direct readable stream does not always flush data when the connection closes

[paperdave]

What version of Bun is running?

No response

What platform is your computer?

No response

What steps can reproduce the bug?

test("direct readable stream flushes data at end", async () => {
  using server = Bun.serve({
    port: 0,
    async fetch(req) {
      return new Response(new ReadableStream({
        type: "direct",
        async pull(ctrl: any) {
          ctrl.write('a');
          await sleep(10);
          ctrl.write('b');
          // ctrl.flush();
        },
      } as any));
    },
  });
  let response = await fetch(server.url);
  expect(await response.text()).toBe('ab');
});

What is the expected behavior?

No response

What do you see instead?

No response

Additional information

No response