* <p>The implementation classes that {@code common.graph} provides are not public, by design. To
 * create an instance of one of the built-in implementations of {@code Graph}, use the {@link
 * GraphBuilder} class:
 *
 * {@snippet :
 * MutableGraph<Integer> graph = GraphBuilder.undirected().build();
 * }
 *
 * <p>{@link GraphBuilder#build()} returns an instance of {@link MutableGraph}, which is a subtype

   *
   * {@snippet :
   * NavigableSet<E> set = synchronizedNavigableSet(new TreeSet<E>());
   *  ...
   * synchronized (set) {
   *   // Must be in the synchronized block
   *   Iterator<E> it = set.iterator();
   *   while (it.hasNext()) {
   *     foo(it.next());
   *   }
   * }
   * }
   *
   * <p>or:
   *
   * {@snippet :

import org.jspecify.annotations.Nullable;

/**
 * Used to represent the order of elements in a data structure that supports different options for
 * iteration order guarantees.
 *
 * <p>Example usage:
 *
 * {@snippet :
 * MutableGraph<Integer> graph =
 *     GraphBuilder.directed().nodeOrder(ElementOrder.<Integer>natural()).build();
 * }
 *
 * @author Joshua O'Madadhain
 * @since 20.0
 */
@Immutable

  BaseGraph<N> delegate() {
    return backingGraph;
  }

  /**
   * A builder for creating {@link ImmutableGraph} instances, especially {@code static final}
   * graphs. Example:
   *
   * {@snippet :
   * static final ImmutableGraph<Country> COUNTRY_ADJACENCY_GRAPH =
   *     GraphBuilder.undirected()
   *         .<Country>immutable()
   *         .putEdge(FRANCE, GERMANY)
   *         .putEdge(FRANCE, BELGIUM)

 * the permits issued each second steadily increases until it hits the stable rate.
 *
 * <p>As an example, imagine that we have a list of tasks to execute, but we don't want to submit
 * more than 2 per second:
 *
 * {@snippet :
 * final RateLimiter rateLimiter = RateLimiter.create(2.0); // rate is "2 permits per second"
 * void submitTasks(List<Runnable> tasks, Executor executor) {
 *   for (Runnable task : tasks) {

 * Double#doubleToRawLongBits}, which differs from both the primitive double {@code ==} operator and
 * from {@link Double#equals}, as if implemented by:
 *
 * {@snippet :
 * static boolean bitEquals(double x, double y) {
 *   long xBits = Double.doubleToRawLongBits(x);
 *   long yBits = Double.doubleToRawLongBits(y);
 *   return xBits == yBits;
 * }
 * }
 *

 * {@link #computeNext} method, and invoke the {@link #endOfData} method when appropriate.
 *
 * <p>Another example is an iterator that skips over null elements in a backing iterator. This could
 * be implemented as:
 *
 * {@snippet :
 * public static Iterator<String> skipNulls(final Iterator<String> in) {
 *   return new AbstractIterator<String>() {
 *     protected String computeNext() {
 *       while (in.hasNext()) {
 *         String s = in.next();

 * Tester to ensure forwarding wrapper works by delegating calls to the corresponding method with
 * the same parameters forwarded and return value forwarded back or exception propagated as is.
 *
 * <p>For example:
 *
 * {@snippet :
 * new ForwardingWrapperTester().testForwarding(Foo.class, new Function<Foo, Foo>() {
 *   public Foo apply(Foo foo) {
 *     return new ForwardingFoo(foo);
 *   }
 * });
 * }
 *
 * @author Ben Yu

   * Builder} constructor.
   */
  public static <B> Builder<B> builder() {
    return new Builder<>();
  }

  /**
   * A builder for creating immutable class-to-instance maps. Example:
   *
   * {@snippet :
   * static final ImmutableClassToInstanceMap<Handler> HANDLERS =
   *     new ImmutableClassToInstanceMap.Builder<Handler>()
   *         .put(FooHandler.class, new FooHandler())

   * through the returned queue.
   *
   * <p>It is imperative that the user manually synchronize on the returned queue when accessing the
   * queue's iterator:
   *
   * {@snippet :
   * Queue<E> queue = Queues.synchronizedQueue(MinMaxPriorityQueue.<E>create());
   * ...
   * queue.add(element); // Needn't be in synchronized block
   * ...
   * synchronized (queue) { // Must synchronize on queue!