anchor.diff:              let lastChild = List.head children
               let initialState = {nextGeneration=[];sofar=0;items=[];nextPage=startingPageNumber;boundaryPage=startingBoundaryPageNumber;overflows=Map.empty}
               let middleState = List.foldBack folder (List.tail children) initialState 
  -            let isRootNode = (middleState.nextGeneration.Length=0)
  +            let isRootNode = (List.isEmpty middleState.nextGeneration)
               let finalState = flushParentPage middleState lastChild isRootNode
               let {nextPage=n;boundaryPage=b;nextGeneration=ng} = finalState
               (n,b,ng)
  
positive.code:             let flushLeaf st isRootPage = 
                  pb.PutInt16At (OFFSET_COUNT_PAIRS, st.keys.Length)
                  let thisPageNumber = st.nextPage
                  let firstLeaf = if st.leaves.Length=0 then thisPageNumber else st.firstLeaf
                  let (nextN,nextB) = 
                      if isRootPage then
                          let blockListPage = pageManager.ReserveBlockList(token, thisPageNumber)
  
negative.code:             let initialState = {firstLeaf=0;keys=[];leaves=[];nextPage=leavesFirstPage;boundaryPage=leavesBoundaryPage}
              let middleState = Seq.fold folder initialState source
              let finalState = 
                  if not (List.isEmpty middleState.keys) then
                      let isRootNode = List.isEmpty middleState.leaves
                      flushLeaf middleState isRootNode
                  else
                      middleState
  