Array pool perf

Program.cs

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

public class Program
{
    private static void Main(string[] args)
    {
        var summary = BenchmarkRunner.Run<PoolBench>();
    }

    [MemoryDiagnoser]
    public class PoolBench
    {
        int Threads = 16;
        int Iterations = 64 * 1024;
        int ArraySize = 1024;

        [Benchmark]
        public void ArrayPool()
        {
            var pool = ArrayPool<byte>.Shared;
            var tasks = new Task[Threads];
            for (int i = 0; i < Threads; i++)
            {
                tasks[i] = Task.Run(() =>
                {
                    for (int j = 0; j < Iterations; j++)
                    {
                        var arr = pool.Rent(ArraySize);
                        Random.Shared.NextBytes(arr);
                        pool.Return(arr);
                    }
                });
            }
            Task.WaitAll(tasks);
        }

        [Benchmark]
        public void HeapArray()
        {
            var tasks = new Task[Threads];
            for (int i = 0; i < Threads; i++)
            {
                tasks[i] = Task.Run(() =>
                {
                    for (int j = 0; j < Iterations; j++)
                    {
                        var arr = new byte[ArraySize];
                        Random.Shared.NextBytes(arr);
                    }
                });
            }
            Task.WaitAll(tasks);
        }
    }
}