future2.set(2L);
    future2 = null;

    /*
     * Futures should be collected even if combiner never runs. This is kind of a silly test, since
     * the combiner is almost certain to hold its own reference to the futures, and a real app would
     * hold a reference to the executor and thus to the combiner. What we really care about is that

    Preconditions.checkNotNull(valueEquivalence);

    Map<K, V> onlyOnLeft = newLinkedHashMap();
    Map<K, V> onlyOnRight = new LinkedHashMap<>(right); // will whittle it down
    Map<K, V> onBoth = newLinkedHashMap();
    Map<K, MapDifference.ValueDifference<V>> differences = newLinkedHashMap();
    doDifference(left, right, valueEquivalence, onlyOnLeft, onlyOnRight, onBoth, differences);

      }
    }

    /**
     * Performs eviction if the segment is over capacity. Avoids flushing the entire cache if the
     * newest entry exceeds the maximum weight all on its own.
     *
     * @param newest the most recently added entry
     */
    @GuardedBy("this")
    void evictEntries(ReferenceEntry<K, V> newest) {
      if (!map.evictsBySize()) {
        return;
      }

    future2.set(2L);
    future2 = null;

    /*
     * Futures should be collected even if combiner never runs. This is kind of a silly test, since
     * the combiner is almost certain to hold its own reference to the futures, and a real app would
     * hold a reference to the executor and thus to the combiner. What we really care about is that

      }
    }

    /**
     * Performs eviction if the segment is over capacity. Avoids flushing the entire cache if the
     * newest entry exceeds the maximum weight all on its own.
     *
     * @param newest the most recently added entry
     */
    @GuardedBy("this")
    void evictEntries(ReferenceEntry<K, V> newest) {
      if (!map.evictsBySize()) {
        return;
      }