Contains the size of the bet that draws the current trade.
It is used normally with bet of bid type * that means if the size is positive create a bet of type back, if the size is negative create a bet of type lay.


<bet index="2" bid_type="*">
<place condition="@trade_profit < -2"
    price="@draw_price" size="@draw_size" />
If the loss of the trade is greater than 2, place a bet (pending) to get a zero profit&loss.