A Comparison about C# For loops

ForLoopsBenchmark.cs

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Jobs;
using System.Runtime.InteropServices;

namespace ForLoopsComparison;

[MemoryDiagnoser(false)]
[SimpleJob(RuntimeMoniker.Net60)]
[SimpleJob(RuntimeMoniker.Net80)]
[SimpleJob(RuntimeMoniker.Net90)]
public class AllForLoopBenchmark
{
    [Params(100_000)]
    public int ItemCount { get; set; }

    public List<int> Items;

    [GlobalSetup]
    public void GlobalSetup()
    {
        Items = Enumerable.Range(0, ItemCount).ToList();
    }

    [Benchmark]
    public void For()
    {
        for (int i = 0; i < ItemCount; i++)
        {
            DoSomeThing(Items[i]);
        }
    }

    [Benchmark]
    public void ForEach()
    {
        foreach (var item in Items)
        {
            DoSomeThing(item);
        }
    }

    [Benchmark]
    public void ForEach_Linq()
    {
        Items.ForEach(DoSomeThing);
    }

    [Benchmark]
    public void ForEach_Parallel()
    {
        Parallel.ForEach(Items, DoSomeThing);
    }

    [Benchmark]
    public void ForEach_LinqParallel()
    {
        Items.AsParallel().ForAll(DoSomeThing);
    }

    [Benchmark]
    public void For_Span()
    {
        var span = CollectionsMarshal.AsSpan(Items);
        for (int i = 0; i < span.Length; i++)
        {
            DoSomeThing(span[i]);
        }
    }

    [Benchmark]
    public void ForEach_Span()
    {
        foreach (var item in CollectionsMarshal.AsSpan(Items))
        {
            DoSomeThing(item);
        }
    }

    private void DoSomeThing(int i)
    {
        _ = i;
    }
}