def write_long_at(self, n, pos, pack_into=Struct('>I').pack_into):
        '''
        Write an unsigned 32bit value at a specific position in the buffer.
        Used for writing tables and frames.
        '''
        if 0 <= n <= 0xFFFFFFFF:
            pack_into(self._output_buffer, pos, n)
        else:
            raise ValueError('Long %d out of range 0..0xFFFFFFFF', n)
        return self
Write an unsigned 32bit value at a specific position in the buffer.
        Used for writing tables and frames.