hasher := h.pool.Get().(hash.Hash)
	h.borrowed = append(h.borrowed, hasher)
	hasher.Reset()
	return hasher
}

// ReturnAll will return all borrowed hashes.
func (h *HashBorrower) ReturnAll() {
	for _, hasher := range h.borrowed {
		h.pool.Put(hasher)
	}
	h.borrowed = nil
}

// StandardClaims are basically standard claims with "accessKey"
type StandardClaims struct {
	AccessKey string `json:"accessKey,omitempty"`

}

// Matches returns whether given content matches c.
func (c Checksum) Matches(content []byte) error {
	if len(c.Encoded) == 0 {
		return nil
	}
	hasher := c.Type.Hasher()
	_, err := hasher.Write(content)
	if err != nil {
		return err
	}
	sum := hasher.Sum(nil)
	if !bytes.Equal(sum, c.Raw) {
		return ChecksumMismatch{
			Want: c.Encoded,
			Got:  base64.StdEncoding.EncodeToString(sum),
		}
	}

	t := time.Now().Unix()
	e.init.Do(func() {
		e.cached.Store(&AccElem{})
		atomic.StoreInt64(&e.cachedSec, t)
	})
	acc := e.cached.Load()
	if lastT := atomic.LoadInt64(&e.cachedSec); lastT != t {
		// Check if lastT was changed by someone else.
		if atomic.CompareAndSwapInt64(&e.cachedSec, lastT, t) {
			// Now we swap in a new.
			newAcc := &AccElem{}
			old := e.cached.Swap(newAcc)
			var a AccElem

	got, err := scanDataFolder(context.Background(), nil, base, dataUsageCache{Info: dataUsageCacheInfo{Name: "bucket"}}, getSize, 0, weSleep)
	if err != nil {
		t.Fatal(err)
	}
	if got.root() == nil {
		t.Log("cached folders:")
		for folder := range got.Cache {
			t.Log("folder:", folder)
		}
		t.Fatal("got nil root.")
	}

	// Test dirs
	want := []struct {
		path       string
		isNil      bool

		return selected, true
	}

	// If cached is nil we shall skip the entry.
	if selected.cached == nil {
		return nil, false
	}

	// Merge if we have disagreement.
	// Create a new merged result.
	selected = &metaCacheEntry{
		name:     selected.name,
		reusable: true,
		cached:   &xlMetaV2{metaV: selected.cached.metaV},
	}

	if cs == nil {
		return nil
	}
	r.contentHash = *cs
	if ignoreValue {
		// Do not validate, but allow for transfer
		return nil
	}

	r.contentHasher = cs.Type.Hasher()
	if r.contentHasher == nil {
		return ErrInvalidChecksum
	}
	return nil
}

func (r *Reader) Read(p []byte) (int, error) {
	n, err := r.src.Read(p)
	r.bytesRead += int64(n)
	if r.sha256 != nil {

	// what decoding mechanisms must be applied to obtain the object referenced
	// by the Content-Type header field.
	ContentEncoding string

	// Date and time at which the object is no longer able to be cached
	Expires time.Time

	// Cache-Control - Specifies caching behavior along the request/reply chain
	CacheControl string

	// Specify object storage class
	StorageClass string

	case f.Header.Length <= len64:
		bts[1] = 127
		binary.BigEndian.PutUint64(bts[2:10], uint64(f.Header.Length))
		n = 10

	default:
		return ws.ErrHeaderLengthUnexpected
	}

	if f.Header.Masked {
		bts[1] |= bit0
		n += copy(bts[n:], f.Header.Mask[:])
	}

	if _, err := w.Write(bts[:n]); err != nil {
		return err
	}

	_, err := w.Write(f.Payload)
	return err

	expirationStr := fmt.Sprintf(`"expiration": "%s"`, expiration.Format(iso8601TimeFormat))
	// Add the bucket condition, only accept buckets equal to the one passed.
	bucketConditionStr := fmt.Sprintf(`["eq", "$bucket", "%s"]`, bucketName)
	// Add the key condition, only accept keys equal to the one passed.
	keyConditionStr := fmt.Sprintf(`["eq", "$key", "%s/upload.txt"]`, objectKey)
	// Add content length condition, only accept content sizes of a given length.

	// The issuing authority of the web identity token presented. For OpenID Connect
	// ID tokens, this contains the value of the iss field. For OAuth 2.0 id_tokens,
	// this contains the value of the ProviderId parameter that was passed in the
	// AssumeRoleWithWebIdentity request.
	Provider string `xml:",omitempty"`

	// The unique user identifier that is returned by the identity provider.