@CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testEntrySet_removeAllPresent() {
    assertTrue(
        "multiset.entrySet.removeAll(presentEntry) returned false",
        getMultiset().entrySet().removeAll(singleton(Multisets.immutableEntry(e0(), 1))));
    assertFalse("multiset contains element after removing its entry", getMultiset().contains(e0()));
  }

     */
    public Set<MavenProject> getUnfinishedProjects() {
        Set<MavenProject> unfinished = new HashSet<>(projectBuilds.getProjects());
        unfinished.removeAll(finishedProjects);
        return unfinished;
    }

    /**
     * @return set of projects that have been successfully processed by the build.
     */
    protected Set<MavenProject> getFinishedProjects() {

 * ordering of values for a given key. See the {@link Multimap} documentation for information common
 * to all multimaps.
 *
 * <p>The {@link #get}, {@link #removeAll}, and {@link #replaceValues} methods each return a {@link
 * List} of values. Though the method signature doesn't say so explicitly, the map returned by
 * {@link #asMap} has {@code List} values.
 *

 * ordering of values for a given key. See the {@link Multimap} documentation for information common
 * to all multimaps.
 *
 * <p>The {@link #get}, {@link #removeAll}, and {@link #replaceValues} methods each return a {@link
 * List} of values. Though the method signature doesn't say so explicitly, the map returned by
 * {@link #asMap} has {@code List} values.
 *

   * Iterables.frequency(occurrencesToRemove, e))}.
   *
   * <p>This is <i>not</i> the same as {@code multisetToModify.} {@link Multiset#removeAll
   * removeAll}{@code (occurrencesToRemove)}, which removes all occurrences of elements that appear
   * in {@code occurrencesToRemove}. However, this operation <i>is</i> equivalent to, albeit

   * Iterables.frequency(occurrencesToRemove, e))}.
   *
   * <p>This is <i>not</i> the same as {@code multisetToModify.} {@link Multiset#removeAll
   * removeAll}{@code (occurrencesToRemove)}, which removes all occurrences of elements that appear
   * in {@code occurrencesToRemove}. However, this operation <i>is</i> equivalent to, albeit

  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testRemoveAllPropagatesToMultimap() {
    assertTrue(multimap().entries().removeAll(singleton(mapEntry(k0(), v0()))));
    expectMissing(mapEntry(k0(), v0()));
    assertEquals(getNumElements() - 1, multimap().size());
    assertFalse(multimap().containsEntry(k0(), v0()));
  }

    public boolean remove(@Nullable Object o) {
      synchronized (mutex) {
        return delegate().remove(o);
      }
    }

    @Override
    public boolean removeAll(Collection<?> c) {
      synchronized (mutex) {
        return delegate().removeAll(c);
      }
    }

    @Override
    public boolean retainAll(Collection<?> c) {
      synchronized (mutex) {
        return delegate().retainAll(c);
      }

    public boolean remove(@Nullable Object o) {
      synchronized (mutex) {
        return delegate().remove(o);
      }
    }

    @Override
    public boolean removeAll(Collection<?> c) {
      synchronized (mutex) {
        return delegate().removeAll(c);
      }
    }

    @Override
    public boolean retainAll(Collection<?> c) {
      synchronized (mutex) {
        return delegate().retainAll(c);
      }

  }

  @CollectionSize.Require(absent = ZERO)
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testRemoveAllPropagatesToMultimap() {
    assertTrue(multimap().entries().removeAll(singleton(mapEntry(k0(), v0()))));
    expectMissing(mapEntry(k0(), v0()));
    assertEquals(getNumElements() - 1, multimap().size());
    assertFalse(multimap().containsEntry(k0(), v0()));
  }