Whilst socket is running receives data from socket,
        till CRLF is detected.

def _receive_all(self):
        """Whilst socket is running receives data from socket,
        till CRLF is detected.
        """
        (data, part) = ('', '')
        if is_py3:
            crlf_bytes = bytes(self.__CRLF, encoding=self.__encoding)
        else:
            crlf_bytes = self.__CRLF

        while self._running and part[-2:] != crlf_bytes:
            try:
                part = self._socket.recv(self.buffer_size)
            except (socket.timeout, socket.error) as e:
                if self._running:
                    self.stop()
                    raise SocketError('[Connect: %s]: Socket %s' % (self._unique_id, e))
                else:
                    return  # 133, prevents error if stop is called mid recv

            # an empty string indicates the server shutdown the socket
            if len(part) == 0:
                self.stop()
                raise SocketError('Connection closed by server')

            data += part.decode(self.__encoding)
        return data