listenSync

declare function listenSync(fn: (event: OrderSyncContract) => void, warned?: boolean): () => void;

Subscribes to signal synchronization events with queued async processing. This is an order GATE: a throw from the listener rejects the open/close.

Emits when signals are being synchronized (e.g. pending signal being opened/closed).

Throw semantics (resolved into IBrokerOrderVerdict, identical to the Broker onOrderOpenCommit / onOrderCloseCommit channel):

plain Error or OrderTransientError → "transient": the open retries identity-stably (same signalId, event.attempt increments) up to CC_ORDER_OPEN_RETRY_ATTEMPTS; the close retries up to CC_ORDER_CLOSE_RETRY_ATTEMPTS, then the engine FORCE-CLOSES its state with the original closeReason. Exhaustion of either signals a fatal exit (exitEmitter).
OrderRejectedError → "rejected", TERMINAL at once: the open is dropped without arming the retry; the close is force-closed immediately. No exit signal (business outcome).
OrderDeletedError here is a userspace protocol violation (it belongs to the CHECK channel) and intentionally degrades to "transient".

Parameters

Parameter	Description
`fn`	Callback function to handle sync events. If the function returns a promise, signal processing will wait until it resolves.
`warned`