# Background Tasks

You can define background tasks to be run *after* returning a response.

This is useful for operations that need to happen after a request, but that the client doesn't really have to be waiting for the operation to complete before receiving the response.

This includes, for example:

* Email notifications sent after performing an action:

<font color="#4E9A06">INFO</font>:     Started server process [<font color="#06989A">2265873</font>]
<font color="#4E9A06">INFO</font>:     Waiting for application startup.
<font color="#4E9A06">INFO</font>:     Application startup complete.
```

</div>

`fastapi`라고 불리는 명령어 프로그램은 **FastAPI CLI**입니다.

FastAPI CLI는 Python 프로그램의 경로(예: `main.py`)를 인수로 받아, `FastAPI` 인스턴스(일반적으로 `app`으로 명명)를 자동으로 감지하고 올바른 임포트 과정을 결정한 후 이를 실행합니다.

    .url("https://www.nytimes.com/")
    .build();
client.newCall(newYorkTimesRequest).enqueue(new Callback() {
  ...
});
```

Running this race over home WiFi shows the Times (`0002`) completes just slightly sooner than the Post (`0001`):

```
0001 https://www.washingtonpost.com/
0001 0.000 callStart
0002 https://www.nytimes.com/
0002 0.000 callStart
0002 0.010 dnsStart
0001 0.013 dnsStart

     */
    void recordMisses(int count);

    /**
     * Records the successful load of a new entry. This should be called when a cache request causes
     * an entry to be loaded, and the loading completes successfully. In contrast to {@link
     * #recordMisses}, this method should only be called by the loading thread.
     *
     * @param loadTime the number of nanoseconds the cache spent computing or retrieving the new

      )
    serverIpv4.protocols = listOf(Protocol.H2_PRIOR_KNOWLEDGE)
    serverIpv6.protocols = listOf(Protocol.H2_PRIOR_KNOWLEDGE)

    // Yield the first IP address so the second IP address completes first.
    val firstConnectLatch = CountDownLatch(1)
    val socketFactory =
      object : DelegatingSocketFactory(SocketFactory.getDefault()) {
        var first = true

Since HTTP requests frequently happen in parallel, connection pooling must be thread-safe.

These are the primary classes involved with establishing, sharing, and terminating connections:

* **Mniejsza ilość błędów**: Zmniejsza ilość ludzkich (dewelopera) błędy o około 40%. *
* **Intuicyjność**: Wspaniałe wsparcie dla edytorów kodu. Dostępne wszędzie <abbr title="znane jako auto-complete, autocompletion, IntelliSense">automatyczne uzupełnianie</abbr> kodu. Krótszy czas debugowania.
* **Łatwość**: Zaprojektowany by być prosty i łatwy do nauczenia. Mniej czasu spędzonego na czytanie dokumentacji.

<font color="#4E9A06">INFO</font>:     Started server process [<font color="#06989A">2265873</font>]
<font color="#4E9A06">INFO</font>:     Waiting for application startup.
<font color="#4E9A06">INFO</font>:     Application startup complete.
```

</div>

该命令行程序 `fastapi` 就是 **FastAPI CLI**。

FastAPI CLI 接收你的 Python 程序路径，自动检测包含 FastAPI 的变量（通常命名为 `app`）及其导入方式，然后启动服务。

在生产环境中，你应该使用 `fastapi run` 命令。🚀

<font color="#4E9A06">INFO</font>:     Started server process [<font color="#06989A">2306215</font>]
<font color="#4E9A06">INFO</font>:     Waiting for application startup.
<font color="#4E9A06">INFO</font>:     Application startup complete.
<font color="#4E9A06">INFO</font>:     Uvicorn running on <b>http://0.0.0.0:8000</b> (Press CTRL+C to quit)
```

</div>

That would work for most of the cases. 😎

			staleWriters[i] = newBitrotWriter(disk, "", "testbucket", "testobject", erasure.ShardFileSize(test.size), test.algorithm, erasure.ShardSize())
		}

		// test case setup is complete - now call Heal()
		err = erasure.Heal(context.Background(), staleWriters, readers, test.size, nil)
		closeBitrotReaders(readers)
		closeBitrotWriters(staleWriters)
		if err != nil && !test.shouldFail {