code: public void clear() {
          switch(type) {
              case EMPTY:
                  return /*do nothing*/;
              case EXPLICIT:
                  explicitStorage.clear();
                  return;
              case SPARSE:
                  sparseProbabilisticStorage.clear();
                  return;
              case FULL:
                  probabilisticStorage.fill(0);
                  return;
              default:
                  throw new RuntimeException("Unsupported HLL type " + type);
          }
      }
docs: Clears the HLL. The HLL will have cardinality zero and will act as if no
  elements have been added.<p/>
  
  NOTE: Unlike {@link #addRaw(long)}, <code>clear</code> does NOT handle
  transitions between {@link HLLType}s - a probabilistic type will remain
  probabilistic after being cleared.