Function push_ticket_face_value 

fn push_ticket_face_value<G>(
    graph: &G,
    ticket_price: &Arc<RwLock<HoprBalance>>,
    win_probability: &Arc<RwLock<WinningProbability>>,
)
where
    G: NetworkGraphUpdate,

Recomputes the single-hop ticket face value and pushes it into the graph.

price / win_probability is the amount that makes the expected payout per packet equal the ticket price, i.e. one ticket’s face value. Edges store only a balance, so this is the one place pricing enters path selection — and a change costs a single write rather than an edge sweep.