'Add a FileDescriptor for notification of data available to write.'

def addWriter(self, writer):

    try:
        self._add(writer, self._writes, self._reads, self._selectables, EPOLLOUT, EPOLLIN)
    except IOError as e:
        if (e.errno == errno.EPERM):
            self._continuousPolling.addWriter(writer)
        else:
            raise
