@Deprecated
  public static <E extends @Nullable Object> Set<E> newSetFromMap(
      Map<E, Boolean> map) {
    return Collections.newSetFromMap(map);
  }

  /**
   * An unmodifiable view of a set which may be backed by other sets; this view will change as the
   * backing sets do. Contains methods to copy the data into a new set which will then remain

    /**
     * Get active resource information
     *
     * @return set of active resource descriptions
     */
    public Set<String> getActiveResources() {
        Set<String> result = Collections.newSetFromMap(new ConcurrentHashMap<>());

        for (ResourceHolder holder : activeResources.values()) {
            if (!holder.closed && holder.isAlive()) {

       * UnsignedBytesBenchmark. TODO(cpovirk): benchmark this
       */
      /*
       * A CopyOnWriteArraySet<WeakReference> is faster than a newSetFromMap of a MapMaker map with
       * weakKeys() and concurrencyLevel(1), even up to at least 12 cached exception types.
       */
      private static final Set<WeakReference<Class<? extends Exception>>> validClasses =

       * UnsignedBytesBenchmark. TODO(cpovirk): benchmark this
       */
      /*
       * A CopyOnWriteArraySet<WeakReference> is faster than a newSetFromMap of a MapMaker map with
       * weakKeys() and concurrencyLevel(1), even up to at least 12 cached exception types.
       */
      private static final Set<WeakReference<Class<? extends Exception>>> validClasses =

        .testAllPublicStaticMethods(Sets.class);
  }

  public void testNewSetFromMap() {
    @SuppressWarnings({"deprecation", "InlineMeInliner"}) // test of a deprecated method
    Set<Integer> set = Sets.newSetFromMap(new HashMap<Integer, Boolean>());
    set.addAll(SOME_COLLECTION);
    verifySetContents(set, SOME_COLLECTION);
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester

  private val requestQueue = LinkedBlockingQueue<RecordedRequest>()
  private val openClientSockets =
    Collections.newSetFromMap(ConcurrentHashMap<Socket, Boolean>())
  private val openConnections =
    Collections.newSetFromMap(ConcurrentHashMap<Http2Connection, Boolean>())

  private val atomicRequestCount = AtomicInteger()

  private var serverSocketFactory_: ServerSocketFactory? = null