[FastAPI docs for Custom Response - HTML, Stream, File, others](https://fastapi.tiangolo.com/advanced/custom-response/).
    """

    def render(self, content: Any) -> bytes:
        assert ujson is not None, "ujson must be installed to use UJSONResponse"
        return ujson.dumps(content, ensure_ascii=False).encode("utf-8")


class ORJSONResponse(JSONResponse):
    """

To achieve this, the backend must have a list of "allowed origins".

In this case, it would have to include `http://localhost:8080` for the frontend to work correctly.

## Wildcards

    name: str
    description: Optional[str] = None
    model_b: ModelB

    @validator("name")
    def lower_username(cls, name: str, values):
        if not name.endswith("A"):
            raise ValueError("name must end in A")
        return name


async def get_model_c() -> ModelC:
    return ModelC(username="test-user", password="test-password")


@app.get("/model/{name}", response_model=ModelA)

                            },
                        },
                    },
                    "summary": "Create an item",
                    "description": "Create an item with all the information:\n\n- **name**: each item must have a name\n- **description**: a long description\n- **price**: required\n- **tax**: if the item doesn't have tax, you can omit this\n- **tags**: a set of unique tag strings for this item",

        Optional[float],
        Doc(
            """
            Greater than. If set, value must be greater than this. Only applicable to
            numbers.
            """
        ),
    ] = None,
    ge: Annotated[
        Optional[float],
        Doc(
            """
            Greater than or equal. If set, value must be greater than or equal to
            this. Only applicable to numbers.
            """

                "msg": "Value error, name must end in A",
                "input": "modelX",
                "ctx": {"error": HasRepr("ValueError('name must end in A')")},
            }
        )
        | IsDict(
            # TODO remove when deprecating Pydantic v1
            {
                "loc": ("response", "name"),
                "msg": "name must end in A",
                "type": "value_error",
            }

        return uuid.UUID

    @property
    def __dict__(self):
        """Spoof a missing __dict__ by raising TypeError, this is how
        asyncpg.pgroto.pgproto.UUID behaves"""
        raise TypeError("vars() argument must have __dict__ attribute")


@needs_pydanticv2
def test_pydanticv2():
    from pydantic import field_serializer

    app = FastAPI()

    @app.get("/fast_uuid")
    def return_fast_uuid():

    with pytest.raises(ResponseValidationError) as err:
        client.get("/model/modelX")
    assert err.value.errors() == [
        {
            "loc": ("response", "name"),
            "msg": "name must end in A",
            "type": "value_error",
        }
    ]


@needs_pydanticv1
def test_openapi_schema(client: TestClient):
    response = client.get("/openapi.json")

The spec also states that the `username` and `password` must be sent as form data (so, no JSON here).

### `scope`

The spec also says that the client can send another form field "`scope`".

The form field name is `scope` (in singular), but it is actually a long string with "scopes" separated by spaces.

Each "scope" is just a string (without spaces).

* Processing data:
    * For example, let's say you receive a file that must go through a slow process, you can return a response of "Accepted" (HTTP 202) and process it in the background.

## Using `BackgroundTasks`