using System;

                    using Microsoft.Extensions.Caching.Memory;

using System.Threading;

public class Program

{

    public static void Main()

    {

        var cacheEntryOptions = new MemoryCacheOptions();

        cacheEntryOptions.ExpirationScanFrequency = TimeSpan.FromSeconds(1);

        var m = new MemoryCache(cacheEntryOptions);

        for (var x =0;x<5;x++)

        {

                    m.Set<object>($"asdsa{x}", null, TimeSpan.FromMilliseconds(2));

                    Console.WriteLine(m.Count);

                    //Thread.Sleep(1000);

        }

Thread.Sleep(5000);

        Console.WriteLine($"final count {m.Count}");

        m.Set<object>($"asdsa", null, TimeSpan.FromMilliseconds(2));

        Console.WriteLine($"final count2 {m.Count}");

    }

}