anchor.diff:      R = encode_fastset(Rest),
       <<R/binary, Idx:32>>.
   
  +-spec extended_msg_contents(port(), string(), integer()) -> binary().
   extended_msg_contents(Port, ClientVersion, ReqQ) ->
       iolist_to_binary(
         etorrent_bcoding:encode(
  
positive.code: 	 {<<"reqq">>, ReqQ},
  	 {<<"m">>, empty_dict}])).
  
  
negative.code: %% completed by a call to complete_handshake/3.</p>
  %% @end
  -spec receive_handshake(port()) ->
      {'error',term() | {'bad_header',binary()}}
      | {'ok',['extended_messaging' | 'fast_extension',...],<<_:160>>}
      | {'ok',['extended_messaging' | 'fast_extension',...],<<_:160>>,<<_:160>>}.
  receive_handshake(Socket) ->
      Header = protocol_header(),
      case gen_tcp:send(Socket, Header) of
  