} catch (Throwable t) {
      threadUnexpectedException(t);
    }
  }

  public void await(Semaphore semaphore) {
    try {
      assertTrue(semaphore.tryAcquire(LONG_DELAY_MS, MILLISECONDS));
    } catch (Throwable t) {
      threadUnexpectedException(t);
    }
  }

  //     /**
  //      * Spin-waits up to LONG_DELAY_MS until flag becomes true.
  //      */