rem: KMFilterAction::ReturnCode KMFilterActionTransport::process(KMMessage* msg) const
add: KMFilterAction::ReturnCode KMFilterActionFakeDisposition::process(KMMessage* msg) const
context: KMFilterAction::ReturnCode KMFilterActionTransport::process(KMMessage* msg) const{  if ( mParameter.isEmpty() )    return ErrorButGoOn;  msg->setHeaderField( "X-KMail-Transport", mParameter );  return GoOn;}