code: @Override
      public void receiveMessage(VoidMessage message) {
          try {
              log.info("Message received, saving...");
              messages.put(message);
          } catch (Exception e) {
              // do nothing
          }
      }
docs: This method saves incoming message to the Queue, for later dispatch from higher-level code, like actual TrainingFunction or VoidParameterServer itself
  
  @param message