*
   * <p>Exceptions thrown by a listener will be propagated up to the executor. Any exception thrown
   * during {@code Executor.execute} (e.g., a {@code RejectedExecutionException} or an exception
   * thrown by {@linkplain MoreExecutors#directExecutor direct execution}) will be caught and
   * logged.
   *
   * <p>Note: If your listener is lightweight -- and will not cause stack overflow by completing

   *
   * <p>If the graph is directed, the resultant edge will be directed; otherwise, it will be
   * undirected.
   *
   * <p>Values do not have to be unique. However, values must be non-null.
   *
   * <p>If {@code nodeU} and {@code nodeV} are not already present in this graph, this method will
   * silently {@link #addNode(Object) add} {@code nodeU} and {@code nodeV} to the graph.
   *

    }

    /**
     * Creates the {@link ListenableFuture} which will return the result of running {@code combiner}
     * when all Futures complete. {@code combiner} will run using {@code executor}.
     *
     * <p>If the combiner throws a {@code CancellationException}, the returned future will be
     * cancelled.
     *
     * <p>Canceling this Future will attempt to cancel all the component futures.
     *
     * @since 23.6

 * entries may be counted in {@link Cache#size}, but will never be visible to read or write
 * operations.
 *
 * <p>Certain cache configurations will result in the accrual of periodic maintenance tasks which
 * will be performed during write operations, or during occasional read operations in the absence of
 * writes. The {@link Cache#cleanUp} method of the returned cache will also perform maintenance, but

   * called once.
   */
  // TODO(cpovirk): @ForOverride
  protected abstract Scheduler scheduler();

  /**
   * Returns the {@link ScheduledExecutorService} that will be used to execute the {@link #startUp},
   * {@link #runOneIteration} and {@link #shutDown} methods. If this method is overridden the

    }

    @Override
    public void execute(Runnable task) {
      // If this operation was successfully cancelled already, calling the runnable will be a noop.
      // This also avoids a race where if outputFuture is cancelled, it will call taskFuture.cancel,
      // which will call newFuture.setFuture(oldFuture), to allow the next task in the queue to run

   * result.
   *
   * @return the next element if there was one. If {@code endOfData} was called during execution,
   *     the return value will be ignored.
   * @throws RuntimeException if any unrecoverable error happens. This exception will propagate
   *     outward to the {@code hasNext()}, {@code next()}, or {@code peek()} invocation that invoked

    @SuppressWarnings("unchecked") // we will only ever read these
    Entry<K, V>[] entries2 = (Entry<K, V>[]) entries;
    return RegularImmutableMap.fromEntries(entries2);
  }

  /**
   * Verifies that {@code key} and {@code value} are non-null, and returns a new immutable entry
   * with those values.
   *
   * <p>A call to {@link Entry#setValue} on the returned entry will always throw {@link

  /**
   * Returns the least of the specified values according to this ordering. If there are multiple
   * least values, the first of those is returned. The iterator will be left exhausted: its {@code
   * hasNext()} method will return {@code false}.
   *
   * <p><b>Java 8+ users:</b> Use {@code Streams.stream(iterator).min(thisComparator).get()} instead

   * with a different behavior in case it is interrupted while waiting. In that case, the operation
   * will continue as usual, and in the end the thread's interruption status will be set (no {@code
   * InterruptedException} is thrown).
   *
   * @param q the blocking queue to be drained
   * @param buffer where to add the transferred elements