com.baidubce
       ├── auth                                        //BCE signature related class
       ├── http                                        //BCE Http communication-related class
       ├── internal                                    //SDK internal class
       ├── model                                       //BCE public model class
       ├── services
       │       └── bmr                                 //BMR service related class
       │           ├── model                           //BMR internal model, such as Request or Response
       │           └── BmrClient.class                 //BMR client entry class
       ├── util                                        //BCE public tool class
       ├── BceClientConfiguration.class                //configuration of BCE HttpClient
       ├── BceClientException.class                    //BCE client exception class
       ├── BceServiceException.class                   //exception class after interaction with BCE server
       ├── ErrorCode.class                             //BCE general error code
       └── Region.class                                //BCE service region