UnityAdsButton.GetCooldownTime C# (CSharp) Method

    private DateTime GetCooldownTime()
    {
        if (object.Equals(_rewardCooldownTime,default(DateTime)))
        {
            if (PlayerPrefs.HasKey(_keyCooldownTime))
            {
                _rewardCooldownTime = DateTime.Parse(PlayerPrefs.GetString(_keyCooldownTime));

                if (Debug.isDebugBuild)
                {
                    DateTime appStartTime = DateTime.UtcNow.AddSeconds(-1*Time.time);
                    DateTime lastRewardTime = _rewardCooldownTime.AddSeconds(-1*cooldownTime);

                    if (DateTime.Compare(appStartTime,lastRewardTime) > 0) ResetCooldownTime();
                }
            }
            else _rewardCooldownTime = DateTime.UtcNow;
        }

        return _rewardCooldownTime;
    }