* @return silence time (in milliseconds) - after this time
* {@link org.opendaylight.yang.gen.v1.urn.opendaylight.openflow.system.rev130927.SwitchIdleEvent}
* message is sent upstream
* @return silence time (in milliseconds) - after this time
* {@link org.opendaylight.yang.gen.v1.urn.opendaylight.openflow.system.rev130927.SwitchIdleEvent}
* message is sent upstream