Function get_vec_len

crates/ixon/src/metadata.rs:555–557

(buf: &mut &[u8])

  match tag {
    0 => Some(env::Int::OfNat(bignat::Nat::from_le_bytes(rest))),
    1 => Some(env::Int::NegSucc(bignat::Nat::from_le_bytes(rest))),
    _ => None,
  }
}

fn deser_substring(