The process that happens when your API app calls the *external API* is named a "callback". Because the software that the external developer wrote sends a request to your API and then your API *calls back*, sending a request to an *external API* (that was probably created by the same developer).

{* ../../docs_src/dependencies/tutorial013_an_py310.py ln[19:21] *}

...would be run after the the response finishes sending the slow data:

{* ../../docs_src/dependencies/tutorial013_an_py310.py ln[30:38] hl[31:33] *}

But as `generate_stream()` doesn't use the database session, it is not really necessary to keep the session open while sending the response.

    }
    body.awaitSuccess()
    assertThat(log.take()!!)
      .contains("StreamResetException: stream was reset: CANCEL")
  }

  /**
   * We delay sending the last byte of the request body 1500 ms. The 1000 ms read timeout should
   * only elapse 1000 ms after the request body is sent.
   */
  @Test
  fun headersReadTimeoutDoesNotStartUntilLastRequestBodyByteFire() {

                updateForm(fessConfig, form);
            });
        });
    }

    /**
     * Sends a test mail using the provided notification settings.
     *
     * @param form the mail form containing notification settings
     * @return HTML response after sending test mail
     */
    @Execute
    @Secured({ ROLE })
    public HtmlResponse sendmail(final MailForm form) {

/// info

To send data, you should use one of: `POST` (the more common), `PUT`, `DELETE` or `PATCH`.

Sending a body with a `GET` request has an undefined behavior in the specifications, nevertheless, it is supported by FastAPI, only for very complex/extreme use cases.

     * @throws JobNotFoundException if no process is found for the given session ID
     * @throws JobProcessingException if there's an error sending the command
     */
    public void sendCommand(final String sessionId, final String command) {
        final Process process;
        synchronized (this) {
            final JobProcess jobProcess = runningProcessMap.get(sessionId);

        "items:read items:write users:read profile openid"
    client_id: optional string. OAuth2 recommends sending the client_id and client_secret (if any)
        using HTTP Basic auth, as: client_id:client_secret
    client_secret: optional string. OAuth2 recommends sending the client_id and client_secret (if any)
        using HTTP Basic auth, as: client_id:client_secret
    """

    def __init__(

This includes, for example:

* Email notifications sent after performing an action:
    * As connecting to an email server and sending an email tends to be "slow" (several seconds), you can return the response right away and send the email notification in the background.
* Processing data:

It enables Brotli support in addition to tranparent Gzip support,
provided Accept-Encoding is not set previously.  Modern web servers
must choose to return Brotli responses.  n.b. It is not used for
sending requests.

```java
OkHttpClient client = new OkHttpClient.Builder()
  .addInterceptor(BrotliInterceptor.INSTANCE)
  .build();
```

```kotlin
implementation("com.squareup.okhttp3:okhttp-brotli:5.3.0")
```

Being able to use asynchronous functions in your tests could be useful, for example, when you're querying your database asynchronously. Imagine you want to test sending requests to your FastAPI application and then verify that your backend successfully wrote the correct data in the database, while using an async database library.

Let's look at how we can make that work.