def receive_trailers(self, event):
        self.response_trailers = HTTPHeaderMap(event.headers)
Called when a channel patern is subscribed to.
dataset/ETHPy150Open Lukasa/hyper/hyper/http20/stream.py/Stream.receive_trailers--crossover with--dataset/ETHPy150Open deldotdr/txRedis/txredis/client.py/RedisSubscriber.channelPatternSubscribed