private static ICollector <GameEntity> Trigger(IGenericContext <GameEntity> context)
        {
            var t1 = context.GetTrigger <ElementComponent>(GroupEvent.Removed);
            var t2 = context.GetTrigger <PositionComponent>(GroupEvent.AddedOrRemoved);

            //var t2 = context.GetTrigger<PositionComponent>(GroupEvent.Removed);
            return(context.CreateCollector(t1, t2));
        }