anchor.diff:  -spec push(msg(), buf()) -> buf().
   push(Msg, Buf = #lpdb{}) ->
       {_, NewBuf} = push_ext(Msg, Buf),
  -    NewBuf;
  -push(Msg, Buf = ?OLDBUF) ->
  -    push(Msg, convert(Buf)).
  +    NewBuf.
   
   -spec push_ext(msg(), buf()) -> {'displace' | 'insert', buf()}.
   push_ext(Msg, Buf = #lpdb{}) ->
  
positive.code: -endif.
  
  -spec lost(buf()) -> non_neg_integer().
  lost(#lpdb{loss_count=N}) -> N;
  lost(Buf = ?OLDBUF) -> lost(convert(Buf)).
  
  -spec to_pkts(buf(), IdealBytes::pos_integer(),
                framing_fun()) ->
  
negative.code:     ].
  
  -endif.
  