func (set TargetIDSet) Union(sset TargetIDSet) TargetIDSet {
	nset := set.Clone()

	for k := range sset {
		nset.add(k)
	}

	return nset
}

// Difference - returns difference with given set as new set.
func (set TargetIDSet) Difference(sset TargetIDSet) TargetIDSet {
	nset := NewTargetIDSet()
	for k := range set {
		if _, ok := sset[k]; !ok {
			nset.add(k)
		}
	}

	return nset
}

   * }
   */
  @Override
  int hashCode();

  /**
   * A difference between the mappings from two maps with the same key. The {@link #leftValue} and
   * {@link #rightValue} are not equal, and one but not both of them may be null.
   *
   * @since 2.0
   */
  @DoNotMock("Use Maps.difference")
  interface ValueDifference<V extends @Nullable Object> {

	}, nil)

	if strings.Contains(buf.String(), "gorm/logger/slog.go") {
		t.Error("Found internal slog.go reference in caller frame. Expected only test file references.")
	}

	if !strings.Contains(buf.String(), "gorm/logger/slog_test.go") {
		t.Error("Missing expected test file reference. 'gorm/logger/slog_test.go' should appear in caller frames.")
	}

    for (N node : copy) {
      successorFunction.successors(node); // Will throw if node doesn't exist
    }
    return copy;
  }

  /**
   * Abstracts away the difference between traversing a graph vs. a tree. For a tree, we just take
   * the next element from the next non-empty iterator; for graph, we need to loop through the next
   * non-empty iterator to find first unvisited node.
   */

#   request - Cache only for current request + its child requests
#   none    - Disable caching entirely
#
# REFERENCE OPTIONS:
#   hard - Strong reference (stays in memory, faster access)
#   soft - Weak reference (can be garbage collected under memory pressure)
#
# CONFIGURATION BREAKDOWN:

 * correctness in the face of external mutations to the backing map. As such, it is <b>strongly</b>
 * recommended that the caller does not persist a reference to the backing map (unless the backing
 * map is immutable).
 *
 * <p>This class is tailored toward use cases in common.graph. It is *NOT* a general purpose map.
 *
 * @author James Sexton
 */

~~ KIND, either express or implied.  See the License for the
~~ specific language governing permissions and limitations
~~ under the License.

 -----
 Maven CLI Options Reference
 -----
 Hervé Boutemy
 -----
 2012-04-29
 -----

Maven CLI Options Reference

 * </ul>
 */
@GwtIncompatible
@J2ktIncompatible
interface ReferenceEntry<K, V> {
  /** Returns the value reference from this entry. */
  @Nullable ValueReference<K, V> getValueReference();

  /** Sets the value reference for this entry. */
  void setValueReference(ValueReference<K, V> valueReference);

  /** Returns the next entry in the chain. */

    // Clear all references to the Stopwatch and wait for it to be gc'd.
    sepStopwatchA.set(null);
    GcFinalization.awaitClear(sepStopwatchRef.get());
    // Return a weak reference to the parallel ClassLoader. This is the reference that should
    // eventually become clear if there are no other references to the ClassLoader.
    return new WeakReference<ClassLoader>(sepLoader);
  }

  /**

       * The future no longer needs to interrupt this task, so it no longer needs a reference to it.
       *
       * TODO(cpovirk): It might be nice for our InterruptibleTask subclasses to null out their
       *  `callable` fields automatically. That would make it less important for us to null out the
       * reference to `task` here (though it's still nice to do so in case our reference to the