docs: public void modify(long orderId, long size) {
      Order order = orders.get(orderId);
      if (order == null) {
        return;
      }
  
      OrderBook book = order.getOrderBook();
  
      long newSize = Math.max(0, size);
  
      boolean bbo =
          book.update(order.getSide(), order.getPrice(), newSize - order.getRemainingQuantity());
  
      if (newSize == 0) {
        orders.remove(orderId);
      } else {
        order.setRemainingQuantity(newSize);
      }
  
      listener.update(book, bbo);
    }