Function scheduled_feedback_sinks 

pub fn scheduled_feedback_sinks<P, T>(
    transport: T,
    config: LogStreamSenderConfig,
    clock: RobotClock,
) -> CuResult<(ScheduledCopperListSink<P>, ScheduledKeyFrameSink, SenderMonitor)>
where
    P: CopperListTuple + Send + Sync,
    T: CuStreamTx + CuFeedbackRx + 'static,

Explicitly enable the advisory receive direction; the manifest must advertise it.