A RequestHandler that wraps another HTTP server callback.
The fallback is a callable object that accepts an HTTPRequest,
such as an Application or tornado.wsgi.WSGIContainer. This is most
useful to use both tornado RequestHandlers and WSGI in the same server.
Typical usage::
wsgi_app = tornado.wsgi.WSGIContainer(
django.core.handlers.wsgi.WSGIHandler())
application = tornado.web.Application([
(r"/foo", FooHandler),
(r".*", FallbackHandler, dict(fallback=wsgi_app),
])
Definition at line 1662 of file web.py.