Function randomized_election_timeout 

pub fn randomized_election_timeout(
    base: Duration,
    jitter: Duration,
    seed: u64,
) -> Duration

A randomized election timeout in [base, base + jitter).

Randomization keeps candidates from standing in lockstep, which is what makes split votes rare and self-correcting (requirement 4). The function is pure in seed so tests pin a deterministic value; production passes an entropy-derived seed.