diff --git a/Assets/UniGLTF/Runtime/UniGLTF/IO/ImporterContextExtensions.cs b/Assets/UniGLTF/Runtime/UniGLTF/IO/ImporterContextExtensions.cs
index d994e6ec5..4ed58c24b 100644
--- a/Assets/UniGLTF/Runtime/UniGLTF/IO/ImporterContextExtensions.cs
+++ b/Assets/UniGLTF/Runtime/UniGLTF/IO/ImporterContextExtensions.cs
@@ -1,4 +1,7 @@
+using System;
+using System.Collections.Generic;
 using System.IO;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace UniGLTF
@@ -27,22 +30,71 @@ namespace UniGLTF
             self.Root.name = Path.GetFileNameWithoutExtension(path);
         }
 
+        class TemporarySynchronizationContext : SynchronizationContext
+        {
+            Queue<Action> m_callbacks = new Queue<Action>();
+
+            /// <summary>
+            /// await して中断された継続がここにくる。
+            /// 
+            /// ex. await Task.Run(() =>{ /* ここ */ });
+            /// </summary>
+            /// <param name="d"></param>
+            /// <param name="state"></param>
+            public override void Post(SendOrPostCallback d, object state)
+            {
+                // Debug.Log($"Post");
+                m_callbacks.Enqueue(() => d(state));
+            }
+
+            /// <summary>
+            /// 一個デキューして実行する。
+            /// Unityであれば毎フレームこのように消化しているであろう。
+            /// 
+            /// https://github.com/Unity-Technologies/UnityCsReference/blob/master/Runtime/Export/Scripting/UnitySynchronizationContext.cs
+            /// </summary>
+            /// <returns></returns>
+            public bool ExecuteOneCallback()
+            {
+                while (m_callbacks.Count == 0)
+                {
+                    // Debug.Log($"empty callbacks");
+                    return false;
+                }
+
+                var callback = m_callbacks.Dequeue();
+                callback();
+                return true;
+            }
+        }
+
         /// <summary>
         /// Build unity objects from parsed gltf
         /// </summary>
         public static void Load(this ImporterContext self)
         {
             var tcs = new TemporarySynchronizationContext();
-            using (tcs.Hijack())
+
+            // 元に戻すためバックアップ
+            var backup = SynchronizationContext.Current;
+            // 一時的に変更
+            SynchronizationContext.SetSynchronizationContext(tcs);
+            try
             {
                 var task = self.LoadAsync();
 
+                // 中断された await を消化する
                 while (!task.IsCompleted)
                 {
                     // execute synchronous
                     tcs.ExecuteOneCallback();
                 }
             }
+            finally
+            {
+                // 元に戻す
+                SynchronizationContext.SetSynchronizationContext(backup);
+            }
         }
     }
 }
diff --git a/Assets/UniGLTF/Runtime/UniGLTF/IO/TemporarySynchronizationContext.cs b/Assets/UniGLTF/Runtime/UniGLTF/IO/TemporarySynchronizationContext.cs
deleted file mode 100644
index 1e9a9c3cf..000000000
--- a/Assets/UniGLTF/Runtime/UniGLTF/IO/TemporarySynchronizationContext.cs
+++ /dev/null
@@ -1,56 +0,0 @@
-using System;
-using System.Collections;
-using System.Collections.Generic;
-using System.Threading;
-using System.Threading.Tasks;
-using UnityEngine;
-
-namespace UniGLTF
-{
-    /// <summary>
-    /// await で post される先を１次的に乗っ取る
-    /// </summary>
-    public class TemporarySynchronizationContext : SynchronizationContext
-    {
-        Queue<Action> m_callbacks = new Queue<Action>();
-
-        public override void Post(SendOrPostCallback d, object state)
-        {
-            // Debug.Log($"Post");
-            m_callbacks.Enqueue(() => d(state));
-        }
-
-        public bool ExecuteOneCallback()
-        {
-            while (m_callbacks.Count == 0)
-            {
-                // Debug.Log($"empty callbacks");
-                return false;
-            }
-
-            var callback = m_callbacks.Dequeue();
-            callback();
-            return true;
-        }
-
-        class Hijacker : IDisposable
-        {
-            SynchronizationContext m_backup;
-            public Hijacker(SynchronizationContext context)
-            {
-                m_backup = SynchronizationContext.Current;
-                SynchronizationContext.SetSynchronizationContext(context);
-            }
-
-            public void Dispose()
-            {
-                SynchronizationContext.SetSynchronizationContext(m_backup);
-            }
-        }
-
-        public IDisposable Hijack()
-        {
-            return new Hijacker(this);
-        }
-    }
-}
diff --git a/Assets/UniGLTF/Runtime/UniGLTF/IO/TemporarySynchronizationContext.cs.meta b/Assets/UniGLTF/Runtime/UniGLTF/IO/TemporarySynchronizationContext.cs.meta
deleted file mode 100644
index c96a371af..000000000
--- a/Assets/UniGLTF/Runtime/UniGLTF/IO/TemporarySynchronizationContext.cs.meta
+++ /dev/null
@@ -1,11 +0,0 @@
-fileFormatVersion: 2
-guid: 62f8f380aadfc284f9bdc2d58f84bf48
-MonoImporter:
-  externalObjects: {}
-  serializedVersion: 2
-  defaultReferences: []
-  executionOrder: 0
-  icon: {instanceID: 0}
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: