@ExperimentalCoroutinesApi class TestCoroutineDispatcher :
By default, TestCoroutineDispatcher is immediate. That means any tasks scheduled to be run without delay are immediately executed. If they were scheduled with a delay, the virtual clock-time must be advanced via one of the methods on DelayController.
When switched to lazy execution using pauseDispatcher any coroutines started via launch or async will not execute until a call to DelayController.runCurrent or the virtual clock-time has been advanced via one of the methods on DelayController.