byte[] buffer = new byte[256];
            System.arraycopy(SMBUtil.SMB2_HEADER, 0, buffer, 0, 4);
            // Set up async message fields
            SMBUtil.writeInt4(ServerMessageBlock2.SMB2_FLAGS_ASYNC_COMMAND, buffer, 16); // flags with async
            SMBUtil.writeInt8(789L, buffer, 32); // async ID
            SMBUtil.writeInt8(456L, buffer, 40); // session ID
            return buffer;
        }

<details markdown="1">
<summary>Or use <code>async def</code>...</summary>

If your code uses `async` / `await`, use `async def`:

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
async def read_item(item_id: int, q: Union[str, None] = None):

from fastapi.responses import JSONResponse

app = FastAPI()

items = {"foo": {"name": "Fighters", "size": 6}, "bar": {"name": "Tenders", "size": 3}}


@app.put("/items/{item_id}")
async def upsert_item(
    item_id: str,
    name: Annotated[Union[str, None], Body()] = None,
    size: Annotated[Union[int, None], Body()] = None,
):
    if item_id in items:
        item = items[item_id]

    if q:
        message = f"found query: {q}\n"
        background_tasks.add_task(write_log, message)
    return q


@app.post("/send-notification/{email}")
async def send_notification(
    email: str, background_tasks: BackgroundTasks, q: Annotated[str, Depends(get_query)]
):
    message = f"message to {email}\n"
    background_tasks.add_task(write_log, message)

    price: float
    tax: Union[float, None] = None


class User(BaseModel):
    username: str
    full_name: Union[str, None] = None


@app.put("/items/{item_id}")
async def update_item(
    *,
    item_id: int,
    item: Item,
    user: User,
    importance: int = Body(gt=0),
    q: Union[str, None] = None,
):

@dataclass
class Author:
    name: str
    items: list[Item] = field(default_factory=list)  # (3)


app = FastAPI()


@app.post("/authors/{author_id}/items/", response_model=Author)  # (4)
async def create_author_items(author_id: str, items: list[Item]):  # (5)
    return {"name": author_id, "items": items}  # (6)


@app.get("/authors/", response_model=list[Author])  # (7)
def get_authors():  # (8)

@dataclass
class Author:
    name: str
    items: list[Item] = field(default_factory=list)  # (3)


app = FastAPI()


@app.post("/authors/{author_id}/items/", response_model=Author)  # (4)
async def create_author_items(author_id: str, items: list[Item]):  # (5)
    return {"name": author_id, "items": items}  # (6)


@app.get("/authors/", response_model=list[Author])  # (7)
def get_authors():  # (8)

<details markdown="1">
<summary>또는 <code>async def</code> 사용하기...</summary>

여러분의 코드가 `async` / `await`을 사용한다면, `async def`를 사용하십시오.

```Python hl_lines="9 14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
async def read_item(item_id: int, q: Union[str, None] = None):

        "email": "******@****.***",
    },
    license_info={
        "name": "Apache 2.0",
        "url": "https://www.apache.org/licenses/LICENSE-2.0.html",
    },
)


@app.get("/items/")
async def read_items():

class JsonApiError(BaseModel):
    errors: list[Error]


@app.get(
    "/a/{id}",
    response_class=JsonApiResponse,
    responses={422: {"description": "Error", "model": JsonApiError}},
)
async def a(id):
    pass  # pragma: no cover


client = TestClient(app)


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text