fix strong mode errors for 1.19.0-dev.4.0

BUG=
R=jmesserly@google.com, leafp@google.com, nweiz@google.com

Review URL: https://codereview.chromium.org//2250513003 .

Committed: https://github.com/dart-lang/async/commit/c230c8128dc6f178743a917136461041036b4157
2 files changed
tree: e067bd09747a429d8e144694ab59242d673985a7
  1. lib/
  2. test/
  3. .analysis_options
  4. .gitignore
  5. .test_config
  6. AUTHORS
  7. CHANGELOG.md
  8. codereview.settings
  9. CONTRIBUTING.md
  10. LICENSE
  11. pubspec.yaml
  12. README.md
README.md

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

Zipping streams

The StreamZip class can combine several streams of events into a single stream of tuples of events.

Results

The package introduces a Result class that can hold either a value or an error. It allows capturing an asynchronous computation which can give either a value or an error, into an asynchronous computation that always gives a Result value, where errors can be treated as data. It also allows releasing the Result back into an asynchronous computation.