OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED

EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

    As always, in FastAPI you can combine `def` and `async def` as needed.

    If you need a refresher about when to use which, check out the section _"In a hurry?"_ in the docs about [`async` and `await`](../async.md#in-a-hurry){.internal-link target=_blank}.

9. This *path operation function* is not returning dataclasses (although it could), but a list of dictionaries with internal data.

     * won't be cleared as long as the enum constant is referenced somewhere, and the enum constant
     * is referenced somewhere for as long as the enum class is loaded. *Maybe in theory* the enum
     * class could be unloaded after the above call to `getEnumConstants` but before we call
     * `get()`, but that is vanishingly unlikely.
     */

 * java.util.function.Supplier}, making conversion code necessary only in one direction. At that
 * time, this interface will be officially discouraged.
 *
 * @author Harry Heymann
 * @since 2.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface Supplier<T extends @Nullable Object>
{
  /**

	// we should get the fd to dev null. note that we can't assert the fd number
	// as the kernel may have given us a different number that refers to the same file.
	assert.Equal(t, len(fds), 1)
	// in theory we should close the fd, but it's just a test..

	assert.Equal(t, m.Payload.(*zdsapi.WorkloadRequest_Add).Add.Uid, uid)
	// send ack so the server doesn't wait for us.
	sendAck(ztunClient)

    再一次，可以把 `dataclasses` 与标准类型注解一起使用；

8. 注意，*路径操作函数*使用的是普通函数，不是异步函数；

    与往常一样，在 FastAPI 中，可以按需组合普通函数与异步函数；

    如果不清楚何时使用异步函数或普通函数，请参阅**急不可待？**一节中对 <a href="https://fastapi.tiangolo.com/async/#in-a-hurry" target="_blank" class="internal-link">`async` 与 `await`</a> 的说明；

9. *路径操作函数*返回的不是数据类（虽然它可以返回数据类），而是返回内含数据的字典列表；

    FastAPI 使用（包含数据类的） `response_model` 参数转换响应。

把 `dataclasses` 与其它类型注解组合在一起，可以组成不同形式的复杂数据结构。

		err = BucketNotFound{Bucket: bucket}
	case "conflict":
		if message == "You already own this bucket. Please select another name." {
			err = BucketAlreadyOwnedByYou{Bucket: bucket}
			break
		}
		if message == "Sorry, that name is not available. Please try a different one." {
			err = BucketAlreadyExists{Bucket: bucket}
			break
		}
		err = BucketNotEmpty{Bucket: bucket}
	}

	return err

8️⃣. 👀 👈 👉 *➡ 🛠️ 🔢* ⚙️ 🥔 `def` ↩️ `async def`.

    🕧, FastAPI 👆 💪 🌀 `def` & `async def` 💪.

    🚥 👆 💪 ↗️ 🔃 🕐❔ ⚙️ ❔, ✅ 👅 📄 _"🏃 ❓" _ 🩺 🔃 <a href="https://fastapi.tiangolo.com/async/#in-a-hurry" target="_blank" class="internal-link">`async` &amp; `await`</a>.

9️⃣. 👉 *➡ 🛠️ 🔢* 🚫 🛬 🎻 (👐 ⚫️ 💪), ✋️ 📇 📖 ⏮️ 🔗 💽.

    FastAPI 🔜 ⚙️ `response_model` 🔢 (👈 🔌 🎻) 🗜 📨.