namespace System.Collections.Generic
{
    [DebuggerDisplay("Count = {Count}")]
    [DebuggerTypeProxy(typeof(HashSetDebugView<?>))]
    public class HashSet<T> : ICollection<T>, IEnumerable, IEnumerable<T>, IDeserializationCallback, ISerializable
    {
        public virtual void OnDeserialization(object sender);
    }
}