Function subscribe

subscribe<Mask extends string>(
    mask: Mask,
    callback: BackendEventCallback<
        Mask extends keyof BackendEvents
            ? BackendEvents[Mask<Mask>]
            : SimpleMarshallableRecord,
    >,
    options?: { signal?: AbortSignal },
): Promise<BackendEventSubscription>

subscribe(
    masks: string[],
    callback: BackendEventCallback,
    options?: { signal?: AbortSignal },
): Promise<BackendEventSubscription>