Write any buffer headers and payloads to the given connection.

        Args:
            conn (object) :
                May be any object with a ``write_message`` method. Typically,
                a Tornado ``WSHandler`` or ``WebSocketClientConnection``

            locked (bool) :

        Returns:
            int : number of bytes sent

def write_buffers(self, conn, locked=True):
        ''' Write any buffer headers and payloads to the given connection.

        Args:
            conn (object) :
                May be any object with a ``write_message`` method. Typically,
                a Tornado ``WSHandler`` or ``WebSocketClientConnection``

            locked (bool) :

        Returns:
            int : number of bytes sent

        '''
        if conn is None:
            raise ValueError("Cannot write_buffers to connection None")
        sent = 0
        for header, payload in self._buffers:
            yield conn.write_message(header, locked=locked)
            yield conn.write_message(payload, binary=True, locked=locked)
            sent += (len(header) + len(payload))
        raise gen.Return(sent)