scanStateStarted
	scanStateSuccess
	scanStateError

	// Time in which the initiator of a scan must have reported back.
	metacacheMaxRunningAge = time.Minute

	// Max time between client calls before dropping an async cache listing.
	metacacheMaxClientWait = 3 * time.Minute

	// metacacheBlockSize is the number of file/directory entries to have in each block.
	metacacheBlockSize = 5000

	kvDstPool   sync.Pool       // pool of []jstream.KV used for output
	close       chan struct{}   // used for shutting down the splitter before end of stream
	readerWg    sync.WaitGroup  // used to keep track of async reader.
}

// queueItem is an item in the queue.
type queueItem struct {
	input []byte             // raw input sent to the worker
	dst   chan []jstream.KVS // result of block decode

// optimization hook is in place.
TEST(CAPI, DISABLED_DistributedFunctionCancelledOnError) {
  TestDistributedFunctionCancellation(true);
}

void TestRemoteExecuteDeleteContextWithOutstandingRPC(bool async) {
  tensorflow::ServerDef server_def = GetServerDef(2);

  // This server def has the task index set to 0.
  string serialized = server_def.SerializeAsString();

  server_def.set_task_index(1);

configured to fall back for broad connectivity.

Using OkHttp is easy. Its request/response API is designed with fluent builders and immutability. It
supports both synchronous blocking calls and async calls with callbacks.


Get a URL
---------

This program downloads a URL and prints its contents as a string. [Full source][get_example].

```java
OkHttpClient client = new OkHttpClient();

高度なシナリオでは、「キャッシュされた」値を使うのではなく、同じリクエストの各ステップ（おそらく複数回）で依存関係を呼び出す必要があることがわかっている場合、`Depens`を使用する際に、`use_cache=False`というパラメータを設定することができます。

```Python hl_lines="1"
async def needy_dependency(fresh_value: str = Depends(get_value, use_cache=False)):
    return {"fresh_value": fresh_value}
```

## まとめ

ここで使われている派手な言葉は別にして、**依存性注入** システムは非常にシンプルです。

*path operation関数*と同じように見えるただの関数です。

 * which is necessarily blocking. By implementing an {@code InputStream} it allows consumers to
 * "pull" as much data as they can handle, which is more convenient when dealing with flow
 * controlled, async APIs.
 *
 * @author Chris Nokleberg
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
final class ReaderInputStream extends InputStream {
  private final Reader reader;

 * which is necessarily blocking. By implementing an {@code InputStream} it allows consumers to
 * "pull" as much data as they can handle, which is more convenient when dealing with flow
 * controlled, async APIs.
 *
 * @author Chris Nokleberg
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
final class ReaderInputStream extends InputStream {
  private final Reader reader;

      get() = originalRequest.url.host

    val request: Request
      get() = originalRequest

    val call: RealCall
      get() = this@RealCall

    /**
     * Attempt to enqueue this async call on [executorService]. This will attempt to clean up
     * if the executor has been shut down by reporting the call as failed.
     */
    fun executeOn(executorService: ExecutorService) {

包括许多与云存储，视频处理等交互的库。

```Python hl_lines="2  10-12  14"
{!../../docs_src/custom_response/tutorial008.py!}
```

/// tip | "小贴士"

注意在这里，因为我们使用的是不支持 `async` 和 `await` 的标准 `open()`，我们使用普通的 `def` 声明了路径操作。

///

### `FileResponse`

异步传输文件作为响应。

与其他响应类型相比，接受不同的参数集进行实例化：

* `path` - 要流式传输的文件的文件路径。
* `headers` - 任何自定义响应头，传入字典类型。

	csvDstPool   sync.Pool        // pool of [][]string used for output
	close        chan struct{}    // used for shutting down the splitter before end of stream
	readerWg     sync.WaitGroup   // used to keep track of async reader.
}

// queueItem is an item in the queue.
type queueItem struct {
	input []byte          // raw input sent to the worker
	dst   chan [][]string // result of block decode