A read-only string containing the member specific unique identifier for the server. This may or may not match the collective ID depending on how the collective was configured.
The object placeholder is an object expression that evaluates to a CollectiveMember object.
The ServerID of a CollectiveMember is typically not used by client applications as these applications connect to the Collective as a whole and persist the Collective ID instead. When a single server is upgraded to become a collective, one of the member IDs may be configured to be the same as the Collective ID so that applications that are not collective aware can continue to connect.