ForkJoinPool pool = new ForkJoinPool(1);
        req.threadPool(pool);

        // ## Act ##
        // execute() should force synchronous execution but restore threadPool afterward
        try (CurlResponse response = req.execute()) {
            assertEquals(200, response.getHttpStatusCode());
        }

        // ## Assert ##
        // After execute(), the threadPool should be restored

    ExecutorService threadPool = newFixedThreadPool(nThreads);
    CountDownLatch tasksFinished = new CountDownLatch(nTasks);
    for (int i = 0; i < nTasks; i++) {
      String s = "a" + i;
      @SuppressWarnings("unused") // https://errorprone.info/bugpattern/FutureReturnValueIgnored
      Future<?> possiblyIgnoredError =
          threadPool.submit(
              () -> {

    ExecutorService threadPool = newFixedThreadPool(nThreads);
    CountDownLatch tasksFinished = new CountDownLatch(nTasks);
    for (int i = 0; i < nTasks; i++) {
      String s = "a" + i;
      @SuppressWarnings("unused") // https://errorprone.info/bugpattern/FutureReturnValueIgnored
      Future<?> possiblyIgnoredError =
          threadPool.submit(
              () -> {

```Python
contents = myfile.file.read()
```

/// note | `async` Technical Details

When you use the `async` methods, **FastAPI** runs the file methods in a threadpool and awaits for them.

///

/// note | Starlette Technical Details

///

To avoid blocking the event loop, you can simply declare the *path operation function* with regular `def` instead of `async def`, that way FastAPI will run it on a threadpool worker, to avoid blocking the main loop.

{* ../../docs_src/stream_data/tutorial002_py310.py ln[30:34] hl[31] *}

/// tip

而且在許多情況下，讀取它們會是阻塞操作（可能阻塞事件迴圈），因為資料是從磁碟或網路讀取。

/// info

上面的範例其實是例外，因為 `io.BytesIO` 物件已在記憶體中，讀取不會阻塞任何東西。

但在多數情況下，讀取檔案或類檔案物件會造成阻塞。

///

為了避免阻塞事件迴圈，你可以將路徑操作函式宣告為一般的 `def`（而非 `async def`），這樣 FastAPI 會在 threadpool worker 上執行它，避免阻塞主事件迴圈。

{* ../../docs_src/stream_data/tutorial002_py310.py ln[30:34] hl[31] *}

/// tip

如果你需要在 async 函式內呼叫阻塞程式碼，或在阻塞函式中呼叫 async 函式，你可以使用 [Asyncer](https://asyncer.tiangolo.com)，它是 FastAPI 的姊妹函式庫。

@defaultMessage Spawns a new thread which is solely under lucenes control use ThreadPool#relativeTimeInMillis instead
org.apache.lucene.search.TimeLimitingCollector#getGlobalTimerThread()
org.apache.lucene.search.TimeLimitingCollector#getGlobalCounter()

@app.get("/items/")
def read_items():
    data = some_blocking_library.fetch_items()
    return data
```

In case of doubt, or by default, use regular `def` functions, those will be run in a threadpool so they don't block the event loop.

The same rules apply to dependencies.

Make sure blocking code is not run inside of `async` functions. The logic will work, but will damage the performance heavily.

common:mkl_threadpool --define=build_with_mkl=true --define=enable_mkl=true
common:mkl_threadpool --define=tensorflow_mkldnn_contraction_kernel=0
common:mkl_threadpool --define=build_with_mkl_opensource=true
common:mkl_threadpool -c opt

# Config setting to build oneDNN with Compute Library for the Arm Architecture (ACL).
# with Eigen threadpool support

 *
 * {@snippet :
 * ListenableFuture<Boolean> adminIsLoggedIn =
 *     FluentFuture.from(usersDatabase.getAdminUser())
 *         .transform(User::getId, directExecutor())
 *         .transform(ActivityService::isLoggedIn, threadPool)
 *         .catching(RpcException.class, e -> false, directExecutor());
 * }
 *
 * <h3>Alternatives</h3>
 *
 * <h4>Frameworks</h4>
 *