func NewFromFunc[T any](ttl time.Duration, opts Opts, update func(ctx context.Context) (T, error)) *Cache[T] {
	return &Cache[T]{
		ttl:      ttl,
		updateFn: update,
		opts:     opts,
	}
}

// InitOnce initializes the cache with a TTL and an update function. It is
// guaranteed to be called only once.
func (t *Cache[T]) InitOnce(ttl time.Duration, opts Opts, update func(ctx context.Context) (T, error)) {
	t.Once.Do(func() {
		t.ttl = ttl

// FIXME: add support for remote version ID in GCS remote tier and remove this.
// Currently it's a no-op.
func (gcs *warmBackendGCS) Put(ctx context.Context, key string, data io.Reader, length int64) (remoteVersionID, error) {
	return gcs.PutWithMeta(ctx, key, data, length, map[string]string{})
}

func (gcs *warmBackendGCS) Get(ctx context.Context, key string, rv remoteVersionID, opts WarmBackendGetOpts) (r io.ReadCloser, err error) {

}

// prepareAdminErasureTestBed - helper function that setups a single-node
// Erasure backend for admin-handler tests.
func prepareAdminErasureTestBed(ctx context.Context) (*adminErasureTestBed, error) {
	ctx, cancel := context.WithCancel(ctx)

	// reset global variables to start afresh.
	resetTestGlobals()

	// Set globalIsErasure to indicate that the setup uses an erasure
	// code backend.

			continue
		}
		info := info
		wg.Add(connectionsPerPeer)
		for range connectionsPerPeer {
			go func() {
				defer wg.Done()
				ctx, cancel := context.WithTimeout(ctx, duration+10*time.Second)
				defer cancel()
				perfNetRequest(
					ctx,
					info.DeploymentID,
					adminPathPrefix+adminAPIVersionPrefix+adminAPISiteReplicationDevNull,
					r,
				)
			}()
		}
	}

// for multiple KMS/KES servers.
func (k *KMS) Version(ctx context.Context) (string, error) {
	return k.conn.Version(ctx)
}

// APIs returns a list of KMS server APIs.
//
// TODO(aead): remove this API since it's hardly useful.
func (k *KMS) APIs(ctx context.Context) ([]madmin.KMSAPI, error) {
	return k.conn.APIs(ctx)
}

// Metrics returns a current snapshot of the KMS metrics.

)

type kesConn struct {
	defaultKeyID string
	client       *kes.Client
}

func (c *kesConn) Version(ctx context.Context) (string, error) {
	return c.client.Version(ctx)
}

func (c *kesConn) APIs(ctx context.Context) ([]madmin.KMSAPI, error) {
	APIs, err := c.client.APIs(ctx)
	if err != nil {
		if errors.Is(err, kes.ErrNotAllowed) {
			return nil, ErrPermission
		}
		return nil, Error{

	if write {
		err = reduceWriteQuorumErrs(ctx, errs, objectOpIgnoredErrs, writeQuorum)
	} else {
		err = reduceReadQuorumErrs(ctx, errs, objectOpIgnoredErrs, readQuorum)
	}
	if err != nil {
		return fi, nil, err
	}

	// Pick one from the first valid metadata.
	fi, err = pickValidFileInfo(ctx, partsMetadata, modTime, etag, quorum)
	return fi, partsMetadata, err
}

	Requests chan<- []byte

	muxID uint64
	ctx   context.Context
}

// Send a payload to the remote server.
func (s *Stream) Send(b []byte) error {
	if s.Requests == nil {
		return errors.New("stream does not accept requests")
	}
	select {
	case s.Requests <- b:
		return nil
	case <-s.ctx.Done():
		return context.Cause(s.ctx)
	}
}

			},
		)
	}
}

func (s *TestSuiteIAM) TestDeleteUserRace(c *check) {
	ctx, cancel := context.WithTimeout(context.Background(), 90*time.Second)
	defer cancel()

	bucket := getRandomBucketName()
	err := s.client.MakeBucket(ctx, bucket, minio.MakeBucketOptions{})
	if err != nil {
		c.Fatalf("bucket creat error: %v", err)
	}

	// Create a policy policy

	// * an error on failure of lock request operation.
	RLock(ctx context.Context, args LockArgs) (bool, error)

	// Do write lock for given LockArgs. It should return
	// * a boolean to indicate success/failure of the operation
	// * an error on failure of lock request operation.
	Lock(ctx context.Context, args LockArgs) (bool, error)

	// Do read unlock for given LockArgs. It should return