def _encodeName(self, name):
        if isinstance(name, unicode):
            return name.lower().encode('iso-8859-1')
        return name.lower()
L{Response._bodyDataReceived} raises L{RuntimeError} if called after
dataset/ETHPy150Open twisted/twisted/twisted/web/http_headers.py/Headers._encodeName--crossover with--dataset/ETHPy150Open twisted/twisted/twisted/web/test/test_newclient.py/ResponseTests.test_bodyDataReceivedAfterDeliveryFails