The added test describes how the new id timestamps fix the race condition.
These timestamps could be any unique opaque values, and the protocol is
extended to exchange them along with node ids.

Internally, nodes also reuse timestamps as a marker to identify the first
NotifyNodeInformation packets from the master: since this packet is a complete
list of nodes in the cluster, any other node in the node manager has left the
cluster definitely and is removed.

The secondary masters didn't receive update about master nodes.
It's also useless to send them information about non-master nodes.