Added benchmark for struct casting

src/TensorFlowNet.Benchmarks/TensorFlowBenchmark.csproj

@@ -6,6 +6,7 @@
     <NoWin32Manifest>true</NoWin32Manifest>
     <AssemblyName>TensorFlowBenchmark</AssemblyName>
     <RootNamespace>TensorFlowBenchmark</RootNamespace>
+	<LangVersion>7.3</LangVersion>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">

src/TensorFlowNet.Benchmarks/Unmanaged/StructCastBenchmark.cs

@@ -0,0 +1,76 @@
+using System;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using BenchmarkDotNet.Attributes;
+using Google.Protobuf.WellKnownTypes;
+using NumSharp;
+using Tensorflow;
+using static Tensorflow.Binding;
+
+namespace TensorFlowBenchmark.Unmanaged
+{
+    public struct UnmanagedStruct
+    {
+        public int a;
+        public long b;
+        public UnmanagedStruct(int _)
+        {
+            a = 2;
+            b = 3;
+        }
+    }
+
+    [SimpleJob(launchCount: 1, warmupCount: 2, targetCount: 10)]
+    [MinColumn, MaxColumn, MeanColumn, MedianColumn]
+    public unsafe class StructCastBenchmark
+    {
+        private static void EnsureIsUnmanaged<T>(T _) where T : unmanaged
+        { }
+
+        static StructCastBenchmark() //if UnmanagedStruct is not unmanaged struct then this will fail to compile.
+            => EnsureIsUnmanaged(new UnmanagedStruct());
+
+        private IntPtr data;
+        private void* dataptr;
+
+        [GlobalSetup]
+        public void Setup()
+        {
+            data = Marshal.AllocHGlobal(Marshal.SizeOf<UnmanagedStruct>());
+            dataptr = data.ToPointer();
+        }
+
+        [Benchmark, MethodImpl(MethodImplOptions.NoOptimization)]
+        public void Marshal_PtrToStructure()
+        {
+            UnmanagedStruct _;
+            for (int i = 0; i < 10000; i++)
+            {
+                _ = Marshal.PtrToStructure<UnmanagedStruct>(data);
+            }
+        }
+
+        [Benchmark, MethodImpl(MethodImplOptions.NoOptimization)]
+        public void PointerCast()
+        {
+            var dptr = dataptr;
+            UnmanagedStruct _;
+            for (int i = 0; i < 10000; i++)
+            {
+                _ = *(UnmanagedStruct*) dptr;
+            }
+        }
+
+        [Benchmark, MethodImpl(MethodImplOptions.NoOptimization)]
+        public void Unsafe_Read()
+        {
+            var dptr = dataptr;
+            UnmanagedStruct _;
+            for (int i = 0; i < 10000; i++)
+            {
+                _ = Unsafe.Read<UnmanagedStruct>(dptr);
+            }
+        }
+
+    }
+}