* 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()));
  }

   * {@link Set}, instead of the {@link Collection} specified in the {@link Multimap} interface.
   */
  @CanIgnoreReturnValue
  @Override
  public Set<V> removeAll(@Nullable Object key) {
    return (Set<V>) super.removeAll(key);
  }

  /**
   * {@inheritDoc}
   *
   * <p>Because a {@code SetMultimap} has unique values for a given key, this method returns a

    return remove(element, 1) > 0;
  }

  /**
   * A sensible definition of {@link #removeAll} in terms of the {@code removeAll} method of {@link
   * #elementSet}. If you override {@link #elementSet}, you may wish to override {@link #removeAll}
   * to forward to this implementation.
   *
   * @since 7.0
   */
  @Override