public Builder setUnwalkablePolygon(
          int index, org.bwapi.proxy.messages.TerrainMessages.Polygon value) {
        if (unwalkablePolygonBuilder_ == null) {
          if (value == null) {
            throw new NullPointerException();
          }
          ensureUnwalkablePolygonIsMutable();
          unwalkablePolygon_.set(index, value);
          onChanged();
        } else {
          unwalkablePolygonBuilder_.setMessage(index, value);
        }
        return this;
      }