Function run 

pub async fn run<T, E, H, S>(
    schedule: SettlementSchedule,
    handler: H,
    settle: S,
) -> ScheduledSettlement<T, E>
where
    T: Send,
    E: Send,
    H: Future<Output = Result<T, E>> + Send,
    S: Future<Output = Result<SettleResponse, FacilitatorError>> + Send + 'static,

Concurrent / Background after-handler settle. Does not inspect transport status.

Sequential schedules are not executed as wait-then-settle; call finish.