code: @Nonnull
    public JDK8TriggerBuilder <T> usingJobData (@Nonnull final JobDataMap newJobDataMap)
    {
      // add any existing data to this new map
      newJobDataMap.putAll (m_aJobDataMap);
      m_aJobDataMap = newJobDataMap; // set new map as the map to use
      return this;
    }
docs: Set the Trigger's {@link JobDataMap}, adding any values to it that were
  already set on this JDK8TriggerBuilder using any of the other
  'usingJobData' methods.
  
  @param newJobDataMap
  New map to use. May not be <code>null</code>.
  @return the updated JDK8TriggerBuilder
  @see ITrigger#getJobDataMap()