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("valueEquivalence", a.valueEquivalence, b.valueEquivalence);

    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("valueEquivalence", a.valueEquivalence, b.valueEquivalence);

    checkState(keyStrength == null, "Key strength was already set to %s", keyStrength);
    keyStrength = checkNotNull(strength);
    if (strength != Strength.STRONG) {
      // STRONG could be used during deserialization.
      useCustomMap = true;
    }
    return this;
  }

  Strength getKeyStrength() {
    return MoreObjects.firstNonNull(keyStrength, Strength.STRONG);
  }

  /**

  }

  private static void checkStrength(
      MapMakerInternalMap<Object, Object, ?, ?> map, Strength keyStrength, Strength valueStrength) {
    assertSame(keyStrength, map.keyStrength());
    assertSame(valueStrength, map.valueStrength());
    assertSame(keyStrength.defaultEquivalence(), map.keyEquivalence);
    assertSame(valueStrength.defaultEquivalence(), map.valueEquivalence());
  }

  }

  private static void checkStrength(
      MapMakerInternalMap<Object, Object, ?, ?> map, Strength keyStrength, Strength valueStrength) {
    assertSame(keyStrength, map.keyStrength());
    assertSame(valueStrength, map.valueStrength());
    assertSame(keyStrength.defaultEquivalence(), map.keyEquivalence);
    assertSame(valueStrength.defaultEquivalence(), map.valueEquivalence());
  }