*/
  private static final SuccessorsFunction<Character> TWO_TREES = createDirectedGraph("ab", "cd");

  /**
   * A graph consisting of a single root {@code a}:
   *
   * <pre>{@code
   * a
   * }</pre>
   */
  private static final SuccessorsFunction<Character> SINGLE_ROOT = createSingleRootGraph();

  /**
   * A graph that is not a tree (for example, it has two antiparallel edge between {@code e} and

    }

    // wait for entries to expire, but don't call expireEntries
    ticker.advance(EXPIRING_TIME * 10, MILLISECONDS);

    // add a single unexpired entry
    cache.getUnchecked(KEY_PREFIX + 11);

    // collections views shouldn't expose expired entries
    assertEquals(1, Iterators.size(cache.asMap().entrySet().iterator()));

      @SuppressWarnings("unchecked") // Since it's unmodifiable, the covariant cast is safe
      Iterable<T> result = (Iterable<T>) iterable;
      return result;
    }
    return new UnmodifiableIterable<>(iterable);
  }

  /**
   * Simply returns its argument.
   *
   * @deprecated no need to use this
   * @since 10.0
   */
  @Deprecated

 * CacheBuilder#from(CacheBuilderSpec)} or {@link CacheBuilder#from(String)}.
 *
 * @author Adam Winer
 * @since 12.0
 */
@SuppressWarnings("GoodTime") // lots of violations (nanosecond math)
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public final class CacheBuilderSpec {
  /** Parses a single value. */
  private interface ValueParser {
    void parse(CacheBuilderSpec spec, String key, @CheckForNull String value);
  }

   */
  @SuppressWarnings("unchecked")
  public static <K extends Comparable<?>, V> ImmutableRangeMap<K, V> of() {
    return (ImmutableRangeMap<K, V>) EMPTY;
  }

  /** Returns an immutable range map mapping a single range to a single value. */
  public static <K extends Comparable<?>, V> ImmutableRangeMap<K, V> of(Range<K> range, V value) {
    return new ImmutableRangeMap<>(ImmutableList.of(range), ImmutableList.of(value));
  }

    }

    // wait for entries to expire, but don't call expireEntries
    ticker.advance(EXPIRING_TIME * 10, MILLISECONDS);

    // add a single unexpired entry
    cache.getUnchecked(KEY_PREFIX + 11);

    // collections views shouldn't expose expired entries
    assertEquals(1, Iterators.size(cache.asMap().entrySet().iterator()));

 * map from keys to <i>nonempty</i> collections of values:
 *
 * <ul>
 *   <li>a → 1, 2
 *   <li>b → 3
 * </ul>
 *
 * ... or as a single "flattened" collection of key-value pairs:
 *
 * <ul>
 *   <li>a → 1
 *   <li>a → 2
 *   <li>b → 3
 * </ul>
 *
 * <p><b>Important:</b> although the first interpretation resembles how most multimaps are

   * loaded) value, or null. Multiple concurrent calls to {@link Cache} lookup methods on an absent
   * value can result in multiple misses, all returning the results of a single cache load
   * operation.
   */
  public long missCount() {
    return missCount;
  }

  /**
   * Returns the ratio of cache requests which were misses. This is defined as {@code missCount /

   * loaded) value, or null. Multiple concurrent calls to {@link Cache} lookup methods on an absent
   * value can result in multiple misses, all returning the results of a single cache load
   * operation.
   */
  public long missCount() {
    return missCount;
  }

  /**
   * Returns the ratio of cache requests which were misses. This is defined as {@code missCount /

   *
   * <p>This test might fail in GWT because the GWT emulations might count on the input collection
   * not to change during the copy. It is safe to do so in GWT because javascript is
   * single-threaded.
   */
  @GwtIncompatible // GWT is single threaded
  public void testCopyOf_threadSafe() {
    /*
     * The actual collections that we pass as inputs will be wrappers around these, so