Close Flyout after click CommandBarButton

[MuZhou233]

Is your feature request related to a problem? Please describe.
I'm using the secondaryItems in CommandBar, it pops up a flyout menu, but I can't find a way to close the flyout after click item. There is an example to close flyout by using Flyout.of(context).close. But not suitable for commandbar.

Describe the solution you'd like
Add an option to CommandBar that close flyout after click.

Describe alternatives you've considered
Navigator.pop(context) works, but not a good solution because of dynamic overflow.