public class RewardCenterState
{
    public Campaign activeCampaign;
    public bool hasShownWelcome;
    public bool hasShownOnboarding;
}

public class Campaign
{
    public string id;
    public string publisherName;
    public string publisherLogoUrl;
    public string currencyName;
    public string currencyIconUrl;
    public string expiresAt;
    public bool   isCompleted;
    public List<Milestone> milestones = new List<Milestone>();
}

public class Milestone
{
    public string eventName;
    public string description;
    public float rewardAmount;
    public bool isCompleted;
    public string completedAt;
}