private static Predicate<StackTraceElement> hasClassName(final Class<?> clazz) {
    return new Predicate<StackTraceElement>() {
      @Override
      public boolean apply(StackTraceElement element) {
        return element.getClassName().equals(clazz.getName());
      }
    };
  }

  private static final class CallerClass1 {
    static ListenableFuture<String> makeImmediateCancelledFuture() {

      public NavigableSet<E> headSet(@ParametricNullness E toElement, boolean inclusive) {
        return removeOnlyNavigableSet(super.headSet(toElement, inclusive));
      }

      @Override
      public SortedSet<E> subSet(
          @ParametricNullness E fromElement, @ParametricNullness E toElement) {
        return removeOnlySortedSet(super.subSet(fromElement, toElement));
      }

      @Override

    /**
     * A queue of elements currently in the map, ordered by write time. Elements are added to the
     * tail of the queue on write.
     */
    @GuardedBy("this")
    final Queue<ReferenceEntry<K, V>> writeQueue;

    /**
     * A queue of elements currently in the map, ordered by access time. Elements are added to the