MapDifference<Integer, String> original = Maps.difference(left, right);
    MapDifference<Integer, String> same = Maps.difference(left, right);
    MapDifference<Integer, String> reverse = Maps.difference(right, left);
    MapDifference<Integer, String> diff2 = Maps.difference(left, right2);

    new EqualsTester()
        .addEqualityGroup(original, same)

    MapDifference<Integer, String> original = Maps.difference(left, right);
    MapDifference<Integer, String> same = Maps.difference(left, right);
    MapDifference<Integer, String> reverse = Maps.difference(right, left);
    MapDifference<Integer, String> diff2 = Maps.difference(left, right2);

    new EqualsTester()
        .addEqualityGroup(original, same)

    assertThat(Multisets.difference(ms1, ms2)).containsExactly("a", "b");
  }

  public void testDifferenceWithRemovedElement() {
    Multiset<String> ms1 = HashMultiset.create(Arrays.asList("a", "b", "a"));
    Multiset<String> ms2 = HashMultiset.create(Arrays.asList("b"));
    assertThat(Multisets.difference(ms1, ms2)).containsExactly("a", "a");
  }

   * propagated. If, on the other hand, the time limit is reached, we attempt to abort the call to
   * the target, and throw a {@link TimeoutException} to the caller.
   *
   * <p>The difference with {@link #callWithTimeout(Callable, long, TimeUnit)} is that this method
   * will ignore interrupts on the current thread.
   *
   * @param callable the Callable to execute

/**
 * An object representing the differences between two maps.
 *
 * @author Kevin Bourrillion
 * @since 2.0
 */
@DoNotMock("Use Maps.difference")
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface MapDifference<K extends @Nullable Object, V extends @Nullable Object> {
  /**
   * Returns {@code true} if there are no differences between the two maps; that is, if the maps are
   * equal.
   */

    Set<String> enemies = Sets.newHashSet("Dick", "Harry", "Tom");

    Set<String> goodFriends = Sets.difference(friends, enemies);
    assertEquals(2, goodFriends.size());

    ImmutableSet<String> immut = Sets.difference(friends, enemies).immutableCopy();
    HashSet<String> mut = Sets.difference(friends, enemies).copyInto(new HashSet<String>());

    enemies.add("Dave");
    assertEquals(1, goodFriends.size());

    Set<String> enemies = Sets.newHashSet("Dick", "Harry", "Tom");

    Set<String> goodFriends = Sets.difference(friends, enemies);
    assertEquals(2, goodFriends.size());

    ImmutableSet<String> immut = Sets.difference(friends, enemies).immutableCopy();
    HashSet<String> mut = Sets.difference(friends, enemies).copyInto(new HashSet<String>());

    enemies.add("Dave");
    assertEquals(1, goodFriends.size());

  }

  public void testOneSecondBurst() {
    RateLimiter limiter = RateLimiter.create(5.0, stopwatch);
    stopwatch.sleepMillis(1000); // max capacity reached
    stopwatch.sleepMillis(1000); // this makes no difference
    limiter.acquire(1); // R0.00, since it's the first request

    limiter.acquire(1); // R0.00, from capacity
    limiter.acquire(3); // R0.00, from capacity

    assertThat(Multisets.difference(ms1, ms2)).containsExactly("a", "b");
  }

  public void testDifferenceWithRemovedElement() {
    Multiset<String> ms1 = HashMultiset.create(Arrays.asList("a", "b", "a"));
    Multiset<String> ms2 = HashMultiset.create(Arrays.asList("b"));
    assertThat(Multisets.difference(ms1, ms2)).containsExactly("a", "a");
  }

    // TODO(kevinb): check more preconditions (as bufferSize >= chunkSize) if this is ever public
    checkArgument(bufferSize % chunkSize == 0);

    // TODO(user): benchmark performance difference with longer buffer
    // always space for a single primitive
    this.buffer = ByteBuffer.allocate(bufferSize + 7).order(ByteOrder.LITTLE_ENDIAN);
    this.bufferSize = bufferSize;
    this.chunkSize = chunkSize;
  }