itty + wsgiref error?

gistfile1.pytb

itty starting up (using wsgiref)...
Listening on http://localhost:8080...
Use Ctrl-C to quit.

Traceback (most recent call last):
  File "/usr/local/Cellar/python/2.7.2/lib/python2.7/wsgiref/handlers.py", line 85, in run
    self.result = application(self.environ, self.start_response)
  File "/Users/benspaulding/dev/virtualenv/sample/lib/python2.7/site-packages/itty.py", line 286, in handle_request
    return response.send(start_response)
  File "/Users/benspaulding/dev/virtualenv/sample/lib/python2.7/site-packages/itty.py", line 253, in send
    start_response(status, final_headers)
  File "/usr/local/Cellar/python/2.7.2/lib/python2.7/wsgiref/handlers.py", line 169, in start_response
    raise AssertionError("Headers already set!")
AssertionError: Headers already set!
localhost - - [03/Feb/2012 13:38:55] "GET / HTTP/1.1" 500 59

sample.py

# -*- coding: utf-8 -*-

"""
TODO: DOC -- add module documentation here.
"""

from itty import *
from jinja2 import Environment, PackageLoader


# Setup templates. http://jinja.pocoo.org/docs/api/#basics
env = Environment(loader=PackageLoader('sample', 'templates'))

@get('/')
def index(request):
    """ Homepage. """
    template = env.get_template('index.html')
    output = template.render()
    response = Response(output)
    return response.send(request._start_response)

# Ready ... GO!
run_itty()