* moderately increased constant factors of CPU. Only use this class when there is a specific reason
 * to prioritize memory over CPU.
 *
 * @author Louis Wasserman
 * @author Jon Noack
 */
@GwtIncompatible // not worth using in GWT for now
@ElementTypesAreNonnullByDefault
class CompactHashMap<K extends @Nullable Object, V extends @Nullable Object>
    extends AbstractMap<K, V> implements Serializable {