anchor.diff:  %%  if no piece is eligible.
   %%--------------------------------------------------------------------
   select_piece_for_queueing(S, N) ->
  +    true = queue:is_empty(S#state.request_queue),
       case torrent_state:request_new_piece(S#state.state_pid,
   					 S#state.piece_set) of
   	{ok, PieceNum, PieceSize} ->
  
positive.code: 		 remote_request_set = none,
  
  		 piece_set = none,
  		 piece_request = none,
  
  		 file_system_pid = none,
  		 master_pid = none,
  
negative.code: 	    BF = torrent_state:retrieve_bitfield(S#state.state_pid),
  	    torrent_peer_send:send(SendPid, {bitfield, BF}),
  	    {noreply, S#state{tcp_socket = Socket,
  			      peer_id = PeerId,
  			      send_pid = SendPid}};
  	{error, _X} ->
  	    exit(shutdown)
  