anchor.diff:    static _forward(Proxy receiver, String member, String kind, List args) {
       if (_depth == 0) throw 'Cannot access a JavaScript proxy out of scope.';
       var result = receiver._port.callSync([receiver._id, member, kind,
  -                                          args.mappedBy(_serialize).toList()]);
  +                                          args.map(_serialize).toList()]);
       switch (result[0]) {
         case 'return': return _deserialize(result[1]);
         case 'throws': throw _deserialize(result[1]);
  
positive.code:       }
        return ['map', entries];
      } else if (data is List) {
        return ['list', data.mappedBy((e) => _serializeDataTree(e)).toList()];
      } else {
        return ['simple', _serialize(data)];
      }
  
negative.code:   noSuchMethod(InvocationMirror invocation) {
      if (invocation.isMethod && invocation.memberName == 'call') {
        var message = [_id, '', 'apply',
                       invocation.positionalArguments.map(_serialize).toList()];
        var result = _port.callSync(message);
        if (result[0] == 'throws') throw result[1];
        return _deserialize(result[1]);
  