message: use sorting method in bench
diff: @@ -35,7 +35,7 @@ fn create_csmat_from_unsorted(bench: &mut Bencher) {
  let mut rng = rand::rngs::SmallRng::seed_from_u64(42);
  indices.shuffle(&mut rng);
  let values = values.clone();
  - let _v = CsVec::new(N, indices, values);
  + let _v = CsVec::new_sorted(N, indices, values).unwrap();
  });
  }
  