def store_downstream_data(self, message):
        """Save websocket data sent from client to server.

        i.e add it to HTTPRequest.response_buffer with direction (<<)
        """
        try:  # Cannot write binary content as a string, so catch it.
            self.handshake_request.response_buffer += ("<<< %s\r\n" % message)
        except __HOLE__:
            self.handshake_request.response_buffer += ("<<< May be binary\r\n")
dataset/ETHPy150Open owtf/owtf/framework/http/proxy/proxy.py/CustomWebSocketHandler.store_downstream_data