Scenario: Kevin and Erik or some other fine contributor to the async_await package on GitHub has committed some changes and you want to use those within the main Dart repo.
About you:
- You already have the repo downloaded locally on your machine.
- You are using Git, not svn. You also probably ride a horseless carriage and no longer use leeches and bloodletting to cure your ailments.
Note that you do not need a separate svn checkout. You already have one, you just don't know it.
Given that, here's the process. This likely alsos work for other third party packages that live on GitHub that we want to use in the Dart repo, but I make no promises there: