Function open_orders_delta 

pub fn open_orders_delta(
    delta: &KrakenFuturesOpenOrdersDelta,
    state: &WsDispatchState,
    emitter: &ExecutionEventEmitter,
    instruments: &Arc<AtomicMap<InstrumentId, InstrumentAny>>,
    truncated_id_map: &Arc<AtomicMap<String, ClientOrderId>>,
    order_instrument_map: &Arc<AtomicMap<String, InstrumentId>>,
    venue_client_map: &Arc<AtomicMap<String, ClientOrderId>>,
    venue_order_qty: &Arc<AtomicMap<String, Quantity>>,
    account_id: AccountId,
    ts_init: UnixNanos,
)

Dispatches a Kraken Futures OpenOrdersDelta message.

Fill-driven cancel deltas (is_cancel=true with reason full_fill) are skipped - the corresponding FillsDelta carries the real fill, so emitting a synthetic Canceled here would race with the genuine OrderFilled. Part-fill removals (is_cancel=true with reason partial_fill) discard the order’s remainder and are terminal: they close the order only once the fills feed has accounted the removal’s cumulative filled, so a fill still in flight is never orphaned.