code: private void fireTunnelConnectEvent(AuthenticatedUser authenticatedUser,
              Credentials credentials, GuacamoleTunnel tunnel) throws GuacamoleException {
          listenerService.handleEvent(new TunnelConnectEvent(authenticatedUser,
                  credentials, tunnel));
      }
docs: Notifies bound listeners that a new tunnel has been connected.
  Listeners may veto a connected tunnel by throwing any GuacamoleException.
  
  @param authenticatedUser
  The AuthenticatedUser associated with the user for whom the tunnel
  is being created.
  
  @param credentials
  Credentials that authenticate the user.
  
  @param tunnel
  The tunnel that was connected.
  
  @throws GuacamoleException
  If thrown by a listener or if any listener vetoes the connected tunnel.