@Override
          public @Nullable Void call() {
            if (currentFuture.get().set("set")) {
              numSuccessfulSetCalls.incrementAndGet();
            }
            awaitUnchecked(barrier);
            return null;
          }
        };
    Callable<@Nullable Void> completeExceptionallyRunnable =
        new Callable<@Nullable Void>() {

      Runnable wrapper =
          new Runnable() {
            @Override
            public void run() {
              awaitUnchecked(barrier);
              task.run();
              awaitUnchecked(barrier);
            }
          };
      for (int j = 0; j < 10; j++) {
        executor.execute(wrapper);
      }
      barrier.await(); // release the threads!