* Processing data:
    * For example, let's say you receive a file that must go through a slow process, you can return a response of "Accepted" (HTTP 202) and process the file in the background.

## Using `BackgroundTasks` { #using-backgroundtasks }

First, import `BackgroundTasks` and define a parameter in your *path operation function* with a type declaration of `BackgroundTasks`:

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

OkHttp Coroutines
=================

Support for Kotlin clients using coroutines.

```kotlin
val call = client.newCall(request)

call.executeAsync().use { response ->
  withContext(Dispatchers.IO) {
    println(response.body?.string())
  }
}
```

This is implemented using `suspendCancellableCoroutine`
but uses the standard Dispatcher in OkHttp. This means
that by default Kotlin's Dispatchers are not used.

            ListTestSuiteBuilder.using(new ShortsAsListGenerator()).named("Shorts.asList"),
            ListTestSuiteBuilder.using(new ShortsAsListHeadSubListGenerator())
                .named("Shorts.asList, head subList"),
            ListTestSuiteBuilder.using(new ShortsAsListTailSubListGenerator())
                .named("Shorts.asList, tail subList"),
            ListTestSuiteBuilder.using(new ShortsAsListMiddleSubListGenerator())

            ListTestSuiteBuilder.using(new LongsAsListGenerator()).named("Longs.asList"),
            ListTestSuiteBuilder.using(new LongsAsListHeadSubListGenerator())
                .named("Longs.asList, head subList"),
            ListTestSuiteBuilder.using(new LongsAsListTailSubListGenerator())
                .named("Longs.asList, tail subList"),
            ListTestSuiteBuilder.using(new LongsAsListMiddleSubListGenerator())

            ListTestSuiteBuilder.using(new ShortsAsListGenerator()).named("Shorts.asList"),
            ListTestSuiteBuilder.using(new ShortsAsListHeadSubListGenerator())
                .named("Shorts.asList, head subList"),
            ListTestSuiteBuilder.using(new ShortsAsListTailSubListGenerator())
                .named("Shorts.asList, tail subList"),
            ListTestSuiteBuilder.using(new ShortsAsListMiddleSubListGenerator())

            } else {
                logger.warn("system.properties not found in test classpath, using defaults");
                setDefaultProperties();
            }
        } catch (IOException e) {
            logger.warn("Failed to load system.properties, using defaults", e);
            setDefaultProperties();
        }
    }

    private void setDefaultProperties() {

 * </p>
 * <ol>
 *   <li>Fetching a URL from the queue using {@link UrlQueueService#poll(String)}.</li>
 *   <li>Checking if the URL is valid using {@link #isValid(UrlQueue)}.</li>
 *   <li>Accessing the content using a {@link CrawlerClient} obtained from {@link CrawlerClientFactory}.</li>
 *   <li>Processing the response using a {@link ResponseProcessor} associated with a {@link Rule}.</li>

`33.4.8-android`. For more about depending on Guava, see
[using Guava in your build].

To add a dependency on Guava using Maven, use the following:

```xml
<dependency>
  <groupId>com.google.guava</groupId>
  <artifactId>guava</artifactId>
  <version>33.4.8-jre</version>
  <!-- or, for Android: -->
  <version>33.4.8-android</version>
</dependency>
```

To add a dependency using Gradle:

```gradle
dependencies {

 * implementation.
 */
@GwtIncompatible
public final class NavigableSetTestSuiteBuilder<E> extends SortedSetTestSuiteBuilder<E> {
  public static <E> NavigableSetTestSuiteBuilder<E> using(TestSortedSetGenerator<E> generator) {
    NavigableSetTestSuiteBuilder<E> builder = new NavigableSetTestSuiteBuilder<>();
    builder.usingGenerator(generator);
    return builder;
  }

  @Override

headers can be added <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers" class="external-link" target="_blank">using the 'X-' prefix</a>.

But if you have custom headers that you want a client in a browser to be able to see, you need to add them to your CORS configurations ([CORS (Cross-Origin Resource Sharing)](cors.md){.internal-link target=_blank}) using the parameter `expose_headers` documented in <a href="https://www.starlette.io/middleware/#corsmiddleware" class="external-link"...