Repro Sveltekit Request Body Consumption

1. Run npm i && npm run dev to start development server.
2. Open http://localhost:5173 to view it in the browser.
3. Open the Network tab of DevTools to see the requests being made.
4. Click the consume and error button. The request to /consume-and-error will fail. Observe that the request to /post finishes quite quickly.
5. Click the error button. The request to /error will fail. Observe that the request to /post takes a long time to finish.

The only difference between the /consume-and-error and /error endpoints is that the former consumes the request body before returning an error, while the latter does not.