Тип ZoneUnaryCallback<R, T>

ZoneUnaryCallback<R, T> = R Function(T arg)

Реализация

typedef R ZoneUnaryCallback<R, T>(T arg);

© 2012 the Dart project authors
Licensed under the BSD 3-Clause "New" or "Revised" License.
https://api.dart.dev/stable/2.18.5/dart-async/ZoneUnaryCallback.html