Umbraco-CMS/src/Umbraco.Web/PublishedCache/NuCache/Snap/LinkedNode.cs

namespace Umbraco.Web.PublishedCache.NuCache.Snap
{
    //NOTE: This cannot be struct because it references itself

    /// <summary>
    /// Used to represent an item in a linked list
    /// </summary>
    /// <typeparam name="TValue"></typeparam>
    internal class LinkedNode<TValue>
        where TValue : class
    {
        public LinkedNode(TValue value, long gen, LinkedNode<TValue> next = null)
        {
            Value = value; // This is allowed to be null, we actually explicitly set this to null in ClearLocked
            Gen = gen;
            Next = next;
        }

        public readonly long Gen;

        // reading & writing references is thread-safe on all .NET platforms
        // mark as volatile to ensure we always read the correct value
        public volatile TValue Value;
        public volatile LinkedNode<TValue> Next;
    }
}