*
 * @param <K> the most general key type this builder will be able to create caches for. This is
 *     normally {@code Object} unless it is constrained by using a method like {@link
 *     #removalListener}. Cache keys may not be null.
 * @param <V> the most general value type this builder will be able to create caches for. This is
 *     normally {@code Object} unless it is constrained by using a method like {@link

    public static final int ACB_PWNOTREQ = 4;
    /** Account control bit flag: Temporary duplicate account */
    public static final int ACB_TEMPDUP = 8;
    /** Account control bit flag: Normal user account */
    public static final int ACB_NORMAL = 16;
    /** Account control bit flag: MNS logon user account */
    public static final int ACB_MNS = 32;
    /** Account control bit flag: Interdomain trust account */

    public static final int ACB_PWNOTREQ = 4;
    /** Account control bit flag: Temporary duplicate account */
    public static final int ACB_TEMPDUP = 8;
    /** Account control bit flag: Normal user account */
    public static final int ACB_NORMAL = 16;
    /** Account control bit flag: MNS logon user account */
    public static final int ACB_MNS = 32;
    /** Account control bit flag: Interdomain trust account */

その後、あなたの API は（仮にこうしましょう）:

* 外部開発者の顧客に請求書を送ります。
* 代金を回収します。
* API 利用者（外部開発者）に通知を送り返します。
    * これは（あなたの API から）外部開発者が提供する *外部 API* に POST リクエストを送ることで行われます（これが「コールバック」です）。

## 通常の FastAPI アプリ { #the-normal-fastapi-app }

まず、コールバックを追加する前の通常の API アプリがどうなるか見てみましょう。

`Invoice` ボディを受け取り、クエリパラメータ `callback_url` にコールバック用の URL を含める *path operation* を持ちます。

この部分はとても普通で、ほとんどのコードはすでに見覚えがあるはずです:

 * passing in unsanitized user data then a malicious user could force it. A light shuffle of the
 * data using an unpredictable seed should normally be enough to thwart this attack.
 *
 * <p>The time taken to compute multiple quantiles on the same dataset using {@link Scale#indexes
 * indexes} is generally less than the total time taken to compute each of them separately, and

                // parentData.setModel( interpolatedParent );
                parentData.setVersion(interpolatedParent.getVersion());
            }
        }

        // url normalization
        modelUrlNormalizer.normalize(resultModel, request);

        // Now the fully interpolated model is available: reconfigure the resolver
        configureResolver(request.getModelResolver(), resultModel, problems, true);

  private final transient ImmutableSet<V> emptySet;

  /**
   * An instance created in {@link #readObject} to be returned from {@link #readResolve}. This field
   * is used only by those methods, and it is never set in a "normal" instance.
   *
   * <p>For more background, see {@code ConcurrentHashMultiset.deserializationReplacement}.
   */
  private transient @Nullable ImmutableSetMultimap<?, ?> deserializationReplacement;

   *         <li>UNSET, meaning "null pointer"
   *         <li>one plus an index into the keys, values, and entries arrays
   *       </ul>
   *   <li>another java.util.Map delegate implementation. In most modern JDKs, normal java.util hash
   *       collections intelligently fall back to a binary search tree if hash table collisions are
   *       detected. Rather than going to all the trouble of reimplementing this ourselves, we

            Clock clock = getClock(step.project);
            switch (step.name) {
                case PLAN:
                    // Planning steps should be executed out of normal execution
                    throw new IllegalStateException();
                case SETUP:
                    attachToThread(step);

abstract class SmoothRateLimiter extends RateLimiter {
  /*
   * How is the RateLimiter designed, and why?
   *
   * The primary feature of a RateLimiter is its "stable rate", the maximum rate that it should
   * allow in normal conditions. This is enforced by "throttling" incoming requests as needed. For
   * example, we could compute the appropriate throttle time for an incoming request, and make the
   * calling thread wait for that time.
   *