func (s *Singleton[T]) IsSet() bool {
	select {
	case <-s.set:
		return true
	default:
		return false
	}
}

// Set the value and unblock all Get requests.
// This may only be called once, a second call will panic.
func (s *Singleton[T]) Set(v *T) {
	s.v = v
	close(s.set)

    @Override
    public final T call() {
      try {
        return realCall();
      } catch (Throwable t) {
        threadUnexpectedException(t);
        return null;
      }
    }
  }

  public abstract class CheckedInterruptedCallable<T> implements Callable<T> {
    protected abstract T realCall() throws Throwable;

    @Override
    public final T call() {
      try {

        private final RequestOptionCall<BulkRequestBuilder> call;

        private final RequestOptionCall<B> entityCall;

        public BulkList(final List<E> parent, final RequestOptionCall<BulkRequestBuilder> call, final RequestOptionCall<B> entityCall) {
            this.parent = parent;
            this.entityCall = entityCall;
            this.call = call;
        }

        public int size() {

        private final RequestOptionCall<BulkRequestBuilder> call;

        private final RequestOptionCall<B> entityCall;

        public BulkList(final List<E> parent, final RequestOptionCall<BulkRequestBuilder> call, final RequestOptionCall<B> entityCall) {
            this.parent = parent;
            this.entityCall = entityCall;
            this.call = call;
        }

        public int size() {

    }
    assertEquals(
        "multiset.size() should be the sum of the counts of all entries",
        size,
        getMultiset().size());
  }

  /** Call the {@code setCount()} method under test, and check its return value. */
  abstract void setCountCheckReturnValue(E element, int count);

  /**
   * Call the {@code setCount()} method under test, but do not check its return value. Callers

        toRemove = mapEntry;
        return mapEntry.getKey();
      }

      @Override
      public void remove() {
        checkState(toRemove != null, "no calls to next() since the last call to remove()");
        size -= toRemove.getValue().getAndSet(0);
        backingEntries.remove();
        toRemove = null;
      }
    };
  }

  @Override
  Iterator<Entry<E>> entryIterator() {

   * <ul>
   *   <li>{@code required}, {@code from}, and {@code to} should all be indexes into {@code array};
   *   <li>{@code required} should be in the range [{@code from}, {@code to}];
   *   <li>all the values with indexes in the range [0, {@code from}) should be less than or equal
   *       to all the values with indexes in the range [{@code from}, {@code to}];

 *
 * <p>{@code RuntimeException}s thrown by tasks are simply logged and the executor keeps trucking.
 * If an {@code Error} is thrown, the error will propagate and execution will stop until it is
 * restarted by a call to {@link #execute}.
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
final class SequentialExecutor implements Executor {

 *
 * <p>{@code RuntimeException}s thrown by tasks are simply logged and the executor keeps trucking.
 * If an {@code Error} is thrown, the error will propagate and execution will stop until it is
 * restarted by a call to {@link #execute}.
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
final class SequentialExecutor implements Executor {

   */
  @CanIgnoreReturnValue
  @CheckForNull
  V putEdgeValue(EndpointPair<N> endpoints, V value);

  /**
   * Removes {@code node} if it is present; all edges incident to {@code node} will also be removed.
   *
   * @return {@code true} if the graph was modified as a result of this call
   */
  @CanIgnoreReturnValue
  boolean removeNode(N node);

  /**
   * Removes the edge connecting {@code nodeU} to {@code nodeV}, if it is present.