* `expose_headers` - Indicate any response headers that should be made accessible to the browser. Defaults to `[]`.
* `max_age` - Sets a maximum time in seconds for browsers to cache CORS responses. Defaults to `600`.

The middleware responds to two particular types of HTTP request...

### CORS preflight requests

	// returns 'nil' once healing is complete or if the disk
	// has never been replaced.
	Healing() *healingTracker
	DiskInfo(ctx context.Context, opts DiskInfoOptions) (info DiskInfo, err error)
	NSScanner(ctx context.Context, cache dataUsageCache, updates chan<- dataUsageEntry, scanMode madmin.HealScanMode, shouldSleep func() bool) (dataUsageCache, error)

	// Volume operations.
	MakeVol(ctx context.Context, volume string) (err error)

        }

        /*
         * Create an NbtAddress for the local interface with
         * the name deduced above possibly with scope applied and
         * cache it forever.
         */
        Name localName = new Name(tc.getConfig(), localHostname, 0x00, tc.getConfig().getNetbiosScope());
        this.localhostAddress = new NbtAddress(
            localName,

    source1.close() // Not exhausted!
    assertThat(relay1.isClosed).isTrue()
    assertFailsWith<IOException> {
      read(file)
    }.also { expected ->
      assertThat(expected.message).isEqualTo("unreadable cache file")
    }
    assertFile(Relay.PREFIX_DIRTY, -1L, -1, null, null)
  }

  @Test
  fun redundantCallsToCloseAreIgnored() {
    val upstream = Buffer()
    upstream.writeUtf8("abcde")

| `minio_system_memory_buffers`    | Buffers memory on the node. <br><br>Type: gauge         | `server` |
| `minio_system_memory_cache`      | Cache memory on the node. <br><br>Type: gauge           | `server` |
| `minio_system_memory_shared`     | Shared memory on the node. <br><br>Type: gauge          | `server` |

	if !s.checkID(params.DiskID) {
		return grid.NewRemoteErr(errDiskNotFound)
	}
	if params.Cache == nil {
		return grid.NewRemoteErrString("NSScannerHandler: provided cache is nil")
	}

	// Collect updates, stream them before the full cache is sent.
	updates := make(chan dataUsageEntry, 1)
	var wg sync.WaitGroup
	wg.Add(1)
	go func() {
		defer wg.Done()

	// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
	for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
		if remain == 0 {
			cache, remain = src.Int63(), letterIdxMax
		}
		if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
			b[i] = letterBytes[idx]
			i--
		}
		cache >>= letterIdxBits
		remain--
	}

	return *(*string)(unsafe.Pointer(&b))
}

              return;
            }

            $.ajax({
              url: settingAjaxInfo.url,
              type: "get",
              dataType: "json",
              cache: false,
              data: {
                q: $textArea.val(),
                field: settingAjaxInfo.fn,
                num: settingAjaxInfo.num * 2,
                lang: settingAjaxInfo.lang
              },

	// which cause by calling Close and executing SQL concurrently
	if db.Stmts == nil {
		db.Mux.Unlock()
		return Stmt{}, ErrInvalidDB
	}
	// cache preparing stmt first
	cacheStmt := Stmt{Transaction: isTransaction, prepared: make(chan struct{})}
	db.Stmts[query] = &cacheStmt
	db.Mux.Unlock()

	// prepare completed
	defer close(cacheStmt.prepared)

	// map for bucket metrics and handle them specially.

	// Add the serverName and poolIndex labels to all non-cluster metrics.
	//
	// Also create metric group maps and set the cache.
	metricsCache := newMetricsCache()
	mgMap := make(map[collectorPath]*MetricsGroup)
	bucketMGMap := make(map[collectorPath]*MetricsGroup)
	for _, mg := range allMetricGroups {