<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 close(self):
 """ Close this request, send all data. You can still run other operations in the handler. """

        if not self._sendHeaders:
            self._startResponse()
        if self.inputstream is not None:
            self.inputstream.close(self.connection.scheduler)
        if self.outputstream is not None:
            await self.flush(True)
        if hasattr(self, 'session') and self.session:
            self.session.unlock()