anchor.diff:      if (!enabled) return next(name, args, context);
       var a = '';
       try {
  -      a = json.encode((args.length > 0 && args.last is Context)
  +      a = json.encode((args.isNotEmpty && args.last is Context)
             ? args.sublist(0, args.length - 1)
             : args);
       } catch (e) {
         print(e);
       }
       final result = next(name, args, context);
  -    result
  +    await result
           .then((value) => print(
               '${name}(${a.substring(1, a.length - 1)}) = ${json.encode(value)}'))
           .catchError(print);
  
positive.code: |                                                          |
  | Log plugin for Dart.                                     |
  |                                                          |
  | LastModified: Mar 6, 2019                                |
  | Author: Ma Bingyao <andot@hprose.com>                    |
  |                                                          |
  \*________________________________________________________*/
  
negative.code:       print(e);
      }
      final response = next(request, context);
      await response.then((value) => print(utf8.decode(value))).catchError(print);
      return response;
    }
  
  