if r.throttle == nil {
		return r.r.Read(buf)
	}
	if r.lastErr != nil {
		err = r.lastErr
		return
	}
	b := r.throttle.Burst()  // maximum available tokens
	need := len(buf)         // number of bytes requested by caller
	hdr := r.opts.HeaderSize // remaining header bytes
	var tokens int           // number of tokens to request

	if hdr > 0 { // available tokens go towards header first
		if hdr < b { // all of header can be accommodated

// 'req' will not be used after the call and caller can reuse.
// If no deadline is set on ctx, a 1-minute deadline will be added.
func (c *Connection) Request(ctx context.Context, h HandlerID, req []byte) ([]byte, error) {
	if !h.valid() {
		return nil, ErrUnknownHandler
	}
	if c.State() != StateConnected {
		return nil, ErrDisconnected
	}
	// Create mux client and call.
	client, err := c.newMuxClient(ctx)

// An Update function must be set to provide an updated value when needed.
type Cache[T any] struct {
	// updateFn must return an updated value.
	// If an error is returned the cached value is not set.
	// Only one caller will call this function at any time, others will be blocking.
	// The returned value can no longer be modified once returned.
	// Should be set before calling Get().
	updateFn func() (T, error)

	// ttl for a cached value.

	Checksum *hash.Checksum
	MD5Hex   string
}

// fanOutPutObject takes an input source reader and fans out multiple PUT operations
// based on the incoming fan-out request, a context cancellation by the caller
// would ensure all fan-out operations are canceled.

//
// -- if input is RRS but RRS is not configured/initialized '-1' parity
//
//	for RRS is assumed, the caller is expected to choose the right parity
//	at that point.
//
// -- if input is STANDARD but STANDARD is not configured/initialized '-1' parity
//
//	is returned, the caller is expected to choose the right parity
//	at that point.
func (sCfg *Config) GetParityForSC(sc string) (parity int) {

	if err = checkGetObjArgs(ctx, bucket, object); err != nil {
		return nil, err
	}

	// This is a special call attempted first to check for SOS-API calls.
	gr, err = veeamSOSAPIGetObject(ctx, bucket, object, rs, opts)
	if err == nil {
		return gr, nil
	}

	// reset any error to 'nil' and any reader to be 'nil'
	gr = nil
	err = nil

// Assumes that c.Lock is held by caller.
func (c *iamCache) buildUserGroupMemberships() {
	for group, gi := range c.iamGroupsMap {
		c.updateGroupMembershipsMap(group, &gi)
	}
}

// updateGroupMembershipsMap - updates the memberships map for a
// group. IMPORTANT: Assumes c.Lock() is held by caller.
func (c *iamCache) updateGroupMembershipsMap(group string, gi *GroupInfo) {

	SuccessorModTime time.Time `msg:"smt"`

	Fresh bool `msg:"fr"` // indicates this is a first time call to write FileInfo.

	// Position of this version or object in a multi-object delete call,
	// no other caller must set this value other than multi-object delete call.
	// usage in other calls in undefined please avoid.
	Idx int `msg:"i"`

	// Combined checksum when object was uploaded.

	}
	return roleArn, rolePolicy, nil
}

// DeletePolicy - deletes a canned policy from backend. `notifyPeers` is true
// whenever this is called via the API. It is false when called via a
// notification from another peer. This is to avoid infinite loops.
func (sys *IAMSys) DeletePolicy(ctx context.Context, policyName string, notifyPeers bool) error {
	if !sys.Initialized() {

	}
	const readLock = true
	for _, path := range li.paths {
		li.ns.unlock(li.volume, path, readLock)
	}
}

func getSource(n int) string {
	var funcName string
	pc, filename, lineNum, ok := runtime.Caller(n)
	if ok {
		filename = pathutil.Base(filename)
		funcName = strings.TrimPrefix(runtime.FuncForPC(pc).Name(),
			"github.com/minio/minio/cmd.")
	} else {
		filename = "<unknown>"
		lineNum = 0
	}