// suppose the maxopen is 1, g1 is creating record and g2 is querying record.
	// 1. g1 begin tx, g1 is requeue because of waiting for the system call, now `db.ConnPool` db.numOpen == 1.
	// 2. g2 select lock `conn.PrepareContext(ctx, query)`, now db.numOpen == db.maxOpen , wait for release.
	// 3. g1 tx exec insert, wait for unlock `conn.PrepareContext(ctx, query)` to finish tx and release.
	stmt, err := conn.PrepareContext(ctx, query)

			return
		}

		if !broken || !retried {
			t.Error(name + ": Failed to simulate broken connection")
		}
		*hook = nil

		if numOpen != db.numOpen {
			t.Errorf(name+": leaked %d connection(s)!", db.numOpen-numOpen)
			numOpen = db.numOpen
		}
	}

	// db.Exec
	dbExec := func() error {
		_, err := db.Exec("INSERT|t1|name=?,age=?,dead=?", "Gordon", 3, true)
		return err
	}

	// maybeOpenNewConnections has already executed db.numOpen++ before it sent
	// on db.openerCh. This function must execute db.numOpen-- if the
	// connection fails or is closed before returning.
	ci, err := db.connector.Connect(ctx)
	db.mu.Lock()
	defer db.mu.Unlock()
	if db.closed {
		if err == nil {
			ci.Close()
		}
		db.numOpen--
		return
	}
	if err != nil {
		db.numOpen--

	}))
	defer cst.close()

	var numOpen, numClose int32 // atomic

	tlsConfig := &tls.Config{InsecureSkipVerify: true}
	tr := &Transport{
		TLSClientConfig: tlsConfig,
		DialTLS: func(_, addr string) (net.Conn, error) {
			time.Sleep(10 * time.Millisecond)
			rc, err := net.Dial("tcp", addr)
			if err != nil {
				return nil, err
			}
			atomic.AddInt32(&numOpen, 1)

	add rule ip testing service-42NFTM6N-ns2/svc2/tcp/p80 numgen random mod 1 vmap { 0 : goto endpoint-SGOXE6O3-ns2/svc2/tcp/p80__10.180.0.2/80 }
	add rule ip testing service-ULMVA6XW-ns1/svc1/tcp/p80 ip daddr 172.30.0.41 tcp dport 80 ip saddr != 10.0.0.0/8 jump mark-for-masquerade
	add rule ip testing service-ULMVA6XW-ns1/svc1/tcp/p80 numgen random mod 1 vmap { 0 : goto endpoint-5OJB2KTY-ns1/svc1/tcp/p80__10.180.0.1/80 }

		add rule ip kube-proxy service-ULMVA6XW-ns1/svc1/tcp/p80 ip daddr 172.30.0.41 tcp dport 80 ip saddr != 10.0.0.0/8 jump mark-for-masquerade
		add rule ip kube-proxy service-ULMVA6XW-ns1/svc1/tcp/p80 numgen random mod 1 vmap { 0 : goto endpoint-5OJB2KTY-ns1/svc1/tcp/p80__10.180.0.1/80 }

		add chain ip kube-proxy endpoint-5OJB2KTY-ns1/svc1/tcp/p80__10.180.0.1/80

                                    BlockArgument& block_arg) {
  // check that inputs length is same as num_replicas.
  if (inputs.size() != replicate.getN()) {
    return replicate.emitError()
           << "Expected numper of inputs (" << inputs.size()
           << ") to append to replicate to be num_replicas ("
           << replicate.getN() << ")";
  }

  // add block arg to region. This is in $body.

		)
		if i != len(endpoints)-1 {
			elements = append(elements, ",")
		}
	}
	tx.Add(&knftables.Rule{
		Chain: svcChain,
		Rule: knftables.Concat(
			"numgen random mod", len(endpoints), "vmap",
			"{", elements, "}",
		),
	})