anchor.diff:                          if sofar = 0 then
                               first <- i
                               overflows.Clear()
  -                            sofar <- PAGE_OVERHEAD
  +                            sofar <- PARENT_PAGE_OVERHEAD
                           if calcAvailable sofar (nextGeneration.Count = 0) >= neededForInline then
                               sofar <- sofar + k.Length
                           else
  
positive.code:                         let couldBeRoot = (nextGeneration.Count = 0)
                          let avail = calcAvailable sofar couldBeRoot
                          let fitsInline = (avail >= neededForInline)
                          let wouldFitInlineOnNextPage = ((pageSize - PAGE_OVERHEAD) >= neededForInline)
                          let fitsOverflow = (avail >= neededForOverflow)
                          let flushThisPage = isLastChild || ((not fitsInline) && (wouldFitInlineOnNextPage || (not fitsOverflow))) 
                          let isRootNode = isLastChild && couldBeRoot
  
negative.code: 
                  pb.PutInt32 (prevPageNumber) // prev page num.
                  pb.PutInt16 (0) // number of pairs in this page. zero for now. written at end.
                  // assert pb.Position is 8 (LEAF_PAGE_OVERHEAD - sizeof(lastInt32))
              (*
               * one of the following cases must now be true:
               * 
  