pub fn stub_order_book_mbp(
instrument_id: InstrumentId,
top_ask_price: f64,
top_bid_price: f64,
top_ask_size: f64,
top_bid_size: f64,
price_precision: u8,
price_increment: f64,
size_precision: u8,
size_increment: f64,
num_levels: usize,
) -> OrderBook