Implement Deck

deck.cs

public interface IDeck<T>
{
    /// <summary>
    /// Draw as many T as the count
    /// will draw the most it possibly can, which may be 0
    /// </summary>
    /// <param name="count"></param>
    /// <returns></returns>
    IEnumerable<T> Draw(int count);

    /// <summary>
    /// Draw items until the deck is empty
    /// Remaining is 0
    /// </summary>
    /// <param name="item"></param>
    /// <returns></returns>
    bool TryDraw(out T item);

    /// <summary>
    /// Get one item, and mark it as dealt
    /// </summary>
    /// <returns></returns>
    T Draw();

    /// <summary>
    /// Shuffles Remaining Items In Deck
    /// </summary>
    void Shuffle();

    /// <summary>
    /// If item was an existing item
    /// then it gets returned. If its
    /// a never before seen item then
    /// it gets added to the original collection
    /// </summary>
    /// <param name="item"></param>
    /// <param name="index"></param>
    void InsertAt(T item, Index? index);

    /// <summary>
    /// Remove item from the deck
    /// this means the card can't be dealt
    /// </summary>
    /// <param name="item"></param>
    void Remove(T item);

    /// <summary>
    /// Reset items to original state
    /// including inserted items.
    /// No dealt cards
    /// </summary>
    void Reset();

    // original deck including items that
    // have been added after initialization
    public IEnumerable<T> All { get; }

    // cards that have been dealt
    public IEnumerable<T> Outstanding { get; }

    // cards that have not been dealt
    public IEnumerable<T> Remaining { get; }
}