listen 1.0.0-beta.4

A package to notify state changes to interested listeners in pure Dart.

1.0.0-beta.4

• ErrorContext is now a required positional, non-nullable parameter.

1.0.0-beta.3

• Updates ErrorCallback to pass the raw error object and original StackTrace.
• Adds an optional ErrorContext parameter to ErrorCallback to distinguish listener errors from assertion errors.

1.0.0-beta.2

• Fixes dart doc example directive.

1.0.0-beta.1

• Adjusts source code to be publishable.
• Moves source code from flutter/flutter to flutter/core-packages.