code: @Nonnull
    public CalendarIntervalScheduleBuilder withIntervalInMinutes (final int intervalInMinutes)
    {
      _validateInterval (intervalInMinutes);
      m_nInterval = intervalInMinutes;
      m_eIntervalUnit = EIntervalUnit.MINUTE;
      return this;
    }
docs: Specify an interval in the IntervalUnit.MINUTE that the produced Trigger
  will repeat at.
  
  @param intervalInMinutes
  the number of minutes at which the trigger should repeat.
  @return the updated CalendarIntervalScheduleBuilder
  @see ICalendarIntervalTrigger#getRepeatInterval()
  @see ICalendarIntervalTrigger#getRepeatIntervalUnit()