridges.
 
+    public partial struct UniTask2
+    {
+        public static IEnumerator ToCoroutine(Func<UniTask2> taskFactory)
+        {
+            return taskFactory().ToCoroutine();
+        }
+    }
+
     public partial struct UniTask
     {
         public static IEnumerator ToCoroutine(Func<UniTask> taskFactory)
diff --git a/Assets/UniRx.Async/UniTask.Delay.cs b/Assets/UniRx.Async/UniTask.Delay.cs
index d828358..25e8b5f 100644
--- a/Assets/UniRx.Async/UniTask.Delay.cs
+++ b/Assets/UniRx.Async/UniTask.Delay.cs
@@ -9,6 +9,449 @@ using UnityEngine;
 
 namespace UniRx.Async
 {
+    // TODO:rename
+    public partial struct UniTask2
+    {
+        public static YieldAwaitable2 Yield(PlayerLoopTiming timing = PlayerLoopTiming.Update)
+        {
+            // optimized for single continuation
+            return new YieldAwaitable2(timing);
+        }
+
+        public static UniTask2 Yield(PlayerLoopTiming timing, CancellationToken cancellationToken)
+        {
+            return new UniTask2(YieldPromise.Create(timing, cancellationToken, out var token), token);
+        }
+
+        public static UniTask2 DelayFrame(int delayFrameCount, PlayerLoopTiming delayTiming = PlayerLoopTiming.Update, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            if (delayFrameCount < 0)
+            {
+                throw new ArgumentOutOfRangeException("Delay does not allow minus delayFrameCount. delayFrameCount:" + delayFrameCount);
+            }
+
+            return new UniTask2(DelayFramePromise.Create(delayFrameCount, delayTiming, cancellationToken, out var token), token);
+        }
+
+        public static UniTask2 Delay(int millisecondsDelay, bool ignoreTimeScale = false, PlayerLoopTiming delayTiming = PlayerLoopTiming.Update, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            var delayTimeSpan = TimeSpan.FromMilliseconds(millisecondsDelay);
+            if (delayTimeSpan < TimeSpan.Zero)
+            {
+                throw new ArgumentOutOfRangeException("Delay does not allow minus millisecondsDelay. millisecondsDelay:" + millisecondsDelay);
+            }
+
+            return (ignoreTimeScale)
+                ? new UniTask2(DelayIgnoreTimeScalePromise.Create(delayTimeSpan, delayTiming, cancellationToken, out var token), token)
+                : new UniTask2(DelayPromise.Create(delayTimeSpan, delayTiming, cancellationToken, out token), token);
+        }
+
+        public static UniTask2 Delay(TimeSpan delayTimeSpan, bool ignoreTimeScale = false, PlayerLoopTiming delayTiming = PlayerLoopTiming.Update, CancellationToken cancellationToken = default(CancellationToken))
+        {
+            if (delayTimeSpan < TimeSpan.Zero)
+            {
+                throw new ArgumentOutOfRangeException("Delay does not allow minus delayTimeSpan. delayTimeSpan:" + delayTimeSpan);
+            }
+
+            return (ignoreTimeScale)
+                ? new UniTask2(DelayIgnoreTimeScalePromise.Create(delayTimeSpan, delayTiming, cancellationToken, out var token), token)
+                : new UniTask2(DelayPromise.Create(delayTimeSpan, delayTiming, cancellationToken, out token), token);
+        }
+
+        class YieldPromise : IUniTaskSource, IPlayerLoopItem, IPromisePoolItem
+        {
+            static readonly PromisePool<YieldPromise> pool = new PromisePool<YieldPromise>();
+
+            CancellationToken cancellationToken;
+            UniTaskCompletionSourceCore<object> core;
+
+            YieldPromise()
+            {
+            }
+
+            public static IUniTaskSource Create(PlayerLoopTiming timing, CancellationToken cancellationToken, out short token)
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    return AutoResetUniTaskCompletionSource.CreateFromCanceled(cancellationToken, out token);
+                }
+
+                var result = pool.TryRent() ?? new YieldPromise();
+
+                result.cancellationToken = cancellationToken;
+
+                TaskTracker2.TrackActiveTask(result, 3);
+
+                PlayerLoopHelper.AddAction(timing, result);
+
+                token = result.core.Version;
+                return result;
+            }
+
+            public void GetResult(short token)
+            {
+                try
+                {
+                    TaskTracker2.RemoveTracking(this);
+                    core.GetResult(token);
+                }
+                finally
+                {
+                    pool.TryReturn(this);
+                }
+            }
+
+            public AwaiterStatus GetStatus(short token)
+            {
+                return core.GetStatus(token);
+            }
+
+            public AwaiterStatus UnsafeGetStatus()
+            {
+                return core.UnsafeGetStatus();
+            }
+
+            public void OnCompleted(Action<object> continuation, object state, short token)
+            {
+                core.OnCompleted(continuation, state, token);
+            }
+
+            public bool MoveNext()
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    core.SetCanceled(cancellationToken);
+                    return false;
+                }
+
+                core.SetResult(null);
+                return false;
+            }
+
+            public void Reset()
+            {
+                core.Reset();
+                cancellationToken = default;
+            }
+        }
+
+        class DelayFramePromise : IUniTaskSource, IPlayerLoopItem, IPromisePoolItem
+        {
+            static readonly PromisePool<DelayFramePromise> pool = new PromisePool<DelayFramePromise>();
+
+            int delayFrameCount;
+            CancellationToken cancellationToken;
+
+            int currentFrameCount;
+            UniTaskCompletionSourceCore<object> core;
+
+            DelayFramePromise()
+            {
+            }
+
+            public static IUniTaskSource Create(int delayFrameCount, PlayerLoopTiming timing, CancellationToken cancellationToken, out short token)
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    return AutoResetUniTaskCompletionSource.CreateFromCanceled(cancellationToken, out token);
+                }
+
+                var result = pool.TryRent() ?? new DelayFramePromise();
+
+                result.delayFrameCount = delayFrameCount;
+                result.cancellationToken = cancellationToken;
+
+                TaskTracker2.TrackActiveTask(result, 3);
+
+                PlayerLoopHelper.AddAction(timing, result);
+
+                token = result.core.Version;
+                return result;
+            }
+
+            public void GetResult(short token)
+            {
+                try
+                {
+                    TaskTracker2.RemoveTracking(this);
+                    core.GetResult(token);
+                }
+                finally
+                {
+                    pool.TryReturn(this);
+                }
+            }
+
+            public AwaiterStatus GetStatus(short token)
+            {
+                return core.GetStatus(token);
+            }
+
+            public AwaiterStatus UnsafeGetStatus()
+            {
+                return core.UnsafeGetStatus();
+            }
+
+            public void OnCompleted(Action<object> continuation, object state, short token)
+            {
+                core.OnCompleted(continuation, state, token);
+            }
+
+            public bool MoveNext()
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    core.SetCanceled(cancellationToken);
+                    return false;
+                }
+
+                if (currentFrameCount == delayFrameCount)
+                {
+                    core.SetResult(null);
+                    return false;
+                }
+
+                currentFrameCount++;
+                return true;
+            }
+
+            public void Reset()
+            {
+                core.Reset();
+                currentFrameCount = default;
+                delayFrameCount = default;
+                cancellationToken = default;
+            }
+        }
+
+        class DelayPromise : IUniTaskSource, IPlayerLoopItem, IPromisePoolItem
+        {
+            static readonly PromisePool<DelayPromise> pool = new PromisePool<DelayPromise>();
+
+            float delayFrameTimeSpan;
+            float elapsed;
+            CancellationToken cancellationToken;
+
+            UniTaskCompletionSourceCore<object> core;
+
+            DelayPromise()
+            {
+            }
+
+            public static IUniTaskSource Create(TimeSpan delayFrameTimeSpan, PlayerLoopTiming timing, CancellationToken cancellationToken, out short token)
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    return AutoResetUniTaskCompletionSource.CreateFromCanceled(cancellationToken, out token);
+                }
+
+                var result = pool.TryRent() ?? new DelayPromise();
+
+                result.elapsed = 0.0f;
+                result.delayFrameTimeSpan = (float)delayFrameTimeSpan.TotalSeconds;
+                result.cancellationToken = cancellationToken;
+
+                TaskTracker2.TrackActiveTask(result, 3);
+
+                PlayerLoopHelper.AddAction(timing, result);
+
+                token = result.core.Version;
+                return result;
+            }
+
+            public void GetResult(short token)
+            {
+                try
+                {
+                    TaskTracker2.RemoveTracking(this);
+                    core.GetResult(token);
+                }
+                finally
+                {
+                    pool.TryReturn(this);
+                }
+            }
+
+            public AwaiterStatus GetStatus(short token)
+            {
+                return core.GetStatus(token);
+            }
+
+            public AwaiterStatus UnsafeGetStatus()
+            {
+                return core.UnsafeGetStatus();
+            }
+
+            public void OnCompleted(Action<object> continuation, object state, short token)
+            {
+                core.OnCompleted(continuation, state, token);
+            }
+
+            public bool MoveNext()
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    core.SetCanceled(cancellationToken);
+                    return false;
+                }
+
+                elapsed += Time.deltaTime;
+                if (elapsed >= delayFrameTimeSpan)
+                {
+                    core.SetResult(null);
+                    return false;
+                }
+
+                return true;
+            }
+
+            public void Reset()
+            {
+                core.Reset();
+                delayFrameTimeSpan = default;
+                elapsed = default;
+                cancellationToken = default;
+            }
+        }
+
+        class DelayIgnoreTimeScalePromise : IUniTaskSource, IPlayerLoopItem, IPromisePoolItem
+        {
+            static readonly PromisePool<DelayIgnoreTimeScalePromise> pool = new PromisePool<DelayIgnoreTimeScalePromise>();
+
+            float delayFrameTimeSpan;
+            float elapsed;
+            CancellationToken cancellationToken;
+
+            UniTaskCompletionSourceCore<object> core;
+
+            DelayIgnoreTimeScalePromise()
+            {
+            }
+
+            public static IUniTaskSource Create(TimeSpan delayFrameTimeSpan, PlayerLoopTiming timing, CancellationToken cancellationToken, out short token)
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    return AutoResetUniTaskCompletionSource.CreateFromCanceled(cancellationToken, out token);
+                }
+
+                var result = pool.TryRent() ?? new DelayIgnoreTimeScalePromise();
+
+                result.elapsed = 0.0f;
+                result.delayFrameTimeSpan = (float)delayFrameTimeSpan.TotalSeconds;
+                result.cancellationToken = cancellationToken;
+
+                TaskTracker2.TrackActiveTask(result, 3);
+
+                PlayerLoopHelper.AddAction(timing, result);
+
+                token = result.core.Version;
+                return result;
+            }
+
+            public void GetResult(short token)
+            {
+                try
+                {
+                    TaskTracker2.RemoveTracking(this);
+                    core.GetResult(token);
+                }
+                finally
+                {
+                    pool.TryReturn(this);
+                }
+            }
+
+            public AwaiterStatus GetStatus(short token)
+            {
+                return core.GetStatus(token);
+            }
+
+            public AwaiterStatus UnsafeGetStatus()
+            {
+                return core.UnsafeGetStatus();
+            }
+
+            public void OnCompleted(Action<object> continuation, object state, short token)
+            {
+                core.OnCompleted(continuation, state, token);
+            }
+
+            public bool MoveNext()
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    core.SetCanceled(cancellationToken);
+                    return false;
+                }
+
+                elapsed += Time.unscaledDeltaTime;
+                if (elapsed >= delayFrameTimeSpan)
+                {
+                    core.SetResult(null);
+                    return false;
+                }
+
+                return true;
+            }
+
+            public void Reset()
+            {
+                core.Reset();
+                delayFrameTimeSpan = default;
+                elapsed = default;
+                cancellationToken = default;
+            }
+        }
+    }
+
+    // TODO:rename
+    public struct YieldAwaitable2
+    {
+        readonly PlayerLoopTiming timing;
+
+        public YieldAwaitable2(PlayerLoopTiming timing)
+        {
+            this.timing = timing;
+        }
+
+        public Awaiter GetAwaiter()
+        {
+            return new Awaiter(timing);
+        }
+
+        public UniTask2 ToUniTask()
+        {
+            return UniTask2.Yield(timing, CancellationToken.None);
+        }
+
+        public struct Awaiter : ICriticalNotifyCompletion
+        {
+            readonly PlayerLoopTiming timing;
+
+            public Awaiter(PlayerLoopTiming timing)
+            {
+                this.timing = timing;
+            }
+
+            public bool IsCompleted => false;
+
+            public void GetResult() { }
+
+            public void OnCompleted(Action continuation)
+            {
+                PlayerLoopHelper.AddContinuation(timing, continuation);
+            }
+
+            public void UnsafeOnCompleted(Action continuation)
+            {
+                PlayerLoopHelper.AddContinuation(timing, continuation);
+            }
+        }
+    }
+
+
+    // TODO:remove
     public partial struct UniTask
     {
         public static YieldAwaitable Yield(PlayerLoopTiming timing = PlayerLoopTiming.Update)
@@ -199,6 +642,7 @@ namespace UniRx.Async
         }
     }
 
+    // TODO:remove
     public struct YieldAwaitable
     {
         readonly PlayerLoopTiming timing;
diff --git a/Assets/UniRx.Async/UniTask.Factory.cs b/Assets/UniRx.Async/UniTask.Factory.cs
index 5bc0b84..9893ad2 100644
--- a/Assets/UniRx.Async/UniTask.Factory.cs
+++ b/Assets/UniRx.Async/UniTask.Factory.cs
@@ -7,6 +7,121 @@ using UnityEngine.Events;
 
 namespace UniRx.Async
 {
+    public partial struct UniTask2
+    {
+        static readonly UniTask2 CanceledUniTask = new Func<UniTask2>(() =>
+        {
+            var promise = new UniTaskCompletionSource2();
+            promise.SetCanceled(CancellationToken.None);
+            promise.MarkHandled();
+            return promise.Task;
+        })();
+
+        static class CanceledUniTaskCache<T>
+        {
+            public static readonly UniTask2<T> Task;
+
+            static CanceledUniTaskCache()
+            {
+                var promise = new UniTaskCompletionSource2<T>();
+                promise.SetCanceled(CancellationToken.None);
+                promise.MarkHandled();
+                Task = promise.Task;
+            }
+        }
+
+        public static readonly UniTask2 CompletedTask = new UniTask2();
+
+        public static UniTask2 FromException(Exception ex)
+        {
+            var promise = new UniTaskCompletionSource2();
+            promise.SetException(ex);
+            promise.MarkHandled();
+            return promise.Task;
+        }
+
+        public static UniTask2<T> FromException<T>(Exception ex)
+        {
+            var promise = new UniTaskCompletionSource2<T>();
+            promise.SetException(ex);
+            promise.MarkHandled();
+            return promise.Task;
+        }
+
+        public static UniTask2<T> FromResult<T>(T value)
+        {
+            return new UniTask2<T>(value);
+        }
+
+        public static UniTask2 FromCanceled(CancellationToken cancellationToken = default)
+        {
+            if (cancellationToken == CancellationToken.None)
+            {
+                return CanceledUniTask;
+            }
+            else
+            {
+                var promise = new UniTaskCompletionSource2();
+                promise.SetCanceled(cancellationToken);
+                promise.MarkHandled();
+                return promise.Task;
+            }
+        }
+
+        public static UniTask2<T> FromCanceled<T>(CancellationToken cancellationToken = default)
+        {
+            if (cancellationToken == CancellationToken.None)
+            {
+                return CanceledUniTaskCache<T>.Task;
+            }
+            else
+            {
+                var promise = new UniTaskCompletionSource2<T>();
+                promise.SetCanceled(cancellationToken);
+                promise.MarkHandled();
+                return promise.Task;
+            }
+        }
+
+        // TODO:...
+
+        /// <summary>shorthand of new UniTask[T](Func[UniTask[T]] factory)</summary>
+        public static UniTask<T> Lazy<T>(Func<UniTask<T>> factory)
+        {
+            return new UniTask<T>(factory);
+        }
+
+        /// <summary>
+        /// helper of create add UniTaskVoid to delegate.
+        /// For example: FooEvent += () => UniTask.Void(async () => { /* */ })
+        /// </summary>
+        public static void Void(Func<UniTask> asyncAction)
+        {
+            asyncAction().Forget();
+        }
+
+        public static Action VoidAction(Func<UniTask> asyncAction)
+        {
+            return () => Void(asyncAction);
+        }
+
+        public static UnityAction VoidUnityAction(Func<UniTask> asyncAction)
+        {
+            return () => Void(asyncAction);
+        }
+
+        /// <summary>
+        /// helper of create add UniTaskVoid to delegate.
+        /// For example: FooEvent += (sender, e) => UniTask.Void(async arg => { /* */ }, (sender, e))
+        /// </summary>
+        public static void Void<T>(Func<T, UniTask> asyncAction, T state)
+        {
+            asyncAction(state).Forget();
+        }
+    }
+
+
+    // TODO:remove
     public partial struct UniTask
     {
         static readonly UniTask CanceledUniTask = new Func<UniTask>(() =>
@@ -120,6 +235,8 @@ namespace UniRx.Async
         }
     }
 
+
+    // TODO:remove
     internal static class CompletedTasks
     {
         public static readonly UniTask<bool> True = UniTask.FromResult(true);
@@ -130,7 +247,7 @@ namespace UniRx.Async
     }
 
 
-
+    // TODO:rename
     internal static class CompletedTasks2
     {
         public static readonly UniTask2 Completed = new UniTask2();
diff --git a/Assets/UniRx.Async/UniTask.cs b/Assets/UniRx.Async/UniTask.cs
index 78cd6e2..bf71764 100644
--- a/Assets/UniRx.Async/UniTask.cs
+++ b/Assets/UniRx.Async/UniTask.cs
@@ -3,136 +3,15 @@
 #pragma warning disable CS0436
 
 using System;
-using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
 using System.Runtime.ExceptionServices;
-using System.Runtime.InteropServices;
-using System.Threading;
-using System.Threading.Tasks;
-using System.Threading.Tasks.Sources;
 using UniRx.Async.CompilerServices;
 using UniRx.Async.Internal;
 
 namespace UniRx.Async
 {
-
-
-    public partial struct UniTask2
-    {
-        public static UniTask2 DelayFrame(int frameCount, PlayerLoopTiming timing = PlayerLoopTiming.Update, CancellationToken cancellationToken = default)
-        {
-            return new UniTask2(DelayPromiseCore2.Create(frameCount, timing, cancellationToken, out var token), token);
-
-
-            //return new ValueTask<int>(DelayPromiseCore2.Create(frameCount, timing, cancellationToken, out var token), token);
-        }
-
-        public static readonly UniTask2 CompletedTask = new UniTask2();
-
-        public static UniTask2<T> FromResult<T>(T result)
-        {
-            return new UniTask2<T>(result);
-        }
-    }
-
-
-
-
-    public class DelayPromiseCore2 : IUniTaskSource, IPlayerLoopItem, IPromisePoolItem
-    {
-        static readonly PromisePool<DelayPromiseCore2> pool = new PromisePool<DelayPromiseCore2>();
-
-        int delayFrameCount;
-        CancellationToken cancellationToken;
-
-        int currentFrameCount;
-        UniTaskCompletionSourceCore<object> core;
-
-        DelayPromiseCore2()
-        {
-        }
-
-        public static IUniTaskSource Create(int delayFrameCount, PlayerLoopTiming timing, CancellationToken cancellationToken, out short token)
-        {
-            if (cancellationToken.IsCancellationRequested)
-            {
-                return AutoResetUniTaskCompletionSource.CreateFromCanceled(cancellationToken, out token);
-            }
-
-            var result = pool.TryRent() ?? new DelayPromiseCore2();
-
-            result.delayFrameCount = delayFrameCount;
-            result.cancellationToken = cancellationToken;
-
-            TaskTracker2.TrackActiveTask(result, 3);
-
-            PlayerLoopHelper.AddAction(timing, result);
-
-            token = result.core.Version;
-            return result;
-        }
-
-        public void GetResult(short token)
-        {
-            try
-            {
-                TaskTracker2.RemoveTracking(this);
-                core.GetResult(token);
-            }
-            finally
-            {
-                pool.TryReturn(this);
-            }
-        }
-
-        public AwaiterStatus GetStatus(short token)
-        {
-            return core.GetStatus(token);
-        }
-
-        public AwaiterStatus UnsafeGetStatus()
-        {
-            return core.UnsafeGetStatus();
-        }
-
-        public void OnCompleted(Action<object> continuation, object state, short token)
-        {
-            core.OnCompleted(continuation, state, token);
-        }
-
-        public bool MoveNext()
-        {
-            if (cancellationToken.IsCancellationRequested)
-            {
-                core.SetCancellation(cancellationToken);
-                return false;
-            }
-
-            if (currentFrameCount == delayFrameCount)
-            {
-                core.SetResult(null);
-                return false;
-            }
-
-            currentFrameCount++;
-            return true;
-        }
-
-        public void Reset()
-        {
-            core.Reset();
-            currentFrameCount = default;
-            delayFrameCount = default;
-            cancellationToken = default;
-        }
-    }
-
-
-
-
-
     internal static class AwaiterActions
     {
         internal static readonly Action<object> InvokeActionDelegate = InvokeAction;
@@ -195,7 +74,20 @@ namespace UniRx.Async
             return "(" + source.UnsafeGetStatus() + ")";
         }
 
-        // TODO:AsTask???
+        /// <summary>
+        /// Memoizing inner IValueTaskSource. The result UniTask can await multiple.
+        /// </summary>
+        public UniTask2 Preserve()
+        {
+            if (source == null)
+            {
+                return this;
+            }
+            else
+            {
+                return new UniTask2(new MemoizeSource(source), token);
+            }
+        }
 
         public static implicit operator UniTask2<AsyncUnit>(UniTask2 task)
         {
@@ -287,6 +179,86 @@ namespace UniRx.Async
             }
         }
 
+        class MemoizeSource : IUniTaskSource
+        {
+            IUniTaskSource source;
+            ExceptionDispatchInfo exception;
+            AwaiterStatus status;
+
+            public MemoizeSource(IUniTaskSource source)
+            {
+                this.source = source;
+            }
+
+            public void GetResult(short token)
+            {
+                if (source == null)
+                {
+                    if (exception != null)
+                    {
+                        exception.Throw();
+                    }
+                }
+                else
+                {
+                    try
+                    {
+                        source.GetResult(token);
+                        status = AwaiterStatus.Succeeded;
+                    }
+                    catch (Exception ex)
+                    {
+                        exception = ExceptionDispatchInfo.Capture(ex);
+                        if (ex is OperationCanceledException)
+                        {
+                            status = AwaiterStatus.Canceled;
+                        }
+                        else
+                        {
+                            status = AwaiterStatus.Faulted;
+                        }
+                        throw;
+                    }
+                    finally
+                    {
+                        source = null;
+                    }
+                }
+            }
+
+            public AwaiterStatus GetStatus(short token)
+            {
+                if (source == null)
+                {
+                    return status;
+                }
+
+                return source.GetStatus(token);
+            }
+
+            public void OnCompleted(Action<object> continuation, object state, short token)
+            {
+                if (source == null)
+                {
+                    continuation(state);
+                }
+                else
+                {
+                    source.OnCompleted(continuation, state, token);
+                }
+            }
+
+            public AwaiterStatus UnsafeGetStatus()
+            {
+                if (source == null)
+                {
+                    return status;
+                }
+
+                return source.UnsafeGetStatus();
+            }
+        }
+
         public readonly struct Awaiter : ICriticalNotifyCompletion
         {
             readonly UniTask2 task;
@@ -343,6 +315,21 @@ namespace UniRx.Async
                     task.source.OnCompleted(AwaiterActions.InvokeActionDelegate, continuation, task.token);
                 }
             }
+
+            /// <summary>
+            /// If register manually continuation, you can use it instead of for compiler OnCompleted methods.
+            /// </summary>
+            public void SourceOnCompleted(Action<object> continuation, object state)
+            {
+                if (task.source == null)
+                {
+                    continuation(state);
+                }
+                else
+                {
+                    task.source.OnCompleted(continuation, state, task.token);
+                }
+            }
         }
     }
 
@@ -391,7 +378,33 @@ namespace UniRx.Async
             return new Awaiter(this);
         }
 
-        // TODO:AsTask???
+        /// <summary>
+        /// Memoizing inner IValueTaskSource. The result UniTask can await multiple.
+        /// </summary>
+        public UniTask2<T> Preserve()
+        {
+            if (source == null)
+            {
+                return this;
+            }
+            else
+            {
+                return new UniTask2<T>(new MemoizeSource(source), token);
+            }
+        }
+
+        public static implicit operator UniTask2(UniTask2<T> task)
+        {
+            if (task.source == null) return UniTask2.CompletedTask;
+
+            var status = task.source.GetStatus(task.token);
+            if (status.IsCompletedSuccessfully())
+            {
+                return UniTask2.CompletedTask;
+            }
+
+            return new UniTask2(task.source, task.token);
+        }
 
         /// <summary>
         /// returns (bool IsCanceled, T Result) instead of throws OperationCanceledException.
@@ -465,6 +478,94 @@ namespace UniRx.Async
             }
         }
 
+        class MemoizeSource : IUniTaskSource<T>
+        {
+            IUniTaskSource<T> source;
+            T result;
+            ExceptionDispatchInfo exception;
+            AwaiterStatus status;
+
+            public MemoizeSource(IUniTaskSource<T> source)
+            {
+                this.source = source;
+            }
+
+            public T GetResult(short token)
+            {
+                if (source == null)
+                {
+                    if (exception != null)
+                    {
+                        exception.Throw();
+                    }
+                    return result;
+                }
+                else
+                {
+                    try
+                    {
+                        result = source.GetResult(token);
+                        status = AwaiterStatus.Succeeded;
+                        return result;
+                    }
+                    catch (Exception ex)
+                    {
+                        exception = ExceptionDispatchInfo.Capture(ex);
+                        if (ex is OperationCanceledException)
+                        {
+                            status = AwaiterStatus.Canceled;
+                        }
+                        else
+                        {
+                            status = AwaiterStatus.Faulted;
+                        }
+                        throw;
+                    }
+                    finally
+                    {
+                        source = null;
+                    }
+                }
+            }
+
+            void IUniTaskSource.GetResult(short token)
+            {
+                GetResult(token);
+            }
+
+            public AwaiterStatus GetStatus(short token)
+            {
+                if (source == null)
+                {
+                    return status;
+                }
+
+                return source.GetStatus(token);
+            }
+
+            public void OnCompleted(Action<object> continuation, object state, short token)
+            {
+                if (source == null)
+                {
+                    continuation(state);
+                }
+                else
+                {
+                    source.OnCompleted(continuation, state, token);
+                }
+            }
+
+            public AwaiterStatus UnsafeGetStatus()
+            {
+                if (source == null)
+                {
+                    return status;
+                }
+
+                return source.UnsafeGetStatus();
+            }
+        }
+
         public readonly struct Awaiter : ICriticalNotifyCompletion
         {
             readonly UniTask2<T> task;
@@ -530,6 +631,22 @@ namespace UniRx.Async
                     s.OnCompleted(AwaiterActions.InvokeActionDelegate, continuation, task.token);
                 }
             }
+
+            /// <summary>
+            /// If register manually continuation, you can use it instead of for compiler OnCompleted methods.
+            /// </summary>
+            public void SourceOnCompleted(Action<object> continuation, object state)
+            {
+                var s = task.source;
+                if (s == null)
+                {
+                    continuation(state);
+                }
+                else
+                {
+                    s.OnCompleted(continuation, state, task.token);
+                }
+            }
         }
     }
 
@@ -1000,4 +1117,4 @@ namespace UniRx.Async
     }
 }
 
-#endif
\ No newline at end of file
+#endif
diff --git a/Assets/UniRx.Async/UniTaskCompletionSource.cs b/Assets/UniRx.Async/UniTaskCompletionSource.cs
index aa42750..27355a4 100644
--- a/Assets/UniRx.Async/UniTaskCompletionSource.cs
+++ b/Assets/UniRx.Async/UniTaskCompletionSource.cs
@@ -480,7 +480,7 @@ namespace UniRx.Async
             SignalCompletion();
         }
 
-        public void SetCancellation(CancellationToken cancellationToken)
+        public void SetCanceled(CancellationToken cancellationToken = default)
         {
             this.error = new OperationCanceledException(cancellationToken);
             SignalCompletion();
@@ -613,7 +613,7 @@ namespace UniRx.Async
         }
 
         [Conditional("UNITY_EDITOR")]
-        void MarkHandled()
+        internal void MarkHandled()
         {
             if (!handled)
             {
@@ -643,9 +643,9 @@ namespace UniRx.Async
             core.SetResult(AsyncUnit.Default);
         }
 
-        public void SetCancellation(CancellationToken cancellationToken)
+        public void SetCanceled(CancellationToken cancellationToken = default)
         {
-            core.SetCancellation(cancellationToken);
+            core.SetCanceled(cancellationToken);
         }
 
         public void SetException(Exception exception)
@@ -701,7 +701,7 @@ namespace UniRx.Async
         public static AutoResetUniTaskCompletionSource CreateFromCanceled(CancellationToken cancellationToken, out short token)
         {
             var source = Create();
-            source.SetCancellation(cancellationToken);
+            source.SetCanceled(cancellationToken);
             token = source.core.Version;
             return source;
         }
@@ -735,7 +735,7 @@ namespace UniRx.Async
             core.SetResult(AsyncUnit.Default);
         }
 
-        public void SetCancellation(CancellationToken cancellationToken)
+        public void SetCanceled(CancellationToken cancellationToken = default)
         {
             core.SetCancellation(cancellationToken);
         }
@@ -800,7 +800,7 @@ namespace UniRx.Async
         }
 
         [Conditional("UNITY_EDITOR")]
-        void MarkHandled()
+        internal void MarkHandled()
         {
             if (!handled)
             {
@@ -829,7 +829,7 @@ namespace UniRx.Async
             core.SetResult(result);
         }
 
-        public void SetCancellation(CancellationToken cancellationToken)
+        public void SetCanceled(CancellationToken cancellationToken = default)
         {
             core.SetCancellation(cancellationToken);
         }
@@ -884,7 +884,7 @@ namespace UniRx.Async
 
         public static AutoResetUniTaskCompletionSource<T> Create()
         {
-            var result =  pool.TryRent() ?? new AutoResetUniTaskCompletionSource<T>();
+            var result = pool.TryRent() ?? new AutoResetUniTaskCompletionSource<T>();
             TaskTracker2.TrackActiveTask(result, 2);
             return result;
         }
@@ -926,7 +926,7 @@ namespace UniRx.Async
             core.SetResult(result);
         }
 
-        public void SetCancellation(CancellationToken cancellationToken)
+        public void SetCanceled(CancellationToken cancellationToken = default)
         {
             core.SetCancellation(cancellationToken);
         }
diff --git a/Assets/UniRx.Async/UniTaskExtensions.cs b/Assets/UniRx.Async/UniTaskExtensions.cs
index 06642df..6cdfaf8 100644
--- a/Assets/UniRx.Async/UniTaskExtensions.cs
+++ b/Assets/UniRx.Async/UniTaskExtensions.cs
@@ -10,6 +10,574 @@ using UniRx.Async.Internal;
 
 namespace UniRx.Async
 {
+    public static partial class UniTaskExtensions2
+    {
+        /// <summary>
+        /// Convert UniTask -> UniTask[AsyncUnit].
+        /// </summary>
+        public static UniTask2<AsyncUnit> AsAsyncUnitUniTask(this UniTask2 task)
+        {
+            // use implicit conversion
+            return task;
+        }
+
+        /// <summary>
+        /// Convert UniTask[T] -> UniTask.
+        /// </summary>
+        public static UniTask2 AsUniTask<T>(this UniTask2<T> task)
+        {
+            // use implicit conversion
+            return task;
+        }
+
+        /// <summary>
+        /// Convert Task[T] -> UniTask[T].
+        /// </summary>
+        public static UniTask2<T> AsUniTask<T>(this Task<T> task, bool useCurrentSynchronizationContext = true)
+        {
+            var promise = new UniTaskCompletionSource2<T>();
+
+            task.ContinueWith((x, state) =>
+            {
+                var p = (UniTaskCompletionSource2<T>)state;
+
+                switch (x.Status)
+                {
+                    case TaskStatus.Canceled:
+                        p.SetCanceled();
+                        break;
+                    case TaskStatus.Faulted:
+                        p.SetException(x.Exception);
+                        break;
+                    case TaskStatus.RanToCompletion:
+                        p.SetResult(x.Result);
+                        break;
+                    default:
+                        throw new NotSupportedException();
+                }
+            }, promise, useCurrentSynchronizationContext ? TaskScheduler.FromCurrentSynchronizationContext() : TaskScheduler.Current);
+
+            return promise.Task;
+        }
+
+        /// <summary>
+        /// Convert Task -> UniTask.
+        /// </summary>
+        public static UniTask2 AsUniTask(this Task task, bool useCurrentSynchronizationContext = true)
+        {
+            var promise = new UniTaskCompletionSource2();
+
+            task.ContinueWith((x, state) =>
+            {
+                var p = (UniTaskCompletionSource2)state;
+
+                switch (x.Status)
+                {
+                    case TaskStatus.Canceled:
+                        p.SetCanceled();
+                        break;
+                    case TaskStatus.Faulted:
+                        p.SetException(x.Exception);
+                        break;
+                    case TaskStatus.RanToCompletion:
+                        p.SetResult();
+                        break;
+                    default:
+                        throw new NotSupportedException();
+                }
+            }, promise, useCurrentSynchronizationContext ? TaskScheduler.FromCurrentSynchronizationContext() : TaskScheduler.Current);
+
+            return promise.Task;
+        }
+
+        public static Task<T> AsTask<T>(this UniTask2<T> task)
+        {
+            try
+            {
+                var awaiter = task.GetAwaiter();
+                if (awaiter.IsCompleted)
+                {
+                    try
+                    {
+                        var result = awaiter.GetResult();
+                        return Task.FromResult(result);
+                    }
+                    catch (Exception ex)
+                    {
+                        return Task.FromException<T>(ex);
+                    }
+                }
+
+                var tcs = new TaskCompletionSource<T>();
+
+                awaiter.SourceOnCompleted(state =>
+                {
+                    var (inTcs, inAwaiter) = ((TaskCompletionSource<T>, UniTask2<T>.Awaiter))state;
+                    try
+                    {
+                        var result = inAwaiter.GetResult();
+                        inTcs.SetResult(result);
+                    }
+                    catch (Exception ex)
+                    {
+                        inTcs.SetException(ex);
+                    }
+                }, (tcs, awaiter));
+
+                return tcs.Task;
+            }
+            catch (Exception ex)
+            {
+                return Task.FromException<T>(ex);
+            }
+        }
+
+        public static Task AsTask(this UniTask2 task)
+        {
+            try
+            {
+                var awaiter = task.GetAwaiter();
+                if (awaiter.IsCompleted)
+                {
+                    try
+                    {
+                        awaiter.GetResult(); // check token valid on Succeeded
+                        return Task.CompletedTask;
+                    }
+                    catch (Exception ex)
+                    {
+                        return Task.FromException(ex);
+                    }
+                }
+
+                var tcs = new TaskCompletionSource<object>();
+
+                awaiter.SourceOnCompleted(state =>
+                {
+                    var (inTcs, inAwaiter) = ((TaskCompletionSource<object>, UniTask2.Awaiter))state;
+                    try
+                    {
+                        inAwaiter.GetResult();
+                        inTcs.SetResult(null);
+                    }
+                    catch (Exception ex)
+                    {
+                        inTcs.SetException(ex);
+                    }
+                }, (tcs, awaiter));
+
+                return tcs.Task;
+            }
+            catch (Exception ex)
+            {
+                return Task.FromException(ex);
+            }
+        }
+
+        public static IEnumerator ToCoroutine<T>(this UniTask2<T> task, Action<T> resultHandler = null, Action<Exception> exceptionHandler = null)
+        {
+            return new ToCoroutineEnumerator<T>(task, resultHandler, exceptionHandler);
+        }
+
+        public static IEnumerator ToCoroutine(this UniTask2 task, Action<Exception> exceptionHandler = null)
+        {
+            return new ToCoroutineEnumerator(task, exceptionHandler);
+        }
+
+        public static UniTask Timeout(this UniTask2 task, TimeSpan timeout, bool ignoreTimeScale = true, PlayerLoopTiming timeoutCheckTiming = PlayerLoopTiming.Update, CancellationTokenSource taskCancellationTokenSource = null)
+        {
+            return Timeout(task.AsAsyncUnitUniTask(), timeout, ignoreTimeScale, timeoutCheckTiming, taskCancellationTokenSource);
+        }
+
+        // TODO: require UniTask2.Delay, WhenAny, etc...
+
+        public static async UniTask<T> Timeout<T>(this UniTask2<T> task, TimeSpan timeout, bool ignoreTimeScale = true, PlayerLoopTiming timeoutCheckTiming = PlayerLoopTiming.Update, CancellationTokenSource taskCancellationTokenSource = null)
+        {
+            // left, right both suppress operation canceled exception.
+
+            var delayCancellationTokenSource = new CancellationTokenSource();
+            var timeoutTask = (UniTask)UniTask.Delay(timeout, ignoreTimeScale, timeoutCheckTiming).SuppressCancellationThrow();
+
+            var (hasValue, value) = await UniTask.WhenAny(task.SuppressCancellationThrow(), timeoutTask);
+
+            if (!hasValue)
+            {
+                if (taskCancellationTokenSource != null)
+                {
+                    taskCancellationTokenSource.Cancel();
+                    taskCancellationTokenSource.Dispose();
+                }
+
+                throw new TimeoutException("Exceed Timeout:" + timeout);
+            }
+            else
+            {
+                delayCancellationTokenSource.Cancel();
+                delayCancellationTokenSource.Dispose();
+            }
+
+            if (value.IsCanceled)
+            {
+                Error.ThrowOperationCanceledException();
+            }
+
+            return value.Result;
+        }
+
+        /// <summary>
+        /// Timeout with suppress OperationCanceledException. Returns (bool, IsCacneled).
+        /// </summary>
+        public static async UniTask2<bool> TimeoutWithoutException(this UniTask2 task, TimeSpan timeout, bool ignoreTimeScale = true, PlayerLoopTiming timeoutCheckTiming = PlayerLoopTiming.Update, CancellationTokenSource taskCancellationTokenSource = null)
+        {
+            var v = await TimeoutWithoutException(task.AsAsyncUnitUniTask(), timeout, ignoreTimeScale, timeoutCheckTiming, taskCancellationTokenSource);
+            return v.IsTimeout;
+        }
+
+
+        /// <summary>
+        /// Timeout with suppress OperationCanceledException. Returns (bool IsTimeout, T Result).
+        /// </summary>
+        public static async UniTask2<(bool IsTimeout, T Result)> TimeoutWithoutException<T>(this UniTask2<T> task, TimeSpan timeout, bool ignoreTimeScale = true, PlayerLoopTiming timeoutCheckTiming = PlayerLoopTiming.Update, CancellationTokenSource taskCancellationTokenSource = null)
+        {
+            // left, right both suppress operation canceled exception.
+
+            var delayCancellationTokenSource = new CancellationTokenSource();
+            var timeoutTask = (UniTask)UniTask.Delay(timeout, ignoreTimeScale, timeoutCheckTiming).SuppressCancellationThrow();
+
+            var (hasValue, value) = await UniTask.WhenAny(task.SuppressCancellationThrow(), timeoutTask);
+
+            if (!hasValue)
+            {
+                if (taskCancellationTokenSource != null)
+                {
+                    taskCancellationTokenSource.Cancel();
+                    taskCancellationTokenSource.Dispose();
+                }
+
+                return (true, default(T));
+            }
+            else
+            {
+                delayCancellationTokenSource.Cancel();
+                delayCancellationTokenSource.Dispose();
+            }
+
+            if (value.IsCanceled)
+            {
+                Error.ThrowOperationCanceledException();
+            }
+
+            return (false, value.Result);
+        }
+
+        public static void Forget(this UniTask2 task)
+        {
+            ForgetCore(task).Forget();
+        }
+
+        public static void Forget(this UniTask2 task, Action<Exception> exceptionHandler, bool handleExceptionOnMainThread = true)
+        {
+            if (exceptionHandler == null)
+            {
+                ForgetCore(task).Forget();
+            }
+            else
+            {
+                ForgetCoreWithCatch(task, exceptionHandler, handleExceptionOnMainThread).Forget();
+            }
+        }
+
+        // UniTask to UniTaskVoid
+        static async UniTaskVoid ForgetCore(UniTask2 task)
+        {
+            await task;
+        }
+
+        static async UniTaskVoid ForgetCoreWithCatch(UniTask2 task, Action<Exception> exceptionHandler, bool handleExceptionOnMainThread)
+        {
+            try
+            {
+                await task;
+            }
+            catch (Exception ex)
+            {
+                try
+                {
+                    if (handleExceptionOnMainThread)
+                    {
+                        await UniTask2.SwitchToMainThread();
+                    }
+                    exceptionHandler(ex);
+                }
+                catch (Exception ex2)
+                {
+                    UniTaskScheduler.PublishUnobservedTaskException(ex2);
+                }
+            }
+        }
+
+        public static void Forget<T>(this UniTask2<T> task)
+        {
+            ForgetCore(task).Forget();
+        }
+
+        public static void Forget<T>(this UniTask2<T> task, Action<Exception> exceptionHandler, bool handleExceptionOnMainThread = true)
+        {
+            if (exceptionHandler == null)
+            {
+                ForgetCore(task).Forget();
+            }
+            else
+            {
+                ForgetCoreWithCatch(task, exceptionHandler, handleExceptionOnMainThread).Forget();
+            }
+        }
+
+        // UniTask to UniTaskVoid
+        static async UniTaskVoid ForgetCore<T>(UniTask2<T> task)
+        {
+            await task;
+        }
+
+        static async UniTaskVoid ForgetCoreWithCatch<T>(UniTask2<T> task, Action<Exception> exceptionHandler, bool handleExceptionOnMainThread)
+        {
+            try
+            {
+                await task;
+            }
+            catch (Exception ex)
+            {
+                try
+                {
+                    if (handleExceptionOnMainThread)
+                    {
+                        await UniTask.SwitchToMainThread();
+                    }
+                    exceptionHandler(ex);
+                }
+                catch (Exception ex2)
+                {
+                    UniTaskScheduler.PublishUnobservedTaskException(ex2);
+                }
+            }
+        }
+
+        public static async UniTask2 ContinueWith<T>(this UniTask2<T> task, Action<T> continuationFunction)
+        {
+            continuationFunction(await task);
+        }
+
+        public static async UniTask2 ContinueWith<T>(this UniTask2<T> task, Func<T, UniTask2> continuationFunction)
+        {
+            await continuationFunction(await task);
+        }
+
+        public static async UniTask2<TR> ContinueWith<T, TR>(this UniTask2<T> task, Func<T, TR> continuationFunction)
+        {
+            return continuationFunction(await task);
+        }
+
+        public static async UniTask2<TR> ContinueWith<T, TR>(this UniTask2<T> task, Func<T, UniTask2<TR>> continuationFunction)
+        {
+            return await continuationFunction(await task);
+        }
+
+        public static async UniTask2 ContinueWith(this UniTask2 task, Action continuationFunction)
+        {
+            await task;
+            continuationFunction();
+        }
+
+        public static async UniTask2 ContinueWith(this UniTask2 task, Func<UniTask2> continuationFunction)
+        {
+            await task;
+            await continuationFunction();
+        }
+
+        public static async UniTask2<T> ContinueWith<T>(this UniTask2 task, Func<T> continuationFunction)
+        {
+            await task;
+            return continuationFunction();
+        }
+
+        public static async UniTask2<T> ContinueWith<T>(this UniTask2 task, Func<UniTask2<T>> continuationFunction)
+        {
+            await task;
+            return await continuationFunction();
+        }
+
+        public static async UniTask2 ConfigureAwait(this Task task, PlayerLoopTiming timing)
+        {
+            await task.ConfigureAwait(false);
+            await UniTask2.Yield(timing);
+        }
+
+        public static async UniTask2<T> ConfigureAwait<T>(this Task<T> task, PlayerLoopTiming timing)
+        {
+            var v = await task.ConfigureAwait(false);
+            await UniTask2.Yield(timing);
+            return v;
+        }
+
+        public static async UniTask2 ConfigureAwait(this UniTask2 task, PlayerLoopTiming timing)
+        {
+            await task;
+            await UniTask2.Yield(timing);
+        }
+
+        public static async UniTask2<T> ConfigureAwait<T>(this UniTask2<T> task, PlayerLoopTiming timing)
+        {
+            var v = await task;
+            await UniTask2.Yield(timing);
+            return v;
+        }
+
+        public static async UniTask2<T> Unwrap<T>(this UniTask2<UniTask2<T>> task)
+        {
+            return await await task;
+        }
+
+        public static async UniTask2 Unwrap<T>(this UniTask2<UniTask2> task)
+        {
+            await await task;
+        }
+
+        class ToCoroutineEnumerator : IEnumerator
+        {
+            bool completed;
+            UniTask2 task;
+            Action<Exception> exceptionHandler = null;
+            bool isStarted = false;
+            ExceptionDispatchInfo exception;
+
+            public ToCoroutineEnumerator(UniTask2 task, Action<Exception> exceptionHandler)
+            {
+                completed = false;
+                this.exceptionHandler = exceptionHandler;
+                this.task = task;
+            }
+
+            async UniTaskVoid RunTask(UniTask2 task)
+            {
+                try
+                {
+                    await task;
+                }
+                catch (Exception ex)
+                {
+                    if (exceptionHandler != null)
+                    {
+                        exceptionHandler(ex);
+                    }
+                    else
+                    {
+                        this.exception = ExceptionDispatchInfo.Capture(ex);
+                    }
+                }
+                finally
+                {
+                    completed = true;
+                }
+            }
+
+            public object Current => null;
+
+            public bool MoveNext()
+            {
+                if (!isStarted)
+                {
+                    isStarted = true;
+                    RunTask(task).Forget();
+                }
+
+                if (exception != null)
+                {
+                    // throw exception on iterator (main)thread.
+                    // unfortunately unity test-runner can not handle throw exception on hand-write IEnumerator.MoveNext.
+                    UnityEngine.Debug.LogException(exception.SourceException);
+                }
+
+                return !completed;
+            }
+
+            public void Reset()
+            {
+            }
+        }
+
+        class ToCoroutineEnumerator<T> : IEnumerator
+        {
+            bool completed;
+            Action<T> resultHandler = null;
+            Action<Exception> exceptionHandler = null;
+            bool isStarted = false;
+            UniTask2<T> task;
+            object current = null;
+            ExceptionDispatchInfo exception;
+
+            public ToCoroutineEnumerator(UniTask2<T> task, Action<T> resultHandler, Action<Exception> exceptionHandler)
+            {
+                completed = false;
+                this.task = task;
+                this.resultHandler = resultHandler;
+                this.exceptionHandler = exceptionHandler;
+            }
+
+            async UniTaskVoid RunTask(UniTask2<T> task)
+            {
+                try
+                {
+                    var value = await task;
+                    current = value; // boxed if T is struct...
+                    if (resultHandler != null)
+                    {
+                        resultHandler(value);
+                    }
+                }
+                catch (Exception ex)
+                {
+                    if (exceptionHandler != null)
+                    {
+                        exceptionHandler(ex);
+                    }
+                    else
+                    {
+                        this.exception = ExceptionDispatchInfo.Capture(ex);
+                    }
+                }
+                finally
+                {
+                    completed = true;
+                }
+            }
+
+            public object Current => current;
+
+            public bool MoveNext()
+            {
+                if (!isStarted)
+                {
+                    isStarted = true;
+                    RunTask(task).Forget();
+                }
+
+                if (exception != null)
+                {
+                    // throw exception on iterator (main)thread.
+                    // unfortunately unity test-runner can not handle throw exception on hand-write IEnumerator.MoveNext.
+                    UnityEngine.Debug.LogException(exception.SourceException);
+                }
+
+                return !completed;
+            }
+
+            public void Reset()
+            {
+            }
+        }
+    }
+
+    // TODO:remove
     public static partial class UniTaskExtensions
     {
         /// <summary>
diff --git a/Assets/UniRx.Async/UnityAsyncExtensions.cs b/Assets/UniRx.Async/UnityAsyncExtensions.cs
index f14bbe5..47314cb 100644
--- a/Assets/UniRx.Async/UnityAsyncExtensions.cs
+++ b/Assets/UniRx.Async/UnityAsyncExtensions.cs
@@ -573,7 +573,7 @@ namespace UniRx.Async
                 {
                     // TODO:Remove Tracking
                     // TaskTracker.RemoveTracking();
-                    core.SetCancellation(cancellationToken);
+                    core.SetCanceled(cancellationToken);
                     return false;
                 }