Async<T extends Object>.err constructor

@unsafeOrError Async<T extends Object>.err(FutureOr<Err<T>> err)

Implementation

@unsafeOrError
Async.err(super.err)
    : assert(
        isSubtype<T, Never>() || !isSubtype<T, Future<Object>>(),
        '$T must never be a Future.',
      ),
      super.err();