}
    }

    override fun iterator() = error("unsupported")

    override fun offer(e: T) = error("unsupported")

    override fun peek(): T = error("unsupported")

    override fun offer(
      element: T,
      timeout: Long,
      unit: TimeUnit,
    ) = error("unsupported")

    override fun take() = error("unsupported")

  }

  @Test fun cancelAllWhenEmptyDoesNotStartWorkerThread() {
    redQueue.execute("red task", 100.µs) {
      error("expected to be canceled")
    }
    assertThat(taskFaker.executeCallCount).isEqualTo(1)

    blueQueue.execute("task", 100.µs) {
      error("expected to be canceled")
    }
    assertThat(taskFaker.executeCallCount).isEqualTo(1)

    redQueue.cancelAll()