fn apply_position_fill(
positions: &mut EnginePositionMap,
wallet: WalletAddress,
symbol: &str,
signed_qty: Decimal,
fill_price: Decimal,
) -> Decimalfn apply_position_fill(
positions: &mut EnginePositionMap,
wallet: WalletAddress,
symbol: &str,
signed_qty: Decimal,
fill_price: Decimal,
) -> Decimal