/// <summary> /// Determines whether [contains] [the specified item]. /// </summary> /// <param name="item">The item.</param> /// <returns> /// <c>true</c> if [contains] [the specified item]; otherwise, <c>false</c>. /// </returns> public bool Contains(TEntity item) { if (item == null) { return(false); } return(_tracker.Any(pair => pair.Key == item.Id)); }