using System;

using System.Collections.Generic;

using Newtonsoft.Json;

​

public class Program

{

    public static void Main()

    {

        string json = """{ "string" = "json", "boolean" = true, "number" = 3}""";

        Console.WriteLine(System.Text.Json.JsonSerializer.Serialize("{ \"string\" = \"json\", \"boolean\" = true, \"number\" = 3}"));

        Console.WriteLine(JsonConvert.SerializeObject("{ \"string\" = \"json\", \"boolean\" = true, \"number\" = 3}"));     

    }

}"{ \"string\" = \"json\", \"boolean\" = true, \"number\" = 3}"