message: Fix flaky stats tests. Fixes
diff: use rand::{Rand, Rng, XorShiftRng, self};
  pub fn vec<T>(size: usize, start: usize) -> Option<Vec<T>> where T: Rand {
  - if size > start + 1 {
  + if size > start + 2 {
  let mut rng: XorShiftRng = rand::thread_rng().gen();
  Some((0..size).map(|_| rng.gen()).collect())
  