* work that preceded this call is complete.
   */
  private fun awaitWatchdogIdle() {
    val latch = CountDownLatch(1)
    val watchdogJob: AsyncTimeout =
      object : AsyncTimeout() {
        override fun timedOut() {
          latch.countDown()
        }
      }
    watchdogJob.deadlineNanoTime(System.nanoTime()) // Due immediately!
    watchdogJob.enter()