pub type ErrEnter<T, TEnter> = TraceEnter<TraceFrontier<TraceAgent<ColKeySpine<DataflowError, T, Diff>>>, TEnter>;
struct ErrEnter<T, TEnter> {
trace: TraceFrontier<TraceAgent<Spine<Rc<OrdKeyBatch<TStack<((DataflowError, ()), T, i64)>>>, ColumnatedMergeBatcher<DataflowError, (), T, i64>, RcBuilder<OrdKeyBuilder<TStack<((DataflowError, ()), T, i64)>>>>>>,
stash1: Antichain<<TraceFrontier<TraceAgent<Spine<Rc<OrdKeyBatch<TStack<((DataflowError, ()), T, i64)>>>, ColumnatedMergeBatcher<DataflowError, (), T, i64>, RcBuilder<OrdKeyBuilder<TStack<((DataflowError, ()), T, i64)>>>>>> as TraceReader>::Time>,
stash2: Antichain<TEnter>,
}