using System;

using System.Text.Json;

public class Program

{

    public class WeatherForecastWithPropertyName

    {

        public DateTimeOffset Date { get; set; }

        public int TemperatureCelsius { get; set; }

        public string Summary { get; set; }

        public int WindSpeed { get; set; }

    }

    public static void Main()

    {

        var options = new JsonSerializerOptions

        {

            PropertyNamingPolicy = JsonNamingPolicy.SnakeCaseLower,

            WriteIndented = true

        };

        var weatherForecast = new WeatherForecastWithPropertyName();

        var jsonString = JsonSerializer.Serialize(weatherForecast, options);

        Console.WriteLine(jsonString);

    }

}