code: @Nonnull
    public static TriggerKey schedule (@Nonnull final IScheduleBuilder <? extends ITrigger> aScheduleBuilder,
                                       @Nonnegative final long nThresholdBytes)
    {
      ValueEnforcer.notNull (aScheduleBuilder, "ScheduleBuilder");
      ValueEnforcer.isGE0 (nThresholdBytes, "ThresholdBytes");
  
      final ICommonsMap <String, Object> aJobDataMap = new CommonsHashMap <> ();
      aJobDataMap.put (JOB_DATA_ATTR_THRESHOLD_BYTES, Long.valueOf (nThresholdBytes));
  
      return GlobalQuartzScheduler.getInstance ().scheduleJob (CheckDiskUsableSpaceJob.class.getName (),
                                                               JDK8TriggerBuilder.newTrigger ()
                                                                                 .startNow ()
                                                                                 .withSchedule (aScheduleBuilder),
                                                               CheckDiskUsableSpaceJob.class,
                                                               aJobDataMap);
    }
docs: Call this method to schedule the check disk usage job to run.
  
  @param aScheduleBuilder
  The schedule builder to be used. May not be <code>null</code>.
  Example:
  <code>SimpleScheduleBuilder.repeatMinutelyForever (60)</code>
  @param nThresholdBytes
  If &le; than this number of bytes are free on the drive, an internal
  notification email is send. Must be &ge; 0.
  @return The created trigger key for further usage. Never <code>null</code>.