public static String createFileDateTimeString(final long ms) {
        return FILE_TIME_STROOM_TIME_FORMATTER.format(Instant.ofEpochMilli(ms).atZone(ZoneOffset.UTC));
    }
Create a 'file' format date string.

@param ms The date to create the string for.
@return string The date as a 'file' format date string.
stroom-legacy/stroom-legacy-model_6_1/src/main/java/stroom/legacy/model_6_1/DateUtil.java