Iterator<String> iterator = asList("a", "b", "a").iterator();
    Multiset<String> multiset = ImmutableMultiset.copyOf(iterator);
    assertEquals(HashMultiset.create(asList("a", "b", "a")), multiset);
  }

  public void testCopyOf_iteratorContainingNull() {
    Iterator<@Nullable String> iterator =
        Arrays.<@Nullable String>asList("a", null, "b").iterator();
    assertThrows(

        if (!logger.isDebugEnabled()) {
            return;
        }

        logger.debug("=== REACTOR BUILD PLAN ================================================");

        for (Iterator<ProjectSegment> it = projectBuilds.iterator(); it.hasNext(); ) {
            ProjectSegment projectBuild = it.next();

            logger.debug("Project: " + projectBuild.getProject().getId());

        @Override
        public @Nullable Object execute(Iterator<?> iterator) {
          iterator.remove();
          return null;
        }
      };

  private static final IteratorOperation NEXT_METHOD =
      new IteratorOperation() {
        @Override
        public @Nullable Object execute(Iterator<?> iterator) {
          return iterator.next();
        }
      };

    assertEquals("b", iterator.previous());
    assertThrows(UnsupportedOperationException.class, () -> iterator.add("c"));
  }

  @SuppressWarnings("DoNotCall")
  public void testSet() {
    ListIterator<String> iterator = create();

    assertTrue(iterator.hasNext());
    assertEquals("a", iterator.next());
    assertEquals("b", iterator.next());
    assertEquals("b", iterator.previous());

    return (MinimalIterable) of(elements.toArray());
  }

  private @Nullable Iterator<E> iterator;

  private MinimalIterable(Iterator<E> iterator) {
    this.iterator = iterator;
  }

  @Override
  public Iterator<E> iterator() {
    if (iterator == null) {
      // TODO: throw something else? Do we worry that people's code and tests

  }

  @CollectionSize.Require(ONE)
  @CollectionFeature.Require(SUPPORTS_ITERATOR_REMOVE)
  public void testKeysEntrySetIteratorRemove() {
    Multiset<K> keys = multimap().keys();
    Iterator<Multiset.Entry<K>> itr = keys.entrySet().iterator();
    assertEquals(Multisets.immutableEntry(k0(), 1), itr.next());
    itr.remove();
    assertTrue(multimap().isEmpty());
  }

  @CollectionSize.Require(SEVERAL)

  protected @Nullable E standardHigher(@ParametricNullness E e) {
    return Iterators.getNext(tailSet(e, false).iterator(), null);
  }

  @Override
  public @Nullable E pollFirst() {
    return delegate().pollFirst();
  }

  /**
   * A sensible definition of {@link #pollFirst} in terms of the {@code iterator} method. If you
   * override {@link #iterator} you may wish to override {@link #pollFirst} to forward to this

    Iterator<String> iterator = asList("a", "b", "a").iterator();
    List<String> list = ImmutableList.copyOf(iterator);
    assertEquals(asList("a", "b", "a"), list);
  }

  public void testCopyOf_iteratorContainingNull() {
    Iterator<@Nullable String> iterator =
        Arrays.<@Nullable String>asList("a", null, "b").iterator();
    assertThrows(

    } catch (UnsupportedOperationException e) {
      return;
    }
    if (map.size() < 2 || !supportsPut) {
      return;
    }
    Iterator<Entry<K, V>> iterator = map.entrySet().iterator();
    Entry<K, V> firstEntry = iterator.next();
    Entry<K, V> secondEntry = iterator.next();
    K key = secondEntry.getKey();
    SortedMap<K, V> subMap = map.tailMap(key);
    V value = getValueNotInPopulatedMap();

    } catch (UnsupportedOperationException e) {
      return;
    }
    if (map.size() < 2 || !supportsPut) {
      return;
    }
    Iterator<Entry<K, V>> iterator = map.entrySet().iterator();
    Entry<K, V> firstEntry = iterator.next();
    Entry<K, V> secondEntry = iterator.next();
    K key = secondEntry.getKey();
    SortedMap<K, V> subMap = map.tailMap(key);
    V value = getValueNotInPopulatedMap();