list.statLock.Lock()
	defer list.statLock.Unlock()

	stats, ok := list.targetStats[id]
	if !ok {
		// should not happen
		return
	}

	stats.currentSendCalls--
	list.targetStats[id] = stats
	return
}

func (list *TargetList) incFailedEvents(id TargetID) {
	list.statLock.Lock()
	defer list.statLock.Unlock()

	stats, ok := list.targetStats[id]
	if !ok {

	if responses == nil {
		return nil, errors.New("RequestStream: responses channel is nil")
	}
	m.init = true
	m.respMu.Lock()
	if m.closed {
		m.respMu.Unlock()
		return nil, ErrDisconnected
	}
	m.respWait = responses // Route directly to output.
	m.respMu.Unlock()

	// Try to grab an initial block.
	m.singleResp = false
	m.RecvSeq = m.SendSeq // Sync
	if cap(requests) > 0 {

}

func (t *tierMetrics) logSuccess(tier string) {
	t.Lock()
	defer t.Unlock()

	stat := t.requestsCount[tier]
	stat.success++
	t.requestsCount[tier] = stat
}

func (t *tierMetrics) logFailure(tier string) {
	t.Lock()
	defer t.Unlock()

	stat := t.requestsCount[tier]
	stat.failure++
	t.requestsCount[tier] = stat
}

var (

type IAMStorageAPI interface {
	// The role of the read-write lock is to prevent go routines from
	// concurrently reading and writing the IAM storage. The (r)lock()
	// functions return the iamCache. The cache can be safely written to
	// only when returned by `lock()`.
	lock() *iamCache
	unlock()
	rlock() *iamCache
	runlock()
	getUsersSysType() UsersSysType

	}

	// if no update is needed return right away.
	if !update {
		z.poolMetaMutex.Lock()
		z.poolMeta = meta
		z.poolMetaMutex.Unlock()
	} else {
		newMeta := newPoolMeta(z, meta)
		if err = newMeta.save(ctx, z.serverPools); err != nil {
			return err
		}
		z.poolMetaMutex.Lock()
		z.poolMeta = newMeta
		z.poolMetaMutex.Unlock()
	}

	pools := meta.returnResumablePools()

	if !ok {
		t.Fatalf("should assign PreparedStatement Manager back to database when using PrepareStmt mode")
	}

	pdb.Mux.Lock()
	if len(pdb.Stmts) == 0 {
		pdb.Mux.Unlock()
		t.Fatalf("prepared stmt can not be empty")
	}
	pdb.Mux.Unlock()

	pdb.Reset()
	pdb.Mux.Lock()
	defer pdb.Mux.Unlock()
	if len(pdb.Stmts) != 0 {
		t.Fatalf("prepared stmt should be empty")
	}

}

func (c *connMgr) addConn(conn *ZtunnelConnection) {
	log.Debug("ztunnel connected")
	c.mu.Lock()
	defer c.mu.Unlock()
	c.connectionSet[conn] = struct{}{}
	c.latestConn = conn
	ztunnelConnected.RecordInt(int64(len(c.connectionSet)))
}

func (c *connMgr) LatestConn() *ZtunnelConnection {
	c.mu.Lock()
	defer c.mu.Unlock()
	return c.latestConn
}

func (c *connMgr) deleteConn(conn *ZtunnelConnection) {

	var funcReturnedMu sync.Mutex
	defer func() {
		funcReturnedMu.Lock()
		funcReturned = true
		funcReturnedMu.Unlock()
	}()
	// Write listing to results and saver.
	go func() {
		var returned bool
		for entry := range inCh {
			if !returned {
				funcReturnedMu.Lock()
				returned = funcReturned
				funcReturnedMu.Unlock()
				outCh <- entry
				if returned {
					xioutil.SafeClose(outCh)

	Endpoint string `json:"-"`
	// Secure is true if the replication target endpoint is secure
	Secure bool `json:"-"`
}

func (sr *SRStats) update(st replStat, dID string) {
	sr.lock.Lock()
	defer sr.lock.Unlock()
	srs, ok := sr.M[dID]
	if !ok {
		srs = &SRStatus{
			XferRateLrg: newXferStats(),
			XferRateSml: newXferStats(),
		}
	}
	srs.Endpoint = st.Endpoint
	srs.Secure = st.Secure

}

// Unlock unlocks the write lock.
//
// It is a run-time error if dm is not locked on entry to Unlock.
func (dm *DRWMutex) Unlock(ctx context.Context) {
	dm.m.Lock()
	dm.cancelRefresh()
	dm.m.Unlock()

	restClnts, owner := dm.clnt.GetLockers()
	// create temp array on stack
	locks := make([]string, len(restClnts))

	{
		dm.m.Lock()
		defer dm.m.Unlock()