add VRM scripts

Scripts/UniTask/StepScheduler.cs

@@ -0,0 +1,30 @@
+namespace UniTask
+{
+    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;
+        }
+    }
+}