Function ticket_created_topic 

pub fn ticket_created_topic() -> B256

Backlog update cost: read + write. Write cost depends on whether the new value is zero (StorageClearCost=5000) or non-zero (StorageWriteCost=20000). This is computed dynamically in handle_redeem based on current backlog.

TicketCreated event topic0. keccak256(“TicketCreated(bytes32)”)