message: Fix `Recipe::hash` in `download_progress` example
diff: @@ -20,7 +20,9 @@ where
  fn hash(&self, state: &mut H) {
  use std::hash::Hash;
  +
  std::any::TypeId::of::<Self>().hash(state);
  + self.url.hash(state);
  }
  fn stream(
  