public static <N> EndpointPair<N> ordered(N source, N target) {
    return new Ordered<>(source, target);
  }

  /** Returns an {@link EndpointPair} representing the endpoints of an undirected edge. */
  public static <N> EndpointPair<N> unordered(N nodeU, N nodeV) {
    // Swap nodes on purpose to prevent callers from relying on the "ordering" of an unordered pair.
    return new Unordered<>(nodeV, nodeU);
  }

  public static <N> EndpointPair<N> ordered(N source, N target) {
    return new Ordered<>(source, target);
  }

  /** Returns an {@link EndpointPair} representing the endpoints of an undirected edge. */
  public static <N> EndpointPair<N> unordered(N nodeU, N nodeV) {
    // Swap nodes on purpose to prevent callers from relying on the "ordering" of an unordered pair.
    return new Unordered<>(nodeV, nodeU);
  }

     */
    return Collector.of(
        () -> new ImmutableSortedMap.Builder<K, V>(comparator),
        (builder, input) -> builder.put(keyFunction.apply(input), valueFunction.apply(input)),
        ImmutableSortedMap.Builder::combine,
        ImmutableSortedMap.Builder::buildOrThrow,
        Collector.Characteristics.UNORDERED);
  }

     */
    return Collector.of(
        () -> new ImmutableSortedMap.Builder<K, V>(comparator),
        (builder, input) -> builder.put(keyFunction.apply(input), valueFunction.apply(input)),
        ImmutableSortedMap.Builder::combine,
        ImmutableSortedMap.Builder::buildOrThrow,
        Collector.Characteristics.UNORDERED);
  }

 *
 * <ul>
 *   <li>directed graphs
 *   <li>undirected graphs
 *   <li>graphs that do/don't allow parallel edges
 *   <li>graphs that do/don't allow self-loops
 *   <li>graphs whose nodes/edges are insertion-ordered, sorted, or unordered
 *   <li>graphs whose edges are <a
 *       href="https://github.com/google/guava/wiki/GraphsExplained#uniqueness">unique</a> objects
 * </ul>
 *
 * <h3>Building a {@code Network}</h3>
 *

    }
    return HashCode.fromBytesNoCopy(resultBytes);
  }

  /**
   * Returns a hash code, having the same bit length as each of the input hash codes, that combines
   * the information of these hash codes in an unordered fashion. That is, whenever two equal hash
   * codes are produced by two calls to this method, it is <i>as likely as possible</i> that each
   * was computed from the <i>same</i> input hash codes in <i>some</i> order.
   *

    }
    return HashCode.fromBytesNoCopy(resultBytes);
  }

  /**
   * Returns a hash code, having the same bit length as each of the input hash codes, that combines
   * the information of these hash codes in an unordered fashion. That is, whenever two equal hash
   * codes are produced by two calls to this method, it is <i>as likely as possible</i> that each
   * was computed from the <i>same</i> input hash codes in <i>some</i> order.
   *

        (a, x) -> a.add(x.doubleValue()),
        (l, r) -> {
          l.addAll(r);
          return l;
        },
        StatsAccumulator::snapshot,
        Collector.Characteristics.UNORDERED);
  }

  /** Returns the number of values. */
  public long count() {
    return count;
  }

  /**
   * Returns the <a href="http://en.wikipedia.org/wiki/Arithmetic_mean">arithmetic mean</a> of the

    void checkAcquiredLock(Policy policy, LockGraphNode acquiredLock) {
      // checkAcquiredLock() should never be invoked by a lock that has already
      // been acquired. For unordered locks, aboutToAcquire() ensures this by
      // checking isAcquiredByCurrentThread(). For ordered locks, however, this
      // can happen because multiple locks may share the same LockGraphNode. In
      // this situation, throw an IllegalStateException as defined by contract

        () -> BloomFilter.create(funnel, expectedInsertions, fpp),
        BloomFilter::put,
        (bf1, bf2) -> {
          bf1.putAll(bf2);
          return bf1;
        },
        Collector.Characteristics.UNORDERED,
        Collector.Characteristics.CONCURRENT);
  }

  /**
   * Creates a {@link BloomFilter} with the expected number of insertions and expected false
   * positive probability.
   *