anchor.diff:  %% @private
   receive_stream(Ref, F, Acc) ->
     receive
  -    {Ref, {_, Stream, _}} ->
  -      receive_stream(Ref, F, F(Stream, Acc));
  -    {Ref, {done, _}} ->
  +    {Ref, {_, Keys, _}} ->
  +      receive_stream(Ref, F, F(Keys, Acc));
  +    {Ref, {done, _Continuation = undefined}} ->
         {ok, Acc};
  -    _ ->
  -      {error, Acc}
  +    Unexpected ->
  +      {error, {unexpected, Unexpected}, Acc}
     after
  -    30000 -> {timeout, Acc}
  +    30000 -> {error, timeout, Acc}
     end.
   
   %% @private
  
positive.code:   case fetch_map(Conn, Bucket, sumo_utils:to_bin(Id), Opts) of
      {ok, RMap} ->
        {ok, rmap_to_doc(DocName, RMap), State};
      {error, {notfound, _}} ->
        {error, notfound, State};
      {error, Error} ->
        {error, Error, State}
  
negative.code:     undefined ->
        case update_map(Conn, Bucket, undefined, doc_to_rmap(Doc), Opts) of
          {ok, RiakMapId} -> RiakMapId;
          {error, Error}  -> exit(Error);
          Unexpected      -> exit({unexpected, Unexpected})
        end;
      Id0 ->
        sumo_utils:to_bin(Id0)
  