code: public static <T> ReservoirItemsSketch<T> newInstance(final int k, final ResizeFactor rf) {
      return new ReservoirItemsSketch<>(k, rf);
    }
docs: Construct a mergeable sampling sketch with up to k samples using a specified resize factor.
  
  @param k   Maximum size of sampling. Allocated size may be smaller until reservoir fills.
  Unlike many sketches in this package, this value does <em>not</em> need to be a
  power of 2.
  @param rf  <a href="{@docRoot}/resources/dictionary.html#resizeFactor">See Resize Factor</a>
  @param <T> The type of object held in the reservoir.
  @return A ReservoirLongsSketch initialized with maximum size k and resize factor rf.