code: @Override
    public DurationFormatterFactory setTimeZone(TimeZone timeZone) {
      if (!timeZone.equals(this.timeZone)) {
        this.timeZone = timeZone;
        if (builder != null) {
            builder = builder.withTimeZone(timeZone);
        }
        reset();
      }
      return this;
    }
docs: Set the name of the locale that will be used when
  creating new formatters.
  
  @param timeZone The time zone to use.
  @return this BasicDurationFormatterFactory