@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());
  }

    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);

    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);

          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

      public <K extends Comparable<K>, V> Map<K, V> create(Map<K, V> map) {
        // We use a "custom" equivalence to force MapMaker to make a MapMakerInternalMap.
        ConcurrentMap<K, V> newMap = new MapMaker().keyEquivalence(Equivalence.equals()).makeMap();
        checkState(newMap instanceof MapMakerInternalMap);
        newMap.putAll(map);
        return newMap;
      }
    },
    MapMakerStrongKeysWeakValues {