public ArkItemTypeGroup(ArkItem[] all)
{
All = all ?? new ArkItem[] { };
_items = new Lazy <ArkItem[]>(() => All.Where(x => !x.IsBlueprint).ToArray());
_blueprints = new Lazy <ArkItem[]>(() => All.Where(x => x.IsBlueprint).ToArray());
_countItems = new Lazy <int>(() => Items.Any() ? (int)Items.Sum(x => x.Quantity) : 0);
_countBlueprints = new Lazy <int>(() => Blueprints.Any() ? (int)Blueprints.Sum(x => x.Quantity) : 0);
_count = new Lazy <int>(() => CountItems + CountBlueprints);
}