message: Premultiply the sum in resize
  post-commit:
  3,690,245 ns/iter (+/- 37,547) = 552 MB/s
diff: @@ -255,6 +255,7 @@ where
  ws.push(w);
  sum += w;
  }
  + ws.iter_mut().for_each(|w| *w /= sum);
  for y in 0..height {
  let t = ws
  @@ -279,13 +280,12 @@ where
  )
  });
  - let (t1, t2, t3, t4) = (t.0 / sum, t.1 / sum, t.2 / sum, t.3 / sum);
  // Keeping the clamp improves performance.
  let t: P = Pixel::from_channels(
  - NumCast::from(clamp(t1.round(), min, max)).unwrap(),
  - NumCast::from(clamp(t2.round(), min, max)).unwrap(),
  - NumCast::from(clamp(t3.round(), min, max)).unwrap(),
  - NumCast::from(clamp(t4.round(), min, max)).unwrap(),
  + NumCast::from(clamp(t.0.round(), min, max)).unwrap(),
  + NumCast::from(clamp(t.1.round(), min, max)).unwrap(),
  + NumCast::from(clamp(t.2.round(), min, max)).unwrap(),
  + NumCast::from(clamp(t.3.round(), min, max)).unwrap(),
  );
  out.put_pixel(outx, y, t);
  @@ -343,6 +343,7 @@ where
  ws.push(w);
  sum += w;
  }
  + ws.iter_mut().for_each(|w| *w /= sum);
  for x in 0..width {
  let t = ws
  @@ -367,12 +368,11 @@ where
  )
  });
  - let (t1, t2, t3, t4) = (t.0 / sum, t.1 / sum, t.2 / sum, t.3 / sum);
  let t: P = Pixel::from_channels(
  - NumCast::from(clamp(t1.round(), min, max)).unwrap(),
  - NumCast::from(clamp(t2.round(), min, max)).unwrap(),
  - NumCast::from(clamp(t3.round(), min, max)).unwrap(),
  - NumCast::from(clamp(t4.round(), min, max)).unwrap(),
  + NumCast::from(clamp(t.0.round(), min, max)).unwrap(),
  + NumCast::from(clamp(t.1.round(), min, max)).unwrap(),
  + NumCast::from(clamp(t.2.round(), min, max)).unwrap(),
  + NumCast::from(clamp(t.3.round(), min, max)).unwrap(),
  );
  out.put_pixel(x, outy, t);
  