using System;

using System.Linq;

using System.Text;

using System.Text.Json;

using System.Diagnostics;

​

public class Program

{

    public static void Main()

    {

        var count = 1000000;

        var message = new string('Q', 1000);

        var json = JsonSerializer.Serialize(message);

        var bytes = Encoding.UTF8.GetBytes(json);

        Console.WriteLine(Enumerable.SequenceEqual(JsonSerializer.SerializeToUtf8Bytes(message), bytes));

        Console.WriteLine(DoTest(count, () =>

        {

            var json = JsonSerializer.Serialize(message);

            var bytes = Encoding.UTF8.GetBytes(json);

        }));

        Console.WriteLine(DoTest(count, () =>

        {

            var bytes = JsonSerializer.SerializeToUtf8Bytes(message);

        }));

    }

​

    static long DoTest(int count, Action action)

    {

        var sw = Stopwatch.StartNew();

        for (int i = 0; i < count; ++i)

        {

            action();

        }

​

        return sw.ElapsedMilliseconds;

    }

}