@Override
      public void onOpen(@NotNull EventSource eventSource, @NotNull Response response) {
        try {
          assertEquals("text/event-stream", response.request().header("Accept"));
        } catch (Exception e) {
          future.completeExceptionally(e);
        }
      }

      @Override

   *
   * <p>This does not always signify that the key is now absent from the cache, as it may have
   * already been re-added.
   */
  // Technically should accept RemovalNotification<? extends K, ? extends V>, but because
  // RemovalNotification is guaranteed covariant, let's make users' lives simpler.
  void onRemoval(RemovalNotification<K, V> notification);

  }

  @Override
  public int size() {
    return 1;
  }

  @Override
  public void forEach(BiConsumer<? super K, ? super V> action) {
    checkNotNull(action).accept(singleKey, singleValue);
  }

  @Override
  public boolean containsKey(@Nullable Object key) {
    return singleKey.equals(key);
  }

  @Override
  public boolean containsValue(@Nullable Object value) {

* `allow_headers` - Uma lista de cabeçalhos de solicitação HTTP que devem ter suporte para requisições de origem cruzada. O padrão é `[]`. Você pode usar `['*']` para permitir todos os cabeçalhos. Os cabeçalhos `Accept`, `Accept-Language`, `Content-Language` e `Content-Type` são sempre permitidos para <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS#simple_requests" class="external-link" rel="noopener" target="_blank">requisições CORS simples</a>.

     *
     * @param file the SMB file to test for inclusion
     * @return whether the given file should be included
     * @throws SmbException if an error occurs while accessing the file
     */
    boolean accept(SmbFile file) throws SmbException;

     * @param name the name of the file
     * @return whether the given filename should be included
     * @throws SmbException if an SMB error occurs during evaluation
     */
    boolean accept(SmbFile dir, String name) throws SmbException;

     * @param name the name of the file
     * @return true if the file should be included, false otherwise
     * @throws SmbException if an SMB error occurs during evaluation
     */
    boolean accept(SmbFile dir, String name) throws SmbException;

    return new ImmutableMapKeySet<>(this);
  }

  @Override
  public void forEach(BiConsumer<? super K, ? super V> action) {
    checkNotNull(action);
    for (Entry<K, V> entry : entries) {
      action.accept(entry.getKey(), entry.getValue());
    }
  }

  @Override
  boolean isHashCodeFast() {
    return true;
  }

  @Override
  public int hashCode() {
    return hashCode;
  }

   *     State#TERMINATED} when this method is called then this will throw an IllegalStateException.
   * @since 15.0
   */
  @SuppressWarnings("GoodTime") // should accept a java.time.Duration
  void awaitRunning(long timeout, TimeUnit unit) throws TimeoutException;

  /**
   * Waits for the {@link Service} to reach the {@linkplain State#TERMINATED terminated state}.
   *

* `allow_methods` - 교차-출처 요청을 허용하는 HTTP 메소드의 리스트입니다. 기본값은 `['GET']` 입니다. `['*']` 을 사용하여 모든 표준 메소드들을 허용할 수 있습니다.
* `allow_headers` - 교차-출처를 지원하는 HTTP 요청 헤더의 리스트입니다. 기본값은 `[]` 입니다. 모든 헤더들을 허용하기 위해 `['*']` 를 사용할 수 있습니다. `Accept`, `Accept-Language`, `Content-Language` 그리고 `Content-Type` 헤더는 CORS 요청시 언제나 허용됩니다.
* `allow_credentials` - 교차-출처 요청시 쿠키 지원 여부를 설정합니다. 기본값은 `False` 입니다. 또한 해당 항목을 허용할 경우 `allow_origins` 는 `['*']` 로 설정할 수 없으며, 출처를 반드시 특정해야 합니다.