return
	}

	// It is required that parent user be set.
	if res.Success.User == "" {
		writeSTSErrorResponse(ctx, w, ErrSTSUpstreamError, errors.New("A valid user was not returned by the authenticator."))
		return
	}

	// Expiry is set as minimum of requested value and value allowed by auth
	// plugin.
	expiry := res.Success.MaxValiditySeconds

      this.alphabet = checkNotNull(alphabet);
      checkArgument(
          paddingChar == null || !alphabet.matches(paddingChar),
          "Padding character %s was already in alphabet",
          paddingChar);
      this.paddingChar = paddingChar;
    }

    @Override
    int maxEncodedSize(int bytes) {

				writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
				return
			}
		}
		// Set this for multipart only operations, we need to differentiate during
		// decryption if the file was actually multipart or not.
		encMetadata[ReservedMetadataPrefix+"Encrypted-Multipart"] = ""
	}

	// Extract metadata that needs to be saved.
	metadata, err := extractMetadataFromReq(ctx, r)
	if err != nil {

	}
	cancel()
	<-serverCanceled
	local.debugMsg(debugIsOutgoingClosed, st.muxID, func(closed bool) {
		if !closed {
			t.Error("expected outgoing closed")
		} else {
			t.Log("outgoing was closed")
		}
	})

	// Drain responses and check if error propagated.
	err = st.Results(func(b []byte) error {
		return nil
	})
	if !errors.Is(err, context.Canceled) {

   * list is a transformed view of {@code fromList}; changes to {@code fromList} will be reflected
   * in the returned list and vice versa.
   *
   * <p>Since functions are not reversible, the transform is one-way and new items cannot be stored
   * in the returned list. The {@code add}, {@code addAll} and {@code set} methods are unsupported
   * in the returned list.
   *

    return burgers
```

使用 `async def`，Python 知道在該函式內需要注意 `await`，並且它可以「暫停」 ⏸ 執行該函式，然後執行其他任務 🔀 後回來。

當你想要呼叫 `async def` 函式時，必須使用「await」。因此，這樣寫將無法運行：

```Python
# This won't work, because get_burgers was defined with: async def
burgers = get_burgers(2)
```

---

如果你正在使用某個函式庫，它告訴你可以使用 `await` 呼叫它，那麼你需要用 `async def` 定義*路徑操作函式*，如：

```Python hl_lines="2-3"
@app.get('/burgers')

  @GwtIncompatible // too slow
  public void testCombinationsExhaustively_startingFromArbitrary() {
    Ordering<Object> arbitrary = Ordering.arbitrary();
    Object[] array = {1, "foo", new Object()};

    // There's no way to tell what the order should be except empirically
    sort(array, arbitrary);
    testExhaustively(arbitrary, array);
  }

  /**

  @GwtIncompatible // too slow
  public void testCombinationsExhaustively_startingFromArbitrary() {
    Ordering<Object> arbitrary = Ordering.arbitrary();
    Object[] array = {1, "foo", new Object()};

    // There's no way to tell what the order should be except empirically
    sort(array, arbitrary);
    testExhaustively(arbitrary, array);
  }

  /**

     */
    @Override
    protected void finalize() throws Throwable {
        try {
            if (isConnected() && this.usageCount.get() != 0) {
                log.warn("Session was not properly released, performing emergency cleanup: " + this);
                // Perform emergency cleanup to prevent memory leaks
                emergencyCleanup();
            }
        } catch (Exception e) {

        return removeOnlyNavigableSet(super.descendingSet());
      }
    };
  }

  /**
   * Returns an immutable map whose keys are the distinct elements of {@code keys} and whose value
   * for each key was computed by {@code valueFunction}. The map's iteration order is the order of
   * the first appearance of each key in {@code keys}.
   *