docs: static synchronized String getTimeZoneDisplay(TimeZone tz, boolean daylight, int style, Locale locale) {
          Object key = new TimeZoneDisplayKey(tz, daylight, style, locale);
          String value = (String) cTimeZoneDisplayCache.get(key);
          if (value == null) {
              // This is a very slow call, so cache the results.
              value = tz.getDisplayName(daylight, style, locale);
              cTimeZoneDisplayCache.put(key, value);
          }
          return value;
      }