Distinct a list of strings ignoring diacritics and cases - v2

Distinct2.cs

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

using BenchmarkDotNet.Attributes;
using BenchmarkDotNet.Running;

namespace UnicodeDistinct
{
    public class Program
    {
        #region Comparers
        class LengthHash : IEqualityComparer<string>
        {
            public bool Equals(string x, string y) =>  x == null || y == null ? x == y : Culture.CompareInfo.IndexOf(x, y, Options) >= 0;
            public int GetHashCode(string obj) => obj?.Length ?? 0;
        }

        class IgnoreHash : IEqualityComparer<string>
        {
            public bool Equals(string x, string y) => x == null || y == null ? x == y : x.Length == y.Length && Culture.CompareInfo.IndexOf(x, y, Options) >= 0;
            public int GetHashCode(string obj) => 1;
        }
        #endregion

        #region Benchmarks
        [Benchmark]
        public List<String> RunDefault() => Itens.Select(c=> c?.Trim().Normalize()).Distinct().ToList();

        [Benchmark]
        public List<String> RunHashAsLength() => Itens.Select(c => c?.Trim().Normalize()).Distinct(new LengthHash()).ToList();

        [Benchmark]
        public List<String> RunIgnoreHash() => Itens.Select(c => c?.Trim().Normalize()).Distinct(new IgnoreHash()).ToList();
        
        [Benchmark]
        public List<String> RunStringComparer() => Itens.Select(c => c?.Trim().Normalize()).Distinct(StringComparer.InvariantCultureIgnoreCase).ToList();
        #endregion

        static CultureInfo Culture = CultureInfo.InvariantCulture;
        static CompareOptions Options = CompareOptions.IgnoreNonSpace | CompareOptions.IgnoreCase | CompareOptions.IgnoreSymbols;

        static readonly string[] Itens = new string[] { "\u212B", "\u00C5", "\u0041\u030A", "hi", " hi   ", "HI", "hí", " Hî", "hi hi", " hí hí ", "olá", "OLÁ", " olá   ", "", "ola", "hola", " holà    ", "aaaa", "áâàa", " aâàa     ", "áaàa", "áâaa ", "aaaa ", "áâaa", "áâaa", };

        static void Main(string[] args)
        {
            BenchmarkRunner.Run<Program>();

            var p = new Program();
            Console.WriteLine($"{p.RunDefault().Count} Default: {string.Join(", ", p.RunDefault())}");
            Console.WriteLine($"{p.RunHashAsLength().Count} HashAsLength: {string.Join(", ", p.RunHashAsLength())}");
            Console.WriteLine($"{p.RunIgnoreHash().Count} IgnoreHash: {string.Join(", ", p.RunIgnoreHash())}");
            Console.WriteLine($"{p.RunStringComparer().Count} RunStringComparer: {string.Join(", ", p.RunStringComparer())}");

            Console.ReadLine();
        }
    }
}