code: public static String[] getAvailableIDs(int rawOffset) {
          List<String> ids = new ArrayList<>();
          for (String id : getAvailableIDs()) {
              TimeZone tz = NativeTimeZone.get(id);
              if (tz.getRawOffset() == rawOffset) {
                  ids.add(id);
              }
          }
          return ids.toArray(new String[0]);
      }
docs: Gets the available IDs according to the given time zone offset in milliseconds.
  
  @param rawOffset the given time zone GMT offset in milliseconds.
  @return an array of IDs, where the time zone for that ID has
  the specified GMT offset. For example, "America/Phoenix" and "America/Denver"
  both have GMT-07:00, but differ in daylight saving behavior.
  @see #getRawOffset()