# 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('/')

func TestReadEmptyAtEOF(t *testing.T) {
	b := new(Buffer)
	slice := make([]byte, 0)
	n, err := b.Read(slice)
	if err != nil {
		t.Errorf("read error: %v", err)
	}
	if n != 0 {
		t.Errorf("wrong count; got %d want 0", n)
	}
}

func TestUnreadByte(t *testing.T) {
	b := new(Buffer)

	// check at EOF
	if err := b.UnreadByte(); err == nil {
		t.Fatal("UnreadByte at EOF: got no error")
	}

		err.Description = fmt.Sprintf("Region does not match; expecting '%s'.", globalSite.Region())
	case "AuthorizationHeaderMalformed":
		err.Description = fmt.Sprintf("The authorization header is malformed; the region is wrong; expecting '%s'.", globalSite.Region())
	}

	// Similar check to http.checkWriteHeaderCode
	if err.HTTPStatusCode < 100 || err.HTTPStatusCode > 999 {

			expectedRespStatus: http.StatusForbidden,
			accessKey:          "",
			secretKey:          "",
			shouldPass:         false,
			fault:              None,
		},
		// Test case - 5
		// Wrong auth header returns as bad request.
		{
			bucketName:         bucketName,
			objectName:         objectName,
			data:               bytesData,
			dataLen:            len(bytesData),

 *  Fix: Don't leak connections when using ALPN on the desktop.
 *  Fix: Update Jetty ALPN to `7.1.2.v20141202` (Java 7) and `8.1.2.v20141202` (Java 8).
    This fixes a bug in resumed TLS sessions where the wrong protocol could be
    selected.
 *  Fix: Don't crash in SPDY and HTTP/2 when disconnecting before connecting.
 *  Fix: Avoid a reverse DNS-lookup for a numeric proxy address
 *  Fix: Resurrect http/2 frame logging.

      <description>
        <![CDATA[
        The {@code <parent>} element contains information required to locate the parent project from which
        this project will inherit from.
        <p><strong>Note:</strong> The children of this element are not interpolated and must be given as literal values.</p>
        ]]>
      </description>
      <fields>
        <field>
          <name>groupId</name>

		f.headerOffset += r.baseOffset
		r.File = append(r.File, f)
	}
	if uint16(len(r.File)) != uint16(end.directoryRecords) { // only compare 16 bits here
		// Return the readDirectoryHeader error if we read
		// the wrong number of directory entries.
		return err
	}
	if zipinsecurepath.Value() == "0" {
		for _, f := range r.File {
			if f.Name == "" {
				// Zip permits an empty file name field.
				continue
			}

		}
	}
	return hr, nil
}

// Populates default heal result item entries with possible values when we are returning prematurely.
// This is to ensure that in any circumstance we are not returning empty arrays with wrong values.
func (er *erasureObjects) defaultHealResult(lfi FileInfo, storageDisks []StorageAPI, storageEndpoints []Endpoint, errs []error, bucket, object, versionID string) madmin.HealResultItem {
	// Initialize heal result object

    }
    return null;
  }

  private static byte @Nullable [] textToNumericFormatV4(String ipString) {
    if (IPV4_DELIMITER_MATCHER.countIn(ipString) + 1 != IPV4_PART_COUNT) {
      return null; // Wrong number of parts
    }

    byte[] bytes = new byte[IPV4_PART_COUNT];
    int start = 0;
    // Iterate through the parts of the ip string.
    // Invariant: start is always the beginning of an octet.

    of unacknowledged data per stream and no per-connection limit.

 *  Fix: Don't close a `Deflater` while we're still using it to compress a web socket message. We
    had a severe bug where web sockets were closed on the wrong thread, which caused
    `NullPointerException` crashes in `Deflater`.

 *  Fix: Don't crash after a web socket fails its connection upgrade. We incorrectly released