pub fn dummy_challenger(config: &BabyBearPoseidon2) -> Challenger<BabyBearPoseidon2> {
    let mut challenger = config.challenger();
    challenger.input_buffer = vec![];
    challenger.output_buffer = vec![BabyBear::zero(); challenger.sponge_state.len()];
    challenger
}
Get a dummy duplex challenger for use in dummy proofs.
crates/recursion/circuit/src/stark.rs