C# 中的数组如何部分实现 IListT

csharp
public class PartialArray : IList
{
    private T[] array;
    public PartialArray()
    {
        array = new T[0];
    }
    public int Count => array.Length;
    public bool IsReadOnly => false;
    public T this[int index]
    {
        get => array[index];
        set => array[index] = value;
    }
    public void Add(T item)
    {
        Array.Resize(ref array, array.Length + 1);
        array[array.Length - 1] = item;
    }
    public void Clear()
    {
        array = new T[0];
    }
    public bool Contains(T item)
    {
        return array.Contains(item);
    }
    public void CopyTo(T[] array, int arrayIndex)
    {
        this.array.CopyTo(array, arrayIndex);
    }
    public IEnumerator GetEnumerator()
    {
        return array.AsEnumerable().GetEnumerator();
    }
    public int IndexOf(T item)
    {
        return Array.IndexOf(array, item);
    }
    public void Insert(int index, T item)
    {
        Array.Resize(ref array, array.Length + 1);
        Array.Copy(array, index, array, index + 1, array.Length - index - 1);
        array[index] = item;
    }
    public bool Remove(T item)
    {
        int index = Array.IndexOf(array, item);
        if (index >= 0)
        {
            RemoveAt(index);
            return true;
        }
        return false;
    }
    public void RemoveAt(int index)
    {
        Array.Copy(array, index + 1, array, index, array.Length - index - 1);
        Array.Resize(ref array, array.Length - 1);
    }
    IEnumerator IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }
}