@GwtIncompatible // To be supported
  MapMaker keyEquivalence(Equivalence<Object> equivalence) {
    checkState(keyEquivalence == null, "key equivalence was already set to %s", keyEquivalence);
    keyEquivalence = checkNotNull(equivalence);
    this.useCustomMap = true;
    return this;
  }

  Equivalence<Object> getKeyEquivalence() {
    return MoreObjects.firstNonNull(keyEquivalence, getKeyStrength().defaultEquivalence());
  }

  }

  private void testIdentityKeyEquality(MapMakerInternalMap.Strength keyStrength) {

    ConcurrentMap<String, AtomicInteger> map =
        new MapMaker().setKeyStrength(keyStrength).keyEquivalence(Equivalence.identity()).makeMap();

    ConcurrentHashMultiset<String> multiset = ConcurrentHashMultiset.create(map);

    String s1 = new String("a");
    String s2 = new String("a");

    final Strength valueStrength;
    final Equivalence<Object> keyEquivalence;
    final Equivalence<Object> valueEquivalence;
    final int concurrencyLevel;

    transient ConcurrentMap<K, V> delegate;

    AbstractSerializationProxy(
        Strength keyStrength,
        Strength valueStrength,
        Equivalence<Object> keyEquivalence,
        Equivalence<Object> valueEquivalence,

    assertEquals("maximumWeight", a.maximumWeight, b.maximumWeight);
    assertEquals("refreshNanos", a.refreshNanos, b.refreshNanos);
    assertEquals("keyEquivalence", a.keyEquivalence, b.keyEquivalence);
    assertEquals("keyStrength", a.keyStrength, b.keyStrength);
    assertEquals("removalListener", a.removalListener, b.removalListener);
    assertEquals("weigher", a.weigher, b.weigher);

        Ticker ticker,
        CacheLoader<? super K, V> loader) {
      this.keyStrength = keyStrength;
      this.valueStrength = valueStrength;
      this.keyEquivalence = keyEquivalence;
      this.valueEquivalence = valueEquivalence;
      this.expireAfterWriteNanos = expireAfterWriteNanos;
      this.expireAfterAccessNanos = expireAfterAccessNanos;
      this.maxWeight = maxWeight;

  @CanIgnoreReturnValue
  CacheBuilder<K, V> keyEquivalence(Equivalence<Object> equivalence) {
    checkState(keyEquivalence == null, "key equivalence was already set to %s", keyEquivalence);
    keyEquivalence = checkNotNull(equivalence);
    return this;
  }

  Equivalence<Object> getKeyEquivalence() {
    return MoreObjects.firstNonNull(keyEquivalence, getKeyStrength().defaultEquivalence());
  }

  /**

          protected int doHash(Object t) {
            return 0;
          }
        };

    MapMakerInternalMap<Object, Object, ?, ?> map =
        makeMap(createMapMaker().keyEquivalence(testEquivalence));
    assertSame(testEquivalence, map.keyEquivalence);
    assertSame(map.valueStrength().defaultEquivalence(), map.valueEquivalence());
  }

  public void testSetConcurrencyLevel() {
    // round up to the nearest power of two

          protected int doHash(Object t) {
            return 0;
          }
        };

    MapMakerInternalMap<Object, Object, ?, ?> map =
        makeMap(createMapMaker().keyEquivalence(testEquivalence));
    assertSame(testEquivalence, map.keyEquivalence);
    assertSame(map.valueStrength().defaultEquivalence(), map.valueEquivalence());
  }

  public void testSetConcurrencyLevel() {
    // round up to the nearest power of two

  }

  private void testIdentityKeyEquality(MapMakerInternalMap.Strength keyStrength) {

    ConcurrentMap<String, AtomicInteger> map =
        new MapMaker().setKeyStrength(keyStrength).keyEquivalence(Equivalence.identity()).makeMap();

    ConcurrentHashMultiset<String> multiset = ConcurrentHashMultiset.create(map);

    String s1 = new String("a");
    String s2 = new String("a");

    assertEquals("maximumWeight", a.maximumWeight, b.maximumWeight);
    assertEquals("refreshNanos", a.refreshNanos, b.refreshNanos);
    assertEquals("keyEquivalence", a.keyEquivalence, b.keyEquivalence);
    assertEquals("keyStrength", a.keyStrength, b.keyStrength);
    assertEquals("removalListener", a.removalListener, b.removalListener);
    assertEquals("weigher", a.weigher, b.weigher);