return null;
      }
      // Successfully crossed over from min to max.
      // Bubble up max levels.
      E parent;
      // If toTrickle is moved up to a parent of removeIndex, the parent is
      // placed in removeIndex position. We must return that to the iterator so
      // that it knows to skip it.
      if (crossOver < removeIndex) {
        // We crossed over to the parent level in crossOver, so the parent

   * <p>This method has no effect (returns {@code this}) when called in GWT: it's unclear whether a
   * precomputed matcher is faster, but it certainly consumes more memory, which doesn't seem like a
   * worthwhile tradeoff in a browser.
   */
  public CharMatcher precomputed() {
    return Platform.precomputeCharMatcher(this);
  }

  private static final int DISTINCT_CHARS = Character.MAX_VALUE - Character.MIN_VALUE + 1;

  /**

    /** The key of the configuration. e.g. location */
    String QUERY_GEO_FIELDS = "query.geo.fields";

    /** The key of the configuration. e.g. browser_lang */
    String QUERY_BROWSER_LANG_PARAMETER_NAME = "query.browser.lang.parameter.name";

    /** The key of the configuration. e.g. true */
    String QUERY_REPLACE_TERM_WITH_PREFIX_QUERY = "query.replace.term.with.prefix.query";

   * ordering information is updated. This is used to avoid lock contention by recording a memento
   * 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;

  /**

        }
        return OptionalObject.empty();
    }

    @Override
    public OptionalThing<Locale> getRequestedLocale(final RequestManager requestManager) {
        return OptionalObject.empty(); // means browser default
    }

    // ===================================================================================
    //                                                                      Basic Override

        out.write(b[i]);
      }
    } else {
      out.write(b, off, len);
    }
    out.flush(); // for coverage
  }

  // TODO(chrisn): only works if we ensure we have crossed file threshold

  public void testWriteErrorAfterClose() throws Exception {
    byte[] data = newPreFilledByteArray(100);
    FileBackedOutputStream out = new FileBackedOutputStream(50);

    assertFalse(Ascii.equalsIgnoreCase("@", "`"));
    assertFalse(Ascii.equalsIgnoreCase("[", "{"));
  }

  @GwtIncompatible // String.toUpperCase() has browser semantics
  public void testEqualsIgnoreCaseUnicodeEquivalence() {
    // Note that it's possible in future that the JDK's idea to toUpperCase() or equalsIgnoreCase()

        return getSystemPropertyAsBoolean(Constants.SEARCH_FILE_PROXY_PROPERTY, true);
    }

    default boolean isBrowserLocaleForSearchUsed() {
        return getSystemPropertyAsBoolean(Constants.USE_BROWSER_LOCALE_FOR_SEARCH_PROPERTY, false);
    }

    default String[] getDefaultSortValues(final OptionalThing<FessUserBean> userBean) {
        @SuppressWarnings("unchecked")

    public static final String GOOGLE_CHAT_WEBHOOK_URLS_PROPERTY = "google.chat.webhook.urls";

    public static final String USE_BROWSER_LOCALE_FOR_SEARCH_PROPERTY = "search.use.browser.locale";

    public static final String SUGGEST_SEARCH_LOG_PROPERTY = "suggest.searchlog";

    public static final String SUGGEST_DOCUMENTS_PROPERTY = "suggest.document";

   * ordering information is updated. This is used to avoid lock contention by recording a memento
   * 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;

  /**