NATSSubject       = "subject"
	NATSUsername      = "username"
	NATSPassword      = "password"
	NATSToken         = "token"
	NATSTLS           = "tls"
	NATSTLSSkipVerify = "tls_skip_verify"
	NATSPingInterval  = "ping_interval"
	NATSQueueDir      = "queue_dir"
	NATSQueueLimit    = "queue_limit"
	NATSCertAuthority = "cert_authority"
	NATSClientCert    = "client_cert"
	NATSClientKey     = "client_key"

		if peer == nil {
			continue
		}
		peer.Listen(ctx, mergeCh, values)
	}

	var (
		emptyEventTicker <-chan time.Time
		keepAliveTicker  <-chan time.Time
	)

	if p := values.Get("ping"); p != "" {
		pingInterval, err := strconv.Atoi(p)
		if err != nil {
			writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrInvalidQueryParams), r.URL)
			return
		}
		if pingInterval < 1 {

	// 		// ReadIdleTimeout is the timeout after which a health check using ping
	// 		// frame will be carried out if no frame is received on the
	// 		// connection. 5 minutes is sufficient time for any idle connection.
	// 		trhttp2.ReadIdleTimeout = 5 * time.Minute
	// 		// PingTimeout is the timeout after which the connection will be closed
	// 		// if a response to Ping is not received.
	// 		trhttp2.PingTimeout = dialTimeout

		if resp.IsError() {
			return fmt.Errorf("Create index err: %v", res)
		}
		return nil
	}
	return nil
}

func (c *esClientV7) ping(ctx context.Context, _ ElasticsearchArgs) (bool, error) {
	resp, err := c.Ping(
		c.Ping.WithContext(ctx),
	)
	if err != nil {
		return false, store.ErrNotConnected
	}
	xhttp.DrainBody(resp.Body)
	return !resp.IsError(), nil
}

const (
	// OpConnect is a connect request.
	OpConnect Op = iota + 1

	// OpConnectResponse is a response to a connect request.
	OpConnectResponse

	// OpPing is a ping request.
	// If a mux id is specified that mux is pinged.
	// Clients send ping requests.
	OpPing

	// OpPong is a OpPing response returned by the server.
	OpPong

	// OpConnectMux will connect a new mux with optional payload.
	OpConnectMux

		producer, err := nsq.NewProducer(target.args.NSQDAddress.String(), target.config)
		if err != nil {
			return false, err
		}
		target.producer = producer
	}

	if err := target.producer.Ping(); err != nil {
		// To treat "connection refused" errors as errNotConnected.
		if xnet.IsConnRefusedErr(err) {
			return false, store.ErrNotConnected
		}
		return false, err
	}
	return true, nil
}

	if err := target.init(); err != nil {
		return false, err
	}
	return target.isActive()
}

func (target *PostgreSQLTarget) isActive() (bool, error) {
	if err := target.db.Ping(); err != nil {
		if IsConnErr(err) {
			return false, store.ErrNotConnected
		}
		return false, err
	}
	return true, nil
}

		return
	}
	// Single calls do not support pinging.
	if v, ok := c.inStream.Load(m.MuxID); ok {
		pong := v.ping(m.Seq)
		gridLogIf(ctx, c.queueMsg(m, &pong))
	} else {
		pong := pongMsg{NotFound: true}
		gridLogIf(ctx, c.queueMsg(m, &pong))
	}
	return
}

func (c *Connection) handleDisconnectClientMux(m message) {
	if v, ok := c.outgoing.Load(m.MuxID); ok {

	case m.outBlock <- struct{}{}:
	default:
		gridLogIf(m.ctx, errors.New("output unblocked overflow"))
	}
}

func (m *muxClient) pong(msg pongMsg) {
	if msg.NotFound || msg.Err != nil {
		err := errors.New("remote terminated call")
		if msg.Err != nil {
			err = fmt.Errorf("remove pong failed: %v", &msg.Err)
		}
		m.addResponse(Response{Err: err})
		return
	}
	atomic.StoreInt64(&m.LastPong, time.Now().Unix())
}

	// 3) Returning, with ID, stream from list.
	//
	// If we don't have a list id we must ask the server if it has a cache or create a new.
	if o.ID != "" && !o.Transient {
		// Create or ping with handout...
		rpc := globalNotificationSys.restClientFromHash(pathJoin(o.Bucket, o.Prefix))
		var c *metacache
		if rpc == nil {
			resp := localMetacacheMgr.getBucket(ctx, o.Bucket).findCache(*o)
			c = &resp