* <p>Note in particular that an equivalence wrapper is never equal to the object it wraps.
   *
   * <pre>{@code
   * equiv.wrap(obj).equals(obj) // always false
   * }</pre>
   *
   * @since 10.0
   */
  public static final class Wrapper<T extends @Nullable Object> implements Serializable {
    /*
     * Equivalence's type argument is always non-nullable: Equivalence<Number>, never

   * <p>Note in particular that an equivalence wrapper is never equal to the object it wraps.
   *
   * <pre>{@code
   * equiv.wrap(obj).equals(obj) // always false
   * }</pre>
   *
   * @since 10.0
   */
  public static final class Wrapper<T extends @Nullable Object> implements Serializable {
    /*
     * Equivalence's type argument is always non-nullable: Equivalence<Number>, never