func crc32Combine(poly uint32, crc1, crc2 uint32, len2 int64) uint32 {
	// degenerate case (also disallow negative lengths)
	if len2 <= 0 {
		return crc1
	}

	even := make([]uint64, 32) // even-power-of-two zeros operator
	odd := make([]uint64, 32)  // odd-power-of-two zeros operator

	// put operator for one zero bit in odd
	odd[0] = uint64(poly) // CRC-32 polynomial
	row := uint64(1)
	for n := 1; n < 32; n++ {

	var retError string
	var totalBytesWritten uint64
	var totalBytesRead uint64

	objCountPerThread := make([]uint64, opts.concurrency)

	uploadsCtx, uploadsCancel := context.WithTimeout(ctx, opts.duration)
	defer uploadsCancel()

	objNamePrefix := pathJoin(speedTest, mustGetUUID())

	userMetadata := make(map[string]string)
	userMetadata[globalObjectPerfUserMetadata] = "true" // Bypass S3 API freeze

	// map peer deployment ID to resync ID
	peerResyncMap map[string]resyncState
}

func newSiteResyncMetrics(ctx context.Context) *siteResyncMetrics {
	s := siteResyncMetrics{
		resyncStatus:  make(map[string]SiteResyncStatus),
		peerResyncMap: make(map[string]resyncState),
	}
	go s.save(ctx)
	go s.init(ctx)
	return &s
}

// init site resync metrics
func (sm *siteResyncMetrics) init(ctx context.Context) {

		Name:             modelType.Name(),
		ModelType:        modelType,
		Table:            tableName,
		DBNames:          make([]string, 0, 10),
		Fields:           make([]*Field, 0, 10),
		FieldsByName:     make(map[string]*Field, 10),
		FieldsByBindName: make(map[string]*Field, 10),
		FieldsByDBName:   make(map[string]*Field, 10),
		Relationships:    Relationships{Relations: map[string]*Relationship{}},
		cacheStore:       cacheStore,

		// not be required but makes reproduction much easier.
		nsLk.lockMapMutex.Lock()

		// lk3 blocks.
		lk3ch := make(chan bool)
		go func() {
			lk3ch <- nsLk.lock(ctx, "volume", "path", "source", "opsID", false, 0)
		}()

		// lk4, blocks.
		lk4ch := make(chan bool)
		go func() {
			lk4ch <- nsLk.lock(ctx, "volume", "path", "source", "opsID", false, 0)
		}()
		runtime.Gosched()

	v := allTierStats{}
	b.ReportAllocs()
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		v.MarshalMsg(nil)
	}
}

func BenchmarkAppendMsgallTierStats(b *testing.B) {
	v := allTierStats{}
	bts := make([]byte, 0, v.Msgsize())
	bts, _ = v.MarshalMsg(bts[0:0])
	b.SetBytes(int64(len(bts)))
	b.ReportAllocs()
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		bts, _ = v.MarshalMsg(bts[0:0])
	}
}

		}
	}
	if trailer {
		// Discard anything unsigned.
		req.Trailer = make(http.Header)
		trailers := req.Header.Values(awsTrailerHeader)
		for _, key := range trailers {
			req.Trailer.Add(key, "")
		}
	} else {
		req.Trailer = nil
	}
	return &s3UnsignedChunkedReader{
		trailers: req.Trailer,
		reader:   bufio.NewReader(req.Body),
		buffer:   make([]byte, 64*1024),
	}, ErrNone
}

	// Map of LDAP user (internal representation) to list of active credential objects
	parentUserToCredsMap := make(map[string][]auth.Credentials)
	// DN to ldap username mapping for each LDAP user
	actualDNToLDAPUsernameMap := make(map[string]string)
	// External (actual) LDAP DN to internal normalized representation
	actualDNToParentUserMap := make(map[string]string)
	for _, cred := range allCreds {

	v := RStat{}
	b.ReportAllocs()
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		v.MarshalMsg(nil)
	}
}

func BenchmarkAppendMsgRStat(b *testing.B) {
	v := RStat{}
	bts := make([]byte, 0, v.Msgsize())
	bts, _ = v.MarshalMsg(bts[0:0])
	b.SetBytes(int64(len(bts)))
	b.ReportAllocs()
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		bts, _ = v.MarshalMsg(bts[0:0])
	}
}

	v := connectReq{}
	b.ReportAllocs()
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		v.MarshalMsg(nil)
	}
}

func BenchmarkAppendMsgconnectReq(b *testing.B) {
	v := connectReq{}
	bts := make([]byte, 0, v.Msgsize())
	bts, _ = v.MarshalMsg(bts[0:0])
	b.SetBytes(int64(len(bts)))
	b.ReportAllocs()
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		bts, _ = v.MarshalMsg(bts[0:0])
	}
}