@Synchronized fun failed(failedRoute: Route) {
    _failedRoutes.add(failedRoute)
  }

  /** Records success connecting to [route]. */
  @Synchronized fun connected(route: Route) {
    _failedRoutes.remove(route)
  }

  /** Returns true if [route] has failed recently and should be avoided. */
  @Synchronized fun shouldPostpone(route: Route): Boolean = route in _failedRoutes

    Iterator<String> iterator = iterable.iterator();
    assertTrue(iterator.hasNext());
    assertEquals("a", iterator.next());
    assertThrows(UnsupportedOperationException.class, () -> iterator.remove());
    assertFalse(iterator.hasNext());
    assertThrows(NoSuchElementException.class, () -> iterator.next());
    assertThrows(IllegalStateException.class, () -> iterable.iterator());
  }

            }
            final int style = STYLES[index++];
            return DateFormat.getTimeInstance(style, locale);
        }

        @Override
        public void remove() {
            throw new ClUnsupportedOperationException("remove");
        }

    }

    /**
     * An {@link Iterator} that iterates over {@link DateFormat} instances corresponding to the styles supported by the locale.
     *

            final int style = STYLES[index++];
            return DateFormat.getDateTimeInstance(style, style, locale);
        }

        @Override
        public void remove() {
            throw new ClUnsupportedOperationException("remove");
        }

    }

    /**
     * An {@link Iterator} that iterates over {@link DateFormat} instances corresponding to the styles supported by the locale.
     *

            return parent.toArray(a);
        }

        public boolean add(final E e) {
            return parent.add(e);
        }

        public boolean remove(final Object o) {
            return parent.remove(o);
        }

        public boolean containsAll(final Collection<?> c) {
            return parent.containsAll(c);
        }

/**
 * This class provides a skeletal implementation of the {@code Iterator} interface for sequences
 * whose next element can always be derived from the previous element. Null elements are not
 * supported, nor is the {@link #remove()} method.
 *
 * <p>Example:
 *
 * {@snippet :
 * Iterator<Integer> powersOfTwo =
 *     new AbstractSequentialIterator<Integer>(1) {
 *       protected Integer computeNext(Integer previous) {

            final TimeoutTask task = e.getElement();
            if (task.isCanceled()) {
                e.remove();
            } else if (!task.isStopped() && task.isExpired()) {
                expiredTask.add(task);
                if (!task.isPermanent()) {
                    e.remove();
                }
            }
        }
        return expiredTask;
    }

    /**

  public boolean isEmpty() {
    return size() == 0;
  }

  @Override
  public void clear() {
    Iterators.clear(cellSet().iterator());
  }

  @CanIgnoreReturnValue
  @Override
  public @Nullable V remove(@Nullable Object rowKey, @Nullable Object columnKey) {
    Map<C, V> row = safeGet(rowMap(), rowKey);
    return (row == null) ? null : Maps.safeRemove(row, columnKey);
  }

  @CanIgnoreReturnValue
  @Override

  // TODO(b/192446998): Remove this override after tools understand nullness better.
  public @Nullable V put(K key, @ParametricNullness V value) {
    return super.put(key, value);
  }

  @CanIgnoreReturnValue
  @Override
  @SuppressWarnings("RedundantOverride") // b/192446478: RedundantOverride ignores some annotations.
  // TODO(b/192446998): Remove this override after tools understand nullness better.

    assertThat(subset).containsExactly("b", "c", "d", "e").inOrder();

    assertTrue(subset.remove("c"));
    assertThat(elementSet).containsExactly("a", "b", "d", "e", "f").inOrder();
    assertThat(subset).containsExactly("b", "d", "e").inOrder();
    assertEquals(10, ms.size());

    assertFalse(subset.remove("a"));
    assertThat(elementSet).containsExactly("a", "b", "d", "e", "f").inOrder();