Method flushNulls

bolt/serializers/PrestoSerializer.cpp:1574–1583

  }

  void flushNulls(OutputStream* out) {
    if (!nullCount_) {
      char zero = 0;
      out->write(&zero, 1);
    } else {
      char one = 1;
      out->write(&one, 1);
      nulls_.flush(out);
    }
  }

  bool isLongDecimal() const {
    return isLongDecimal_;