@Contract(value = "-> new", pure = true)
  public static <K> @NotNull Set<K> createSmallMemoryFootprintSet() {
    //noinspection SSBasedInspection
    return new ObjectOpenHashSet<>();
  }
@Contract(value = "-> new", pure = true)
  public static <K> @NotNull Set<K> createSmallMemoryFootprintSet()