So, you will have to make sure your data is of the correct type. E.g. it is compatible with JSON, if you are returning a `JSONResponse`.

And also that you are not sending any data that should have been filtered by a `response_model`.

///

### More info { #more-info }

/// note | Technical Details

          .build(),
      )
    call1.execute().use { response -> response.body.string() }

    listener.shouldClose = true
    // Large headers are a likely reason the servers would cut off the connection before it completes sending
    // request headers.
    // 431 "Request Header Fields Too Large"
    val largeHeaders =
      Headers
        .Builder()
        .apply {
          repeat(32) {

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.internal.http2

/**
 * Settings describe characteristics of the sending peer, which are used by the receiving peer.
 * Settings are [connection][Http2Connection] scoped.
 */
class Settings {
  /** Bitfield of which flags that values. */
  private var set: Int = 0

  /** Flag values. */

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).

import org.codelibs.fess.mylasta.direction.FessConfig;
import org.codelibs.fess.util.ComponentUtil;
import org.dbflute.mail.CardView;
import org.dbflute.mail.send.supplement.SMailPostingDiscloser;

/**
 * Helper class for sending notifications to various platforms.
 */
public class NotificationHelper {

    /**
     * Default constructor.
     */
    public NotificationHelper() {
        // Default constructor
    }

                resp = new NtTransNotifyChangeResponse(th.getConfig());
            }

            if (log.isTraceEnabled()) {
                log.trace("Sending NtTransNotifyChange for " + this.handle);
            }
            try {
                resp = th.send(req, resp, RequestParam.NO_TIMEOUT, RequestParam.NO_RETRY);
            } catch (final SmbException e) {

For example, to declare a header of `X-Token` that can appear more than once, you can write:

{* ../../docs_src/header_params/tutorial003_an_py310.py hl[9] *}

If you communicate with that *path operation* sending two HTTP headers like:

```
X-Token: foo
X-Token: bar
```

The response would be like:

```JSON
{
    "X-Token values": [
        "bar",
        "foo"
    ]
}
```

 * doesn't include the motivating request's HTTP headers or even its full URL; only the target
 * server's hostname is sent to the proxy.
 *
 * Prior to sending any CONNECT request OkHttp always calls the proxy authenticator so that it may
 * prepare preemptive authentication. OkHttp will call [authenticate] with a fake `HTTP/1.1 407

the server (the machine, host, etc.) and **managing all the HTTPS parts**: receiving the **encrypted HTTPS requests**, sending the **decrypted HTTP requests** to the actual HTTP application running in the same server (the **FastAPI** application, in this case), take the **HTTP response** from the application, **encrypt it** using the appropriate **HTTPS certificate** and sending it back to the client using **HTTPS**. This server is often called a **<a href="https://en.wikipedia.org/wiki/TLS_termination_proxy"...

```

</div>

It is **HIGHLY encouraged** that you write or copy the code, edit it and run it locally.

Using it in your editor is what really shows you the benefits of FastAPI, seeing how little code you have to write, all the type checks, autocompletion, etc.

---

## Install FastAPI { #install-fastapi }

The first step is to install FastAPI.