diff --git a/src/UniTask.NetCoreSandbox/Program.cs b/src/UniTask.NetCoreSandbox/Program.cs
index 24807f2..ff83580 100644
--- a/src/UniTask.NetCoreSandbox/Program.cs
+++ b/src/UniTask.NetCoreSandbox/Program.cs
@@ -43,7 +43,7 @@ namespace NetCoreSandbox
                 .SelectAwait(x => UniTask.Run(() => x))
                 .TakeLast(6)
 
-
+                
 
                 )
             {
@@ -51,7 +51,7 @@ namespace NetCoreSandbox
                 Console.WriteLine(item);
             }
 
-
+// AsyncEnumerable.Range(1,10).FirstAsync(
             // AsyncEnumerable.Range(1, 10).GroupBy(x=>x).Select(x=>x.first
 
 
diff --git a/src/UniTask/Assets/Plugins/UniTask/Internal/PromisePool.cs b/src/UniTask/Assets/Plugins/UniTask/Internal/PromisePool.cs
index e43aad2..83c3ada 100644
--- a/src/UniTask/Assets/Plugins/UniTask/Internal/PromisePool.cs
+++ b/src/UniTask/Assets/Plugins/UniTask/Internal/PromisePool.cs
@@ -4,12 +4,14 @@ using System.Threading;
 
 namespace Cysharp.Threading.Tasks.Internal
 {
-    internal interface IPromisePoolItem
+    // public, allow to user create custom operator with pool.
+
+    public interface IPromisePoolItem
     {
         void Reset();
     }
 
-    internal class PromisePool<T>
+    public class PromisePool<T>
         where T : class, IPromisePoolItem
     {
         int count = 0;
diff --git a/src/UniTask/Assets/Plugins/UniTask/UnityAsyncExtensions.uGUI.cs b/src/UniTask/Assets/Plugins/UniTask/UnityAsyncExtensions.uGUI.cs
index b90e183..c324ac5 100644
--- a/src/UniTask/Assets/Plugins/UniTask/UnityAsyncExtensions.uGUI.cs
+++ b/src/UniTask/Assets/Plugins/UniTask/UnityAsyncExtensions.uGUI.cs
@@ -162,22 +162,25 @@ namespace Cysharp.Threading.Tasks
         }
     }
 
-    public interface IAsyncClickEventHandler : IDisposable
+    public interface IAsyncClickEventHandler : IDisposable, IUniTaskAsyncEnumerable<AsyncUnit>
     {
         UniTask OnClickAsync();
+        IAsyncClickEventHandler DisableAutoClose();
     }
 
-    public interface IAsyncValueChangedEventHandler<T> : IDisposable
+    public interface IAsyncValueChangedEventHandler<T> : IDisposable, IUniTaskAsyncEnumerable<T>
     {
         UniTask<T> OnValueChangedAsync();
+        IAsyncValueChangedEventHandler<T> DisableAutoClose();
     }
 
-    public interface IAsyncEndEditEventHandler<T> : IDisposable
+    public interface IAsyncEndEditEventHandler<T> : IDisposable, IUniTaskAsyncEnumerable<T>
     {
         UniTask<T> OnEndEditAsync();
+        IAsyncEndEditEventHandler<T> DisableAutoClose();
     }
 
-    public class AsyncUnityEventHandler : IUniTaskSource, IDisposable, IAsyncClickEventHandler
+    public class AsyncUnityEventHandler : IUniTaskSource, IDisposable, IAsyncClickEventHandler, IUniTaskAsyncEnumerable<AsyncUnit>
     {
         static Action<object> cancellationCallback = CancellationCallback;
 
@@ -222,6 +225,7 @@ namespace Cysharp.Threading.Tasks
 
         void Invoke()
         {
+            asyncEnumerator?.SetResult();
             core.TrySetResult(AsyncUnit.Default);
         }
 
@@ -230,6 +234,13 @@ namespace Cysharp.Threading.Tasks
             var self = (AsyncUnityEventHandler)state;
             self.Dispose();
 
+            // call child cancel
+            if (self.asyncEnumerator != null)
+            {
+                self.asyncEnumerator.CancelFromParent(self.cancellationToken);
+                self.asyncEnumerator = null;
+            }
+
             self.core.TrySetCanceled(self.cancellationToken);
         }
 
@@ -281,9 +292,118 @@ namespace Cysharp.Threading.Tasks
         {
             core.OnCompleted(continuation, state, token);
         }
+
+        // AsyncEnumerator
+
+        bool disableAutoClose;
+        Enumerator asyncEnumerator;
+
+        public AsyncUnityEventHandler DisableAutoClose()
+        {
+            disableAutoClose = true;
+            return this;
+        }
+
+        IAsyncClickEventHandler IAsyncClickEventHandler.DisableAutoClose()
+        {
+            disableAutoClose = true;
+            return this;
+        }
+
+        IUniTaskAsyncEnumerator<AsyncUnit> IUniTaskAsyncEnumerable<AsyncUnit>.GetAsyncEnumerator(CancellationToken cancellationToken)
+        {
+            if (this.asyncEnumerator != null)
+            {
+                throw new InvalidOperationException("Already acquired GetAsyncEnumerator, does not allow get twice before previous enumerator completed.");
+            }
+
+            this.asyncEnumerator = new Enumerator(this, cancellationToken);
+            return asyncEnumerator;
+        }
+
+        class Enumerator : Cysharp.Threading.Tasks.Linq.MoveNextSource, IUniTaskAsyncEnumerator<AsyncUnit>
+        {
+            static Action<object> cancellationCallback = CancellationCallback;
+
+            AsyncUnityEventHandler parent;
+            CancellationToken cancellationToken;
+            CancellationTokenRegistration registration;
+            bool isDisposed;
+
+            public Enumerator(AsyncUnityEventHandler parent, CancellationToken cancellationToken)
+            {
+                this.parent = parent;
+                this.cancellationToken = cancellationToken;
+
+                if (cancellationToken.CanBeCanceled && parent.cancellationToken != cancellationToken)
+                {
+                    registration = cancellationToken.RegisterWithoutCaptureExecutionContext(cancellationCallback, this);
+                }
+
+                TaskTracker.TrackActiveTask(this, 3);
+            }
+
+            static void CancellationCallback(object state)
+            {
+                var self = (Enumerator)state;
+                self.DisposeCore(self.cancellationToken);
+            }
+
+            public void CancelFromParent(CancellationToken cancellationToken)
+            {
+                // call from parent, avoid parent close.
+                parent.disableAutoClose = true;
+                DisposeCore(cancellationToken);
+            }
+
+            public void SetResult()
+            {
+                completionSource.TrySetResult(true);
+            }
+
+            public AsyncUnit Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
+            {
+                completionSource.Reset();
+                return new UniTask<bool>(this, completionSource.Version);
+            }
+
+            public UniTask DisposeAsync()
+            {
+                DisposeCore(CancellationToken.None);
+                return default;
+            }
+
+            void DisposeCore(CancellationToken cancellationToken)
+            {
+                if (!isDisposed)
+                {
+                    isDisposed = true;
+                    registration.Dispose();
+                    TaskTracker.RemoveTracking(this);
+
+                    if (!parent.disableAutoClose)
+                    {
+                        parent.Dispose(); // dispose parent.
+                    }
+
+                    if (parent.asyncEnumerator == this)
+                    {
+                        parent.asyncEnumerator = null;
+                    }
+
+                    try
+                    {
+                        completionSource.TrySetCanceled(cancellationToken);
+                    }
+                    catch (OperationCanceledException) { }
+                }
+            }
+        }
     }
 
-    public class AsyncUnityEventHandler<T> : IUniTaskSource<T>, IDisposable, IAsyncValueChangedEventHandler<T>, IAsyncEndEditEventHandler<T>
+    public class AsyncUnityEventHandler<T> : IUniTaskSource<T>, IDisposable, IAsyncValueChangedEventHandler<T>, IAsyncEndEditEventHandler<T>, IUniTaskAsyncEnumerable<T>
     {
         static Action<object> cancellationCallback = CancellationCallback;
 
@@ -328,6 +448,7 @@ namespace Cysharp.Threading.Tasks
 
         void Invoke(T result)
         {
+            asyncEnumerator?.SetResult(result);
             core.TrySetResult(result);
         }
 
@@ -336,6 +457,13 @@ namespace Cysharp.Threading.Tasks
             var self = (AsyncUnityEventHandler<T>)state;
             self.Dispose();
 
+            // call child cancel
+            if (self.asyncEnumerator != null)
+            {
+                self.asyncEnumerator.CancelFromParent(self.cancellationToken);
+                self.asyncEnumerator = null;
+            }
+
             self.core.TrySetCanceled(self.cancellationToken);
         }
 
@@ -350,6 +478,13 @@ namespace Cysharp.Threading.Tasks
                 {
                     unityEvent.RemoveListener(action);
                 }
+
+                asyncEnumerator?.DisposeAsync().Forget();
+                try
+                {
+                    core.TrySetCanceled();
+                }
+                catch (OperationCanceledException) { }
             }
         }
 
@@ -397,5 +532,121 @@ namespace Cysharp.Threading.Tasks
         {
             core.OnCompleted(continuation, state, token);
         }
+
+        // AsyncEnumerator
+
+        bool disableAutoClose;
+        Enumerator asyncEnumerator;
+
+        public AsyncUnityEventHandler<T> DisableAutoClose()
+        {
+            disableAutoClose = true;
+            return this;
+        }
+
+        IAsyncValueChangedEventHandler<T> IAsyncValueChangedEventHandler<T>.DisableAutoClose()
+        {
+            disableAutoClose = true;
+            return this;
+        }
+
+        IAsyncEndEditEventHandler<T> IAsyncEndEditEventHandler<T>.DisableAutoClose()
+        {
+            disableAutoClose = true;
+            return this;
+        }
+
+        IUniTaskAsyncEnumerator<T> IUniTaskAsyncEnumerable<T>.GetAsyncEnumerator(CancellationToken cancellationToken)
+        {
+            if (this.asyncEnumerator != null)
+            {
+                throw new InvalidOperationException("Already acquired GetAsyncEnumerator, does not allow get twice before previous enumerator completed.");
+            }
+
+            this.asyncEnumerator = new Enumerator(this, cancellationToken);
+            return asyncEnumerator;
+        }
+
+        class Enumerator : Cysharp.Threading.Tasks.Linq.MoveNextSource, IUniTaskAsyncEnumerator<T>
+        {
+            static Action<object> cancellationCallback = CancellationCallback;
+
+            AsyncUnityEventHandler<T> parent;
+            CancellationToken cancellationToken;
+            CancellationTokenRegistration registration;
+            bool isDisposed;
+
+            public Enumerator(AsyncUnityEventHandler<T> parent, CancellationToken cancellationToken)
+            {
+                this.parent = parent;
+                this.cancellationToken = cancellationToken;
+
+                if (cancellationToken.CanBeCanceled && parent.cancellationToken != cancellationToken)
+                {
+                    registration = cancellationToken.RegisterWithoutCaptureExecutionContext(cancellationCallback, this);
+                }
+
+                TaskTracker.TrackActiveTask(this, 3);
+            }
+
+            static void CancellationCallback(object state)
+            {
+                var self = (Enumerator)state;
+                self.DisposeCore(self.cancellationToken);
+            }
+
+            public void CancelFromParent(CancellationToken cancellationToken)
+            {
+                // call from parent, avoid parent close.
+                parent.disableAutoClose = true;
+                DisposeCore(cancellationToken);
+            }
+
+            public void SetResult(T result)
+            {
+                Current = result;
+                completionSource.TrySetResult(true);
+            }
+
+            public T Current { get; private set; }
+
+            public UniTask<bool> MoveNextAsync()
+            {
+                completionSource.Reset();
+                return new UniTask<bool>(this, completionSource.Version);
+            }
+
+            public UniTask DisposeAsync()
+            {
+                DisposeCore(CancellationToken.None);
+                return default;
+            }
+
+            void DisposeCore(CancellationToken cancellationToken)
+            {
+                if (!isDisposed)
+                {
+                    isDisposed = true;
+                    registration.Dispose();
+                    TaskTracker.RemoveTracking(this);
+
+                    if (!parent.disableAutoClose)
+                    {
+                        parent.Dispose(); // dispose parent.
+                    }
+
+                    if (parent.asyncEnumerator == this)
+                    {
+                        parent.asyncEnumerator = null;
+                    }
+
+                    try
+                    {
+                        completionSource.TrySetCanceled(cancellationToken);
+                    }
+                    catch (OperationCanceledException) { }
+                }
+            }
+        }
     }
 }
\ No newline at end of file
diff --git a/src/UniTask/Assets/Scenes/SandboxMain.cs b/src/UniTask/Assets/Scenes/SandboxMain.cs
index ff9c1e6..66a82bb 100644
--- a/src/UniTask/Assets/Scenes/SandboxMain.cs
+++ b/src/UniTask/Assets/Scenes/SandboxMain.cs
@@ -1,4 +1,5 @@
 using System;
+using Cysharp.Threading.Tasks.Linq;
 using Cysharp.Threading.Tasks.Triggers;
 using System.Collections;
 using System.Collections.Generic;
@@ -12,7 +13,6 @@ using Unity.Jobs;
 using UnityEngine;
 using UnityEngine.Networking;
 using UnityEngine.UI;
-using Cysharp.Threading.Tasks.Linq;
 
 public struct MyJob : IJob
 {
@@ -105,16 +105,16 @@ public class SandboxMain : MonoBehaviour
 
     }
 
-    void Start()
+    async void Start()
     {
         Application.SetStackTraceLogType(LogType.Error, StackTraceLogType.Full);
         Application.SetStackTraceLogType(LogType.Exception, StackTraceLogType.Full);
 
         var playerLoop = UnityEngine.LowLevel.PlayerLoop.GetCurrentPlayerLoop();
-        ShowPlayerLoop.DumpPlayerLoop("Current", playerLoop);
+        //ShowPlayerLoop.DumpPlayerLoop("Current", playerLoop);
 
 
-        Update2().Forget();
+        //Update2().Forget();
 
         //RunStandardDelayAsync().Forget();
 
@@ -144,7 +144,6 @@ public class SandboxMain : MonoBehaviour
 
         //StartCoroutine(cor);
 
-        Debug.Log(EqualityComparer<MyEnum>.Default.GetType().FullName);
 
 
         //this.TryGetComponent(
@@ -163,12 +162,36 @@ public class SandboxMain : MonoBehaviour
         Application.logMessageReceived += Application_logMessageReceived;
 
 
-        UniTask<int> foo = UniTask.FromResult(10);
+
         // foo.Status.IsCanceled
 
 
+        // 5回クリックされるまで待つ、とか。
+        Debug.Log("Await start.");
+
+
+
+        await okButton.GetAsyncClickEventHandler().DisableAutoClose()
+            .Select((_, clickCount) => clickCount + 1)
+            .FirstAsync(x => x == 5);
+
+        Debug.Log("Click 5 times.");
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
 
-        Foo(foo);
 
         //ucs = new UniTaskCompletionSource();