code: public ItemsSketch<T> getResultAndReset() {
      if (gadget_ == null) { return null; } //Intentionally return null here for speed.
      final ItemsSketch<T> hqs = gadget_;
      gadget_ = null;
      return hqs;
    }
docs: Gets the result of this Union operation (without a copy) and resets this Union to the
  virgin state.
  
  @return the result of this Union operation and reset.