anchor.diff:      } catch (e) {
         throw 'Unable to get ondevicechange: ${e.toString()}';
       }
  +    return null;
     }
   }
  
positive.code:         throw UnimplementedError('selectAudioOutput is missing');
        }
      } catch (e) {
        throw 'Unable to selectAudioOutput: ${e.toString()}';
      }
    }
  
  
negative.code: import 'dart:async';
  import 'dart:html' as html;
  import 'dart:html_common';
  import 'dart:js' as js;
  import 'dart:js_util' as jsutil;
  import 'package:webrtc_interface/webrtc_interface.dart';
  