anchor.diff:                              else
                                   let keyOverflowFirstPage = nextPageNumber
                                   let kRange = writeOverflow nextPageNumber boundaryPageNumber (new MemoryStream(k))
  -                                {args with sofar=sofar + neededForOverflow; nextPage=fst kRange; boundaryPage=snd kRange; overflows=overflows.Add(i,keyOverflowFirstPage)}
  +                                {args with sofar=sofar + neededForOverflow; nextPage=fst kRange; boundaryPage=snd kRange; overflows=overflows.Add(k,keyOverflowFirstPage)}
   
   
                       // this is the body of the folder function
  
positive.code:             nextPage:int; 
              boundaryPage:int; 
              //children:(int32*byte[]); 
              overflows:Map<int,int32>;
          }
  
      let Create(fs:Stream, pageManager:IPages, csr:ICursor) :int32 = 
  
negative.code:                     let allowanceForRootNode = if couldBeRoot then sizeof<int32> else 0 // first/last Leaf, lastInt32 already
                      basicSize - allowanceForRootNode
  
                  let buildParentPage stop start (overflows:Map<byte[],int32>) =
                      // assert stop > start
                      let countKeys = stop - start
                      pb.Reset ()
  