El usuario de tu API (un desarrollador externo) creará una factura en tu API con un request POST.

Luego tu API (imaginemos):

* Enviará la factura a algún cliente del desarrollador externo.
* Recogerá el dinero.
* Enviará una notificación de vuelta al usuario de la API (el desarrollador externo).
    * Esto se hará enviando un request POST (desde *tu API*) a alguna *API externa* proporcionada por ese desarrollador externo (este es el "callback").

  void setUp() {
    eventBus = new EventBus("for benchmarking purposes");
    eventBus.register(this);
  }

  @Benchmark
  void postStrings(int reps) {
    for (int i = 0; i < reps; i++) {
      eventBus.post("hello there");
    }
  }

  @Subscribe
  public void handleStrings(String string) {
    // Nothing to do here.
  }

The next sections are **not necessarily "advanced"**.

And it's possible that for your use case, the solution is in one of them.

///

## Read the Tutorial first { #read-the-tutorial-first }

You could still use most of the features in **FastAPI** with the knowledge from the main [Tutorial - User Guide](../tutorial/index.md){.internal-link target=_blank}.

   * writing.
   *
   * [grpc]: https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md
   */
  open fun isDuplex(): Boolean = false

  /**
   * Returns true if this body expects at most one call to [writeTo] and can be transmitted
   * at most once. This is typically used when writing the request body is destructive and it is not
   * possible to recreate the request body after it has been sent.
   *

        final CurlHelper curlHelper = ComponentUtil.getCurlHelper();
        switch (values[0].toUpperCase(Locale.ROOT)) {
        case "GET":
            return curlHelper.get(path);
        case "POST":
            return curlHelper.post(path);
        case "PUT":
            return curlHelper.put(path);
        case "DELETE":
            return curlHelper.delete(path);
        default:
            break;
        }

 * limitations under the License.
 */

package com.google.common.collect.testing;

import com.google.common.annotations.GwtCompatible;

/**
 * A generator that relies on a preexisting generator for most of its work. For example, a derived
 * iterator generator may delegate the work of creating the underlying collection to an inner
 * collection generator.
 *

 * limitations under the License.
 */

package com.google.common.collect.testing;

import com.google.common.annotations.GwtCompatible;

/**
 * A generator that relies on a preexisting generator for most of its work. For example, a derived
 * iterator generator may delegate the work of creating the underlying collection to an inner
 * collection generator.
 *

     *
     * @param body the label type data to create
     * @return JSON response containing the created label type setting ID
     */
    // POST /api/admin/labeltype/setting
    @Execute
    public JsonResponse<ApiResult> post$setting(final CreateBody body) {
        validateApi(body, messages -> {});
        body.crudMode = CrudMode.CREATE;

if exist "%HOME%\mavenrc_pre.bat" call "%HOME%\mavenrc_pre.bat"
if exist "%HOME%\mavenrc_pre.cmd" call "%HOME%\mavenrc_pre.cmd"
:skipRcPre

@setlocal

set ERROR_CODE=0

@REM To isolate internal variables from possible post scripts, we use another setlocal
@setlocal

@REM ==== START VALIDATION ====
if not "%JAVA_HOME%" == "" goto OkJHome

echo.
echo Error: JAVA_HOME not found in your environment. >&2

        })).status(ApiResult.Status.OK).result());
    }

    // POST /api/admin/group/setting
    /**
     * Creates a new group setting.
     *
     * @param body group setting data to create
     * @return JSON response with created setting ID and status
     */
    @Execute
    public JsonResponse<ApiResult> post$setting(final CreateBody body) {
        validateApi(body, messages -> {});