anchor.diff:                                                 ref=Ref}) ->
       FoldFun = fold_buckets_fun(FoldBucketsFun),
       FirstKey = to_first_key(undefined),
  -    FoldOpts1 = [{first_key, FirstKey} | FoldOpts],
  +    FoldOpts1 = [{start_key, FirstKey} | FoldOpts],
       BucketFolder =
           fun() ->
                   try
  
positive.code: 
      %% Set up the fold...
      FirstKey = to_first_key(Limiter),
      FoldOpts1 = IteratorRefresh ++ [{first_key, FirstKey} | FoldOpts],
      FoldFun = fold_objects_fun(FoldObjectsFun, Limiter),
  
      ObjectFolder =
  
negative.code:     %% Set up the fold...
      FirstKey = to_first_key(Limiter),
      FoldFun = fold_keys_fun(FoldKeysFun, Limiter),
      FoldOpts1 = [{start_key, FirstKey} | FoldOpts],
      ExtraFold = not FixedIdx orelse WriteLegacyIdx,
      KeyFolder =
          fun() ->
  