code: protected void addAdditionalContentParts(HTTPFaxClientSpi faxClientSpi,FaxActionType faxActionType,FaxJob faxJob,List<ContentPart<?>> contentList)
      {
          //empty hook for extending classes
      }
docs: This function enables extending classes to add additional content parts.
  
  @param   faxClientSpi
  The HTTP fax client SPI
  @param   faxActionType
  The fax action type
  @param   faxJob
  The fax job object
  @param   contentList
  The content list with all the created parts