return err
	}
	defer resp.Body.Close()

	var accessToken Token
	if err = json.NewDecoder(resp.Body).Decode(&accessToken); err != nil {
		return err
	}

	k.Lock()
	k.accessToken = accessToken
	k.Unlock()
	return nil
}

// LookupUser lookup user by their userid.
func (k *KeycloakProvider) LookupUser(userid string) (User, error) {
	req, err := http.NewRequest(http.MethodGet, k.adminURL, nil)
	if err != nil {

 * If the type is {@link org.apache.maven.api.Node Node} or
 * {@code List<}{@link org.apache.maven.api.Node Node}{@code >},
 * and {@code pathScope != ""}, the dependencies will be <i>flattened</i>.
 * Else the dependencies will be <i>resolved</i> and {@code pathScope} must be non empty,
 * and the field type can be {@link org.apache.maven.api.Node Node},
 * {@code List<}{@link org.apache.maven.api.Node Node}{@code >},

* <a href="https://strawberry.rocks/" class="external-link" target="_blank">Strawberry</a> 🍓
    * Mit <a href="https://strawberry.rocks/docs/integrations/fastapi" class="external-link" target="_blank">Dokumentation für FastAPI</a>
* <a href="https://ariadnegraphql.org/" class="external-link" target="_blank">Ariadne</a>
    * Mit <a href="https://ariadnegraphql.org/docs/fastapi-integration" class="external-link" target="_blank">Dokumentation für FastAPI</a>

    }
  }

  /**
   * Invokes {@code future.}{@link Future#get() get()} uninterruptibly.
   *
   * <p>Similar methods:
   *
   * <ul>
   *   <li>To retrieve a result from a {@code Future} that is already done, use {@link
   *       Futures#getDone Futures.getDone}.
   *   <li>To treat {@link InterruptedException} uniformly with other exceptions, use {@link
   *       Futures#getChecked(Future, Class) Futures.getChecked}.

		if t.updating.TryLock() {
			go func() {
				defer t.updating.Unlock()
				t.update(context.Background())
			}()
		}
		return *v, nil
	}

	// Get lock. Either we get it or we wait for it.
	t.updating.Lock()
	defer t.updating.Unlock()

	if time.Since(time.UnixMilli(t.lastUpdateMs.Load())) < ttl {
		// There is a new value, release lock and return it.

  }

  @Override
  @ParametricNullness
  public E element() {
    return delegate().element();
  }

  /**
   * A sensible definition of {@link #offer} in terms of {@link #add}. If you override {@link #add},
   * you may wish to override {@link #offer} to forward to this implementation.
   *
   * @since 7.0
   */
  protected boolean standardOffer(@ParametricNullness E e) {
    try {
      return add(e);

            cal.setTime(date);
            return cal;
        }
        return null;
    }

    /**
     * Converts to a {@link Calendar} with the local {@link TimeZone} and {@link Locale}.
     *
     * @param calendar
     *            {@link Calendar}
     * @return The converted {@link Calendar}
     */
    public static Calendar localize(final Calendar calendar) {
        assertArgumentNotNull("calendar", calendar);

    * 您还可以关注<a href="https://x.com/fastapi" class="external-link" target="_blank">@fastapi on X (Twitter)</a>，这是个独立的账号
* <a href="https://www.linkedin.com/in/tiangolo/" class="external-link" target="_blank">在**领英**上联系我</a>
    * 接收我发布公告或新工具的消息（虽然我用 X (Twitter) 比较多）
* 阅读我在 <a href="https://dev.to/tiangolo" class="external-link" target="_blank">**Dev.to**</a> 或 <a href="https://medium.com/@tiangolo" class="external-link" target="_blank">**Medium**</a> 上的文章，或关注我

 *   <li>{@link Collections2}
 *   <li>{@link Comparators}
 *   <li>{@link Iterables}
 *   <li>{@link Iterators}
 *   <li>{@link Lists}
 *   <li>{@link Maps}
 *   <li>{@link MoreCollectors}
 *   <li>{@link Multimaps}
 *   <li>{@link Multisets}
 *   <li>{@link ObjectArrays}
 *   <li>{@link Queues}
 *   <li>{@link Sets}
 *   <li>{@link Streams}
 *   <li>{@link Tables}
 * </ul>
 *
 * <h2>Abstract implementations</h2>
 *

  /**
   * A sensible implementation of {@link Multiset#elementSet} in terms of the following methods:
   * {@link ForwardingMultiset#clear}, {@link ForwardingMultiset#contains}, {@link
   * ForwardingMultiset#containsAll}, {@link ForwardingMultiset#count}, {@link
   * ForwardingMultiset#isEmpty}, the {@link Set#size} and {@link Set#iterator} methods of {@link
   * ForwardingMultiset#entrySet}, and {@link ForwardingMultiset#remove(Object, int)}. In many