public static Period createToDateWithOffset(final long to, final int days) {
        final ZonedDateTime dateTime = Instant.ofEpochMilli(to).atZone(UTC);
        final long millis = dateTime.plusDays(days).toInstant().toEpochMilli();
        return new Period(null, millis);
    }
Create a period up to a date with a number of day offset.
stroom-util/src/main/java/stroom/util/PeriodUtil.java