import java.util.concurrent.atomic.AtomicReference;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Serializes execution of tasks, somewhat like an "asynchronous {@code synchronized} block." Each
 * {@linkplain #submit enqueued} callable will not be submitted to its associated executor until the

**FastAPI** ⤴️ ✊ 👈 🎻 🔗 💽 & 🚮 ⚫️ 🗄, ↖️ ⚪️➡️ 🌐 🎏 👜 ⚫️ 🔨.

///

### <a href="https://www.starlette.io/" class="external-link" target="_blank">💃</a>

💃 💿 <abbr title="The new standard for building asynchronous Python web">🔫</abbr> 🛠️/🧰, ❔ 💯 🏗 ↕-🎭 ✳ 🐕‍🦺.

⚫️ 📶 🙅 &amp; 🏋️. ⚫️ 🔧 💪 🏧, &amp; ✔️ 🔧 🦲.

⚫️ ✔️:

* 🤙 🎆 🎭.
*  *️⃣ 🐕‍🦺.
* -🛠️ 🖥 📋.
* 🕴 &amp; 🤫 🎉.
* 💯 👩‍💻 🏗 🔛 🇸🇲.

///

### <a href="https://www.starlette.io/" class="external-link" target="_blank">Starlette</a>

Starlette — це легкий фреймворк/набір інструментів <abbr title="The new standard for build asynchronous Python web">ASGI</abbr>, який ідеально підходить для створення високопродуктивних asyncio сервісів.

  /** http://tools.ietf.org/html/draft-ietf-httpbis-http2-17#section-5.1.1 */
  internal var nextStreamId = if (builder.client) 3 else 2

  private var isShutdown = false

  /** For scheduling everything asynchronous. */
  private val taskRunner = builder.taskRunner

  /** Asynchronously writes frames to the outgoing socket. */
  private val writerQueue = taskRunner.newQueue()

streaming                         (on|off)    set to 'on', to use streaming NATS server
streaming_async                   (on|off)    set to 'on', to enable asynchronous publish
streaming_max_pub_acks_in_flight  (number)    number of messages to publish without waiting for ACKs
streaming_cluster_id              (string)    unique ID for NATS streaming cluster

 * article on <a href="https://github.com/google/guava/wiki/ListenableFutureExplained">{@code
 * ListenableFuture}</a>.
 *
 * <p>The main purpose of {@code ListenableFuture} is to help you chain together a graph of
 * asynchronous operations. You can chain them together manually with calls to methods like {@link
 * Futures#transform(ListenableFuture, Function, Executor) Futures.transform}, but you will often

      this.routeDatabase = okHttpClient.routeDatabase
      this.taskRunner = okHttpClient.taskRunner
    }

    /**
     * Sets the dispatcher used to set policy and execute asynchronous requests. Must not be null.
     */
    fun dispatcher(dispatcher: Dispatcher) =
      apply {
        this.dispatcher = dispatcher
      }

    /**

    releases of OkHttp are not compatible with OkHttp 3.5. When upgrading to the new package
    please note that the `WebSocket` and `WebSocketCall` classes have been merged. Sending messages
    is now asynchronous and they may be enqueued before the web socket is connected.

 *  **OkHttp no longer attempts a direct connection if the system's HTTP proxy fails.** This

# 並行処理と async / await

*path operation 関数*のための `async def` に関する詳細と非同期 (asynchronous) コード、並行処理 (Concurrency)、そして、並列処理 (Parallelism) の背景について。

## 急いでいますか？

<abbr title="too long; didn't read (長すぎて読めない人のための要約という意味のスラング)"><strong>TL;DR:</strong></abbr>

次のような、`await` を使用して呼び出すべきサードパーティライブラリを使用している場合:

```Python
results = await some_library()
```

以下の様に `async def` を使用して*path operation 関数*を宣言します。

```Python hl_lines="2"
@app.get('/')

 * article on <a href="https://github.com/google/guava/wiki/ListenableFutureExplained">{@code
 * ListenableFuture}</a>.
 *
 * <p>The main purpose of {@code ListenableFuture} is to help you chain together a graph of
 * asynchronous operations. You can chain them together manually with calls to methods like {@link
 * Futures#transform(ListenableFuture, Function, Executor) Futures.transform}, but you will often