* @param b the byte array to check
     * @return true if the bytes represent UTF-8 BOM, false otherwise
     */
    private boolean isUtf8BomBytes(final byte[] b) {
        return b[0] == (byte) 0xEF && b[1] == (byte) 0xBB && b[2] == (byte) 0xBF;
    }

    /**
     * Sets whether to process Google on/off comment directives.
     *
     * @param useGoogleOffOn true to enable Google on/off processing, false to disable

   * of reads and delaying a lock acquisition until the threshold is crossed or a mutation occurs.
   *
   * <p>This must be a (2^n)-1 as it is used as a mask.
   */
  static final int DRAIN_THRESHOLD = 0x3F;

  /**
   * Maximum number of entries to be drained in a single cleanup run. This applies independently to
   * the cleanup queue and both reference queues.
   */
  // TODO(fry): empirically optimize this