Function start_incoming_ack_pipeline 

async fn start_incoming_ack_pipeline<AckIn, T, TEvt>(
    ack_incoming: AckIn,
    ticket_events: TEvt,
    ticket_proc: Arc<T>,
    counters: PeerProtocolCounterRegistry,
    concurrency: usize,
)
where
    AckIn: Stream<Item = (OffchainPublicKey, Vec<Acknowledgement>)> + Send + 'static,
    T: UnacknowledgedTicketProcessor + Sync + Send + 'static,
    TEvt: Sink<TicketEvent> + Clone + Unpin + Send + 'static,
    TEvt::Error: Error,