gistfile1.cs

using System;
using System.Collections.Generic;
using System.Linq;

namespace MemTestPlain
{
    class Program
    {
        static void Main(string[] args)
        {
            GC.Collect(); // so the stats are available

            var i = 0;
            while (i++ < 256)
            {
                MemoryUtils.LogMemoryInfo();
                Console.WriteLine($"Allocating next 10Mb, i = {i} (total: {i*10}Mb)");
                MemoryUtils.AllocateMemory(10);
            }
            Console.WriteLine(MemoryUtils.UseBuffers());
        }
    }

    internal static class MemoryUtils
    {
        private static readonly List<byte[]> _buffers = new();

        public static string GetMemInfo()
        {
            var info = GC.GetGCMemoryInfo();
            using var proc = System.Diagnostics.Process.GetCurrentProcess();

            return $"ENV: {f(info.MemoryLoadBytes)}/{f(info.TotalAvailableMemoryBytes)}. PrivateMemorySize {f(proc.PrivateMemorySize64)}";
            string f(long i) => i.HumanReadableSize();
        }

        public static string HumanReadableSize(this long size)
        {
            var sizes = new[] { "B", "KB", "MB", "GB", "TB" };
            var order = 0;
            while (size >= 1024 && order < sizes.Length - 1)
            {
                order++;
                size /= 1024;
            }

            return $"{size:0.##} {sizes[order]}";
        }

        public static void LogMemoryInfo()
        {
            Console.WriteLine(GetMemInfo());
        }

        public static void AllocateMemory(int sizeInMb)
        {
            try
            {
                var buf = new byte[sizeInMb * 1024 * 1024];
                Array.Clear(buf, 0, buf.Length);
                buf[buf.Length / 2] = (byte)sizeInMb;
                _buffers.Add(buf);
            }
            catch (OutOfMemoryException ex)
            {
                Console.WriteLine("Okay, got OutOfMemoryException!");
                throw;
            }
        }

        public static int UseBuffers() => _buffers.Sum(b => b[b.Length / 2]);
    }
}