docs: @Override
    public final void onMessageSent(Session session, Object msg) {
      Command command = (Command) msg;
      command.setStatus(OperationStatus.SENT);
      // After message sent,we can set the buffer to be null for gc friendly.
      command.setIoBuffer(EMPTY_BUF);
      switch (command.getCommandType()) {
        case ADD:
        case APPEND:
        case SET:
        case SET_MANY:
          // After message sent,we can set the value to be null for gc
          // friendly.
          if (command instanceof StoreCommand) {
            ((StoreCommand) command).setValue(null);
          }
          break;
      }
    }