QueryOp.create(
            "Map.get",
            (map, key) -> {
              Object unused = map.get(key);
            },
            Math::log);

    static final QueryOp<Set<Object>> SET_CONTAINS =
        QueryOp.create(
            "Set.contains",
            (set, key) -> {
              boolean unused = set.contains(key);
            },
            Math::log);

 * application-specific ordering in addition to performing general cycle detection.
 *
 * <p><strong>Garbage Collection</strong>
 *
 * <p>In order to allow proper garbage collection of unused locks, the edges of the lock graph are
 * weak references.
 *
 * <p><strong>Performance</strong>
 *
 * <p>The extra bookkeeping done by cycle detecting locks comes at some cost to performance.

    for (int i = 0; i < CONTAINS_VALUE_RETRIES; i++) {
      long sum = 0L;
      for (Segment<K, V, E, S> segment : segments) {
        // ensure visibility of most recent completed write
        int unused = segment.count; // read-volatile

        AtomicReferenceArray<E> table = segment.table;
        for (int j = 0; j < table.length(); j++) {
          for (E e = table.get(j); e != null; e = e.getNext()) {

    long last = -1L;
    for (int i = 0; i < CONTAINS_VALUE_RETRIES; i++) {
      long sum = 0L;
      for (Segment<K, V> segment : segments) {
        // ensure visibility of most recent completed write
        int unused = segment.count; // read-volatile

        AtomicReferenceArray<ReferenceEntry<K, V>> table = segment.table;
        for (int j = 0; j < table.length(); j++) {

            .get()
            .log(
                SEVERE,
                "Uh oh! An open ClosingFuture has leaked and will close: {0}",
                closingFutureToString());
        FluentFuture<V> unused = finishToFuture();
      }
    }

    String closingFutureToString() {
      // TODO(dpb): Better toString, in the style of Futures.transform etc.
      return toStringHelper("ClosingFuture")

    long last = -1L;
    for (int i = 0; i < CONTAINS_VALUE_RETRIES; i++) {
      long sum = 0L;
      for (Segment<K, V> segment : segments) {
        // ensure visibility of most recent completed write
        int unused = segment.count; // read-volatile

        AtomicReferenceArray<ReferenceEntry<K, V>> table = segment.table;
        for (int j = 0; j < table.length(); j++) {

    for (int i = 0; i < CONTAINS_VALUE_RETRIES; i++) {
      long sum = 0L;
      for (Segment<K, V, E, S> segment : segments) {
        // ensure visibility of most recent completed write
        int unused = segment.count; // read-volatile

        AtomicReferenceArray<E> table = segment.table;
        for (int j = 0; j < table.length(); j++) {
          for (E e = table.get(j); e != null; e = e.getNext()) {