Umbraco-CMS/src/Umbraco.Infrastructure/Search/SearchableTreeCollectionBuilder.cs

using Umbraco.Core.Composing;
using Umbraco.Web.Trees;

namespace Umbraco.Web.Search
{
    public class SearchableTreeCollectionBuilder : LazyCollectionBuilderBase<SearchableTreeCollectionBuilder, SearchableTreeCollection, ISearchableTree>
    {
        protected override SearchableTreeCollectionBuilder This => this;

        //per request because generally an instance of ISearchableTree is a controller
        protected override Lifetime CollectionLifetime => Lifetime.Request;
    }
}