Is your feature request related to a problem? Please describe.
When contributing to flutter-packages, as soon as you open the folder as a whole, you'll need to pub get for all packages. And since there are 205 (at the time of writing) projects, and all pub gets are sequential, this takes a long time.

Describe the solution you'd like
Since dart-lang/pub#1178 is closed, could we make some commands run in parallel?