Illustrate why `isFinished` and `isExecuting` KVN is actually important

Your operation wasn't finishing asynchronously (you were setting `isFinished` before `main` terminated), so the failure to do the appropriate KVN did not manifest the relevant problem. I changed the operation to actually complete asynchronously.

Having done that, I also changed this sample to do two sample operations, with a dependency between them. Now, if you remove the `isFinished` KVN, you'll see that the second operation doesn't fire. You have to KVN `isFinished` in order to have dependencies honored.