pub fn trading_params(id: &InstrumentId, i: &Instrument) -> TradingParamsExpand description
lot_size is units per lot. min_qty is one lot: an order is a whole number of lots (and the library
counts the quantity of an order in units).
price_step_value equals the step (price is per one instrument in the settlement currency);
futures need GetFuturesMargin for the step in money, not requested here.