Add object benchmark test

test/UnionType.Benchmarks/Runs/StoreObject.cs

@@ -0,0 +1,35 @@
+using BenchmarkDotNet.Attributes;
+
+namespace UnionType.Benchmarks.Runs
+{
+    [MemoryDiagnoser]
+    public class StoreObject
+    {
+        [Params(500, 1_000_000)]
+        public int Count { get; set; }
+
+        [Benchmark(Baseline = true)]
+        public void Normal()
+        {
+            var obj = new object[Count];
+            for (int i = 0; i < Count; i++)
+            {
+                obj[i] = new object();
+            }
+        }
+        [Benchmark]
+        public void UnionObject()
+        {
+            var obj = new UnionValue[Count];
+            for (int i = 0; i < Count; i++)
+            {
+                obj[i] = new UnionValue { Object = new object() };
+            }
+            for (int i = 0; i < obj.Length; i++)
+            {
+                obj[i].Dispose();
+            }
+        }
+    }
+
+}