## 協程

**協程** 只是 `async def` 函式所回傳的非常特殊的事物名稱。Python 知道它是一個類似函式的東西，可以啟動它，並且在某個時刻它會結束，但它也可能在內部暫停 ⏸，只要遇到 `await`。

這種使用 `async` 和 `await` 的非同步程式碼功能通常被概括為「協程」。這與 Go 語言的主要特性「Goroutines」相似。

## 結論

讓我們再次回顧之前的句子：

> 現代版本的 Python 支持使用 **"協程"** 的 **`async` 和 `await`** 語法來寫 **"非同步程式碼"**。

現在應該能明白其含意了。✨

這些就是驅動 FastAPI（通過 Starlette）運作的原理，也讓它擁有如此驚人的效能。

## 非常技術性的細節

      V value = entry.getValue();
      if (value == null) {
        tryDrainReferenceQueues();
        return null;
      }

      return value;
    }

    /**
     * Performs routine cleanup following a read. Normally cleanup happens during writes, or from
     * the cleanupExecutor. If cleanup is not observed after a sufficient number of reads, try
     * cleaning up from the read thread.
     */

		g.Go(func() error {
			_ = storageDisks[index].DeleteBulk(ctx, minioMetaMultipartBucket, paths...)
			return nil
		}, index)
	}
	g.Wait()
}

// Clean-up the old multipart uploads. Should be run in a Go routine.
func (er erasureObjects) cleanupStaleUploads(ctx context.Context) {
	// run multiple cleanup's local to this server.
	var wg sync.WaitGroup
	for _, disk := range er.getLocalDisks() {
		if disk != nil {
			wg.Add(1)

**FastAPI**を使用している場合、その「最初の」関数が*path operation 関数*であり、FastAPIが正しく実行する方法を知っているので、心配する必要はありません。

しかし、FastAPI以外で `async` / `await` を使用したい場合は、<a href="https://docs.python.org/3/library/asyncio-task.html#coroutine" class="external-link" target="_blank">公式Pythonドキュメントを参照して下さい</a>。

### 非同期コードの他の形式

`async` と `await` を使用するスタイルは、この言語では比較的新しいものです。

非同期コードの操作がはるかに簡単になります。

// using a delete-marker and MetaSys entries. It's used to track tiered content of a
// deleted/overwritten version. This version is visible _only_to the scanner routine, for subsequent deletion.
// This kind of tracking is necessary since a version's tiered content is deleted asynchronously.

// Backend directory tree structure:
// disk1/
// └── bucket
//     └── object

		maps.Copy(sys.rolesMap, authn.GetRoleInfo())
	}

	sys.printIAMRoles()
	sys.Unlock()

	retryCtx, cancel := context.WithCancel(ctx)

	// Indicate to our routine to exit cleanly upon return.
	defer cancel()

	// Migrate storage format if needed.
	for {
		// Migrate IAM configuration, if necessary.
		if err := saveIAMFormat(retryCtx, sys.store); err != nil {

  * Fix AWS EBS volumes not getting detached from node if routine to verify volumes are attached runs while the node is down ([#46463](https://github.com/kubernetes/kubernetes/pull/46463), [@wongma7](https://github.com/wongma7))

	}

	pr, pw := xioutil.WaitPipe()
	go func() {
		pw.CloseWithError(er.getObjectWithFileInfo(ctx, bucket, object, off, length, pw, fi, metaArr, onlineDisks))
	}()

	// Cleanup function to cause the go routine above to exit, in
	// case of incomplete read.
	pipeCloser := func() {
		pr.CloseWithError(nil)
	}

	if !unlockOnDefer {
		return fn(pr, h, pipeCloser, nsUnlocker)
	}

            final char[] out = new char[in.length];
            final int length = in.length;
            int i, o, state;
            final int s;

            /* The canonicalization routine
             */
            state = 0;
            o = 0;
            for (i = 0; i < length; i++) {
                switch (state) {
                case 0:
                    if (in[i] != '/') {

Sealed-Key":"IAAfAO9a/NaH0+0MKscdm+NL+AbVJkA78wAeP/+yJutEhk6EpDuvTRUpbzl==","X-Minio-Internal-Server-Side-Encryption-Seal-Algorithm":"DAREv2-HMAC-SHA256","content-type":"application/octet-stream"}},{"Bucket":"buck1","Name":"go_113/src/cmd/trace/goroutines.go","UserDef":{"X-Minio-Internal-Server-Side-Encryption-Iv":"X3+eO4vJp/nKeywGLAy+kjPz6MYWHUc1Qc+Aw5bf6ng=","X-Minio-Internal-Server-Side-Encryption-S3-Kms-Key-Id":"my-minio-key","X-Minio-Internal-Server-Side-Encryption-S3-Kms-Sealed-Key":"IAAfA...