Allow 2.12.0 dev SDK versions (#141)

Drop dependency overrides and update deps to `-nullsafety` versions.
2 files changed
tree: 0ec96eab39bf69c1ab3b44b25661580c30a6f8ec
  1. .gitignore
  2. .test_config
  3. .travis.yml
  4. AUTHORS
  5. CHANGELOG.md
  6. CONTRIBUTING.md
  7. LICENSE
  8. README.md
  9. analysis_options.yaml
  10. lib/
  11. pubspec.yaml
  12. test/
README.md

Contains utility classes in the style of dart:async to work with asynchronous computations.