* independent stream each time it is called.
   *
   * <p>The caller is responsible for ensuring that the returned stream is closed.
   *
   * @throws IOException if an I/O error occurs while opening the stream
   */
  public abstract InputStream openStream() throws IOException;

  /**
   * Opens a new buffered {@link InputStream} for reading from this source. The returned stream is

        assertTrue(primaryScore > baseScore);

        // High error rate should reduce score
        channelInfo.setState(ChannelState.ESTABLISHED);
        channelInfo.setPrimary(false);
        for (int i = 0; i < 20; i++) {
            channelInfo.incrementRequestsSent();
            channelInfo.incrementErrors(); // 100% error rate
        }
        int highErrorScore = channelInfo.getScore();

  static IncrementingLoader incrementingLoader() {
    return new IncrementingLoader();
  }

  /** Returns a {@link CacheLoader} that throws the given error for every request. */
  static <K, V> CacheLoader<K, V> errorLoader(Error e) {
    checkNotNull(e);
    return new CacheLoader<K, V>() {
      @Override
      public V load(K key) {
        throw e;
      }
    };
  }

}

// Returns an initialized setup for erasure tests.
func newErasureTestSetup(tb testing.TB, dataBlocks int, parityBlocks int, blockSize int64) (*erasureTestSetup, error) {
	diskPaths := make([]string, dataBlocks+parityBlocks)
	disks := make([]StorageAPI, len(diskPaths))
	var err error
	for i := range diskPaths {
		disks[i], diskPaths[i], err = newXLStorageTestSetup(tb)
		if err != nil {
			return nil, err
		}

)

// loadClusterUsageObjectMetrics - reads cluster usage metrics.
//
// This is a `MetricsLoaderFn`.
func loadClusterUsageObjectMetrics(ctx context.Context, m MetricValues, c *metricsCache) error {
	dataUsageInfo, err := c.dataUsageInfo.Get()
	if err != nil {
		metricsLogIf(ctx, err)
		return nil
	}

	// data usage has not captured any data yet.
	if dataUsageInfo.LastUpdate.IsZero() {
		return nil

// from the metadata using the SSE-Copy client key of the HTTP headers
// and returns the decrypted object key.
func (sse ssecCopy) UnsealObjectKey(h http.Header, metadata map[string]string, bucket, object string) (key ObjectKey, err error) {
	clientKey, err := sse.ParseHTTP(h)
	if err != nil {
		return key, err
	}
	return unsealObjectKey(clientKey[:], metadata, bucket, object)
}

// unsealObjectKey decrypts and returns the sealed object key

// If the object is not found, a nil error with empty data usage cache is returned.
func (d *dataUsageCache) load(ctx context.Context, store objectIO, name string) error {
	// By default, empty data usage cache
	*d = dataUsageCache{}

	load := func(name string, timeout time.Duration) (bool, error) {
		// Abandon if more than time.Minute, so we don't hold up scanner.

    /**
     * Simply parse the given xml string.
     *
     * @param xml the input xml string
     * @return the parsed object
     * @throws XmlReaderException if an error occurs during the parsing
     * @see #toXmlString(Object)
     */
    @Nonnull
    default T fromXmlString(@Nonnull String xml) throws XmlReaderException {
        return read(new StringReader(xml));
    }

}

// MarshalXML - produces the xml representation of the Filter struct
// only one of Prefix, And and Tag should be present in the output.
func (f Filter) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
	if !f.set {
		return nil
	}

	if err := e.EncodeToken(start); err != nil {
		return err
	}

	switch {
	case !f.And.isEmpty():

                            "content": {"application/json": {"schema": {}}},
                        },
                        "422": {
                            "description": "Validation Error",
                            "content": {
                                "application/json": {
                                    "schema": {