'Extract the content-* headers from the L{DummyRequest} C{request}.
This returns the subset of C{request.outgoingHeaders} of headers that
start with \'content-\'.'

def contentHeaders(self, request):

    contentHeaders = {}
    for (k, v) in request.responseHeaders.getAllRawHeaders():
        if k.lower().startswith('content-'):
            contentHeaders[k.lower()] = v[0]
    return contentHeaders
