def __init__(self, reactor=None):
        """
        @param reactor: An L{IReactorFDSet} provider which this descriptor will
            use to get readable and writeable event notifications.  If no value
            is given, the global reactor will be used.
        """
        if not reactor:
            from twisted.internet import reactor
        self.reactor = reactor
        self._tempDataBuffer = [] # will be added to dataBuffer in doWrite
        self._tempDataLen = 0

        @param reactor: An L{IReactorFDSet} provider which this descriptor will
            use to get readable and writeable event notifications.  If no value
            is given, the global reactor will be used.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/abstract.py