volatile boolean finalizeReferentCalled;

    MockReference(FinalizableReferenceQueue frq) {
      super(new Object(), frq);
    }

    @Override
    public void finalizeReferent() {
      finalizeReferentCalled = true;
    }
  }

  /**
   * Keeps a weak reference to the underlying reference queue. When this reference is cleared, we

 * {@link FinalizableReference#finalizeReferent()} on them. Java 9+ users should prefer {@link
 * java.lang.ref.Cleaner Cleaner}; see example <a href="#cleaner">below</a>.
 *
 * <p>Keep a strong reference to this object until all of the associated referents have been
 * finalized. If this object is garbage collected earlier, the backing thread will not invoke {@code
 * finalizeReferent()} on the remaining references.
 *

 * {@link FinalizableReference#finalizeReferent()} on them. Java 9+ users should prefer {@link
 * java.lang.ref.Cleaner Cleaner}; see example <a href="#cleaner">below</a>.
 *
 * <p>Keep a strong reference to this object until all of the associated referents have been
 * finalized. If this object is garbage collected earlier, the backing thread will not invoke {@code
 * finalizeReferent()} on the remaining references.
 *

      ReferenceQueue<Object> queue,
      PhantomReference<Object> frqReference) {
    /*
     * We use finalizableReferenceClass for two things:
     *
     * 1) To invoke FinalizableReference.finalizeReferent()
     *
     * 2) To detect when FinalizableReference's class loader has to be garbage collected, at which
     * point, Finalizer can stop running
     */

    public MyFinalizableWeakReference(Object x, FinalizableReferenceQueue queue) {
      super(x, queue);
    }

    @Override
    public void finalizeReferent() {}
  }

  private WeakReference<ClassLoader> useFrqInSeparateLoader() throws Exception {
    ClassLoader myLoader = getClass().getClassLoader();

    final CountDownLatch latch;

    FinalizableReference(Object referent, CountDownLatch latch) {
      super(referent, referenceQueue);
      this.latch = latch;
    }

    @Override
    public void finalizeReferent() {
      references.remove(this);
      latch.countDown();
    }
  }

  @FormatMethod
  private static RuntimeException formatRuntimeException(String format, Object... args) {

    final State state;

    FinalizableReference(FbosByteSource referent) {
      super(referent, referenceQueue);
      this.state = referent.state;
    }

    @Override
    public void finalizeReferent() {
      references.remove(this);
      try {
        state.reset();
      } catch (Throwable t) {
        t.printStackTrace(System.err);
      }
    }
  }

    final CountDownLatch latch;

    FinalizableReference(Object referent, CountDownLatch latch) {
      super(referent, referenceQueue);
      this.latch = latch;
    }

    @Override
    public void finalizeReferent() {
      references.remove(this);
      latch.countDown();
    }
  }

  @FormatMethod
  private static RuntimeException formatRuntimeException(String format, Object... args) {