Comment 2 for bug 740831

"dm.zopepatches.fix_responsewrite_conflict" essentially prepends to "ZPublisher.HTTPRequest.HTTPRequest.supports_retry" an

  if getattr(self.response, "_streaming", False):
    # we try to retry a request whose response has already (at least partially)
    # been written -- this leads to desaster (wrong responses to subsequents
    # requests). Prevent it.
    logger.error("prevent request retry for which part of its response has already been written")
    return False