// We could make this a Map<E, EndpointPair<N>>. It would make incidentNodes(edge) slightly
  // faster, but also make Networks consume 5 to 20+% (increasing with average degree) more memory.
  final MapIteratorCache<E, N> edgeToReferenceNode; // referenceNode == source if directed

  /** Constructs a graph with the properties specified in {@code builder}. */

      // Another variant of Double Checked Locking.
      //
      // We use two volatile reads. We could reduce this to one by
      // putting our fields into a holder class, but (at least on x86)
      // the extra memory consumption and indirection are more
      // expensive than the extra volatile reads.
      long nanos = expirationNanos;
      long now = System.nanoTime();
      if (nanos == 0 || now - nanos >= 0) {

      // Another variant of Double Checked Locking.
      //
      // We use two volatile reads. We could reduce this to one by
      // putting our fields into a holder class, but (at least on x86)
      // the extra memory consumption and indirection are more
      // expensive than the extra volatile reads.
      long nanos = expirationNanos;
      long now = System.nanoTime();
      if (nanos == 0 || now - nanos >= 0) {

rate.limit.blocked.ips=
# Comma-separated list of trusted proxy IPs. Only trust X-Forwarded-For/X-Real-IP from these IPs.
rate.limit.trusted.proxies=127.0.0.1,::1
# Number of requests between cleanup operations to prevent memory leaks.
rate.limit.cleanup.interval=1000

# Virtual Host: Host:fess.codelibs.org=fess
virtual.host.headers=

# Hostname for the HTTP proxy server.
http.proxy.host=

  /**
   * Returns a fresh {@link MapMakerInternalMap} with {@link MapMaker.Dummy} values but otherwise as
   * specified by the given {@code builder}. The returned {@link MapMakerInternalMap} will be
   * optimized to saved memory. Since {@link MapMaker.Dummy} is a singleton, we don't need to store
   * any values at all. Because of this optimization, {@code build.getValueStrength()} must be
   * {@link Strength#STRONG}.
   *

  /**
   * Returns a fresh {@link MapMakerInternalMap} with {@link MapMaker.Dummy} values but otherwise as
   * specified by the given {@code builder}. The returned {@link MapMakerInternalMap} will be
   * optimized to saved memory. Since {@link MapMaker.Dummy} is a singleton, we don't need to store
   * any values at all. Because of this optimization, {@code build.getValueStrength()} must be
   * {@link Strength#STRONG}.
   *

  static <E> Queue<E> discardingQueue() {
    return (Queue) DISCARDING_QUEUE;
  }

  /*
   * Note: All of this duplicate code sucks, but it saves a lot of memory. If only Java had mixins!
   * To maintain this code, make a change for the strong reference type. Then, cut and paste, and
   * replace "Strong" with "Soft" or "Weak" within the pasted text. The primary difference is that

  static <E> Queue<E> discardingQueue() {
    return (Queue) DISCARDING_QUEUE;
  }

  /*
   * Note: All of this duplicate code sucks, but it saves a lot of memory. If only Java had mixins!
   * To maintain this code, make a change for the strong reference type. Then, cut and paste, and
   * replace "Strong" with "Soft" or "Weak" within the pasted text. The primary difference is that

    /**
     * Get the value for the key 'rate.limit.cleanup.interval'. <br>
     * The value is, e.g. 1000 <br>
     * comment: Number of requests between cleanup operations to prevent memory leaks.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getRateLimitCleanupInterval();

    /**