`IterPinRef` yields `Pin<&Fut>` (shared references), so sending it
across threads requires `Fut: Sync`, not `Fut: Send`. The previous
bound allowed a data race when a `Send + !Sync` type (e.g. `Cell`)
was shared via iterators on two threads simultaneously.

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [futures](https://rust-lang.github.io/futures-rs) ([source](https://github.com/rust-lang/futures-rs)) | dependencies | patch | `0.3.32` → `0.3.34` |

---

### Release Notes

<details>
<summary>rust-lang/futures-rs (futures)</summary>

### [`v0.3.34`](https://github.com/rust-lang/futures-rs/blob/HEAD/CHANGELOG.md#0334---2026-08-11)

[Compare Source](rust-lang/futures-rs@0.3.33...0.3.34)

- Preserve cloned waker identity. ([#&#8203;3032](rust-lang/futures-rs#3032))
- Updato `syn` to 3. ([#&#8203;3028](rust-lang/futures-rs#3028))

### [`v0.3.33`](https://github.com/rust-lang/futures-rs/blob/HEAD/CHANGELOG.md#0333---2026-07-18)

[Compare Source](rust-lang/futures-rs@0.3.32...0.3.33)

- Fix `ReadLine`'s soundness issue regarding to exception safety. ([#&#8203;3020](rust-lang/futures-rs#3020))
- Fix unsound `Send` impl for `IterPinRef` and `Iter`. ([#&#8203;3003](rust-lang/futures-rs#3003))
- Fix stacked borrows violation in `compat01as03` implementation. ([#&#8203;3012](rust-lang/futures-rs#3012))
- Fix memory leak in `FuturesUnordered::IntoIter`. ([#&#8203;3005](rust-lang/futures-rs#3005))
- Add `portable-atomic-alloc` feature and use it in `FuturesUnordered`. ([#&#8203;3007](rust-lang/futures-rs#3007))
- Re-export `alloc::task::Wake`. ([#&#8203;3010](rust-lang/futures-rs#3010))
- Update `spin` to 0.12. ([#&#8203;3014](rust-lang/futures-rs#3014))

</details>

---

### Configuration

📅 **Schedule**: (UTC)

- Branch creation
  - "before 9am on tuesday"
- Automerge
  - At any time (no schedule defined)

🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update again.

---

 - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box

---

This PR has been generated by [Mend Renovate CLI](https://github.com/renovatebot/renovate).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0NC4xMzMuMCIsInVwZGF0ZWRJblZlciI6IjQ0LjEzMy4wIiwidGFyZ2V0QnJhbmNoIjoiZGV2ZWxvcCIsImxhYmVscyI6WyJkZXBlbmRlbmNpZXMiLCJyZW5vdmF0ZSJdfQ==-->

Reviewed-on: https://code.futo.org/harbor/harbor/pulls/1791
Reviewed-by: Thomas de Zeeuw <thomas@futo.org>