using System;

using System.Text.Json;

using System.Text.Json.Serialization;

​

class activeEffect

{

    public float multiplier{ get; set; }

    public double durationMillis{ get; set; }

    public double expiryTsMillis{ get; set; }

}

​

class ClubBoosts

{

    public activeEffect [] boosts { get; set; }

}

​

public class Program

{

    public static void Main()

    {

        ClubBoosts boo = new ClubBoosts();

        boo.boosts = new activeEffect[2];

        boo.boosts[0] = new activeEffect();

        boo.boosts[0].multiplier = 0.25f;

        boo.boosts[0].expiryTsMillis = DateTimeOffset.UtcNow.AddMinutes(2).ToUnixTimeMilliseconds();// DateTime.UtcNow.AddMinutes(10).Ticks / TimeSpan.TicksPerMillisecond;

        boo.boosts[0].durationMillis = TimeSpan.FromMinutes(2).Ticks / TimeSpan.TicksPerMillisecond;

        boo.boosts[1] = new activeEffect();

        boo.boosts[1].multiplier = 0.25f;

        boo.boosts[1].expiryTsMillis = DateTimeOffset.UtcNow.AddMinutes(2).ToUnixTimeMilliseconds(); //DateTime.UtcNow.AddMinutes(15).Ticks / TimeSpan.TicksPerMillisecond;

        boo.boosts[1].durationMillis = TimeSpan.FromMinutes(4).Ticks / TimeSpan.TicksPerMillisecond;

        string jsonString;

        var options = new JsonSerializerOptions

        {

            IgnoreNullValues = true,

            WriteIndented = true,

        };

        jsonString = JsonSerializer.Serialize(boo, options);

        Console.WriteLine(jsonString);

    }

}