if (atomic.compareAndSet(oldValue, newValue)) {
          return oldValue;
        }
        // value changed
      }
    }
  }

  /**
   * Copies all of the mappings from the specified map to this map. The effect of this call is
   * equivalent to that of calling {@code put(k, v)} on this map once for each mapping from key
   * {@code k} to value {@code v} in the specified map. The behavior of this operation is undefined

 * value and the old value.
 *
 * <p>Keys and values may be null. All optional multimap methods are supported, and all returned
 * views are modifiable.
 *
 * <p>The lists returned by {@link #get}, {@link #removeAll}, and {@link #replaceValues} all
 * implement {@link java.util.RandomAccess}.
 *

    };
  }

  static ListFrobber nop() {
    return new ListFrobber() {
      @Override
      public void perform(List<Integer> list) {}
    };
  }

  /** A list that mutates itself after every call to each of its {@link List} methods. */
  interface ConcurrentlyMutatedList<E> extends List<E> {
    /**
     * The elements of a {@link ConcurrentlyMutatedList} are added and removed over time. This

   * @return a newly-allocated array into which all the elements of the iterator have been copied
   */
  @GwtIncompatible // Array.newInstance(Class, int)
  public static <T extends @Nullable Object> T[] toArray(
      Iterator<? extends T> iterator, Class<@NonNull T> type) {
    List<T> list = Lists.newArrayList(iterator);
    return Iterables.<T>toArray(list, type);
  }

  /**

 * maintained with a doubly linked list through the entries. All optional operations (put and
 * remove) are supported. Null keys and values are supported.
 *
 * <p>{@code containsKey(k)}, {@code put(k, v)} and {@code remove(k)} are all (expected and
 * amortized) constant time operations. Expected in the hashtable sense (depends on the hash

            init = true;
          }
        } finally {
          busy = 0;
        }
        if (init) break;
      } else if (casBase(v = base, fn(v, x))) break; // Fall back on using base
    }
  }

  /** Sets base and all cells to the given value. */
  final void internalReset(long initialValue) {
    Cell[] as = cells;
    base = initialValue;
    if (as != null) {
      int n = as.length;

   * words, the new supplier's value will be computed by retrieving the value from {@code supplier},
   * and then applying {@code function} to that value. Note that the resulting supplier will not
   * call {@code supplier} or invoke {@code function} until it is called.
   */
  public static <F extends @Nullable Object, T extends @Nullable Object> Supplier<T> compose(
      Function<? super F, T> function, Supplier<F> supplier) {

    }
  }

  private enum LinkedListSupplier implements Supplier<List<?>> {
    INSTANCE;

    public static <V extends @Nullable Object> Supplier<List<V>> instance() {
      // Each call generates a fresh LinkedList, which can serve as a List<V> for any V.
      @SuppressWarnings({"rawtypes", "unchecked"})
      Supplier<List<V>> result = (Supplier) INSTANCE;
      return result;
    }

    @Override

   *
   * <p>This method is equivalent to {@code fuzzyEquals(a, b, tolerance) ? 0 : Double.compare(a,
   * b)}. In particular, like {@link Double#compare(double, double)}, it treats all NaN values as
   * equal and greater than all other values (including {@link Double#POSITIVE_INFINITY}).
   *
   * <p>This is not a total ordering and is not suitable for use in {@link

      return obj instanceof IsOdd;
    }

    @Override
    public String toString() {
      return "IsOdd";
    }
  }

  /**
   * Generates a new Predicate per call.
   *
   * <p>Creating a new Predicate each time helps catch cases where code is using {@code x == y}
   * instead of {@code x.equals(y)}.
   */
  private static IsOdd isOdd() {
    return new IsOdd();
  }