@Override
    String allRequiredBitmask(
        ImmutableList<Property> trackedProperties, int bitBase, int remainingBits) {
      int requiredBits = 0;
      for (int bit = 0; bit < remainingBits; bit++) {
        Property p = trackedProperties.get(bitBase + bit);
        if (requiredProperties.contains(p)) {
          requiredBits |= 1 << bit;
        }
      }
      return hex(requiredBits);
    }
Subclass for when there are Kotlin default properties.
value/src/main/java/com/google/auto/value/processor/BuilderRequiredProperties.java