// DEK is a data encryption key. It consists of a
// plaintext-ciphertext pair and the ID of the key
// used to generate the ciphertext.
//
// The plaintext can be used for cryptographic
// operations - like encrypting some data. The
// ciphertext is the encrypted version of the
// plaintext data and can be stored on untrusted
// storage.
type DEK struct {
	KeyID      string // Name of the master key

	}
	return nil
}

// startReader will start a reader that accepts input from r.input.
// Input should be root -> object input. Each root indicates a record.
// If r.input is closed, it is assumed that no more input will come.
// When this function returns r.readerWg will be decremented and r.decoded will be closed.
// On errors, r.err will be set. This should only be accessed after r.decoded has been closed.
func (r *Reader) startReader() {

             Searching for package file structure from directories
             with <font color="#3465A4">__init__.py</font> files
             Importing from <font color="#75507B">/home/user/code/</font><font color="#AD7FA8">awesomeapp</font>

   <span style="background-color:#007166"><font color="#D3D7CF"> module </font></span>  🐍 main.py

            List<UpgradedProperty> upgradedProperties = new Gson().fromJson(reader, new TypeToken<List<UpgradedProperty>>() {}.getType());
            // FIXME There should be no duplicates, yet there are some
            return upgradedProperties.stream()
                .distinct()
                .collect(ImmutableList.toImmutableList());
        } catch (IOException e) {

    // Don't copy this into your own test!
    // Use e.g. awaitClear or await(CountDownLatch) instead.
    GcFinalization.awaitFullGc();

    // Attempt to help with some flakiness that we've seen: b/387521512.
    GcFinalization.awaitFullGc();

    assertEquals(0, finalizerRan.getCount());
    assertThat(ref.get()).isNull();
  }

    /*
     * No mutable Table exactly matches the insertion order behavior of ImmutableTable.Builder, but
     * the Builder can't efficiently support merging of duplicate values.  Getting around this
     * requires some work.
     */

    return Collector.of(
        ImmutableTableCollectorState<R, C, V>::new,
        (state, input) ->
            state.put(
                rowFunction.apply(input),

   *
   * <p>The {@code @Nullable} annotations on the {@code equalityGroup} parameter imply that the
   * objects, and the array itself, can be null. That is for programmer convenience, when the
   * objects come from factory methods that are themselves {@code @Nullable}. In reality neither the
   * array nor its contents can be null, but it is not useful to force the use of {@code
   * requireNonNull} or the like just to assert that.
   *

在路徑操作函式內，使用 `.add_task()` 將任務函式加入背景任務物件：

{* ../../docs_src/background_tasks/tutorial001_py310.py hl[14] *}

`.add_task()` 的引數包括：

* 要在背景執行的任務函式（`write_notification`）。
* 依序傳給任務函式的位置引數（`email`）。
* 要傳給任務函式的關鍵字引數（`message="some notification"`）。

## 相依性注入 { #dependency-injection }

在相依性注入系統中也可使用 `BackgroundTasks`。你可以在多個層級宣告 `BackgroundTasks` 型別的參數：路徑操作函式、相依項（dependable）、次級相依項等。

**FastAPI** 會在各種情況下正確處理並重用同一個物件，將所有背景任務合併，並在之後於背景執行：

	}
	if isSysErrHandleInvalid(err) {
		return errFileNotFound
	}
	if isSysErrIO(err) {
		return errFaultyDisk
	}
	if isSysErrInvalidArg(err) {
		storageLogIf(context.Background(), err)
		// For some odd calls with O_DIRECT reads
		// filesystems can return EINVAL, handle
		// these as FileNotFound instead.
		return errFileNotFound
	}
	if isSysErrNoSpace(err) {
		return errDiskFull
	}
	return err

   * the {@link Multimap} class documentation for clarification.
   */
  int size();

  /**
   * Returns {@code true} if this multimap contains no key-value pairs. Equivalent to {@code size()
   * == 0}, but can in some cases be more efficient.
   */
  boolean isEmpty();

  /**
   * Returns {@code true} if this multimap contains at least one key-value pair with the key {@code
   * key}.
   */