}
  }

  private boolean hasRemaining() {
    return remaining() > 0;
  }

  private int remaining() {
    requireNonNull(seq); // safe as long as we call this only after checkOpen
    return seq.length() - pos;
  }

  /*
   * To avoid the need to call requireNonNull so much, we could consider more clever approaches,
   * such as:
   *

    E initialValue = getList().get(index);
    assertEquals(
        "set(i, x) should return the old element at position i.",
        initialValue,
        getList().set(index, newValue));
    assertEquals("After set(i, x), get(i) should return x", newValue, getList().get(index));
    assertEquals("set() should not change the size of a list.", getNumElements(), getList().size());
  }

  @ListFeature.Require(SUPPORTS_SET)

 *       href="https://bugs.openjdk.java.net/browse/JDK-8202469">JDK-8202469</a>
 * </ul>
 *
 * <p>This annotation is a temporary hack. We will remove it after we're able to adopt the <a
 * href="https://jspecify.dev/">JSpecify</a> nullness annotations and <a
 * href="https://github.com/google/guava/issues/6126#issuecomment-1203145963">tools no longer need
 * it</a>.
 */

 */
@ElementTypesAreNonnullByDefault
class MapIteratorCache<K, V> {
  private final Map<K, V> backingMap;

  /*
   * Per JDK: "the behavior of a map entry is undefined if the backing map has been modified after
   * the entry was returned by the iterator, except through the setValue operation on the map entry"
   * As such, this field must be cleared before every map mutation.
   *

 *       href="https://bugs.openjdk.java.net/browse/JDK-8202469">JDK-8202469</a>
 * </ul>
 *
 * <p>This annotation is a temporary hack. We will remove it after we're able to adopt the <a
 * href="https://jspecify.dev/">JSpecify</a> nullness annotations and <a
 * href="https://github.com/google/guava/issues/6126#issuecomment-1203145963">tools no longer need
 * it</a>.
 */

 *       href="https://bugs.openjdk.java.net/browse/JDK-8202469">JDK-8202469</a>
 * </ul>
 *
 * <p>This annotation is a temporary hack. We will remove it after we're able to adopt the <a
 * href="https://jspecify.dev/">JSpecify</a> nullness annotations and <a
 * href="https://github.com/google/guava/issues/6126#issuecomment-1203145963">tools no longer need
 * it</a>.
 */

    }
  }

  private boolean hasRemaining() {
    return remaining() > 0;
  }

  private int remaining() {
    requireNonNull(seq); // safe as long as we call this only after checkOpen
    return seq.length() - pos;
  }

  /*
   * To avoid the need to call requireNonNull so much, we could consider more clever approaches,
   * such as:
   *

 *       href="https://bugs.openjdk.java.net/browse/JDK-8202469">JDK-8202469</a>
 * </ul>
 *
 * <p>This annotation is a temporary hack. We will remove it after we're able to adopt the <a
 * href="https://jspecify.dev/">JSpecify</a> nullness annotations and <a
 * href="https://github.com/google/guava/issues/6126#issuecomment-1203145963">tools no longer need
 * it</a>.
 */

 *       href="https://bugs.openjdk.java.net/browse/JDK-8202469">JDK-8202469</a>
 * </ul>
 *
 * <p>This annotation is a temporary hack. We will remove it after we're able to adopt the <a
 * href="https://jspecify.dev/">JSpecify</a> nullness annotations and <a
 * href="https://github.com/google/guava/issues/6126#issuecomment-1203145963">tools no longer need
 * it</a>.
 */

         */
        void update(@Nonnull ByteBuffer input);

        /**
         * Returns the algorithm end result as string, never {@code null}. After invoking this method, this instance should
         * be discarded and not reused. For new checksum calculation you have to get new instance.
         */
        @Nonnull
        String checksum();
    }