// assumes that each set is a singleton or less (as is done for the samples)
      for (Object elem : elements) {
        @SuppressWarnings("unchecked") // safe by generator contract
        Entry<String, Collection<Integer>> entry = (Entry<String, Collection<Integer>>) elem;
        Integer value = Iterables.getOnlyElement(entry.getValue());
        builder.put(entry.getKey(), value);
      }

    testRotate(new boolean[] {true}, 0, 0, 1, new boolean[] {true});
    testRotate(new boolean[] {true}, 1, 0, 1, new boolean[] {true});
    testRotate(new boolean[] {true}, 1, 1, 1, new boolean[] {true});

    // Rotate the central 5 elements, leaving the ends as-is
    testRotate(
        new boolean[] {false, true, false, true, false, true, false},
        -6,
        1,
        6,

    testRotate(new boolean[] {true}, 0, 0, 1, new boolean[] {true});
    testRotate(new boolean[] {true}, 1, 0, 1, new boolean[] {true});
    testRotate(new boolean[] {true}, 1, 1, 1, new boolean[] {true});

    // Rotate the central 5 elements, leaving the ends as-is
    testRotate(
        new boolean[] {false, true, false, true, false, true, false},
        -6,
        1,
        6,

      return Iterators.unmodifiableIterator(iterable.iterator());
    }

    @Override
    public String toString() {
      return iterable.toString();
    }
    // no equals and hashCode; it would break the contract!
  }

  /** Returns the number of elements in {@code iterable}. */
  public static int size(Iterable<?> iterable) {
    return (iterable instanceof Collection)
        ? ((Collection<?>) iterable).size()

    testRotate(new short[] {1}, 0, 0, 1, new short[] {1});
    testRotate(new short[] {1}, 1, 0, 1, new short[] {1});
    testRotate(new short[] {1}, 1, 1, 1, new short[] {1});

    // Rotate the central 5 elements, leaving the ends as-is
    testRotate(new short[] {0, 1, 2, 3, 4, 5, 6}, -6, 1, 6, new short[] {0, 2, 3, 4, 5, 1, 6});
    testRotate(new short[] {0, 1, 2, 3, 4, 5, 6}, -1, 1, 6, new short[] {0, 2, 3, 4, 5, 1, 6});

    testRotate(new float[] {1}, 0, 0, 1, new float[] {1});
    testRotate(new float[] {1}, 1, 0, 1, new float[] {1});
    testRotate(new float[] {1}, 1, 1, 1, new float[] {1});

    // Rotate the central 5 elements, leaving the ends as-is
    testRotate(new float[] {0, 1, 2, 3, 4, 5, 6}, -6, 1, 6, new float[] {0, 2, 3, 4, 5, 1, 6});
    testRotate(new float[] {0, 1, 2, 3, 4, 5, 6}, -1, 1, 6, new float[] {0, 2, 3, 4, 5, 1, 6});

 *   <li>These tests are "conformance tests", and do not attempt to test throughput, latency,
 *       scalability or other performance factors (see the separate "jtreg" tests for a set intended
 *       to check these for the most central aspects of functionality.) So, most tests use the
 *       smallest sensible numbers of threads, collection sizes, etc needed to check basic
 *       conformance.

 *
 * <p><b>Warning:</b> The comparison must be <i>consistent with equals</i> as explained by the
 * {@link Comparable} class specification. Otherwise, the resulting multiset will violate the {@link
 * java.util.Collection} contract, which is specified in terms of {@link Object#equals}.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#multiset">{@code Multiset}</a>.
 *

   * #intersection(Multiset, Multiset) intersection} {@code (multisetToModify, multisetToRetain)},
   * but mutates {@code multisetToModify} instead of returning a view.
   *
   * <p>In contrast, {@code multisetToModify.retainAll(multisetToRetain)} keeps all occurrences of
   * elements that appear at all in {@code multisetToRetain}, and deletes all occurrences of all
   * other elements.
   *

   * documentation.
   */
  public void add(Runnable runnable, Executor executor) {
    // Fail fast on a null. We throw NPE here because the contract of Executor states that it throws
    // NPE on null listener, so we propagate that contract up into the add method as well.
    checkNotNull(runnable, "Runnable was null.");
    checkNotNull(executor, "Executor was null.");