assertEquals("B", peekingIterator.peek());

    /* Should complain on attempt to remove() after peek(). */
    try {
      peekingIterator.remove();
      fail("remove() should throw IllegalStateException after a peek()");
    } catch (IllegalStateException e) {
      /* expected */
    }

    assertEquals(
        "After remove() throws exception, peek should still be ok", "B", peekingIterator.peek());

    runConcurrentlyMutatedTest(elements(1), ops(remove(), add(2)), wrap);

    runConcurrentlyMutatedTest(elements(1, 2), ops(remove(), remove()), wrap);

    runConcurrentlyMutatedTest(elements(1, 2), ops(remove(), nop()), wrap);

    runConcurrentlyMutatedTest(elements(1, 2), ops(remove(), add(3)), wrap);

    runConcurrentlyMutatedTest(elements(1, 2), ops(nop(), remove()), wrap);

    AtomicLong atomic = map.get(key);
    if (atomic == null) {
      return false;
    }

    long oldValue = atomic.get();
    if (oldValue != value) {
      return false;
    }

    if (oldValue == 0L || atomic.compareAndSet(oldValue, 0L)) {
      // only remove after setting to zero, to avoid concurrent updates
      map.remove(key, atomic);

      if (hasNext()) {
        toRemove = iterator;
        return iterator.next();
      } else {
        throw new NoSuchElementException();
      }
    }

    @Override
    public void remove() {
      if (toRemove == null) {
        throw new IllegalStateException("no calls to next() since the last call to remove()");
      }
      toRemove.remove();
      toRemove = null;
    }

  @Override
  @CheckForNull
  public V remove(@CheckForNull Object rowKey, @CheckForNull Object columnKey) {
    if ((rowKey == null) || (columnKey == null)) {
      return null;
    }
    Map<C, V> map = safeGet(backingMap, rowKey);
    if (map == null) {
      return null;
    }
    V value = map.remove(columnKey);
    if (map.isEmpty()) {
      backingMap.remove(rowKey);
    }
    return value;
  }

    assertEquals((Integer) 2, it.next());
    it.remove();
    // After this remove, 400 has moved up and 20 down past cursor
    assertTrue("Heap is not intact after remove", mmHeap.isIntact());
    assertEquals((Integer) 10, it.next());
    assertEquals((Integer) 3, it.next());
    it.remove();
    // After this remove, 400 moved down again and 500 up past the cursor

  public void testRemoveNullValueAbsent() {
    assertFalse(multimap().remove(k0(), null));
    expectUnchanged();
  }

  @MapFeature.Require(value = SUPPORTS_REMOVE, absent = ALLOWS_NULL_VALUE_QUERIES)
  public void testRemoveNullValueForbidden() {
    try {
      multimap().remove(k0(), null);
      fail("Expected NullPointerException");
    } catch (NullPointerException expected) {

    }
    assertTrue(collection.contains(element)); // sanity check
    iterator.remove();
    assertFalse(collection.contains(element));
    assertEquals(originalSize - 1, collection.size());
  }

  @CollectionFeature.Require({KNOWN_ORDER, SUPPORTS_ITERATOR_REMOVE})
  public void testIterator_knownOrderRemoveSupported() {

    expectMissing(e0());
  }

  @CollectionFeature.Require({KNOWN_ORDER, SUPPORTS_REMOVE})
  @CollectionSize.Require(SEVERAL)
  public void testRemove_sizeMany() {
    assertEquals("sizeManyQueue.remove() should return first element", e0(), getQueue().remove());
    expectMissing(e0());
  }

    }
  }

  void expectRemoveZero(SortedMultiset<E> multiset, Entry<E> entry) {
    assertEquals(0, multiset.remove(entry.getElement(), entry.getCount()));
    assertFalse(multiset.remove(entry.getElement()));
    assertFalse(multiset.elementSet().remove(entry.getElement()));
  }

  void expectSetCountFailure(SortedMultiset<E> multiset, Entry<E> entry) {
    try {