return doBuild(this);
  }

  // Split out so that the anonymous ThreadFactory can't contain a reference back to the builder.
  // At least, I assume that's why. TODO(cpovirk): Check, and maybe add a test for this.
  @SuppressWarnings("ThreadPriorityCheck") // We only propagate user requests (which we discourage).
  private static ThreadFactory doBuild(ThreadFactoryBuilder builder) {

  }

  // Class unloading test:

  public static final class WillBeUnloadedException extends Exception {}

  @AndroidIncompatible // "Parent ClassLoader may not be null"; maybe avoidable if we try?
  public void testGetChecked_classUnloading() throws Exception {
    WeakReference<?> classUsedByGetChecked = doTestClassUnloading();
    GcFinalization.awaitClear(classUsedByGetChecked);
  }

    assertThrows(NullPointerException.class, () -> builder.add((String[]) elements));
    ImmutableList<String> result = builder.build();

    /*
     * Maybe it rejects all elements, or maybe it adds "a" before failing.
     * Either way is fine with us.
     */
    if (result.isEmpty()) {
      return;
    }
    assertTrue(ImmutableList.of("a").equals(result));

    @LazyInit @Nullable TimeoutFuture<V> timeoutFutureRef;

    Fire(TimeoutFuture<V> timeoutFuture) {
      this.timeoutFutureRef = timeoutFuture;
    }

    @Override
    // TODO: b/227335009 - Maybe change interruption behavior, but it requires thought.
    @SuppressWarnings("Interruption")
    public void run() {
      // If either of these reads return null then we must be after a successful cancel or another

   * process it; all should produce the same answer, the only difference should be the number of
   * process()/processRemaining() invocations, due to alignment.
   */
  @AndroidIncompatible // slow. TODO(cpovirk): Maybe just reduce iterations under Android.
  public void testExhaustive() throws Exception {
    Random random = new Random(0); // will iteratively make more debuggable, each time it breaks

/// tip

The `shutdown` would happen when you are **stopping** the application.

Maybe you need to start a new version, or you just got tired of running it. 🤷

///

### Lifespan function { #lifespan-function }

    assertThrows(NullPointerException.class, () -> builder.add((String[]) elements));
    ImmutableList<String> result = builder.build();

    /*
     * Maybe it rejects all elements, or maybe it adds "a" before failing.
     * Either way is fine with us.
     */
    if (result.isEmpty()) {
      return;
    }
    assertTrue(ImmutableList.of("a").equals(result));

      return;
    }

    /*
     * Any of the setException() calls below can fail if the output Future is cancelled between now
     * and then. This means that we're silently swallowing an exception -- maybe even an Error. But
     * this is no worse than what FutureTask does in that situation. Additionally, because the
     * Future was cancelled, its listeners have been run, so its consumers will not hang.
     *

  }

  /*
   * Under Android, MyError propagates up and fails the test?
   *
   * TODO(b/218700094): Does this matter to prod users, or is it just a feature of our testing
   * environment? If the latter, maybe write a custom Executor that avoids failing the test when it
   * sees an Error?
   */
  @AndroidIncompatible
  public void testTaskThrowsError() throws Exception {
    class MyError extends Error {}

INHERIT: ../en/mkdocs.maybe-insiders.yml
site_name: FastAPI
site_description: FastAPI framework, high performance, easy to learn, fast to code, ready for production
site_url: https://fastapi.tiangolo.com/
theme:
  name: material
  custom_dir: ../en/overrides
  palette:
  - media: (prefers-color-scheme)
    toggle:
      icon: material/lightbulb-auto
      name: Switch to light mode
  - media: '(prefers-color-scheme: light)'
    scheme: default