Connects to Telegram.

async def connect(self):
        """
        Connects to Telegram.
        """
        await self._sender.connect(self._connection(
            self.session.server_address,
            self.session.port,
            self.session.dc_id,
            loop=self._loop,
            loggers=self._log,
            proxy=self._proxy
        ))
        self.session.auth_key = self._sender.auth_key
        self.session.save()

        await self._sender.send(self._init_with(
            functions.help.GetConfigRequest()))

        self._updates_handle = self._loop.create_task(self._update_loop())