internal JsConfigScope()
        {
            PclExport.Instance.BeginThreadAffinity();

            parent = head;
            head   = this;
        }
        public void Dispose()
        {
            if (!disposed)
            {
                disposed = true;
                Debug.Assert(this == head, "Disposed out of order.");

                head = parent;

                PclExport.Instance.EndThreadAffinity();
            }
        }