alt method
When this TaskEither returns Right, then return the current TaskEither.
Otherwise return the result of orElse.
Used to provide an alternative TaskEither in case the current one returns Left.
Implementation
@override
TaskEither<L, R> alt(covariant TaskEither<L, R> Function() orElse) =>
TaskEither(() async => (await run()).match((_) => orElse().run(), right));