code: func (proxy *ProxyHttpServer) OnResponse(conds ...RespCondition) *ProxyConds {
  	return &ProxyConds{proxy, make([]ReqCondition, 0), conds}
  }
docs: // OnResponse is used when adding a response-filter to the HTTP proxy, usual pattern is
  //	proxy.OnResponse(cond1,cond2).Do(handler) // handler.Handle(resp,ctx) will be used
  //				// if cond1.HandleResp(resp) && cond2.HandleResp(resp)