throw new AssertionError(impossible);
    }
  }

  /**
   * Returns an optional enum constant for the given type, using {@link Enum#valueOf}. If the
   * constant does not exist, {@link Optional#absent} is returned. A common use case is for parsing
   * user input or falling back to a default enum constant. For example, {@code
   * Enums.getIfPresent(Country.class, countryInput).or(Country.DEFAULT);}
   *
   * @since 12.0

    return implied;
  }

  @Retention(RetentionPolicy.RUNTIME)
  @Inherited
  @TesterAnnotation
  public @interface Require {
    CollectionFeature[] value() default {};

    CollectionFeature[] absent() default {};
  }

 *  Include `Content-Type` and `Content-Encoding` in the Apache HTTP client
    adapter. (thanks kwuollett)
 *  Add a media type class to OkHttp.
 *  Change custom header prefix:

    ```
    X-Android-Sent-Millis is now OkHttp-Sent-Millis
    X-Android-Received-Millis is now OkHttp-Received-Millis
    X-Android-Response-Source is now OkHttp-Response-Source
    X-Android-Selected-Transport is now OkHttp-Selected-Transport
    ```

provide OkHttp with an HTTP request, you’re describing the request at a high-level: _“fetch me this URL with these headers.”_ For correctness and efficiency, OkHttp rewrites your request before transmitting it.

OkHttp may add headers that are absent from the original request, including `Content-Length`, `Transfer-Encoding`, `User-Agent`, `Host`, `Connection`, and `Content-Type`. It will add an `Accept-Encoding` header for transparent response compression unless the header is already present....

    // clear absent
    assertFalse(segment.clearValueForTesting(key, hash, valueRef));

    segment.setTableEntryForTesting(0, entry);
    // don't increment count; this is used during computation
    assertTrue(segment.clearValueForTesting(key, hash, valueRef));
    // no notification sent with clearValue
    assertEquals(0, segment.count);

    // clear absent
    assertFalse(segment.clearValueForTesting(key, hash, valueRef));

    segment.setTableEntryForTesting(0, entry);
    // don't increment count; this is used during computation
    assertTrue(segment.clearValueForTesting(key, hash, valueRef));
    // no notification sent with clearValue
    assertEquals(0, segment.count);

    entry.setValueReference(valueRef);

    // absent
    assertThat(segment.removeLoadingValue(key, hash, valueRef)).isFalse();

    // live
    table.set(0, entry);
    // don't increment count; this is used during computation
    assertThat(segment.removeLoadingValue(key, hash, valueRef)).isTrue();
    // no notification sent with removeLoadingValue

    entry.setValueReference(valueRef);

    // absent
    assertThat(segment.removeLoadingValue(key, hash, valueRef)).isFalse();

    // live
    table.set(0, entry);
    // don't increment count; this is used during computation
    assertThat(segment.removeLoadingValue(key, hash, valueRef)).isTrue();
    // no notification sent with removeLoadingValue

   *     previous entry. (If the bimap contains null values, then {@code forcePut}, like {@code
   *     put}, returns {@code null} both if the key is absent and if it is present with a null
   *     value.)
   */
  @CanIgnoreReturnValue
  @Nullable V forcePut(@ParametricNullness K key, @ParametricNullness V value);

  // Bulk Operations

  /**
   * {@inheritDoc}

        array[getNumElements()]);
    // array[getNumElements() + 1] might or might not have been nulled
  }

  @CollectionSize.Require(absent = ZERO)
  public void testToArray_emptyArrayOfWrongTypeForNonEmptyCollection() {
    assertThrows(
        ArrayStoreException.class,
        () -> {
          WrongType[] array = new WrongType[0];