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