Benchmarking Enumerable.MaxBy() against Enumerable.OrderByDescending() followed by Enumerable.First()

MaxByBenchmarks.cs

using System;
using System.Collections.Generic;
using System.Linq;
using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Configs;

namespace LinqBenchmarks;

public record Person(int Age);


[GroupBenchmarksBy(BenchmarkLogicalGroupRule.ByCategory)]
[CategoriesColumn]
public class MaxByBenchmarks
{
    List<Person>? random;
    List<Person>? bestCase;
    List<Person>? worstCase;

    [Params(100, 10_000)]
    public int Count { get; set; }

    [GlobalSetup]
    public void GlobalSetup()
    {
        var rnd = new Random(0);
        random = Enumerable.Range(0, Count).Select(_ => new Person(rnd.Next())).ToList();
        bestCase = Enumerable.Range(0, Count).Select(age => new Person(Count - age)).ToList();
        worstCase = Enumerable.Range(0, Count).Select(age => new Person(age)).ToList();
    }

    [BenchmarkCategory("Random")]
    [Benchmark(Baseline = true)]
    public Person Random_OrderBy()
        => random!.OrderByDescending(person => person.Age).First();

    [BenchmarkCategory("Random")]
    [Benchmark]
    public Person? Random_MaxBy()
        => random!.MaxBy(person => person.Age);

    [BenchmarkCategory("Best Case")]
    [Benchmark(Baseline = true)]
    public Person BestCase_OrderBy()
        => bestCase!.OrderByDescending(person => person.Age).First();

    [BenchmarkCategory("Best Case")]
    [Benchmark]
    public Person? BestCase_MaxBy()
        => bestCase!.MaxBy(person => person.Age);

    [BenchmarkCategory("Worst Case")]
    [Benchmark(Baseline = true)]
    public Person WorstCase_OrderBy()
        => worstCase!.OrderByDescending(person => person.Age).First();

    [BenchmarkCategory("Worst Case")]
    [Benchmark]
    public Person? WorstCase_MaxBy()
        => worstCase!.MaxBy(person => person.Age);
}