docs: public UpdateSketch build(final WritableMemory dstMem) {
      UpdateSketch sketch = null;
      switch (bFam) {
        case ALPHA: {
          if (dstMem == null) {
            sketch = HeapAlphaSketch.newHeapInstance(bLgNomLongs, bSeed, bP, bRF);
          }
          else {
            throw new SketchesArgumentException("AlphaSketch cannot be made Direct to Memory.");
          }
          break;
        }
        case QUICKSELECT: {
          if (dstMem == null) {
            sketch =  new HeapQuickSelectSketch(bLgNomLongs, bSeed, bP, bRF, false);
          }
          else {
            sketch = new DirectQuickSelectSketch(
                bLgNomLongs, bSeed, bP, bRF, bMemReqSvr, dstMem, false);
          }
          break;
        }
        default: {
          throw new SketchesArgumentException(
            "Given Family cannot be built as a Theta Sketch: " + bFam.toString());
        }
      }
      return sketch;
    }