* iterable}. The iterator's {@code hasNext()} method returns {@code true} until {@code iterable}
   * is empty.
   *
   * <p><b>Warning:</b> Typical uses of the resulting iterator may produce an infinite loop. You
   * should use an explicit {@code break} or be certain that you will eventually remove all the
   * elements.
   */

   * iterable}. The iterator's {@code hasNext()} method returns {@code true} until {@code iterable}
   * is empty.
   *
   * <p><b>Warning:</b> Typical uses of the resulting iterator may produce an infinite loop. You
   * should use an explicit {@code break} or be certain that you will eventually remove all the
   * elements.
   */

  protected abstract boolean doEquivalent(T a, T b);

  /**
   * <i>May</i> return {@code true} if {@code object} is a {@code Equivalence} that behaves
   * identically to this equivalence.
   *
   * <p><b>Warning: do not depend</b> on the behavior of this method.
   *
   * <p>Historically, {@code Equivalence} instances in this library have implemented this method to

    assertThrows(IllegalArgumentException.class, () -> Bytes.ensureCapacity(ARRAY1, 1, -1));
  }

  public void testToArray() {
    // need explicit type parameter to avoid javac warning!?
    List<Byte> none = Arrays.<Byte>asList();
    assertThat(Bytes.toArray(none)).isEqualTo(EMPTY);

    List<Byte> one = Arrays.asList((byte) 1);
    assertThat(Bytes.toArray(one)).isEqualTo(ARRAY1);

当 `with` 代码块结束时，它会确保文件被关闭，即使期间发生了异常。

当你用 `yield` 创建一个依赖时，**FastAPI** 会在内部为它创建一个上下文管理器，并与其他相关工具结合使用。

### 在带有 `yield` 的依赖中使用上下文管理器 { #using-context-managers-in-dependencies-with-yield }

/// warning | 警告

这算是一个“高级”概念。

如果你刚开始使用 **FastAPI**，现在可以先跳过。

///

在 Python 中，你可以通过[创建一个带有 `__enter__()` 和 `__exit__()` 方法的类](https://docs.python.org/3/reference/datamodel.html#context-managers)来创建上下文管理器。

 * <p>See the Guava User Guide article on <a
 * href="https://github.com/google/guava/wiki/PrimitivesExplained">primitive utilities</a>.
 *
 * @author Kevin Bourrillion
 * @since 1.0
 */
// TODO(kevinb): how to prevent warning on UnsignedBytes when building GWT
// javadoc?
@GwtCompatible
public final class Bytes {
  private Bytes() {}

  /**
   * Returns a hash code for {@code value}; obsolete alternative to {@link Byte#hashCode(byte)}.

      // "C:foo" ("C:" - working dir of drive C on Windows)
      return parent;
    }

    // Paths that don't have a parent:
    if (path.getNameCount() == 0) {
      // "/", "C:\", "\" (no parent)
      // "" (undefined, though typically parent of working dir)
      // "C:" (parent of working dir of drive C on Windows)
      //
      // For working dir paths ("" and "C:"), return null because:

また、`from starlette.responses import PlainTextResponse`を使用することもできます。

**FastAPI** は開発者の利便性を考慮して、`fastapi.responses`と同じ`starlette.responses`を提供しています。しかし、利用可能なレスポンスのほとんどはStarletteから直接提供されます。

///

/// warning | 注意

`RequestValidationError`には、検証エラーが発生したファイル名と行番号の情報が含まれているため、必要であれば関連情報と一緒にログに表示できます。

しかし、そのまま文字列に変換して直接その情報を返すと、システムに関する情報が多少漏えいする可能性があります。そのため、ここではコードが各エラーを個別に抽出して表示します。

///

  /**
   * Returns a new target iterator each time it's called. This is the iterator you are trying to
   * test. This must return an Iterator that returns the expected elements passed to the constructor
   * in the given order. Warning: it is not enough to simply pull multiple iterators from the same
   * source Iterable, unless that Iterator is unmodifiable.
   */
  protected abstract I newTargetIterator();

  /**

 *       {@link #verifyNotNull(Object)} and {@link Preconditions#checkNotNull(Object)} perform the
 *       same function with more clarity.
 * </ul>
 *
 * <h3>Warning about performance</h3>
 *
 * <p>Remember that parameter values for message construction must all be computed eagerly, and
 * autoboxing and varargs array creation may happen as well, even when the verification succeeds and