def _realsize(self):
        '''
        Get the struct size without padding (or the "real size")
        
        :returns: the "real size" in bytes
        
        '''
        current = self
        size= 0
        while current is not None:
            size += current._parser.sizeof(current)
            last = current
            current = getattr(current, '_sub', None)
        size += len(getattr(last, '_extra', b''))
        return size
Get the struct size without padding (or the "real size")
        
        :returns: the "real size" in bytes