pub type KeyValEnter<K, V, T, R, TEnter> = TraceEnter<TraceFrontier<TraceAgent<ColValSpine<K, V, T, R>>>, TEnter>;
struct KeyValEnter<K, V, T, R, TEnter> {
trace: TraceFrontier<TraceAgent<Spine<Rc<OrdValBatch<TStack<((K, V), T, R)>>>, ColumnatedMergeBatcher<K, V, T, R>, RcBuilder<OrdValBuilder<TStack<((K, V), T, R)>>>>>>,
stash1: Antichain<<TraceFrontier<TraceAgent<Spine<Rc<OrdValBatch<TStack<((K, V), T, R)>>>, ColumnatedMergeBatcher<K, V, T, R>, RcBuilder<OrdValBuilder<TStack<((K, V), T, R)>>>>>> as TraceReader>::Time>,
stash2: Antichain<TEnter>,
}