"""
        if self.cid is not None:
            fetcher = self._create_credentials_fetcher()
            return RefreshableCredentials.create_from_metadata(
                metadata=fetcher(),
                refresh_using=fetcher,
                method=self.METHOD,
            )
        else:
            return None

    def _create_credentials_fetcher(self):
        method = self.METHOD

        def fetch_credentials():

	switch cfg.Name {
	case storageclass.STANDARD, storageclass.RRS:
		writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, errTierReservedName), r.URL)
		return
	}

	// Refresh from the disk in case we had missed notifications about edits from peers.
	if err := globalTierConfigMgr.Reload(ctx, objAPI); err != nil {
		writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, err), r.URL)
		return
	}

	}
}

func (lh *lockServerHandler) RefreshHandler(w http.ResponseWriter, r *http.Request) {
	args, err := getLockArgs(r)
	if err != nil {
		lh.writeErrorResponse(w, err)
		return
	}

	reply, err := lh.lsrv.Refresh(&args)
	if err != nil {
		lh.writeErrorResponse(w, err)
		return
	}

	if !reply {
		lh.writeErrorResponse(w, errLockNotFound)
		return
	}
}

	return restClient.Call("/v1/unlock", args)
}

func (restClient *ReconnectRESTClient) Refresh(ctx context.Context, args LockArgs) (refreshed bool, err error) {
	return restClient.Call("/v1/refresh", args)
}

func (restClient *ReconnectRESTClient) ForceUnlock(ctx context.Context, args LockArgs) (reply bool, err error) {

	// Canceling the context will abort the remote call.
	// In that case, the resource may or may not be unlocked.
	Unlock(ctx context.Context, args LockArgs) (bool, error)

	// Refresh the given lock to prevent it from becoming stale
	Refresh(ctx context.Context, args LockArgs) (bool, error)

	// Unlock (read/write) forcefully for given LockArgs. It should return
	// * a boolean to indicate success/failure of the operation

	if err != nil {
		return nil, err
	}

	// Refresh obtains a fresh token
	err = spt.Refresh()
	if err != nil {
		return nil, err
	}

	tc := azblob.NewTokenCredential(spt.Token().AccessToken, func(tc azblob.TokenCredential) time.Duration {
		err := spt.Refresh()
		if err != nil {
			return 0
		}
		// set the new token value

)

// To abstract a node over network.
type lockRESTServer struct {
	ll *localLocker
}

// RefreshHandler - refresh the current lock
func (l *lockRESTServer) RefreshHandler(args *dsync.LockArgs) (*dsync.LockResp, *grid.RemoteErr) {
	resp := lockRPCRefresh.NewResponse()
	refreshed, err := l.ll.Refresh(context.Background(), *args)
	if err != nil {
		return l.makeResp(resp, err)
	}
	if !refreshed {

// RUnlock calls read unlock REST API.
func (c *lockRESTClient) RUnlock(ctx context.Context, args dsync.LockArgs) (reply bool, err error) {
	return c.call(ctx, lockRPCRUnlock, &args)
}

// Refresh calls Refresh REST API.
func (c *lockRESTClient) Refresh(ctx context.Context, args dsync.LockArgs) (reply bool, err error) {
	return c.call(ctx, lockRPCRefresh, &args)
}

// Unlock calls write unlock RPC.