316128d6cd
Since Dart 2.1, Future and Stream have been exported from dart:core Change-Id: Ib452692ea2ce02bcc84fa50ffb054410114de56f Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/164100 Auto-Submit: Mike Fairhurst <mfairhurst@google.com> Commit-Queue: Aske Simon Christensen <askesc@google.com> Reviewed-by: Aske Simon Christensen <askesc@google.com>