This feature lets you display offline clients of topics. If your topics are read in external way (e.g. messages getting transferred to Hadoop and analysed there by users), you can provide implementation that will be used to show this information in Console.
The first step is to create bean in Management module context that implements
pl.allegro.tech.hermes.management.domain.clients.OfflineClientsService interface (see packaging section for more information on Management customization).
The bean should implement fetching of the clients, which could be for example REST request to another service.
topic.offlineClientsEnabled property in Console should be enabled. (see console section for more information.)
The clients should now be displayed in topic details view in Console.