using System;

using System.Collections.Generic;

using System.Linq;

using System.Text.Json;

using System.Text.Json.Serialization;

using System.Collections.Concurrent;

​

public class Program

{

    public static void Main()

    {

        var dict = new ConcurrentDictionary<string, Test>();

        dict.TryAdd("1", new Test(){A = 5, B=10});

        if(dict.TryGetValue("1", out var val))

        {

            dict.TryRemove("1", out _);

            var update = dict.TryUpdate("1", val with { A = 6}, val);

            Console.WriteLine(update);

        }

    }

}

​

​

public record Test

{

    public int A{get;set;}

    public int B{get;set;}

}