Error Handler Not Being Called

[cycloss]

I've come up with a minimum viable example that shows my problem below. For some reason, print('Error occured: $e'); is never called. Instead I get Unhandled Exception: Exception. I can't understand why the error handler on the channel in the main function isn't picking up this error. Is this a bug?

import 'dart:isolate';

import 'package:stream_channel/isolate_channel.dart';

void main() async {
  var rp = ReceivePort();
  var channel = IsolateChannel.connectReceive(rp);
  channel.stream.listen(print);
  channel.stream.handleError((e) {
    print('Error occured: $e');
  });
  await Isolate.spawn(task, rp.sendPort);
}

void task(SendPort sp) {
  var channel = IsolateChannel.connectSend(sp);
  channel.sink.add('Hello');
  channel.sink.addError(Exception());
}