Constant solana_sdk::epoch_schedule::DEFAULT_LEADER_SCHEDULE_SLOT_OFFSET

pub const DEFAULT_LEADER_SCHEDULE_SLOT_OFFSET: u64 = DEFAULT_SLOTS_PER_EPOCH; // 0x0000_0000_0006_9780u64

The number of slots before an epoch starts to calculate the leader schedule. Default is an entire epoch, i.e. leader schedule for epoch X is calculated at the beginning of epoch X - 1.