code: function errno(err, syscall) {
      var code;
      switch (err.name) {
      case 'NotFoundError':
      case 'DirectoryDoesNotExistError':
      case 'ResourceNotFoundError':
          code = 'ENOENT';
          break;
  
      case 'DirectoryNotEmptyError':
          code = 'ENOTEMPTY';
          break;
  
      case 'LinkNotObjectError':
          code = 'EISDIR';
          break;
  
      case 'ParentNotDirectoryError':
          code = 'ENOTDIR';
          break;
  
      default:
          code = 'EIO';
          break;
      }
  
      return (new ErrnoError(code, syscall || 'manta', err));
  }
docs: /--- Helpers