*
   * @return null if an explanation cannot be provided (e.g. because the future is done).
   * @since 23.0
   */
  @CheckForNull
  protected String pendingToString() {
    // TODO(diamondm) consider moving this into addPendingString so it's always in the output
    if (this instanceof ScheduledFuture) {
      return "remaining delay=["
          + ((ScheduledFuture) this).getDelay(TimeUnit.MILLISECONDS)
          + " ms]";

    @SuppressWarnings("nullness") // Unsafe, but we can't fix it now.
    public ImmutableSet<@NonNull E> immutableCopy() {
      return ImmutableSet.copyOf((SetView<@NonNull E>) this);
    }

    /**
     * Copies the current contents of this set view into an existing set. This method has equivalent
     * behavior to {@code set.addAll(this)}, assuming that all the sets involved are based on the
     * same notion of equivalence.
     *

      setMap(map);
    }

    @GwtIncompatible // not needed in emulated source
    @J2ktIncompatible
    private static final long serialVersionUID = 0;
  }

  /**
   * Copies each key-value mapping in {@code source} into {@code dest}, with its key and value
   * reversed.
   *
   * <p>If {@code source} is an {@link ImmutableMultimap}, consider using {@link
   * ImmutableMultimap#inverse} instead.

et?jnihs?ynan??ukohak???iin!.&a&ga?k&ium?oagan??munou!imanim??t&a&bihs?giin??ioy??w&a&gioti?kikes?zuy??irak??yijo??e&kustim?mabust??i&aniat?hcamakot?kaz&awihsak?omuzi??m&a&gat?karum??o???n&anust?esog??o&das?ihcot?jnas?k&ihay?oym??mak?naga?ries??u&ories?steoj?????i&k&a!.&a&go?k&asok?oimak??t&ago!rihcah??ika!atik???w&aki?oyk???e&mojog?natim?suranihsagih?t&ado?okoy???i&hsoyirom?magatak?naokimak??nesiad?o&hakin?jnoh!iruy??nuzak?rihson?tasi&juf?m??yjnoh??u&kobmes?oppah????in,?o!.&a&dakatognub?m&asah?...

      Iterator<? extends T> iterator, @ParametricNullness T defaultValue) {
    return iterator.hasNext() ? getOnlyElement(iterator) : defaultValue;
  }

  /**
   * Copies an iterator's elements into an array. The iterator will be left exhausted: its {@code
   * hasNext()} method will return {@code false}.
   *
   * @param iterator the iterator to copy
   * @param type the type of the elements