Update UniTask Sample

Assets/YooAsset/Samples~/UniTask Sample/UniTask/Runtime/AsyncUnit.cs

@@ -0,0 +1,26 @@
+#pragma warning disable CS1591 // Missing XML comment for publicly visible type or 
+
+using System;
+
+namespace Cysharp.Threading.Tasks
+{
+    public readonly struct AsyncUnit : IEquatable<AsyncUnit>
+    {
+        public static readonly AsyncUnit Default = new AsyncUnit();
+
+        public override int GetHashCode()
+        {
+            return 0;
+        }
+
+        public bool Equals(AsyncUnit other)
+        {
+            return true;
+        }
+
+        public override string ToString()
+        {
+            return "()";
+        }
+    }
+}