AsyncMeetsUnsafe.cs

using System;
using System.Numerics;
using System.Runtime.InteropServices;
using System.Threading.Tasks;

namespace AsyncMeetsUnsafe
{
    [StructLayout(LayoutKind.Sequential)]
    public class LocalityCriticalData : IDisposable
    {
        public Matrix4x4 Block1;
        public Matrix4x4 Block2;

        public GCHandle Handle;
        public IntPtr BasePtr;

        public unsafe Matrix4x4* Block1Ptr;
        public unsafe Matrix4x4* Block2Ptr;

        public unsafe LocalityCriticalData()
        {
            Block1 = Matrix4x4.CreateScale(1, 2, 3);
            Block2 = Matrix4x4.CreateScale(4, 5, 6);

            Handle = GCHandle.Alloc(this, GCHandleType.Pinned);
            BasePtr = Handle.AddrOfPinnedObject();
            Block1Ptr = (Matrix4x4*) (float*) BasePtr;
            Block2Ptr = Block1Ptr + 1;
        }

        public unsafe float GetBlock1Element(int idx)
        {
            float* p = (float*) Block1Ptr + idx;
            return *p;
        }

        public unsafe float GetBlock2Element(int idx)
        {
            float* p = (float*)Block2Ptr+idx;
            return *p;
        }

        public async Task<float> CalculateStuff()
        {
            float a = GetBlock1Element(5);

            float b = await RecieveDataFromMars();
            float c = GetBlock2Element(5);

            return a + b + c;
        }

        private async Task<float> RecieveDataFromMars()
        {
            await Task.Delay(100);
            return 4.8f;
        }

        public void Dispose()
        {
            Handle.Free();
        }
    }

    public class Program
    {
        
        public static void Main(string[] args)
        {
           DoWorkAsync().Wait();
        }

        private static async Task DoWorkAsync()
        {
            using (var data = new LocalityCriticalData())
            {
                Assert.Equal(data.GetBlock1Element(0), 1);
                Assert.Equal(data.GetBlock2Element(0), 4);

                float result = await data.CalculateStuff();
                float expected = 2 + 4.8f + 5;
                
                Assert.Equal(result, expected);
            }

            Console.ReadLine();
        }
    }


    static class Assert
    {
        public static void Equal<T>(T a, T b)
        {
            if (!a.Equals(b)) throw new Exception("Assertion failed!");
        }
    }

}