def register_tunnel_down(self, handler):
        self.down_handler = handler
Get a dict of key-value pairs from wsgi_env that work as env variables.
dataset/ETHPy150Open EricssonResearch/calvin-base/calvin/runtime/north/calvin_proto.py/CalvinTunnel.register_tunnel_down--crossover with--dataset/ETHPy150Open GoogleCloudPlatform/python-compat-runtime/appengine-vmruntime/vmruntime/middleware.py/request_environment_for_wsgi_env