*
 *  * **Connecting:** the initial state of each web socket. Messages may be enqueued but they won't
 *    be transmitted until the web socket is open.
 *
 *  * **Open:** the web socket has been accepted by the remote peer and is fully operational.
 *    Messages in either direction are enqueued for immediate transmission.
 *
 *  * **Closing:** one of the peers on the web socket has initiated a graceful shutdown. The web

     *
     * @param visitor the visitor to call back, must not be {@code null}
     * @return {@code true} to visit siblings nodes of this node as well, {@code false} to skip siblings
     */
    boolean accept(@Nonnull NodeVisitor visitor);

    /**
     * Returns a new tree starting at this node, filtering the children.
     * Note that this node will not be filtered and only the children
     * and its descendant will be checked.

    CountDownLatch valueAndCloserSet = new CountDownLatch(1);
    closingFuture.finishToValueAndCloser(
        new ValueAndCloserConsumer<V>() {
          @Override
          public void accept(ValueAndCloser<V> valueAndCloser) {
            ClosingFutureFinishToValueAndCloserTest.this.valueAndCloser = valueAndCloser;
            valueAndCloserSet.countDown();
          }
        },

        return createPathMatcher(baseDirectory, includes, null, false);
    }

    /**
     * Returns a filter for directories that may contain paths accepted by the given matcher.
     * The given path matcher should be an instance created by this service.
     * The path matcher returned by this method expects directory paths.

# 后台任务

你可以定义在返回响应后运行的后台任务。

这对需要在请求之后执行的操作很有用，但客户端不必在接收响应之前等待操作完成。

包括这些例子：

* 执行操作后发送的电子邮件通知：
    * 由于连接到电子邮件服务器并发送电子邮件往往很“慢”（几秒钟），您可以立即返回响应并在后台发送电子邮件通知。
* 处理数据：
    * 例如，假设您收到的文件必须经过一个缓慢的过程，您可以返回一个"Accepted"(HTTP 202)响应并在后台处理它。

## 使用 `BackgroundTasks`

首先导入 `BackgroundTasks` 并在 *路径操作函数* 中使用类型声明 `BackgroundTasks` 定义一个参数：

{* ../../docs_src/background_tasks/tutorial001.py hl[1, 13] *}

// Write is non-blocking, if the writer's queue is not full.
// Write is blocking otherwise.
func (w *Writer) Write(p []byte) (n int, err error) {
	return w.pw.Write(p)
}

// Close closes the writer.
// Any accepted writes will be flushed. Any new writes will be rejected.
// Once Close() exits, files are synchronized to disk.
func (w *Writer) Close() error {
	w.pw.CloseWithError(nil)

	if w.f != nil {

Si una request entrante no se valida correctamente, se enviará un response `400`.

## `GZipMiddleware` { #gzipmiddleware }

Maneja responses GZip para cualquier request que incluya `"gzip"` en el header `Accept-Encoding`.

El middleware manejará tanto responses estándar como en streaming.

{* ../../docs_src/advanced_middleware/tutorial003_py39.py hl[2,6] *}

Se soportan los siguientes argumentos:

Если входящий запрос не проходит валидацию, будет отправлен ответ `400`.

## `GZipMiddleware` { #gzipmiddleware }

Обрабатывает GZip‑ответы для любых запросов, которые включают `"gzip"` в заголовке `Accept-Encoding`.

Это middleware обрабатывает как обычные, так и потоковые ответы.

{* ../../docs_src/advanced_middleware/tutorial003_py39.py hl[2,6] *}

Поддерживаются следующие аргументы:

            writer.accept(CLIReportingUtils.showVersionMinimal());
        } else if (context.invokerRequest.effectiveVerbose()) {
            writer.accept(CLIReportingUtils.showVersion(
                    ProcessHandle.current().info().commandLine().orElse(null), describe(context.terminal)));

        } else {
            writer.accept(CLIReportingUtils.showVersion());
        }
    }

	case http.StatusUnauthorized:
		return User{}, ErrAccessTokenExpired
	}
	return User{}, fmt.Errorf("Unable to lookup - keycloak user lookup returned %v", resp.Status)
}

// Option is a function type that accepts a pointer Target
type Option func(*KeycloakProvider)

// WithTransport provide custom transport
func WithTransport(transport http.RoundTripper) Option {
	return func(p *KeycloakProvider) {
		p.client = http.Client{