<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 async def _write_ssl(self):
 """ Flush outgoing data which OpenSSL put in our BIO to the transport. """

        pending = lib.BIO_ctrl_pending(self.write_bio)
        if pending > 0:
            result = lib.BIO_read(self.write_bio, self.write_cdata, len(self.write_cdata))
            await self.transport._send(ffi.buffer(self.write_cdata)[0:result])
            self.__tx_bytes += result
            self.__tx_packets += 1