code: void handleAgentCallbackLogoffEvent(AgentCallbackLogoffEvent event)
      {
          AsteriskAgentImpl agent = getAgentByAgentId("Agent/" + event.getAgent());
          if (agent == null)
          {
              logger.error("Ignored AgentCallbackLogoffEvent for unknown agent "
                      + event.getAgent() + ". Agents: "
                      + agents.values().toString());
              return;
          }
          agent.updateState(AgentState.AGENT_LOGGEDOFF);
  
      }
docs: Change state if agent logs out.
  
  @param event