* one as it is because one of our users has defined a wrapper API around Preconditions,
       * declaring a checkState method that accepts a possibly null template. So we'd need to update
       * that user first.
       */
      @CheckForNull String errorMessageTemplate,
      @CheckForNull @Nullable Object... errorMessageArgs) {
    if (!expression) {

        AbstractFuture<?> future, @CheckForNull Waiter expect, @CheckForNull Waiter update) {
      return waitersUpdater.compareAndSet(future, expect, update);
    }

    @Override
    boolean casListeners(AbstractFuture<?> future, @CheckForNull Listener expect, Listener update) {
      return listenersUpdater.compareAndSet(future, expect, update);
    }

    /** Performs a GAS operation on the {@link #listeners} field. */

   * across different segments.
   *
   * The page replacement algorithm's data structures are kept casually consistent with the map. The
   * ordering of writes to a segment is sequentially consistent. An update to the map and recording
   * of reads may not be immediately reflected on the algorithm's data structures. These structures
   * are guarded by a lock and operations are applied in batches to avoid lock contention. The

   * {@code factory}, and the multimap contents are all serializable.
   *
   * <p>The multimap is not threadsafe when any concurrent operations update the multimap, even if
   * {@code map} and the instances generated by {@code factory} are. Concurrent read operations will
   * work correctly. To allow concurrent update operations, wrap the multimap with a call to {@link
   * #synchronizedMultimap}.
   *