assertThrows(
        ConcurrentModificationException.class,
        () -> {
          Iterator<Entry<K, V>> iterator = getMap().entrySet().iterator();
          put(e3());
          iterator.next();
        });
  }

  @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION, SUPPORTS_PUT})
  @CollectionSize.Require(absent = ZERO)
  public void testPutAbsentConcurrentWithKeySetIteration() {
    assertThrows(

        backingItr.next();
      }
      return new AbstractIterator<Entry<Cut<C>, Range<C>>>() {
        @Override
        protected @Nullable Entry<Cut<C>, Range<C>> computeNext() {
          if (!backingItr.hasNext()) {
            return endOfData();
          }
          Range<C> range = backingItr.next();
          return upperBoundWindow.lowerBound.isLessThan(range.upperBound)

    Iterator<T> right = rightIterable.iterator();
    while (left.hasNext()) {
      if (!right.hasNext()) {
        return LEFT_IS_GREATER; // because it's longer
      }
      int result = elementOrder.compare(left.next(), right.next());
      if (result != 0) {
        return result;
      }
    }
    if (right.hasNext()) {
      return RIGHT_IS_GREATER; // because it's longer
    }
    return 0;
  }

  @Override

    Iterator<T> right = rightIterable.iterator();
    while (left.hasNext()) {
      if (!right.hasNext()) {
        return LEFT_IS_GREATER; // because it's longer
      }
      int result = elementOrder.compare(left.next(), right.next());
      if (result != 0) {
        return result;
      }
    }
    if (right.hasNext()) {
      return RIGHT_IS_GREATER; // because it's longer
    }
    return 0;
  }

  @Override

    Iterator<Range<C>> itr = rangeSet.asRanges().iterator();
    Range<C> expectedSpan = null;
    if (itr.hasNext()) {
      expectedSpan = itr.next();
      while (itr.hasNext()) {
        expectedSpan = expectedSpan.span(itr.next());
      }
    }

    try {
      Range<C> span = rangeSet.span();
      assertEquals(expectedSpan, span);
    } catch (NoSuchElementException e) {

  public void testIteratorRemoveOnly() {
    Set<Entry<K, V>> entrySet = getMap().entrySet();
    Iterator<Entry<K, V>> entryItr = entrySet.iterator();
    assertEquals(e0(), entryItr.next());
    entryItr.remove();
    assertTrue(getMap().isEmpty());
    assertFalse(entrySet.contains(e0()));
  }

  @CollectionSize.Require(SEVERAL)
  @CollectionFeature.Require(SUPPORTS_ITERATOR_REMOVE)

  public void testIteratorRemoveOnly() {
    Set<Entry<K, V>> entrySet = getMap().entrySet();
    Iterator<Entry<K, V>> entryItr = entrySet.iterator();
    assertEquals(e0(), entryItr.next());
    entryItr.remove();
    assertTrue(getMap().isEmpty());
    assertFalse(entrySet.contains(e0()));
  }

  @CollectionSize.Require(SEVERAL)
  @CollectionFeature.Require(SUPPORTS_ITERATOR_REMOVE)

		mu := PaddedMutex{NewDRWMutex(ds, "")}
		for pb.Next() {
			mu.Lock(id, source)
			mu.Unlock(b.Context())
		}
	})
}

func benchmarkMutex(b *testing.B, slack, work bool) {
	b.ResetTimer()
	b.ReportAllocs()

	mu := NewDRWMutex(ds, "")
	if slack {
		b.SetParallelism(10)
	}
	b.RunParallel(func(pb *testing.PB) {
		foo := 0
		for pb.Next() {
			mu.Lock(id, source)
			mu.Unlock(b.Context())

    assertThrows(
        ConcurrentModificationException.class,
        () -> {
          Iterator<E> iterator = collection.iterator();
          assertTrue(collection.remove(e0()));
          iterator.next();
        });
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testRemove_notPresent() {
    assertFalse("remove(notPresent) should return false", collection.remove(e3()));
    expectUnchanged();

    assertEquals(mapEntry(k0(), v0()), iterator.next());
    iterator.remove();
    assertTrue(multimap().isEmpty());
  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testEntriesRemainValidAfterRemove() {
    Iterator<Entry<K, V>> iterator = multimap().entries().iterator();
    Entry<K, V> entry = iterator.next();
    K key = entry.getKey();