<version>1.0.0</version>
      <description><![CDATA[Root element of the <code>extension.xml</code> file.]]></description>
      <fields>
        <field>
          <name>exportedPackages</name>
          <version>1.0.0</version>
          <association>
            <type>String</type>
            <multiplicity>*</multiplicity>
          </association>

`UploadFile` tiene los siguientes métodos `async`. Todos ellos llaman a los métodos correspondientes del archivo por debajo (usando el `SpooledTemporaryFile` interno).

* `write(data)`: Escribe `data` (`str` o `bytes`) en el archivo.
* `read(size)`: Lee `size` (`int`) bytes/caracteres del archivo.
* `seek(offset)`: Va a la posición de bytes `offset` (`int`) en el archivo.

    def post_router(item1: Item, item2: Item):
        return item1, item2  # pragma: nocover

    app.include_router(router)
    client = TestClient(app)
    response = client.get("/openapi.json")
    data = response.json()
    assert data == {
        "openapi": "3.1.0",
        "info": {"title": "FastAPI", "version": "0.1.0"},
        "paths": {
            "/": {
                "post": {
                    "summary": "Post Root",

        .setHeader("content-type", "text/event-stream")
        .body("data: hey\n\n")
        .build(),
    )
    newEventSource()
    listener.assertFailure("timeout")
  }

  @Test
  fun retainsAccept() {
    server.enqueue(
      MockResponse
        .Builder()
        .body(
          """
          |data: hey
          |
          |
          """.trimMargin(),

  const val FLAG_END_STREAM = 0x1 // Used for headers and data.
  const val FLAG_END_HEADERS = 0x4 // Used for headers and continuation.
  const val FLAG_END_PUSH_PROMISE = 0x4
  const val FLAG_PADDED = 0x8 // Used for headers and data.
  const val FLAG_PRIORITY = 0x20 // Used for headers.
  const val FLAG_COMPRESSED = 0x20 // Used for data.

  /** Lookup table for valid frame types. */
  private val FRAME_NAMES =

- **Size of Serialized Data:**
Java serialization tends to produce larger serialized objects because it includes class metadata and other overhead.

- **Flexibility and Control:**
Java serialization offers limited control over the serialization process, such as excluding certain fields, customizing naming conventions, and handling complex data structures more gracefully.

- **Security:**

    company_name: str
    industry: str


@app.post("/form-union/")
def post_union_form(data: Annotated[Union[UserForm, CompanyForm], Form()]):
    return {"received": data}


client = TestClient(app)


def test_post_user_form():
    response = client.post(
        "/form-union/", data={"name": "John Doe", "email": "******@****.***"}
    )
    assert response.status_code == 200, response.text

`UploadFile` має такі асинхронні `async` методи. Вони викликають відповідні методи файлу під капотом (використовуючи внутрішній `SpooledTemporaryFile`).

* `write(data)`: Записує `data` (`str` або `bytes`) у файл.
* `read(size)`: Читає `size` (`int`) байтів/символів з файлу.
* `seek(offset)`: Переміщується до позиції `offset` (`int`) у файлі.

@pytest.mark.anyio
async def test_upload_file():
    stream = io.BytesIO(b"data")
    file = UploadFile(filename="file", file=stream, size=4)
    assert await file.read() == b"data"
    assert file.size == 4
    await file.write(b" and more data!")
    assert await file.read() == b""
    assert file.size == 19
    await file.seek(0)
    assert await file.read() == b"data and more data!"

   * data, and vertical if there is variance in the {@code y} data but not the {@code x} data.
   *
   * <p>This fit minimizes the root-mean-square error in {@code y} as a function of {@code x}. This
   * error is defined as the square root of the mean of the squares of the differences between the
   * actual {@code y} values of the data and the values predicted by the fit for the {@code x}