anchor.diff:                      else
                           st
   
  -                let addPairToLeaf (st:LeafState) =
  +                let st =
                       // TODO ignore prefixLen for overflowed keys?
                       let newPrefixLen = 
                           if List.isEmpty st.keys then
  
positive.code:                         prefixLen=newPrefixLen
                          }
                          
                  maybeWriteLeaf {st with blk=blkAfterValue} |> addPairToLeaf
  
              // this is the body of writeLeaves
              //let source = seq { csr.First(); while csr.IsValid() do yield (csr.Key(), csr.Value()); csr.Next(); done }
  
negative.code: 
                  // TODO is it possible for this to conclude that the key must be overflowed
                  // when it would actually fit because of prefixing?
  
                  let blkAfterKey,kloc = 
                      if k.Length <= maxKeyInline then
  