C# Dequeue implementation

Dequeue.cs

using System;

public class Dequeue<T>
{
    public Dequeue(int capacity)
    {
        this.array = new T[capacity];
    }

    public Dequeue() : this(5)
    { }

    T[] array;

    public int Capacity => this.array.Length;
    public int Count { get; private set; }

    int _offset = 0;
    public int Offset
    {
        get
        {
            return _offset;
        }
        set
        {
            _offset = NormalizeIndex(value);
        }
    }

    public T PeekLast()
    {
        EnsureIsNotEmpty();
        return array[NormalizeIndex(Offset + Count - 1)];
    }

    public T PopLast()
    {
        EnsureIsNotEmpty();
        return array[NormalizeIndex(Offset + Count-- - 1)];
    }

    public T PeekFirst()
    {
        EnsureIsNotEmpty();
        return array[NormalizeIndex(Offset)];
    }

    public T PopFirst()
    {
        EnsureIsNotEmpty();
        Count--;
        return array[NormalizeIndex(Offset++)];
    }

    public void PushLast(T last)
    {
        if (Count == Capacity)
        {
            Relocate();
        }
        array[NormalizeIndex(Offset + Count++)] = last;
    }

    public void PushFirst(T first)
    {
        if (Count == Capacity)
        {
            Relocate();
        }
        Count++;
        array[NormalizeIndex(--Offset)] = first;
    }

    private int NormalizeIndex(int index)
    {
        return (index + Capacity) % Capacity;
    }

    private void EnsureIsNotEmpty()
    {
        if (Count == 0)
        {
            throw new InvalidOperationException("Dequeue is empty");
        }
    }

    private void Relocate()
    {
        var newArray = new T[Capacity * 2];
        for (int i = 0; i < Count; i++)
        {
            newArray[i] = array[NormalizeIndex(Offset + i)];
        }
        array = newArray;
        Offset = 0;
    }
}