"The total number of connection errors from envoy",
	)

	// TODO: Add type url as type for requeasts and responses if needed.

	// XdsProxyRequests records total number of downstream requests.
	XdsProxyRequests = monitoring.NewSum(
		"xds_proxy_requests",
		"The total number of Xds Proxy Requests",
	)

	// XdsProxyResponses records total number of upstream responses.
	XdsProxyResponses = monitoring.NewSum(

				"sub", len(req.ResourceNamesSubscribe),
				"unsub", len(req.ResourceNamesUnsubscribe),
				"nonce", req.ResponseNonce,
				"initial", len(req.InitialResourceVersions),
			).Debugf("delta request")
			metrics.XdsProxyRequests.Increment()
			if req.TypeUrl == model.ExtensionConfigurationType {
				p.ecdsLastNonce.Store(req.ResponseNonce)
			}

			if err := con.upstreamDeltas.Send(req); err != nil {

				// only send healthcheck probe after LDS request has been sent
				continue
			}
			proxyLog.Debugf("request for type url %s", req.TypeUrl)
			metrics.XdsProxyRequests.Increment()
			if req.TypeUrl == model.ExtensionConfigurationType {
				if req.VersionInfo != "" {
					p.ecdsLastAckVersion.Store(req.VersionInfo)
				}
				p.ecdsLastNonce.Store(req.ResponseNonce)
			}