code: public static long calculateOffsetInMs(int intervalInMinutes, int offsetInMinutes) {
  		while (offsetInMinutes < 0) {
  			offsetInMinutes = intervalInMinutes + offsetInMinutes;
  		}
  		while (offsetInMinutes > intervalInMinutes) {
  			offsetInMinutes -= intervalInMinutes;
  		}
  		return offsetInMinutes * MINUTE_IN_MS;
  	}
docs: Reformulates negative offsets or offsets larger than interval.
  
  @param intervalInMinutes
  @param offsetInMinutes
  @return offset in milliseconds