...LP6E/Examples/Chapter20$ python3 all_async_demos.py 
1-----------------------------------------------------
Start => [19:00:28]
All done, serial task 1, [19:00:30]
All done, serial task 2, [19:00:32]
All done, serial task 3, [19:00:34]
Stop  => [19:00:34]
2-----------------------------------------------------
Start => [19:00:34]
All done, async task 1, [19:00:36]
All done, async task 2, [19:00:36]
All done, async task 3, [19:00:36]
Stop  => [19:00:36]
3-----------------------------------------------------
Start => [19:00:36]
All done, async task 1, [19:00:38]
All done, async task 2, [19:00:38]
All done, async task 3, [19:00:38]
Stop  at [19:00:38]
4-----------------------------------------------------
Start => [19:00:38]
All done, async task 2, [19:00:40]
All done, async task 3, [19:00:40]
All done, async task 1, [19:00:40]
Stop  at [19:00:40]
5-----------------------------------------------------
Start => [19:00:40]
['All done, async task 1, [19:00:42]', 'All done, async task 2, [19:00:42]', 'All done, async task 3, [19:00:42]']
Stop  at [19:00:42]
6-----------------------------------------------------
Start => [19:00:42]
['All done, async task 1, [19:00:44]', 'All done, async task 2, [19:00:44]', 'All done, async task 3, [19:00:44]']
Stop  at [19:00:44]
7-----------------------------------------------------
Start => [19:00:44]
All done, async task 1, [19:00:46]
All done, async task 2, [19:00:46]
All done, async task 3, [19:00:46]
Stop  at [19:00:46]
8-----------------------------------------------------
Start => [19:00:46]
All done, async task 1, [19:00:48]
All done, async task 2, [19:00:50]
All done, async task 3, [19:00:52]
Stop  at [19:00:52]