anchor.diff:  
   
   -spec parse_properties(binary()) -> {ok, [mqtt5_property()], binary} |
  -                                    {error, {reason_code, reason_type()}}.
  +                                    {error, any()}.
   parse_properties(Data) ->
       case parse_varint(Data) of
           {PropertiesData, Rest} ->
  
positive.code: ensure_binary(empty) -> empty. % for test purposes
  
  properties(undefined) ->
      <<0:16>>;
  properties([]) ->
      <<0:16>>.
  
  %%%%%%% packet generator functions (useful for testing)
  gen_connect(ClientId, Opts) ->
  
negative.code:                                                 client_id = ClientId},
                      parse_will_properties(Rest2, Flags, Conn1);
                  _ ->
                      {error, cant_parse_client_id}
              end;
          E -> E
      end;
  