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).

/* jcifs smb client library in Java
 * Copyright (C) 2004  "Michael B. Allen" <jcifs at samba dot org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,

/* jcifs smb client library in Java
 * Copyright (C) 2003  "Michael B. Allen" <jcifs at samba dot org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,

試してみるには、

* いくつかのブラウザタブでアプリを開きます。
* それらのタブでメッセージを記入してください。
* そして、タブのうち1つを閉じてください。

これにより例外 `WebSocketDisconnect` が発生し、他のすべてのクライアントは次のようなメッセージを受信します。

```
Client #1596980209979 left the chat
```

/// tip | 豆知識

上記のアプリは、複数の WebSocket 接続に対してメッセージを処理し、ブロードキャストする方法を示すための最小限のシンプルな例です。

しかし、すべての接続がメモリ内の単一のリストで処理されるため、プロセスの実行中にのみ機能し、単一のプロセスでのみ機能することに注意してください。

			if ok {
				for _, kv := range kvs {
					if sset.Contains(kv.Key) {
						// Reject duplicate conditions or expiration.
						return nil, fmt.Errorf("input policy has multiple %s, please fix your client code", kv.Key)
					}
					sset.Add(kv.Key)
				}
			}
			e.Encode(kvs)
		}
	}
	return &buf, d.Err()
}

// parsePostPolicyForm - Parse JSON policy string into typed PostPolicyForm structure.

import org.codelibs.fess.helper.SystemHelper;
import org.codelibs.fess.ingest.IngestFactory;
import org.codelibs.fess.ingest.Ingester;
import org.codelibs.fess.mylasta.direction.FessConfig;
import org.codelibs.fess.opensearch.client.SearchEngineClient;
import org.codelibs.fess.opensearch.log.exbhv.ClickLogBhv;
import org.codelibs.fess.opensearch.log.exbhv.FavoriteLogBhv;
import org.codelibs.fess.unit.UnitFessTestCase;

// set XLA flag values to prepare for XLA compilation. Otherwise set
// global_jit_level to OFF.
//
// This and the next API are syntax sugar over TF_SetConfig(), and is used by
// clients that cannot read/write the tensorflow.ConfigProto proto.
// TODO: Migrate to TF_CreateConfig() below.
TF_CAPI_EXPORT extern void TF_EnableXLACompilation(TF_SessionOptions* options,

Volviendo al ejemplo de código anterior, **FastAPI**:

* Validará que haya un `item_id` en el path para requests `GET` y `PUT`.
* Validará que el `item_id` sea del tipo `int` para requests `GET` y `PUT`.
    * Si no lo es, el cliente verá un error útil y claro.
* Comprobará si hay un parámetro de query opcional llamado `q` (como en `http://127.0.0.1:8000/items/foo?q=somequery`) para requests `GET`.

/* jcifs smb client library in Java
 * Copyright (C) 2000  "Michael B. Allen" <jcifs at samba dot org>
 *                     "Paul Walker" <jcifs at samba dot org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *

/* jcifs smb client library in Java
 * Copyright (C) 2000  "Michael B. Allen" <jcifs at samba dot org>
 *                     "Christopher R. Hertel" <jcifs at samba dot org>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *