Program.cs

using System;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

namespace Benchmarks
{
    class Program
    {
        static void Main(string[] args)
            => BenchmarkRunner.Run<BenchmarkClass>();
    }

    [MemoryDiagnoser]
    public class BenchmarkClass
    {
        private NoFinalizer noFinalizer;
        private WithFinalizer withFinalizer;

        [Benchmark]
        public void NoFinalizer()
        {
            for (int i = 0; i < 1000; i++)
                noFinalizer = new NoFinalizer();
        }

        [Benchmark]
        public void WithFinalizer()
        {
            for (int i = 0; i < 1000; i++)
                withFinalizer = new WithFinalizer();
        }

        [IterationCleanup]
        public void Cleanup()
        {
            if (withFinalizer != null)
                GC.SuppressFinalize(withFinalizer);
        }
    }

    public class NoFinalizer
    {
    }

    public class WithFinalizer
    {
        public WithFinalizer()
        {
        }

        ~WithFinalizer()
        {
        }
    }
}