}

  /*
   * AbstractCollection fails the removeAll(null) test when the subject
   * collection is empty, but we'd still like to test removeAll(null) when we
   * can. We split the test into empty and non-empty cases. This allows us to
   * suppress only the former.
   */

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(ZERO)
  public void testRemoveAll_nullCollectionReferenceEmptySubject() {

   * {@link #add(Object)} or {@link #pollFirstEntry}. This skeleton implementation correctly
   * delegates each of its operations to the appropriate methods of this {@code
   * ForwardingSortedMultiset}.
   *
   * <p>In many cases, you may wish to override {@link #descendingMultiset()} to return an instance
   * of a subclass of {@code StandardDescendingMultiset}.
   *
   * @since 15.0
   */

   *       future.transform(...).transform(...).transform(...)....}), they may overflow the stack.
   *       (In simple cases, callers can avoid this by registering all tasks with the same {@link
   *       MoreExecutors#newSequentialExecutor} wrapper around {@code directExecutor()}. More
   *       complex cases may require using thread pools or making deeper changes.)

  }

  @Override
  public @Nullable E edgeConnectingOrNull(N nodeU, N nodeV) {
    Set<E> edgesConnecting = edgesConnecting(nodeU, nodeV);
    switch (edgesConnecting.size()) {
      case 0:
        return null;
      case 1:
        return edgesConnecting.iterator().next();
      default:
        throw new IllegalArgumentException(String.format(MULTIPLE_EDGES_CONNECTING, nodeU, nodeV));
    }
  }

   *       // perform a unit of work
   *     }
   *   }
   * </pre>
   *
   * <p>...or you could respond to stop requests by implementing {@link #triggerShutdown()}, which
   * should cause {@link #run()} to return.
   */
  protected abstract void run() throws Exception;

  /**
   * Stop the service. This method is invoked on the execution thread.
   *
   * <p>By default this method does nothing.

{* ../../docs_src/background_tasks/tutorial001_py39.py hl[6:9] *}

## Adicione a tarefa em segundo plano { #add-the-background-task }

Dentro da sua *função de operação de rota*, passe sua função de tarefa para o objeto de *tarefas em segundo plano* com o método `.add_task()`:

{* ../../docs_src/background_tasks/tutorial001_py39.py hl[14] *}

O `.add_task()` recebe como argumentos:

	if err != nil {
		c.Fatalf("Unable to attach policy: %v", err)
	}

	cases := []struct {
		tokenType  string
		fullRevoke bool
		selfRevoke bool
	}{
		{"", true, false},        // Case 1
		{"", true, true},         // Case 2
		{"type-1", false, false}, // Case 3
		{"type-2", false, true},  // Case 4
		{"type-2", true, true},   // Case 5 - repeat type 2 to ensure previous revoke does not affect it.
	}

	defer cancel()

	switch {
	case usersPrefix:
		accessKey := path.Dir(strings.TrimPrefix(event.keyPath, iamConfigUsersPrefix))
		err = sys.store.UserNotificationHandler(ctx, accessKey, regUser)
	case stsPrefix:
		accessKey := path.Dir(strings.TrimPrefix(event.keyPath, iamConfigSTSPrefix))
		err = sys.store.UserNotificationHandler(ctx, accessKey, stsUser)
	case svcPrefix:

 * allowed to be reclaimed if nobody is holding on to them. This is useful, for example, if one
 * wants to create a {@code Striped<Lock>} of many locks, but worries that in most cases only a
 * small portion of these would be in use.
 *
 * <p>Prior to this class, one might be tempted to use {@code Map<K, Lock>}, where {@code K}

    switch (type) {
        case DURABLE_V1:
            addCreateContext(new DurableHandleRequest());
            break;
            
        case DURABLE_V2:
            addCreateContext(new DurableHandleV2Request(timeout, false));
            break;
            
        case PERSISTENT:
            addCreateContext(new DurableHandleV2Request(0, true));