Assessing the state of affairs.

You can still do it, but it's not really supported.

There are the obvious arguments, the non-obvious arguments, and the invisible arguments.

Once destruction begins, strong references mean nothing.

You still need to filter to your window, so you don't mess up another window on the same thread.

You may be overriding an SDK header by mistake.

It lets you change the thing being iterated over, on the fly.

Provide a hint for the location of the next item.

You also have to catch the exception when it comes out the end of the task chain.

How can you unring the bell?