return nil, errors.New("MasterKeyID is allowed with aws:kms only")
			}
		case AWSKms:
			keyID := rule.DefaultEncryptionAction.MasterKeyID
			if keyID == "" {
				return nil, errors.New("MasterKeyID is missing with aws:kms")
			}
			spaces := strings.HasPrefix(keyID, " ") || strings.HasSuffix(keyID, " ")
			if spaces {
				return nil, errors.New("MasterKeyID contains unsupported characters")
			}
		}
	}

	// Check if bucket exists.
	if _, err := objAPI.GetBucketInfo(ctx, bucket, BucketOptions{}); err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
		return
	}

	// Error out if Content-Length is missing.
	// PutBucketPolicy always needs Content-Length.
	if r.ContentLength <= 0 {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrMissingContentLength), r.URL)
		return
	}

	if !ok {
		return errors.New("STS JWT Token has `aud` claim invalid, `aud` must match configured OpenID Client ID")
	}
	if !audValues.Contains(pCfg.ClientID) {
		// if audience claims is missing, look for "azp" claims.
		// OPTIONAL. Authorized party - the party to which the ID
		// Token was issued. If present, it MUST contain the OAuth
		// 2.0 Client ID of this party. This Claim is only needed

	}

	// Calculate the webhook addr with the port number format
	target.addr = args.Endpoint.Host
	if _, _, err := net.SplitHostPort(args.Endpoint.Host); err != nil && strings.Contains(err.Error(), "missing port in address") {
		switch strings.ToLower(args.Endpoint.Scheme) {
		case "http":
			target.addr += ":80"
		case "https":
			target.addr += ":443"
		default:
			return nil, errors.New("unsupported scheme")

There is no cancellation propagation for single payload requests.
When the context is canceled, the request will return at once with an appropriate error. 
However, the remote call will not see the cancellation - as can be seen from the 'missing' context on the handler.
The result will be discarded.

### Typed handlers

Typed handlers are handlers that have a specific type for the request and response payloads.

	buf := make([]byte, smallFileThreshold*16)
	if _, err = io.ReadFull(crand.Reader, buf); err != nil {
		t.Fatal(err)
	}

	// Test use case 1: All disks are online, xl.meta are present, but data are missing
	_, err = obj.PutObject(ctx, bucket, object, mustGetPutObjReader(t, bytes.NewReader(buf), int64(len(buf)), "", ""), opts)
	if err != nil {
		t.Fatal(err)
	}

	for _, disk := range xl.getDisks() {

	lastOnline      time.Time
	lastHCAt        time.Time
	offlineDuration time.Duration
	latency         latencyStat
}

// isOffline returns current liveness result of remote target. Add endpoint to
// healthCheck map if missing and default to online status
func (sys *BucketTargetSys) isOffline(ep *url.URL) bool {
	sys.hMutex.RLock()
	defer sys.hMutex.RUnlock()
	if h, ok := sys.hc[ep.Host]; ok {
		return !h.Online
	}
	go sys.initHC(ep)

	}
	z.rebalMu.Unlock()

	return nil
}

// updates rebalance.bin from let's say 2 pool setup in the middle
// of a rebalance, was expanded can cause z.rebalMeta to be outdated
// due to a missing new pool. This function tries to handle this
// scenario, albeit rare it seems to have occurred in the wild.
//
// since we do not explicitly disallow it, but it is okay for them
// expand and then we continue to rebalance.

	if contextCanceled(ctx) {
		return ctx, done, ctx.Err()
	}

	if p.health.status.Load() != diskHealthOK {
		return ctx, done, errFaultyDisk
	}

	// Verify if the disk is not stale
	// - missing format.json (unformatted drive)
	// - format.json is valid but invalid 'uuid'
	if err = p.checkDiskStale(); err != nil {
		return ctx, done, err
	}

	// Disallow recursive tracking to avoid deadlocks.

		return
	}

	clientETag, err := etag.FromContentMD5(r.Header)
	if err != nil {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrInvalidDigest), r.URL)
		return
	}

	// if Content-Length is unknown/missing, throw away
	size := r.ContentLength

	rAuthType := getRequestAuthType(r)
	// For auth type streaming signature, we need to gather a different content length.
	switch rAuthType {