resourceMetricsMapMu sync.RWMutex
	// resourceMetricsHelpMap maps metric name to its help string
	resourceMetricsHelpMap map[MetricName]string
	resourceMetricsGroups  []*MetricsGroupV2
	// initial values for drives (at the time  of server startup)
	// used for calculating avg values for drive metrics
	latestDriveStats      map[string]madmin.DiskIOStats
	latestDriveStatsMu    sync.RWMutex
	lastDriveStatsRefresh time.Time
)

	var (
		// prevDriveIOStats is used to calculate "per second"
		// values for IOStat related disk metrics e.g. reads/sec.
		prevDriveIOStats            map[string]madmin.DiskIOStats
		prevDriveIOStatsMu          sync.RWMutex
		prevDriveIOStatsRefreshedAt time.Time
	)

	loadDriveMetrics := func(ctx context.Context) (v storageMetrics, err error) {
		objLayer := newObjectLayerFn()
		if objLayer == nil {
			return v, err
		}

// Therefore no cluster locks are required.
var localMetacacheMgr = &metacacheManager{
	buckets: make(map[string]*bucketMetacache),
	trash:   make(map[string]metacache),
}

type metacacheManager struct {
	mu      sync.RWMutex
	init    sync.Once
	buckets map[string]*bucketMetacache
	trash   map[string]metacache // Recently deleted lists.
}

const metacacheMaxEntries = 5000

// initManager will start async saving the cache.

	// Name of bucket
	bucket string

	// caches indexed by id.
	caches map[string]metacache
	// cache ids indexed by root paths
	cachesRoot map[string][]string `msg:"-"`

	// Internal state
	mu      sync.RWMutex `msg:"-"`
	updated bool         `msg:"-"`
}

type deleteAllStorager interface {
	deleteAll(ctx context.Context, bucket, prefix string)
}

// newBucketMetacache creates a new bucketMetacache.

// errLimitExceeded error is sent when the maximum limit is reached.
var errLimitExceeded = errors.New("the maximum store limit reached")

// QueueStore - Filestore for persisting items.
type QueueStore[_ any] struct {
	sync.RWMutex
	entryLimit uint64
	directory  string
	fileExt    string

	entries map[string]int64 // key -> modtime as unix nano
}

// NewQueueStore - Creates an instance for QueueStore.

	ReplicaCount int64                `json:"replicaCount"`
	M            map[string]*SRStatus `json:"srStatusMap"`

	movingAvgTicker *time.Ticker // Ticker for calculating moving averages
	lock            sync.RWMutex // mutex for srStats
}

// SRStatus has replication stats at deployment level
type SRStatus struct {
	ReplicatedSize int64 `json:"completedReplicationSize"`

)

type resyncState struct {
	resyncID  string
	LastSaved time.Time
}

//msgp:ignore siteResyncMetrics
type siteResyncMetrics struct {
	sync.RWMutex
	// resyncStatus maps resync ID to resync status for peer
	resyncStatus map[string]SiteResyncStatus
	// map peer deployment ID to resync ID
	peerResyncMap map[string]resyncState
}

	"github.com/minio/minio/internal/arn"
	"github.com/minio/minio/internal/auth"
	xnet "github.com/minio/pkg/v3/net"
	"github.com/minio/pkg/v3/policy"
)

type publicKeys struct {
	*sync.RWMutex

	// map of kid to public key
	pkMap map[string]any
}

func (pk *publicKeys) parseAndAdd(b io.Reader) error {
	var jwk JWKS
	err := json.NewDecoder(b).Decode(&jwk)
	if err != nil {
		return err
	}

	select{}
}
</pre>

<h3 id="locks">Locks</h3>

<p>
The <code>sync</code> package implements two lock data types,
<code>sync.Mutex</code> and <code>sync.RWMutex</code>.
</p>

<p class="rule">
For any <code>sync.Mutex</code> or <code>sync.RWMutex</code> variable <code>l</code> and <i>n</i> &lt; <i>m</i>,
call <i>n</i> of <code>l.Unlock()</code> is synchronized before call <i>m</i> of <code>l.Lock()</code> returns.
</p>

	// Channel of log entries.
	// Reading logCh must hold read lock on logChMu (to avoid read race)
	// Sending a value on logCh must hold read lock on logChMu (to avoid closing)
	logCh   chan any
	logChMu sync.RWMutex

	// store to persist and replay the logs to the target
	// to avoid missing events when the target is down.
	store          store.Store[any]
	storeCtxCancel context.CancelFunc

	initKafkaOnce      once.Init