diff --git a/DepthFirstScheduler/Editor.meta b/DepthFirstScheduler/Editor.meta
new file mode 100644
index 000000000..d8c297a96
--- /dev/null
+++ b/DepthFirstScheduler/Editor.meta
@@ -0,0 +1,9 @@
+fileFormatVersion: 2
+guid: cc0ab91a2011fcf4d925dd94bccdb243
+folderAsset: yes
+timeCreated: 1540294739
+licenseType: Free
+DefaultImporter:
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/DepthFirstScheduler/Editor/DepthFirstScheduler.cs b/DepthFirstScheduler/Editor/DepthFirstScheduler.cs
new file mode 100644
index 000000000..fe09df4dd
--- /dev/null
+++ b/DepthFirstScheduler/Editor/DepthFirstScheduler.cs
@@ -0,0 +1,24 @@
+using NUnit.Framework;
+using System.Linq;
+
+
+namespace DepthFirstScheduler
+{
+    public class DepthFirstScheduler
+    {
+        [Test]
+        public void ScheduleTreeTest()
+        {
+            var s = Schedulable.Create();
+
+            var tasks = s.GetRoot().Traverse().ToArray();
+            Assert.AreEqual(2, tasks.Length);
+
+            var task_int = s.AddTask(Scheduler.CurrentThread, () => 0);
+            task_int = task_int.ContinueWith(Scheduler.CurrentThread, _ => 1);
+
+            var status = s.Execute();
+            Assert.AreEqual(ExecutionStatus.Done, status);
+        }
+    }
+}
diff --git a/DepthFirstScheduler/Editor/DepthFirstScheduler.cs.meta b/DepthFirstScheduler/Editor/DepthFirstScheduler.cs.meta
new file mode 100644
index 000000000..8053a0ee4
--- /dev/null
+++ b/DepthFirstScheduler/Editor/DepthFirstScheduler.cs.meta
@@ -0,0 +1,12 @@
+fileFormatVersion: 2
+guid: 3003e87b5df13394eadfda925bb816e5
+timeCreated: 1540294752
+licenseType: Free
+MonoImporter:
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/DepthFirstScheduler/Functor.cs b/DepthFirstScheduler/Functor.cs
new file mode 100644
index 000000000..3ddf9fd97
--- /dev/null
+++ b/DepthFirstScheduler/Functor.cs
@@ -0,0 +1,192 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+namespace DepthFirstScheduler
+{
+    public enum ExecutionStatus
+    {
+        Unknown,
+        Done,
+        Continue, // coroutine or schedulable
+        Error,
+    }
+
+    public interface IFunctor<T>
+    {
+        T GetResult();
+        Exception GetError();
+        ExecutionStatus Execute();
+    }
+
+    #region Functor
+    public class Functor<T> : IFunctor<T>
+    {
+        T m_result;
+        public T GetResult()
+        {
+            return m_result;
+        }
+
+        Exception m_error;
+        public Exception GetError()
+        {
+            return m_error;
+        }
+
+        Action m_pred;
+        public Functor(Func<T> func)
+        {
+            m_pred = () => m_result = func();
+        }
+
+        public ExecutionStatus Execute()
+        {
+            try
+            {
+                m_pred();
+                return ExecutionStatus.Done;
+            }
+            catch (Exception ex)
+            {
+                m_error = ex;
+                return ExecutionStatus.Error;
+            }
+        }
+    }
+
+    public static class Functor
+    {
+        /// <summary>
+        /// 引数の型を隠蔽した実行器を生成する
+        /// </summary>
+        /// <typeparam name="S">引数の型</typeparam>
+        /// <typeparam name="T">結果の型</typeparam>
+        /// <param name="arg"></param>
+        /// <param name="pred"></param>
+        /// <returns></returns>
+        public static Functor<T> Create<S, T>(Func<S> arg, Func<S, T> pred)
+        {
+            return new Functor<T>(() => pred(arg()));
+        }
+    }
+    #endregion
+
+    #region CoroutineFunctor
+    public class CoroutineFunctor<T> : IFunctor<T>
+    {
+        T m_result;
+        public T GetResult()
+        {
+            return m_result;
+        }
+
+        Exception m_error;
+        public Exception GetError()
+        {
+            return m_error;
+        }
+
+        Func<T> m_arg;
+        Func<T, IEnumerator> m_starter;
+        Stack<IEnumerator> m_it;
+        public CoroutineFunctor(Func<T> arg, Func<T, IEnumerator> starter)
+        {
+            m_arg = arg;
+            m_starter = starter;
+        }
+
+        public ExecutionStatus Execute()
+        {
+            if (m_it == null)
+            {
+                m_result = m_arg();
+                m_it = new Stack<IEnumerator>();
+                m_it.Push(m_starter(m_result));
+            }
+
+            try
+            {
+                if (m_it.Count!=0)
+                {
+                    if (m_it.Peek().MoveNext())
+                    {
+                        var nested = m_it.Peek().Current as IEnumerator;
+                        if (nested!=null)
+                        {
+                            m_it.Push(nested);
+                        }
+                    }
+                    else
+                    {
+                        m_it.Pop();
+                    }
+                    return ExecutionStatus.Continue;
+                }
+                else
+                {
+                    return ExecutionStatus.Done;
+                }
+
+            }
+            catch(Exception ex)
+            {
+                m_error = ex;
+                return ExecutionStatus.Error;
+            }
+        }
+    }
+
+    public static class CoroutineFunctor
+    {
+        public static CoroutineFunctor<T> Create<T>(Func<T> arg, Func<T, IEnumerator> starter)
+        {
+            return new CoroutineFunctor<T>(arg, starter);
+        }
+    }
+    #endregion
+
+    /*
+    public class SchedulableFunctor<T> : IFunctor<T>
+    {
+        Schedulable<T> m_schedulable;
+        Func<Schedulable<T>> m_starter;
+        TaskChain m_chain;
+
+        public SchedulableFunctor(Func<Schedulable<T>> starter)
+        {
+            m_starter = starter;
+        }
+
+        public ExecutionStatus Execute()
+        {
+            if (m_chain == null)
+            {
+                m_schedulable = m_starter();
+                m_chain = TaskChain.Schedule(m_schedulable, ex => m_error = ex);
+            }
+
+            return m_chain.Next();
+        }
+
+        Exception m_error;
+        public Exception GetError()
+        {
+            return m_error;
+        }
+
+        public T GetResult()
+        {
+            return m_schedulable.Func.GetResult();
+        }
+    }
+
+    public static class SchedulableFunctor
+    {
+        public static SchedulableFunctor<T> Create<T>(Func<Schedulable<T>> starter)
+        {
+            return new SchedulableFunctor<T>(starter);
+        }
+    }
+    */
+}
diff --git a/DepthFirstScheduler/Functor.cs.meta b/DepthFirstScheduler/Functor.cs.meta
new file mode 100644
index 000000000..713019b19
--- /dev/null
+++ b/DepthFirstScheduler/Functor.cs.meta
@@ -0,0 +1,12 @@
+fileFormatVersion: 2
+guid: c320f3f577dde634a871dc88266c2a20
+timeCreated: 1520084196
+licenseType: Free
+MonoImporter:
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/DepthFirstScheduler/IEnumeratorExtensions.cs b/DepthFirstScheduler/IEnumeratorExtensions.cs
new file mode 100644
index 000000000..2d11c0ebc
--- /dev/null
+++ b/DepthFirstScheduler/IEnumeratorExtensions.cs
@@ -0,0 +1,31 @@
+using System.Collections;
+using System.Collections.Generic;
+
+
+namespace
+    DepthFirstScheduler
+{
+    public static class IEnumeratorExtensions
+    {
+        public static void CoroutinetoEnd(this IEnumerator coroutine)
+        {
+            var stack = new Stack<IEnumerator>();
+            stack.Push(coroutine);
+            while (stack.Count > 0)
+            {
+                if (stack.Peek().MoveNext())
+                {
+                    var nested = stack.Peek().Current as IEnumerator;
+                    if (nested != null)
+                    {
+                        stack.Push(nested);
+                    }
+                }
+                else
+                {
+                    stack.Pop();
+                }
+            }
+        }
+    }
+}
diff --git a/DepthFirstScheduler/IEnumeratorExtensions.cs.meta b/DepthFirstScheduler/IEnumeratorExtensions.cs.meta
new file mode 100644
index 000000000..b8a9f110a
--- /dev/null
+++ b/DepthFirstScheduler/IEnumeratorExtensions.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 4719fc9e6319c654b8a4818bef2c3a85
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/DepthFirstScheduler/LICENSE b/DepthFirstScheduler/LICENSE
new file mode 100644
index 000000000..3299d454f
--- /dev/null
+++ b/DepthFirstScheduler/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2018 ousttrue
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/DepthFirstScheduler/LICENSE.meta b/DepthFirstScheduler/LICENSE.meta
new file mode 100644
index 000000000..2ea0914dd
--- /dev/null
+++ b/DepthFirstScheduler/LICENSE.meta
@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: b673d33707cbc5446870804437f3cbea
+timeCreated: 1535290899
+licenseType: Free
+DefaultImporter:
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/DepthFirstScheduler/LockQueue.cs b/DepthFirstScheduler/LockQueue.cs
new file mode 100644
index 000000000..22f88ddd1
--- /dev/null
+++ b/DepthFirstScheduler/LockQueue.cs
@@ -0,0 +1,95 @@
+using System.Collections;
+using System.Collections.Generic;
+
+
+namespace DepthFirstScheduler
+{
+    public class LockQueue<T> where T : class
+    {
+        List<T> m_queue = new List<T>();
+        public int Count
+        {
+            get
+            {
+                lock (((ICollection)m_queue).SyncRoot)
+                {
+                    return m_queue.Count;
+                }
+            }
+        }
+
+        public void Enqueue(T t)
+        {
+            lock (((ICollection)m_queue).SyncRoot)
+            {
+                m_queue.Add(t);
+            }
+        }
+
+        public T Dequeue(out int remain)
+        {
+            lock (((ICollection)m_queue).SyncRoot)
+            {
+                if (m_queue.Count == 0)
+                {
+                    remain = 0;
+                    return null;
+                }
+                var item = m_queue[0];
+                m_queue.RemoveAt(0);
+                remain = m_queue.Count;
+                return item;
+            }
+        }
+
+        public T Dequeue()
+        {
+            lock (((ICollection)m_queue).SyncRoot)
+            {
+                if (m_queue.Count == 0) return null;
+                var item = m_queue[0];
+                m_queue.RemoveAt(0);
+                return item;
+            }
+        }
+    }
+
+    public class LockQueueForValue<T> where T : struct
+    {
+        List<T> m_queue = new List<T>();
+        public int Count
+        {
+            get
+            {
+                lock (((ICollection)m_queue).SyncRoot)
+                {
+                    return m_queue.Count;
+                }
+            }
+        }
+
+        public void Enqueue(T t)
+        {
+            lock (((ICollection)m_queue).SyncRoot)
+            {
+                m_queue.Add(t);
+            }
+        }
+
+        public bool TryDequeue(out T t)
+        {
+            lock (((ICollection)m_queue).SyncRoot)
+            {
+                if (m_queue.Count == 0)
+                {
+                    t = default(T);
+                    return false;
+                }
+
+                t = m_queue[0];
+                m_queue.RemoveAt(0);
+                return true;
+            }
+        }
+    }
+}
diff --git a/DepthFirstScheduler/LockQueue.cs.meta b/DepthFirstScheduler/LockQueue.cs.meta
new file mode 100644
index 000000000..cc5d5cfa9
--- /dev/null
+++ b/DepthFirstScheduler/LockQueue.cs.meta
@@ -0,0 +1,12 @@
+fileFormatVersion: 2
+guid: f6b1eb436e400704ab6e2ad6eff29f4b
+timeCreated: 1519978475
+licenseType: Free
+MonoImporter:
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/DepthFirstScheduler/MainThreadDispatcher.cs b/DepthFirstScheduler/MainThreadDispatcher.cs
new file mode 100644
index 000000000..ee2bdcfc4
--- /dev/null
+++ b/DepthFirstScheduler/MainThreadDispatcher.cs
@@ -0,0 +1,150 @@
+using System;
+using System.Collections.Generic;
+using UnityEngine;
+
+namespace DepthFirstScheduler
+{
+    /// <summary>
+    /// UniRxのMainThreadDispatcherを参考にした。
+    /// * https://github.com/neuecc/UniRx/blob/master/Assets/Plugins/UniRx/Scripts/UnityEngineBridge/MainThreadDispatcher.cs
+    /// </summary>
+    public class MainThreadDispatcher : MonoBehaviour
+    {
+
+        [Header("Debug")]
+        public int TaskCount;
+
+        IEnumerable<Transform> Ancestors(Transform t)
+        {
+            yield return t;
+
+            if (t.parent != null)
+            {
+                foreach (var x in Ancestors(t.parent))
+                {
+                    yield return x;
+                }
+            }
+        }
+
+        private void Update()
+        {
+            TaskCount = Scheduler.MainThread.UpdateAndGetTaskCount();
+        }
+
+        static MainThreadDispatcher instance;
+        static bool initialized;
+        static bool isQuitting = false;
+
+        public static bool IsInitialized
+        {
+            get { return initialized && instance != null; }
+        }
+
+        [ThreadStatic]
+        static object mainThreadToken;
+
+        public static MainThreadDispatcher Instance
+        {
+            get
+            {
+                Initialize();
+                return instance;
+            }
+        }
+
+        public static void Initialize()
+        {
+            if (!initialized)
+            {
+#if UNITY_EDITOR
+                if (!Application.isPlaying)
+                {
+                    return;
+                }
+#endif
+                MainThreadDispatcher dispatcher = null;
+
+                try
+                {
+                    dispatcher = GameObject.FindObjectOfType<MainThreadDispatcher>();
+                }
+                catch
+                {
+                    // Throw exception when calling from a worker thread.
+                    var ex = new Exception(
+                        "DepthFirstScheduler requires a MainThreadDispatcher component created on the main thread."
+                        + " Make sure it is added to the scene before calling DepthFirstScheduler from a worker thread.");
+                    UnityEngine.Debug.LogException(ex);
+                    throw ex;
+                }
+
+                if (isQuitting)
+                {
+                    // don't create new instance after quitting
+                    // avoid "Some objects were not cleaned up when closing the scene find target" error.
+                    return;
+                }
+
+                if (dispatcher == null)
+                {
+                    // awake call immediately from UnityEngine
+                    new GameObject("DepthFirstScheduler").AddComponent<MainThreadDispatcher>();
+                }
+                else
+                {
+                    dispatcher.Awake(); // force awake
+                }
+            }
+        }
+
+        public static bool IsInMainThread
+        {
+            get
+            {
+                return (mainThreadToken != null);
+            }
+        }
+
+
+        void Awake()
+        {
+            if (instance == null)
+            {
+                Debug.Log("Initialize UniTask.MainThredDispatcher");
+
+                instance = this;
+                mainThreadToken = new object();
+                initialized = true;
+
+                DontDestroyOnLoad(gameObject);
+            }
+            else
+            {
+                if (this != instance)
+                {
+                    Debug.LogWarning("There is already a MainThreadDispatcher in the scene.");
+                }
+            }
+        }
+
+        void OnDestroy()
+        {
+            if (instance == this)
+            {
+                instance = GameObject.FindObjectOfType<MainThreadDispatcher>();
+                initialized = instance != null;
+            }
+
+            if (Scheduler.SingleWorkerThread != null)
+            {
+                Scheduler.SingleWorkerThread.Dispose();
+            }
+        }
+
+        void OnApplicationQuit()
+        {
+            isQuitting = true;
+        }
+    }
+}
diff --git a/DepthFirstScheduler/MainThreadDispatcher.cs.meta b/DepthFirstScheduler/MainThreadDispatcher.cs.meta
new file mode 100644
index 000000000..5777e1aba
--- /dev/null
+++ b/DepthFirstScheduler/MainThreadDispatcher.cs.meta
@@ -0,0 +1,12 @@
+fileFormatVersion: 2
+guid: b030a9507e46dd3488c080be0227b219
+timeCreated: 1519977925
+licenseType: Free
+MonoImporter:
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/DepthFirstScheduler/MonitorQueue.cs b/DepthFirstScheduler/MonitorQueue.cs
new file mode 100644
index 000000000..ace9ef219
--- /dev/null
+++ b/DepthFirstScheduler/MonitorQueue.cs
@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Generic;
+using System.Threading;
+
+
+namespace DepthFirstScheduler
+{
+    /// <summary>
+    /// http://blogs.msdn.com/b/toub/archive/2006/04/12/blocking-queues.aspx
+    /// 
+    /// 終了を通知するにはnullを投入する手が使える
+    /// </summary>
+    /// <typeparam name="T"></typeparam>
+    public class MonitorQueue<T>
+    {
+        private Int32 _count = 0;
+        public Int32 Count
+        {
+            get
+            {
+                return _count;
+            }
+        }
+
+        private Queue<T> _queue = new Queue<T>();
+
+        public T Dequeue()
+        {
+            lock (_queue)
+            {
+                while (_count <= 0) Monitor.Wait(_queue);
+                _count--;
+                return _queue.Dequeue();
+            }
+        }
+
+        public void Enqueue(T data)
+        {
+            lock (_queue)
+            {
+                _queue.Enqueue(data);
+                _count++;
+                Monitor.Pulse(_queue);
+            }
+        }
+    }
+}
diff --git a/DepthFirstScheduler/MonitorQueue.cs.meta b/DepthFirstScheduler/MonitorQueue.cs.meta
new file mode 100644
index 000000000..2b6391747
--- /dev/null
+++ b/DepthFirstScheduler/MonitorQueue.cs.meta
@@ -0,0 +1,12 @@
+fileFormatVersion: 2
+guid: 5e968e04ff53e1c4a9a2869b7cf76055
+timeCreated: 1519990411
+licenseType: Free
+MonoImporter:
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/DepthFirstScheduler/README.md b/DepthFirstScheduler/README.md
new file mode 100644
index 000000000..f62408945
--- /dev/null
+++ b/DepthFirstScheduler/README.md
@@ -0,0 +1,66 @@
+# DepthFirstScheduler(深さ優先スケジューラー)
+Asynchronous task scheduler for Unity-5.6 or later
+
+これは、Unity5.6でTaskが無いことを補完するためのライブラリです。
+木構造にタスクを組み立てて深さ優先で消化します。
+
+* タスクの実行スケジューラー(Unityメインスレッドやスレッドプール)を指定できる
+
+# 使い方
+
+```cs
+var schedulable = new Schedulable<Unit>();
+
+schedulable
+    .AddTask(Scheduler.ThreadPool, () => // 子供のタスクを追加する
+    {
+        return glTF_VRM_Material.Parse(ctx.Json);
+    })
+    .ContinueWith(Scheduler.MainThread, gltfMaterials => // 兄弟のタスクを追加する
+    {
+        ctx.MaterialImporter = new VRMMaterialImporter(ctx, gltfMaterials);
+    })
+    .Subscribe(Scheduler.MainThread, onLoaded, onError);
+    ;
+```
+
+# Schedulable<T>
+T型の結果を返すタスク。
+
+## AddTask(IScheduler scheduler, Func<T> firstTask) 
+
+子供のタスクを追加する。
+
+ToDo: 一つ目の子供に引数を渡す手段が無い
+
+## ContinueWith
+
+## ContinueWithCoroutine
+
+## OnExecute
+
+動的にタスクを追加するためのHook。
+
+中で、
+
+```
+parent.AddTask
+```
+
+することで実行時に子タスクを追加できる。
+
+## Subscribe
+タスクの実行を開始する。
+実行結果を得る。
+
+
+# Scheduler
+## StepScheduler
+Unity
+## CurrentThreadScheduler
+即時
+## ThreadPoolScheduler
+スレッド
+## ThreadScheduler
+スレッド
+
diff --git a/DepthFirstScheduler/README.md.meta b/DepthFirstScheduler/README.md.meta
new file mode 100644
index 000000000..7d1cb78be
--- /dev/null
+++ b/DepthFirstScheduler/README.md.meta
@@ -0,0 +1,8 @@
+fileFormatVersion: 2
+guid: 1231fa531fdd33f4baccc935c18c0872
+timeCreated: 1535290899
+licenseType: Free
+DefaultImporter:
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/DepthFirstScheduler/Schedulable.cs b/DepthFirstScheduler/Schedulable.cs
new file mode 100644
index 000000000..96a198d1d
--- /dev/null
+++ b/DepthFirstScheduler/Schedulable.cs
@@ -0,0 +1,241 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+#if ((NET_4_6 || NET_STANDARD_2_0) && UNITY_2017_1_OR_NEWER)
+using System.Threading.Tasks;
+#endif
+
+namespace DepthFirstScheduler
+{
+    public interface ISchedulable
+    {
+        /// <returns>実行が終了したか？Coroutineの実行が一回で終わらない場合がある</returns>
+        ExecutionStatus Execute();
+        Exception GetError();
+        IScheduler Schedulder { get; }
+
+        ISchedulable Parent { get; set; }
+        void AddChild(ISchedulable child);
+        IEnumerable<ISchedulable> Traverse();
+    }
+
+    public static class ISchedulableExtensions
+    {
+        public static ISchedulable GetRoot(this ISchedulable self)
+        {
+            var current = self;
+            while (current.Parent != null)
+            {
+                current = current.Parent;
+            }
+            return current;
+        }
+    }
+
+    public class NoParentException: Exception
+    {              
+        public NoParentException():base("No parent task can't ContinueWith or OnExecute. First AddTask")
+        {
+        }
+    }
+
+    public class Schedulable<T> : ISchedulable
+    {
+        List<ISchedulable> m_children = new List<ISchedulable>();
+        public void AddChild(ISchedulable child)
+        {
+            child.Parent = this;
+            m_children.Add(child);
+        }
+        public IEnumerable<ISchedulable> Traverse()
+        {
+            yield return this;
+
+            foreach (var child in m_children)
+            {
+                foreach (var x in child.Traverse())
+                {
+                    yield return x;
+                }
+            }
+        }
+
+        public ISchedulable Parent
+        {
+            get;
+            set;
+        }
+
+        public IScheduler Schedulder
+        {
+            get;
+            private set;
+        }
+
+        public IFunctor<T> Func
+        {
+            get;
+            private set;
+        }
+
+        public Exception GetError()
+        {
+            return Func.GetError();
+        }
+
+        public Schedulable()
+        {
+        }
+
+        public Schedulable(IScheduler scheduler, IFunctor<T> func)
+        {
+            Schedulder = scheduler;
+            Func = func;
+        }
+
+        public ExecutionStatus Execute()
+        {
+            if (Func == null)
+            {
+                return ExecutionStatus.Done;
+            }
+            return Func.Execute();
+        }
+
+        /// <summary>
+        /// スケジュールされたタスクをすべて即時に実行する
+        /// </summary>
+        public void ExecuteAll()
+        {
+            foreach (var x in this.GetRoot().Traverse())
+            {
+                while (true)
+                {
+                    var status = x.Execute();
+                    if (status != ExecutionStatus.Continue)
+                    {
+                        if (status == ExecutionStatus.Error)
+                        {
+                            throw x.GetError();
+                        }
+                        break;
+                    }
+                    // Coroutineタスクが継続している
+                }
+            }
+        }
+
+        public Schedulable<Unit> AddTask(IScheduler scheduler, Action pred)
+        {
+            return AddTask(scheduler, () => { pred(); return Unit.Default; });
+        }
+
+        public Schedulable<U> AddTask<U>(IScheduler scheduler, Func<U> pred)
+        {
+            var schedulable = new Schedulable<U>(scheduler, Functor.Create(() => Unit.Default, _ => pred()));
+            AddChild(schedulable);
+            return schedulable;
+        }
+
+        public Schedulable<T> AddCoroutine(IScheduler scheduler, Func<IEnumerator> starter)
+        {
+            var func = CoroutineFunctor.Create(() => default(T), _ => starter());
+            var schedulable = new Schedulable<T>(scheduler, func);
+            AddChild(schedulable);
+            return schedulable;
+        }
+
+        public Schedulable<Unit> ContinueWith(IScheduler scheduler, Action<T> pred)
+        {
+            return ContinueWith(scheduler, t => { pred(t); return Unit.Default; });
+        }
+
+        public Schedulable<U> ContinueWith<U>(IScheduler scheduler, Func<T, U> pred)
+        {
+            if (Parent == null)
+            {
+                throw new NoParentException();
+            }
+
+            Func<T> getResult = null;
+            if (Func != null)
+            {
+                getResult = Func.GetResult;
+            }
+            var func = Functor.Create(getResult, pred);
+            var schedulable = new Schedulable<U>(scheduler, func);
+            Parent.AddChild(schedulable);
+            return schedulable;
+        }
+
+        public Schedulable<T> ContinueWithCoroutine(IScheduler scheduler, Func<IEnumerator> starter)
+        {
+            if (Parent == null)
+            {
+                throw new NoParentException();
+            }
+
+            var func = CoroutineFunctor.Create(() => default(T), _ => starter());
+            var schedulable = new Schedulable<T>(scheduler, func);
+            Parent.AddChild(schedulable);
+            return schedulable;
+        }
+
+        public Schedulable<Unit> OnExecute(IScheduler scheduler, Action<Schedulable<Unit>> pred)
+        {
+            if (Parent == null)
+            {
+                throw new NoParentException();
+            }
+
+            Func<T> getResult = null;
+            if (Func != null)
+            {
+                getResult = Func.GetResult;
+            }
+
+            var schedulable = new Schedulable<Unit>();
+            schedulable.Func = Functor.Create(getResult, _ => { pred(schedulable); return Unit.Default; });
+            Parent.AddChild(schedulable);
+            return schedulable;
+        }
+    }
+
+    public static class Schedulable
+    {
+        public static Schedulable<Unit> Create()
+        {
+            return new Schedulable<Unit>().AddTask(Scheduler.CurrentThread, () =>
+            {
+            });
+        }
+    }
+
+    public static class SchedulableExtensions
+    {
+        public static void Subscribe<T>(
+            this Schedulable<T> schedulable,
+            IScheduler scheduler,
+            Action<T> onCompleted,
+            Action<Exception> onError)
+        {
+            schedulable.ContinueWith(scheduler, onCompleted);
+            TaskChain.Schedule(schedulable.GetRoot(), onError);
+        }
+
+#if ((NET_4_6 || NET_STANDARD_2_0) && UNITY_2017_1_OR_NEWER)
+        public static Task<T> ToTask<T>(this Schedulable<T> schedulable)
+        {
+            return ToTask(schedulable, Scheduler.MainThread);
+        }
+
+        public static Task<T> ToTask<T>(this Schedulable<T> schedulable, IScheduler scheduler)
+        {
+            var tcs = new TaskCompletionSource<T>();
+            schedulable.Subscribe(scheduler, r => tcs.TrySetResult(r), ex => tcs.TrySetException(ex));
+            return tcs.Task;
+        }
+#endif
+
+    }
+}
diff --git a/DepthFirstScheduler/Schedulable.cs.meta b/DepthFirstScheduler/Schedulable.cs.meta
new file mode 100644
index 000000000..439f4a26b
--- /dev/null
+++ b/DepthFirstScheduler/Schedulable.cs.meta
@@ -0,0 +1,12 @@
+fileFormatVersion: 2
+guid: 45e21e7db278f344fbaeffc4c4b82b1e
+timeCreated: 1519981307
+licenseType: Free
+MonoImporter:
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
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diff --git a/DepthFirstScheduler/Scheduler.cs b/DepthFirstScheduler/Scheduler.cs
new file mode 100644
index 000000000..20ae4d4a1
--- /dev/null
+++ b/DepthFirstScheduler/Scheduler.cs
@@ -0,0 +1,9 @@
+using System;
+
+namespace DepthFirstScheduler
+{
+    public interface IScheduler : IDisposable
+    {
+        void Enqueue(TaskChain item);
+    }
+}
diff --git a/DepthFirstScheduler/Scheduler.cs.meta b/DepthFirstScheduler/Scheduler.cs.meta
new file mode 100644
index 000000000..38b437574
--- /dev/null
+++ b/DepthFirstScheduler/Scheduler.cs.meta
@@ -0,0 +1,12 @@
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+  executionOrder: 0
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diff --git a/DepthFirstScheduler/Scheduler.meta b/DepthFirstScheduler/Scheduler.meta
new file mode 100644
index 000000000..efdb87bad
--- /dev/null
+++ b/DepthFirstScheduler/Scheduler.meta
@@ -0,0 +1,8 @@
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diff --git a/DepthFirstScheduler/Scheduler/CurrentThreadScheduler.cs b/DepthFirstScheduler/Scheduler/CurrentThreadScheduler.cs
new file mode 100644
index 000000000..2fa03e26b
--- /dev/null
+++ b/DepthFirstScheduler/Scheduler/CurrentThreadScheduler.cs
@@ -0,0 +1,102 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+
+namespace DepthFirstScheduler
+{
+    public static partial class Scheduler
+    {
+        private static IScheduler currentThread;
+
+        public static IScheduler CurrentThread
+        {
+            get { return currentThread ?? (currentThread = new CurrentThreadScheduler()); }
+        }
+
+        public class CurrentThreadScheduler : IScheduler
+        {
+            [ThreadStatic]
+            private static Queue<TaskChain> queue;
+
+            private static Queue<TaskChain> GetQueue()
+            {
+                return queue;
+            }
+
+            private static void SetQueue(Queue<TaskChain> newQueue)
+            {
+                queue = newQueue;
+            }
+
+            public void Enqueue(TaskChain item)
+            {
+                var q = GetQueue();
+
+                if (q == null)
+                {
+                    q = new Queue<TaskChain>(5);
+                    q.Enqueue(item);
+                    SetQueue(q);
+
+                    try
+                    {
+                        Trampoline.Run(q);
+                    }
+                    finally
+                    {
+                        SetQueue(null);
+                    }
+                }
+                else
+                {
+                    q.Enqueue(item);
+                }
+            }
+
+            #region IDisposable Support
+
+            private bool disposedValue = false;
+
+            protected virtual void Dispose(bool disposing)
+            {
+                if (!disposedValue)
+                {
+                    if (disposing)
+                    {
+                        var queue = GetQueue();
+                        if (queue != null) queue.Clear();
+                        SetQueue(null);
+                    }
+                    disposedValue = true;
+                }
+            }
+
+            public void Dispose()
+            {
+                Dispose(true);
+            }
+
+            #endregion
+        }
+
+        static class Trampoline
+        {
+            public static void Run(Queue<TaskChain> queue)
+            {
+                while (queue.Count > 0)
+                {
+                    var chain = queue.Dequeue();
+
+                    while (true)
+                    {
+                        var status = chain.Next();
+                        if (status != ExecutionStatus.Continue)
+                        {
+                            break;
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/DepthFirstScheduler/Scheduler/CurrentThreadScheduler.cs.meta b/DepthFirstScheduler/Scheduler/CurrentThreadScheduler.cs.meta
new file mode 100644
index 000000000..57b7907fd
--- /dev/null
+++ b/DepthFirstScheduler/Scheduler/CurrentThreadScheduler.cs.meta
@@ -0,0 +1,11 @@
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+guid: 21979cc7137a17d4ea8b6202381a02d0
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diff --git a/DepthFirstScheduler/Scheduler/StepScheduler.cs b/DepthFirstScheduler/Scheduler/StepScheduler.cs
new file mode 100644
index 000000000..e5406ebe0
--- /dev/null
+++ b/DepthFirstScheduler/Scheduler/StepScheduler.cs
@@ -0,0 +1,52 @@
+namespace DepthFirstScheduler
+{
+    public static partial class Scheduler
+    {
+        private static StepScheduler mainThread;
+
+        public static StepScheduler MainThread
+        {
+            get
+            {
+                if (mainThread != null) return mainThread;
+                mainThread = new StepScheduler();
+                MainThreadDispatcher.Initialize();
+                return mainThread;
+            }
+        }
+
+        public class StepScheduler : IScheduler
+        {
+            LockQueue<TaskChain> m_taskQueue = new LockQueue<TaskChain>();
+
+            public void Enqueue(TaskChain item)
+            {
+                m_taskQueue.Enqueue(item);
+            }
+
+            TaskChain m_chain;
+
+            public int UpdateAndGetTaskCount()
+            {
+                if (m_chain != null)
+                {
+                    var status = m_chain.Next();
+                    if (status == ExecutionStatus.Continue)
+                    {
+                        // m_item継続中
+                        return m_taskQueue.Count;
+                    }
+                    m_chain = null;
+                }
+
+                int count;
+                m_chain = m_taskQueue.Dequeue(out count);
+                return count;
+            }
+
+            public void Dispose()
+            {
+            }
+        }
+    }
+}
diff --git a/DepthFirstScheduler/Scheduler/StepScheduler.cs.meta b/DepthFirstScheduler/Scheduler/StepScheduler.cs.meta
new file mode 100644
index 000000000..f5e8c0920
--- /dev/null
+++ b/DepthFirstScheduler/Scheduler/StepScheduler.cs.meta
@@ -0,0 +1,12 @@
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+guid: 84161938c020c37419bc79f021f849fb
+timeCreated: 1520062584
+licenseType: Free
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+  serializedVersion: 2
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+  executionOrder: 0
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diff --git a/DepthFirstScheduler/Scheduler/ThreadPoolScheduler.cs b/DepthFirstScheduler/Scheduler/ThreadPoolScheduler.cs
new file mode 100644
index 000000000..6c2dbea93
--- /dev/null
+++ b/DepthFirstScheduler/Scheduler/ThreadPoolScheduler.cs
@@ -0,0 +1,42 @@
+using System;
+
+namespace DepthFirstScheduler
+{
+    public static partial class Scheduler
+    {
+        private static IScheduler threadPool;
+
+        public static IScheduler ThreadPool
+        {
+            get { return threadPool ?? (threadPool = new ThreadPoolScheduler()); }
+        }
+
+        public class ThreadPoolScheduler : IScheduler
+        {
+            public void Enqueue(TaskChain item)
+            {
+                System.Threading.ThreadPool.QueueUserWorkItem(_ =>
+                {
+                    if (item == null)
+                    {
+                        return;
+                    }
+
+                    while (true)
+                    {
+                        var status = item.Next();
+                        if (status != ExecutionStatus.Continue)
+                        {
+                            break;
+                        }
+                    }
+
+                });
+            }
+
+            public void Dispose()
+            {
+            }
+        }
+    }
+}
diff --git a/DepthFirstScheduler/Scheduler/ThreadPoolScheduler.cs.meta b/DepthFirstScheduler/Scheduler/ThreadPoolScheduler.cs.meta
new file mode 100644
index 000000000..42a8066ec
--- /dev/null
+++ b/DepthFirstScheduler/Scheduler/ThreadPoolScheduler.cs.meta
@@ -0,0 +1,12 @@
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+timeCreated: 1524110819
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diff --git a/DepthFirstScheduler/Scheduler/ThreadScheduler.cs b/DepthFirstScheduler/Scheduler/ThreadScheduler.cs
new file mode 100644
index 000000000..0c44c5507
--- /dev/null
+++ b/DepthFirstScheduler/Scheduler/ThreadScheduler.cs
@@ -0,0 +1,101 @@
+using System;
+using System.Threading;
+
+namespace DepthFirstScheduler
+{
+    public static partial class Scheduler
+    {
+        private static IScheduler singleWorkerThread;
+
+        public static IScheduler SingleWorkerThread
+        {
+            get { return singleWorkerThread ?? (singleWorkerThread = new ThreadScheduler()); }
+        }
+
+        public class ThreadScheduler : IScheduler
+        {
+            MonitorQueue<TaskChain> m_queue = new MonitorQueue<TaskChain>();
+
+            Thread m_thread;
+
+            public ThreadScheduler()
+            {
+                // start worker thread
+                m_thread = new Thread(new ParameterizedThreadStart(Worker));
+                m_thread.Start(m_queue);
+            }
+
+            static void Worker(Object arg)
+            {
+                MonitorQueue<TaskChain> queue = (MonitorQueue<TaskChain>)arg;
+                while (true)
+                {
+                    var chain = queue.Dequeue();
+                    if (chain == null)
+                    {
+                        break;
+                    }
+
+                    while (true)
+                    {
+                        var status = chain.Next();
+                        if (status != ExecutionStatus.Continue)
+                        {
+                            break;
+                        }
+                    }
+                }
+
+                // end
+            }
+
+            public void Enqueue(TaskChain item)
+            {
+                m_queue.Enqueue(item);
+            }
+
+            #region IDisposable Support
+
+            private bool disposedValue = false; // 重複する呼び出しを検出するには
+
+            protected virtual void Dispose(bool disposing)
+            {
+                if (!disposedValue)
+                {
+                    if (disposing)
+                    {
+                        // TODO: マネージ状態を破棄します (マネージ オブジェクト)。
+                        if (m_thread != null)
+                        {
+                            m_queue.Enqueue(null);
+                            m_thread.Join();
+                            m_thread = null;
+                        }
+                    }
+
+                    // TODO: アンマネージ リソース (アンマネージ オブジェクト) を解放し、下のファイナライザーをオーバーライドします。
+                    // TODO: 大きなフィールドを null に設定します。
+
+                    disposedValue = true;
+                }
+            }
+
+            // TODO: 上の Dispose(bool disposing) にアンマネージ リソースを解放するコードが含まれる場合にのみ、ファイナライザーをオーバーライドします。
+            // ~ThreadScheduler() {
+            //   // このコードを変更しないでください。クリーンアップ コードを上の Dispose(bool disposing) に記述します。
+            //   Dispose(false);
+            // }
+
+            // このコードは、破棄可能なパターンを正しく実装できるように追加されました。
+            public void Dispose()
+            {
+                // このコードを変更しないでください。クリーンアップ コードを上の Dispose(bool disposing) に記述します。
+                Dispose(true);
+                // TODO: 上のファイナライザーがオーバーライドされる場合は、次の行のコメントを解除してください。
+                // GC.SuppressFinalize(this);
+            }
+
+            #endregion
+        }
+    }
+}
diff --git a/DepthFirstScheduler/Scheduler/ThreadScheduler.cs.meta b/DepthFirstScheduler/Scheduler/ThreadScheduler.cs.meta
new file mode 100644
index 000000000..9e4cb5569
--- /dev/null
+++ b/DepthFirstScheduler/Scheduler/ThreadScheduler.cs.meta
@@ -0,0 +1,12 @@
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+guid: 8df1de98bdc0b534bbe68e8f2f8a858f
+timeCreated: 1520062592
+licenseType: Free
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+  serializedVersion: 2
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diff --git a/DepthFirstScheduler/TaskChain.cs b/DepthFirstScheduler/TaskChain.cs
new file mode 100644
index 000000000..7928e5bd6
--- /dev/null
+++ b/DepthFirstScheduler/TaskChain.cs
@@ -0,0 +1,91 @@
+using System;
+using System.Linq;
+using System.Collections.Generic;
+
+
+namespace DepthFirstScheduler
+{
+    public enum ChainStatus
+    {
+        Unknown,
+        Continue,
+        Done,
+        Error,
+    }
+
+    public class TaskChain
+    {
+        public IEnumerator<ISchedulable> Enumerator;
+        public Action<Exception> OnError;
+        public ChainStatus ChainStatus;
+
+        public static TaskChain Schedule(ISchedulable schedulable, Action<Exception> onError)
+        {
+            var item = new TaskChain
+            {
+                Enumerator = schedulable.Traverse().GetEnumerator(),
+                OnError = onError
+            };
+
+            if (item.Enumerator.MoveNext())
+            {
+                if (item.Enumerator.Current.Schedulder == null)
+                {
+                    // default
+                    Scheduler.MainThread.Enqueue(item);
+                }
+                else
+                {
+                    item.Enumerator.Current.Schedulder.Enqueue(item);
+                }
+            }
+
+            return item;
+        }
+
+        /// <summary>
+        /// 
+        /// </summary>
+        /// <returns></returns>
+        public ExecutionStatus Next()
+        {
+            if (this.ChainStatus == ChainStatus.Done
+                || this.ChainStatus== ChainStatus.Error)
+            {
+                return ExecutionStatus.Done;
+            }
+
+            {
+                var status = Enumerator.Current.Execute();
+                if (status == ExecutionStatus.Error)
+                {
+                    ChainStatus = ChainStatus.Error;
+                    OnError(Enumerator.Current.GetError());
+                }
+                if (status == ExecutionStatus.Continue)
+                {
+                    // 中断(coroutine)
+                    ChainStatus = ChainStatus.Continue;
+                    return ExecutionStatus.Continue;
+                }
+            }
+
+            if (!Enumerator.MoveNext())
+            {
+                // 終了
+                ChainStatus = ChainStatus.Done;
+                return ExecutionStatus.Done;
+            }
+
+            if (Enumerator.Current.Schedulder != null)
+            {
+                // Scheduleして中断
+                ChainStatus = ChainStatus.Continue;
+                Enumerator.Current.Schedulder.Enqueue(this);
+                return ExecutionStatus.Done;
+            }
+
+            return Next();
+        }
+    }
+}
diff --git a/DepthFirstScheduler/TaskChain.cs.meta b/DepthFirstScheduler/TaskChain.cs.meta
new file mode 100644
index 000000000..e50b9f19b
--- /dev/null
+++ b/DepthFirstScheduler/TaskChain.cs.meta
@@ -0,0 +1,12 @@
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+guid: 38fc7e076ba93a847ad72d3d459d06b6
+timeCreated: 1520084019
+licenseType: Free
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+  serializedVersion: 2
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diff --git a/DepthFirstScheduler/Unit.cs b/DepthFirstScheduler/Unit.cs
new file mode 100644
index 000000000..c3a041d1e
--- /dev/null
+++ b/DepthFirstScheduler/Unit.cs
@@ -0,0 +1,41 @@
+using System;
+
+namespace DepthFirstScheduler
+{
+    [Serializable]
+    public struct Unit : IEquatable<Unit>
+    {
+        static readonly Unit @default = new Unit();
+
+        public static Unit Default { get { return @default; } }
+
+        public static bool operator ==(Unit first, Unit second)
+        {
+            return true;
+        }
+
+        public static bool operator !=(Unit first, Unit second)
+        {
+            return false;
+        }
+
+        public bool Equals(Unit other)
+        {
+            return true;
+        }
+        public override bool Equals(object obj)
+        {
+            return obj is Unit;
+        }
+
+        public override int GetHashCode()
+        {
+            return 0;
+        }
+
+        public override string ToString()
+        {
+            return "()";
+        }
+    }
+}
diff --git a/DepthFirstScheduler/Unit.cs.meta b/DepthFirstScheduler/Unit.cs.meta
new file mode 100644
index 000000000..24f0ea548
--- /dev/null
+++ b/DepthFirstScheduler/Unit.cs.meta
@@ -0,0 +1,12 @@
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+timeCreated: 1520081817
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