Avoids issues where they are lazily created in a different current zone and that zone messes with, for example, schedule microtask, which the future uses to schedule invocations of its callbacks.
Change-Id: I6697ca469426472523089fcf7ca44312b9c6ff5f
Reviewed-on: https://dart-review.googlesource.com/49509
Commit-Queue: Lasse R.H. Nielsen <lrn@google.com>
Reviewed-by: Florian Loitsch <floitsch@google.com>