} else {
            displaySize = size + "bytes";
        }
        return displaySize;
    }

    /**
     * Gets the currently used memory in bytes.
     *
     * @return used memory in bytes
     */
    public static long getUsedMemory() {
        final Runtime runtime = Runtime.getRuntime();
        final long freeBytes = runtime.freeMemory();

 * used. HTTP/1.x connections can carry either zero or one streams. HTTP/2 connections can carry any
 * number of streams, dynamically configured with `SETTINGS_MAX_CONCURRENT_STREAMS`. A connection
 * currently carrying zero streams is an idle stream. We keep it alive because reusing an existing
 * connection is typically faster than establishing a new one.
 *

        if (StringUtil.isNotBlank(form.logLevel)) {
            systemHelper.setLogLevel(form.logLevel);
        }
    }

    /**
     * Updates the form with current configuration values.
     *
     * @param fessConfig the current Fess configuration
     * @param form the form to populate with configuration values
     */
    public static void updateForm(final FessConfig fessConfig, final EditForm form) {

        if (shouldStop) {
          break;
        }
        interruptee.interrupt();
      }
    }

    void stopInterrupting() {
      shouldStop = true;
    }
  }

  /** Interrupts the current thread after sleeping for the specified delay. */
  static void requestInterruptIn(long time, TimeUnit unit) {
    checkNotNull(unit);
    Thread interruptee = Thread.currentThread();
    new Thread(

 * `MODERN_TLS` is a secure configuration that connects to modern HTTPS servers.
 * `COMPATIBLE_TLS` is a secure configuration that connects to secure–but not current–HTTPS servers.
 * `CLEARTEXT` is an insecure configuration that is used for `http://` URLs.

    /**
     * Constructs a new FileTransformer.
     */
    public FileTransformer() {
        // Default constructor
    }

    /**
     * A path to store downloaded files. The default path is a current
     * directory.
     */
    protected String path;

    /**
     * A string to replace ?.
     */
    protected String questionStr = "_QUEST_";

    /**
     * A string to replace :.
     */

   * fail. If it is too short, slow connections will be marked as failed and extra TCP and TLS
   * handshakes will be required.
   *
   * The deadline is currently hardcoded. We may make this configurable in the future!
   */
  internal fun sendDegradedPingLater() {
    withLock {
      if (degradedPongsReceived < degradedPingsSent) return // Already awaiting a degraded pong.

        // This test assumes that the AvPair constructor does NOT make a defensive copy of the raw array.
        // If a defensive copy were made, this test would fail, and the behavior would be more robust.
        // Given the current implementation, direct modification of the passed array affects the AvPair.
        // If this is not desired, a defensive copy should be added in the AvPair constructor.
        assertEquals(0x05, avPair.getRaw()[0],

    /** The request attribute key for storing cached user agent type */
    protected static final String USER_AGENT_TYPE = "ViewHelper.UserAgent";

    /**
     * Determines the user agent type from the current HTTP request.
     * The method analyzes the User-Agent header to categorize the browser type
     * and caches the result in the request attribute for subsequent calls.
     *

  }

  @Override
  public void close() throws IOException {
    if (in != null) {
      try {
        in.close();
      } finally {
        in = null;
      }
    }
  }

  /** Closes the current input stream and opens the next one, if any. */
  private void advance() throws IOException {
    close();
    if (it.hasNext()) {
      in = it.next().openStream();
    }
  }

  @Override