code: @Override
      public long getTotalSize() {
          if (totalSize == HasTotalSize.NOT_DEPLETED && !hasNext()) {
              totalSize = hasTotalSize == null ? HasTotalSize.NOT_DEPLETED : hasTotalSize.getTotalSize();
          }
          return totalSize;
      }
docs: This returns <ul>
  <li>-1 if the iterator hasn't been depleted</li>
  <li>the total size otherwise</li>
  </ul>
  
  @return the total number of results of which this page is a subset of