{* ../../docs_src/background_tasks/tutorial001_py310.py hl[14] *}

`.add_task()` は以下の引数を受け取ります:

* バックグラウンドで実行されるタスク関数 (`write_notification`)。
* タスク関数に順番に渡す必要のある引数の列 (`email`)。
* タスク関数に渡す必要のあるキーワード引数 (`message="some notification"`)。

## 依存性注入 { #dependency-injection }

`BackgroundTasks` の使用は依存性注入システムでも機能し、様々な階層 (*path operation function*、依存性 (dependable)、サブ依存性など) で `BackgroundTasks` 型のパラメーターを宣言できます。

    @SuppressWarnings({
      // b/345822163
      "SunApi",
      "deprecation",
      // The `deprecation` suppression is for Unsafe APIs that aren't deprecated under some versions
      "UnnecessaryJavacSuppressWarnings"
    })
    @VisibleForTesting
    enum UnsafeComparator implements LexicographicalComparator {
      INSTANCE;

common --host_copt=-DGRPC_BAZEL_BUILD
common --action_env=GRPC_BAZEL_RUNTIME=1
common --repo_env=PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=upb
common --action_env=PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=upb
# Some targets have the same py source file, but use different
# configurations via `requires-` tags. This results in an action
# conflict when precompiling. Disable to avoid that problem.

            Thread.currentThread().setContextClassLoader(projectRealm);
        }
    }

    // TODO I'm really wondering where this method belongs; smells like it should be on MavenProject, but for some
    // reason it isn't ? This localization is kind-of a code smell.

    public static String getKey(MavenProject project) {
        return project.getGroupId() + ':' + project.getArtifactId() + ':' + project.getVersion();

 * <p>{@code RateLimiter} is safe for concurrent use: It will restrict the total rate of calls from
 * all threads. Note, however, that it does not guarantee fairness.
 *
 * <p>Rate limiters are often used to restrict the rate at which some physical or logical resource
 * is accessed. This is in contrast to {@link java.util.concurrent.Semaphore} which restricts the
 * number of concurrent accesses instead of the rate (note though that concurrency and rate are

import java.util.concurrent.atomic.AtomicReference;
import org.jspecify.annotations.Nullable;

/**
 * A step in a pipeline of an asynchronous computation. When the last step in the computation is
 * complete, some objects captured during the computation are closed.
 *
 * <p>A pipeline of {@code ClosingFuture}s is a tree of steps. Each step represents either an

It is also possible to set the default `GODEBUG` for a given program
(discussed below).

When preparing any change that is permitted by Go 1 compatibility
but may nonetheless break some existing programs,
we first engineer the change to keep as many existing programs working as possible.
For the remaining programs,
we define a new GODEBUG setting that
allows individual programs to opt back in to the old behavior.

      connectionPool.evictAll()
      if (connectionPool.connectionCount() > 0) {
        // Minimise test flakiness due to possible race conditions with connections closing.
        // Some number of tests will report here, but not fail due to this delay.
        println("Delaying to avoid flakes")
        Thread.sleep(500L)
        println("After delay: " + connectionPool.connectionCount())
      }

 *
 * @author Kyle Maddison
 * @author Geoff Pike
 */
final class FarmHashFingerprint64 extends AbstractNonStreamingHashFunction {
  static final HashFunction FARMHASH_FINGERPRINT_64 = new FarmHashFingerprint64();

  // Some primes between 2^63 and 2^64 for various uses.
  private static final long K0 = 0xc3a5c85c97cb3127L;
  private static final long K1 = 0xb492b66fbe98f273L;
  private static final long K2 = 0x9ae16a3b2f90404fL;

  @Override

   * "inherited" from superclasses of the same package.
   */
  public void testAllPublicStaticMethods(Class<?> c) {
    testStaticMethods(c, Visibility.PUBLIC);
  }

  /**
   * Runs {@link #testMethod} on every instance method of the class of {@code instance} with at
   * least {@code minimalVisibility}, including those inherited from superclasses of the same
   * package.
   */