This may be a useful way to quickly update a list after a device has been removed abruptly from the network (without announcing its removal). The 'added' callback may run any time after this is called to notify new devices. Any removed devices will be notified by a burst of calls to the 'removed' callback Core.InitParams::MsearchTimeSecs() seconds after this call is made. There is no notification that a refresh has completed. Existing CpDevice instances can be used as normal throughout the refresh.