`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 operations 関数*、依存性 (依存可能性)、サブ依存性など) で `BackgroundTasks` 型のパラメーターを宣言できます。

**FastAPI** は、それぞれの場合の処理​​方法と同じオブジェクトの再利用方法を知っているため、すべてのバックグラウンドタスクがマージされ、バックグラウンドで後で実行されます。

{* ../../docs_src/background_tasks/tutorial002.py hl[13,15,22,25] *}

この例では、レスポンスが送信された *後* にメッセージが `log.txt` ファイルに書き込まれます。

リクエストにクエリがあった場合、バックグラウンドタスクでログに書き込まれます。

  }

  @Test @Ignore
  fun pushPromise() {
    val pushPromise: PushPromise = PushPromise("", "", headersOf(), MockResponse())
    val method: String = pushPromise.method
    val path: String = pushPromise.path
    val headers: Headers = pushPromise.headers
    val response: MockResponse = pushPromise.response
  }

  @Test @Ignore
  fun queueDispatcher() {

        assertThat(traverser instanceof FileSystemTraverser, is(true));

        final List<String> list = new ArrayList<String>();
        traverser.forEach((ResourceHandler) (path, is) -> list.add(path));
        assertThat(list.size(), is(1));
        assertThat(list.get(0).endsWith("DummyTest.class"), is(true));
    }

    /**
     * @throws Exception
     */
    @Test

   * href="https://url.spec.whatwg.org/#syntax-url-path-segment">URL path segments</a>. The returned
   * escaper escapes all non-ASCII characters, even though <a
   * href="https://url.spec.whatwg.org/#url-code-points">many of these are accepted in modern
   * URLs</a>. (<a href="https://url.spec.whatwg.org/#path-state">If the escaper were to leave these

///

### Use your tags { #use-your-tags }

Use the `tags` parameter with your *path operations* (and `APIRouter`s) to assign them to different tags:

{* ../../docs_src/metadata/tutorial004.py hl[21,26] *}

/// info

Read more about tags in [Path Operation Configuration](path-operation-configuration.md#tags){.internal-link target=_blank}.

///

### Check the docs { #check-the-docs }

 * limitations under the License.
 */

package com.google.common.math;

import static com.google.common.math.MathBenchmarking.ARRAY_MASK;
import static com.google.common.math.MathBenchmarking.ARRAY_SIZE;
import static com.google.common.math.MathBenchmarking.randomDouble;
import static com.google.common.math.MathBenchmarking.randomPositiveDouble;

import com.google.caliper.BeforeExperiment;

/** Impersonate TCP-style ServerSocketFactory over UNIX domain sockets. */
public final class UnixDomainServerSocketFactory extends ServerSocketFactory {
  private final File path;

  public UnixDomainServerSocketFactory(File path) {
    this.path = path;
  }

  @Override public ServerSocket createServerSocket() throws IOException {
    return new UnixDomainServerSocket();
  }

 * the License.
 */

package com.google.common.math;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import java.math.BigDecimal;
import java.math.RoundingMode;

/**
 * A class for arithmetic on {@link BigDecimal} that is not covered by its built-in methods.
 *

        AtomicInteger calls = new AtomicInteger();
        doAnswer(inv -> {
            int len = inv.getArgument(2);
            // First call returns len-1, second returns 1
            return calls.getAndIncrement() == 0 ? Math.max(1, len - 1) : 1;
        }).when(raf).read(any(byte[].class), anyInt(), anyInt());
        byte[] dst = new byte[4];
        assertDoesNotThrow(() -> raf.readFully(dst));
        assertEquals(2, calls.get());
    }

* It takes each **request** that comes to your application.
* It can then do something to that **request** or run any needed code.
* Then it passes the **request** to be processed by the rest of the application (by some *path operation*).