anchor.diff:  
   %% @doc Return the number of requests in the queue.
   %% @end
  --spec size(#requestqueue{}) -> non_neg_integer().
  +-spec size(rqueue()) -> non_neg_integer().
   size(Requestqueue) ->
       #requestqueue{queue=Queue} = Requestqueue,
       queue:len(Queue).
  
positive.code: %% @doc Delete a specific request from the request queue
  %% @end
  -spec delete(pieceindex(), chunkoffset(),
               chunklength(), #requestqueue{}) -> rqueue().
  delete(Piece, Offset, Length, Requestqueue) ->
      %% The implementation of queue will not change in a 1000 years
      #requestqueue{queue=Queue} = Requestqueue,
  
negative.code: %% The queue returns a new queue including the new request.
  %% @end
  -spec push(pieceindex(), chunkoffset(),
             chunklength(), rqueue()) -> rqueue().
  push(Pieceindex, Offset, Length, Requestqueue) ->
      #requestqueue{queue=Queue} = Requestqueue,
      NewQueue = queue:in({Pieceindex, Offset, Length}, Queue),
  