}
        val priorResponse = userResponse.priorResponse
        if (priorResponse != null && priorResponse.code == HTTP_CLIENT_TIMEOUT) {
          // We attempted to retry and got another timeout. Give up.
          return null
        }

        if (retryAfter(userResponse, 0) > 0) {
          return null
        }

        return userResponse.request
      }

      HTTP_UNAVAILABLE -> {

keep intact all notices stating that this License and any
non-permissive terms added in accord with section 7 apply to the code;
keep intact all notices of the absence of any warranty; and give all
recipients a copy of this License along with the Program.

  You may charge any price or no price for each copy that you convey,
and you may offer support or warranty protection for a fee.

a.internal-link::after {
  /* \00A0 is a non-breaking space
        to make the mark be on the same line as the link
    */
  content: "\00A0↪";
}

.shadow {
  box-shadow: 5px 5px 10px #999;
}

/* Give space to lower icons so Gitter chat doesn't get on top of them */
.md-footer-meta {
  padding-bottom: 2em;
}

.user-list {
  display: flex;
  flex-wrap: wrap;
  margin-bottom: 2rem;
}

- Click `Create subproject` button at the bottom of the "Subprojects" region of [this page](https://builds.gradle.org/admin/editProject.html?projectId=Gradle&tab=projectGeneralTab)
  - Select `Manually`.
  - Give it a name. The name will be displayed on TeamCity web UI. We highly recommend it be capitalized from the branch name, i.e. `MyTestBranch`.

        But Guava aims to provide functionality that is useful across boundaries of projects,
        companies, or even industries — utilities useful for a sizable proportion of all Java
        programmers everywhere. If you can give enough detail such that any of us can imagine coming
        across a similar need in our own work, that's extremely helpful in studying how broadly
        useful the proposed change will be.

  - type: textarea

{* ../../docs_src/header_param_models/tutorial001_an_py310.py hl[9:14,18] *}

**FastAPI** will **extract** the data for **each field** from the **headers** in the request and give you the Pydantic model you defined.

## Check the Docs { #check-the-docs }

You can see the required headers in the docs UI at `/docs`:

<div class="screenshot">

  // to the given dividend, so that we don't have half of our divisions being
  // trivial because the divisor is bigger than the dividend.
  // Using remainder here does not give us a uniform distribution but it should
  // not have a big impact on the measurement.
  private static long randomDivisor(long dividend) {
    long r = randomSource.nextLong();
    if (dividend == -1) {
      return r;

    }

    /**
     * Creates a string with all location details for the specified model problem. If the project identifier is
     * provided, the generated location will omit the model id and source information and only give line/column
     * information for problems originating directly from this POM.
     *
     * @param problem The problem whose location should be formatted, must not be {@code null}.

            @Throws(IOException::class)
            override fun authenticate(route: Route?, response: Response): Request? {
              if (response.request.header("Authorization") != null) {
                return null // Give up, we've already attempted to authenticate.
              }

              println("Authenticating for response: $response")
              println("Challenges: ${response.challenges()}")

  // to the given dividend, so that we don't have half of our divisions being
  // trivial because the divisor is bigger than the dividend.
  // Using remainder here does not give us a uniform distribution but it should
  // not have a big impact on the measurement.
  private static long randomDivisor(long dividend) {
    long r = randomSource.nextLong();
    if (dividend == -1) {
      return r;