StatusCodes enum
定义 StatusCodes 的值。 可能的值包括：200、400、401、404、405、409、426、500、501、502
字段
| OK = 200 | |
| CREATED = 201 | |
| MULTIPLE_CHOICES = 300 | |
| BAD_REQUEST = 400 | |
| UNAUTHORIZED = 401 | |
| NOT_FOUND = 404 | |
| METHOD_NOT_ALLOWED = 405 | |
| CONFLICT = 409 | |
| PRECONDITION_FAILED = 412 | |
| UPGRADE_REQUIRED = 426 | |
| INTERNAL_SERVER_ERROR = 500 | |
| NOT_IMPLEMENTED = 501 | |
| BAD_GATEWAY = 502 |