Nightly stability failure: write ltx file: persistent error" elapsed=151.476343ms remaining=9.848523226s

## Nightly Stability Failure

**Latest run:** https://github.com/benbjohnson/litestream/actions/runs/33352442494
**Branch:** `main`
**Commit:** `25ac743d`
**First seen:** 2026-07-27T19:48:34.762Z
**Last seen:** 2026-08-31T03:35:04.903Z
**Occurrences:** 4
**Fingerprint:** `bee53f356207dd15`

### Failed Jobs

| Job | Failed step | Summary |
|---|---|---|
| Race Detector Sweep | Run tests with race detector (3x) | write ltx file: persistent error" elapsed=151.476343ms remaining=9.848523226s |

### Failure Details

#### Race Detector Sweep

- Job: https://github.com/benbjohnson/litestream/actions/runs/33352442494/job/99368268209
- Failed step: `Run tests with race detector (3x)`
- Summary: write ltx file: persistent error" elapsed=151.476343ms remaining=9.848523226s

```text
2026-08-31T03:03:43.2976934Z time=2026-08-31T03:03:12.903Z level=WARN msg="shutdown sync failed, retrying (press Ctrl+C again to skip)" attempts=4 error="write ltx file: persistent error" elapsed=151.476343ms remaining=9.848523226s
2026-08-31T03:03:43.2974696Z time=2026-08-31T03:03:12.752Z level=WARN msg="shutdown sync failed, retrying (press Ctrl+C again to skip)" attempts=1 error="write ltx file: persistent error" elapsed=228.878µs remaining=9.999770902s
2026-08-31T03:03:43.2970408Z time=2026-08-31T03:03:12.602Z level=WARN msg="shutdown sync failed, retrying" attempts=3 error="write ltx file: error" elapsed=100.890042ms remaining=9.899109637s
```

Start by reproducing the “Run tests with race detector (3x)” failure from the linked nightly run and tracing the shutdown sync path that reports “write ltx file: persistent error.” Done means the race-detector tests complete without this recurring shutdown-sync failure.

Written by the indexing model from the issue text.