ResourceManager.ManagedResource<TestResource> managed = resourceManager.manage(resource);

        managed.close();
        assertTrue(resource.isClosed());

        // Second close should not throw
        assertDoesNotThrow(managed::close);
    }

    @Test
    @DisplayName("Test null resource registration throws exception")
    void testNullResourceRegistration() {

     * simple approach would be for each caller CAS it from null to a Set populated with its
     * exception. But there's another race: If the first thread fails with an exception and a second
     * thread immediately fails with the same exception:
     *
     * Thread1: calls setException(), which returns true, context switch before it can CAS
     * seenExceptionsField to its exception
     *

      // return condition1 || condition2;
      if (nodeU().equals(other.nodeU())) { // check condition1
        // Here's the tricky bit. We don't have to explicitly check for condition2 in this case.
        // Why? The second half of condition2 requires that nodeV equals other.nodeU.
        // We already know that nodeU equals other.nodeU. Combined with the earlier statement,

        long total = requestsSent.get();
        if (total == 0)
            return 0.0;
        return (double) errors.get() / total;
    }

    /**
     * Get throughput in bytes per second
     *
     * @return throughput in bps
     */
    public long getThroughput() {
        long duration = System.currentTimeMillis() - establishedTime;
        if (duration == 0)
            return 0;

   * </pre>
   *
   * @throws IllegalArgumentException if there is a loop in the causal chain
   */
  public static Throwable getRootCause(Throwable throwable) {
    // Keep a second pointer that slowly walks the causal chain. If the fast pointer ever catches
    // the slower pointer, then there's a loop.
    Throwable slowPointer = throwable;
    boolean advanceSlowPointer = false;

	Gname string // Group name of owner

	// If the Format is unspecified, then Writer.WriteHeader rounds ModTime
	// to the nearest second and ignores the AccessTime and ChangeTime fields.
	//
	// To use AccessTime or ChangeTime, specify the Format as PAX or GNU.
	// To use sub-second resolution, specify the Format as PAX.
	ModTime    time.Time // Modification time

    @Override
    public void clear() {
      backingMap.clear();
    }
  }

  /**
   * {@inheritDoc}
   *
   * <p>The set's iterator traverses the mappings for the first row, the mappings for the second
   * row, and so on.
   *
   * <p>Each cell is an immutable snapshot of a row key / column key / value mapping, taken at the
   * time the cell is returned by a method call to the set or its iterator.
   */

 *
 * Regular lines contain fields separated by semicolons.
 *
 * The first element on each line is a single hex code point (like 0041) or a hex code point range
 * (like 0030..0039).
 *
 * The second element on each line is a mapping type, like `valid` or `mapped`.
 *
 * For lines that contain a mapping target, the next thing is a sequence of hex code points (like
 * 0031 2044 0034).
 *
 * All other data is ignored.

    //    were added to the queue. It's easily possible for one thread to take the head of the
    //    queue, immediately followed by another thread taking the next element in the queue. That
    //    second thread can then dispatch to the subscriber it took before the first thread does.
    //
    // All this makes me really wonder if there's any value in queueing here at all. A dispatcher

    Serialization.writeMultiset(this, stream);
  }

  /**
   * @serialData the {@code Class<E>} for the enum type, the number of distinct elements, the first
   *     element, its count, the second element, its count, and so on
   */
  @GwtIncompatible // java.io.ObjectInputStream
  private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
    stream.defaultReadObject();