code: public <K extends Comparable<K>, V> SortingBufferMaker<K, V> createSortingWithDuplicatesBuffer( Serializer<K> keySerializer,
                                                                                                      Comparator<?> keyComparator,
                                                                                                      Serializer<V> valueSerializer ) {
          return new MakeSortingWithDuplicatesBuffer<K, V>("buffer-" + dbCounter.incrementAndGet(), keySerializer, keyComparator,
                                                           valueSerializer);
      }
docs: Obtain a maker object that can create a new {@link SortingBuffer} that can store multiple values for any given key.
  
  @param keySerializer the serializer for the keys
  @param keyComparator the comparator for the keys, or null if natural ordering should be used
  @param valueSerializer the serializer for the values
  @return the maker; never null