private protected PipelineColumn(Reconciler reconciler, PipelineColumn[] dependencies)
        {
            Contracts.CheckValue(reconciler, nameof(reconciler));
            Contracts.CheckValueOrNull(dependencies);

            ReconcilerObj = reconciler;
            Dependencies  = dependencies;
        }
 protected Key(Reconciler reconciler, params PipelineColumn[] dependencies)
     : base(reconciler, dependencies)
 {
 }