if (useBarriers) {
        firstBarrier.await();
        secondBarrier.await();
      }
    }

    @Override
    protected ScheduledExecutorService executor() {
      // use a bunch of threads so that weird overlapping schedules are more likely to happen.
      return Executors.newScheduledThreadPool(10);
    }

    @Override
    protected Scheduler scheduler() {

    }
  }

  interface Receiver<T> {
    void accept(@Nullable T object);
  }

  /**
   * Assuming the given cache has maximum size {@code maxSize}, this method populates the cache (by
   * getting a bunch of different keys), then makes sure all the items in the cache are also in the
   * eviction queue. It will invoke the given {@code operation} on the first element in the eviction

    assertWithMessage("Nothing should be logged")
        .that(aggregateFutureLogHandler.getStoredLogRecords())
        .isEmpty();

    // Not even if there are a bunch of failures.
    assertEquals(
        newArrayList(null, null, null),
        getDone(
            successfulAsList(
                immediateFailedFuture(new MyException()),

      if (useBarriers) {
        firstBarrier.await();
        secondBarrier.await();
      }
    }

    @Override
    protected ScheduledExecutorService executor() {
      // use a bunch of threads so that weird overlapping schedules are more likely to happen.
      return Executors.newScheduledThreadPool(10);
    }

    @Override
    protected Scheduler scheduler() {

    }
  }

  interface Receiver<T> {
    void accept(@Nullable T object);
  }

  /**
   * Assuming the given cache has maximum size {@code maxSize}, this method populates the cache (by
   * getting a bunch of different keys), then makes sure all the items in the cache are also in the
   * eviction queue. It will invoke the given {@code operation} on the first element in the eviction

  }

  @J2ktIncompatible
  @GwtIncompatible // NullPointerTester
  public void testNullPointers() {
    /*
     * Don't bother testing: Preconditions defines a bunch of methods that accept a template (or
     * even entire message) that simultaneously:
     *
     * - _shouldn't_ be null, so we don't annotate it with @Nullable
     *